diff --git a/adb/Android.bp b/adb/Android.bp
index 57872b0..9ef82bf 100644
--- a/adb/Android.bp
+++ b/adb/Android.bp
@@ -629,6 +629,7 @@
         "libselinux",
     ],
     test_suites: ["device-tests"],
+    require_root: true,
 }
 
 python_test_host {
diff --git a/adb/adb.cpp b/adb/adb.cpp
index ba6df7a..1ec145b 100644
--- a/adb/adb.cpp
+++ b/adb/adb.cpp
@@ -1131,7 +1131,9 @@
 
     if (service == "features") {
         std::string error;
-        atransport* t = acquire_one_transport(type, serial, transport_id, nullptr, &error);
+        atransport* t =
+                s->transport ? s->transport
+                             : acquire_one_transport(type, serial, transport_id, nullptr, &error);
         if (t != nullptr) {
             SendOkay(reply_fd, FeatureSetToString(t->features()));
         } else {
@@ -1190,7 +1192,9 @@
     // These always report "unknown" rather than the actual error, for scripts.
     if (service == "get-serialno") {
         std::string error;
-        atransport* t = acquire_one_transport(type, serial, transport_id, nullptr, &error);
+        atransport* t =
+                s->transport ? s->transport
+                             : acquire_one_transport(type, serial, transport_id, nullptr, &error);
         if (t) {
             SendOkay(reply_fd, !t->serial.empty() ? t->serial : "unknown");
         } else {
@@ -1200,7 +1204,9 @@
     }
     if (service == "get-devpath") {
         std::string error;
-        atransport* t = acquire_one_transport(type, serial, transport_id, nullptr, &error);
+        atransport* t =
+                s->transport ? s->transport
+                             : acquire_one_transport(type, serial, transport_id, nullptr, &error);
         if (t) {
             SendOkay(reply_fd, !t->devpath.empty() ? t->devpath : "unknown");
         } else {
@@ -1210,7 +1216,9 @@
     }
     if (service == "get-state") {
         std::string error;
-        atransport* t = acquire_one_transport(type, serial, transport_id, nullptr, &error);
+        atransport* t =
+                s->transport ? s->transport
+                             : acquire_one_transport(type, serial, transport_id, nullptr, &error);
         if (t) {
             SendOkay(reply_fd, t->connection_state_name());
         } else {
@@ -1234,7 +1242,9 @@
 
     if (service == "reconnect") {
         std::string response;
-        atransport* t = acquire_one_transport(type, serial, transport_id, nullptr, &response, true);
+        atransport* t = s->transport ? s->transport
+                                     : acquire_one_transport(type, serial, transport_id, nullptr,
+                                                             &response, true);
         if (t != nullptr) {
             kick_transport(t, true);
             response =
@@ -1246,8 +1256,15 @@
 
     // TODO: Switch handle_forward_request to string_view.
     std::string service_str(service);
-    if (handle_forward_request(
-                service_str.c_str(), [=](std::string* error) { return s->transport; }, reply_fd)) {
+    auto transport_acquirer = [=](std::string* error) {
+        if (s->transport) {
+            return s->transport;
+        } else {
+            std::string error;
+            return acquire_one_transport(type, serial, transport_id, nullptr, &error);
+        }
+    };
+    if (handle_forward_request(service_str.c_str(), transport_acquirer, reply_fd)) {
         return HostRequestResult::Handled;
     }
 
diff --git a/adb/client/adb_install.cpp b/adb/client/adb_install.cpp
index a6e8998..042a2d6 100644
--- a/adb/client/adb_install.cpp
+++ b/adb/client/adb_install.cpp
@@ -201,69 +201,68 @@
 #else
         error_exit("fastdeploy is disabled");
 #endif
-    } else {
-        struct stat sb;
-        if (stat(file, &sb) == -1) {
-            fprintf(stderr, "adb: failed to stat %s: %s\n", file, strerror(errno));
-            return 1;
-        }
+    }
 
-        unique_fd local_fd(adb_open(file, O_RDONLY | O_CLOEXEC));
-        if (local_fd < 0) {
-            fprintf(stderr, "adb: failed to open %s: %s\n", file, strerror(errno));
-            return 1;
-        }
-
-#ifdef __linux__
-        posix_fadvise(local_fd.get(), 0, 0, POSIX_FADV_SEQUENTIAL | POSIX_FADV_NOREUSE);
-#endif
-
-        const bool use_abb = can_use_feature(kFeatureAbb);
-        std::string error;
-        std::vector<std::string> cmd_args = {use_abb ? "package" : "exec:cmd package"};
-        cmd_args.reserve(argc + 3);
-
-        // don't copy the APK name, but, copy the rest of the arguments as-is
-        while (argc-- > 1) {
-            if (use_abb) {
-                cmd_args.push_back(*argv++);
-            } else {
-                cmd_args.push_back(escape_arg(*argv++));
-            }
-        }
-
-        // add size parameter [required for streaming installs]
-        // do last to override any user specified value
-        cmd_args.push_back("-S");
-        cmd_args.push_back(
-                android::base::StringPrintf("%" PRIu64, static_cast<uint64_t>(sb.st_size)));
-
-        if (is_apex) {
-            cmd_args.push_back("--apex");
-        }
-
-        unique_fd remote_fd;
-        if (use_abb) {
-            remote_fd = send_abb_exec_command(cmd_args, &error);
-        } else {
-            remote_fd.reset(adb_connect(android::base::Join(cmd_args, " "), &error));
-        }
-        if (remote_fd < 0) {
-            fprintf(stderr, "adb: connect error for write: %s\n", error.c_str());
-            return 1;
-        }
-
-        copy_to_file(local_fd.get(), remote_fd.get());
-
-        char buf[BUFSIZ];
-        read_status_line(remote_fd.get(), buf, sizeof(buf));
-        if (!strncmp("Success", buf, 7)) {
-            fputs(buf, stdout);
-            return 0;
-        }
-        fprintf(stderr, "adb: failed to install %s: %s", file, buf);
+    struct stat sb;
+    if (stat(file, &sb) == -1) {
+        fprintf(stderr, "adb: failed to stat %s: %s\n", file, strerror(errno));
         return 1;
     }
+
+    unique_fd local_fd(adb_open(file, O_RDONLY | O_CLOEXEC));
+    if (local_fd < 0) {
+        fprintf(stderr, "adb: failed to open %s: %s\n", file, strerror(errno));
+        return 1;
+    }
+
+#ifdef __linux__
+    posix_fadvise(local_fd.get(), 0, 0, POSIX_FADV_SEQUENTIAL | POSIX_FADV_NOREUSE);
+#endif
+
+    const bool use_abb = can_use_feature(kFeatureAbbExec);
+    std::string error;
+    std::vector<std::string> cmd_args = {use_abb ? "package" : "exec:cmd package"};
+    cmd_args.reserve(argc + 3);
+
+    // don't copy the APK name, but, copy the rest of the arguments as-is
+    while (argc-- > 1) {
+        if (use_abb) {
+            cmd_args.push_back(*argv++);
+        } else {
+            cmd_args.push_back(escape_arg(*argv++));
+        }
+    }
+
+    // add size parameter [required for streaming installs]
+    // do last to override any user specified value
+    cmd_args.push_back("-S");
+    cmd_args.push_back(android::base::StringPrintf("%" PRIu64, static_cast<uint64_t>(sb.st_size)));
+
+    if (is_apex) {
+        cmd_args.push_back("--apex");
+    }
+
+    unique_fd remote_fd;
+    if (use_abb) {
+        remote_fd = send_abb_exec_command(cmd_args, &error);
+    } else {
+        remote_fd.reset(adb_connect(android::base::Join(cmd_args, " "), &error));
+    }
+    if (remote_fd < 0) {
+        fprintf(stderr, "adb: connect error for write: %s\n", error.c_str());
+        return 1;
+    }
+
+    copy_to_file(local_fd.get(), remote_fd.get());
+
+    char buf[BUFSIZ];
+    read_status_line(remote_fd.get(), buf, sizeof(buf));
+    if (!strncmp("Success", buf, 7)) {
+        fputs(buf, stdout);
+        return 0;
+    }
+    fprintf(stderr, "adb: failed to install %s: %s", file, buf);
+    return 1;
 }
 
 static int install_app_legacy(int argc, const char** argv, bool use_fastdeploy,
diff --git a/adb/client/commandline.cpp b/adb/client/commandline.cpp
index fe2bdfe..a0818d3 100644
--- a/adb/client/commandline.cpp
+++ b/adb/client/commandline.cpp
@@ -1713,8 +1713,12 @@
         }
 
         if (CanUseFeature(features, kFeatureRemountShell)) {
-            const char* arg[2] = {"shell", "remount"};
-            return adb_shell(2, arg);
+            std::vector<const char*> args = {"shell"};
+            args.insert(args.cend(), argv, argv + argc);
+            return adb_shell(args.size(), args.data());
+        } else if (argc > 1) {
+            auto command = android::base::StringPrintf("%s:%s", argv[0], argv[1]);
+            return adb_connect_command(command);
         } else {
             return adb_connect_command("remount:");
         }
diff --git a/adb/client/file_sync_client.cpp b/adb/client/file_sync_client.cpp
index 5d10238..703eb2f 100644
--- a/adb/client/file_sync_client.cpp
+++ b/adb/client/file_sync_client.cpp
@@ -849,6 +849,16 @@
     return true;
 }
 
+// dirname("//foo") returns "//", so we can't do the obvious `path == "/"`.
+static bool is_root_dir(std::string_view path) {
+    for (char c : path) {
+        if (c != '/') {
+            return false;
+        }
+    }
+    return true;
+}
+
 static bool copy_local_dir_remote(SyncConnection& sc, std::string lpath,
                                   std::string rpath, bool check_timestamps,
                                   bool list_only) {
@@ -862,8 +872,8 @@
     std::vector<copyinfo> file_list;
     std::vector<std::string> directory_list;
 
-    for (std::string dirpath = rpath; dirpath != "/"; dirpath = android::base::Dirname(dirpath)) {
-        directory_list.push_back(dirpath);
+    for (std::string path = rpath; !is_root_dir(path); path = android::base::Dirname(path)) {
+        directory_list.push_back(path);
     }
     std::reverse(directory_list.begin(), directory_list.end());
 
diff --git a/adb/fastdeploy/deploypatchgenerator/deploy_patch_generator.cpp b/adb/fastdeploy/deploypatchgenerator/deploy_patch_generator.cpp
index 22c9243..154c9b9 100644
--- a/adb/fastdeploy/deploypatchgenerator/deploy_patch_generator.cpp
+++ b/adb/fastdeploy/deploypatchgenerator/deploy_patch_generator.cpp
@@ -46,10 +46,10 @@
 
 void DeployPatchGenerator::APKEntryToLog(const APKEntry& entry) {
     Log("Filename: %s", entry.filename().c_str());
-    Log("CRC32: 0x%08llX", entry.crc32());
-    Log("Data Offset: %lld", entry.dataoffset());
-    Log("Compressed Size: %lld", entry.compressedsize());
-    Log("Uncompressed Size: %lld", entry.uncompressedsize());
+    Log("CRC32: 0x%08" PRIX64, entry.crc32());
+    Log("Data Offset: %" PRId64, entry.dataoffset());
+    Log("Compressed Size: %" PRId64, entry.compressedsize());
+    Log("Uncompressed Size: %" PRId64, entry.uncompressedsize());
 }
 
 void DeployPatchGenerator::APKMetaDataToLog(const char* file, const APKMetaData& metadata) {
@@ -164,4 +164,4 @@
                   return lhs.localEntry->dataoffset() < rhs.localEntry->dataoffset();
               });
     return totalSize;
-}
\ No newline at end of file
+}
diff --git a/adb/sockets.cpp b/adb/sockets.cpp
index 75993b3..e78530c 100644
--- a/adb/sockets.cpp
+++ b/adb/sockets.cpp
@@ -757,6 +757,8 @@
 
 #if ADB_HOST
     service = std::string_view(s->smart_socket_data).substr(4);
+
+    // TODO: These should be handled in handle_host_request.
     if (android::base::ConsumePrefix(&service, "host-serial:")) {
         // serial number should follow "host:" and could be a host:port string.
         if (!internal::parse_host_service(&serial, &service, service)) {
diff --git a/adb/test_device.py b/adb/test_device.py
index f95a5b3..32d797e 100755
--- a/adb/test_device.py
+++ b/adb/test_device.py
@@ -139,6 +139,25 @@
         msg = self.device.forward_list()
         self.assertEqual('', msg.strip())
 
+    def test_forward_old_protocol(self):
+        serialno = subprocess.check_output(self.device.adb_cmd + ['get-serialno']).strip()
+
+        msg = self.device.forward_list()
+        self.assertEqual('', msg.strip(),
+                         'Forwarding list must be empty to run this test.')
+
+        s = socket.create_connection(("localhost", 5037))
+        service = b"host-serial:%s:forward:tcp:5566;tcp:6655" % serialno
+        cmd = b"%04x%s" % (len(service), service)
+        s.sendall(cmd)
+
+        msg = self.device.forward_list()
+        self.assertTrue(re.search(r'tcp:5566.+tcp:6655', msg))
+
+        self.device.forward_remove_all()
+        msg = self.device.forward_list()
+        self.assertEqual('', msg.strip())
+
     def test_forward_tcp_port_0(self):
         self.assertEqual('', self.device.forward_list().strip(),
                          'Forwarding list must be empty to run this test.')
@@ -884,6 +903,18 @@
             remote_path += '/filename'
             self.device.push(local=tmp_file.name, remote=remote_path)
 
+    def test_push_multiple_slash_root(self):
+        """Regression test for pushing to //data/local/tmp.
+
+        Bug: http://b/141311284
+        """
+        with tempfile.NamedTemporaryFile() as tmp_file:
+            tmp_file.write('\0' * 1024 * 1024)
+            tmp_file.flush()
+            remote_path = '/' + self.DEVICE_TEMP_DIR + '/test_push_multiple_slash_root'
+            self.device.shell(['rm', '-rf', remote_path])
+            self.device.push(local=tmp_file.name, remote=remote_path)
+
     def _test_pull(self, remote_file, checksum):
         tmp_write = tempfile.NamedTemporaryFile(mode='wb', delete=False)
         tmp_write.close()
diff --git a/adb/transport.h b/adb/transport.h
index 61a3d9a..c38cb1d 100644
--- a/adb/transport.h
+++ b/adb/transport.h
@@ -65,8 +65,10 @@
 extern const char* const kFeatureApex;
 // adbd has b/110953234 fixed.
 extern const char* const kFeatureFixedPushMkdir;
-// adbd supports android binder bridge (abb).
+// adbd supports android binder bridge (abb) in interactive mode using shell protocol.
 extern const char* const kFeatureAbb;
+// adbd supports abb using raw pipe.
+extern const char* const kFeatureAbbExec;
 // adbd properly updates symlink timestamps on push.
 extern const char* const kFeatureFixedPushSymlinkTimestamp;
 extern const char* const kFeatureRemountShell;
diff --git a/base/Android.bp b/base/Android.bp
index 357ce01..f5000c1 100644
--- a/base/Android.bp
+++ b/base/Android.bp
@@ -20,8 +20,14 @@
         "-Wall",
         "-Werror",
         "-Wextra",
-        "-D_FILE_OFFSET_BITS=64",
     ],
+    target: {
+        android: {
+            cflags: [
+                "-D_FILE_OFFSET_BITS=64",
+            ],
+        },
+    },
 }
 
 cc_library_headers {
diff --git a/base/include/android-base/endian.h b/base/include/android-base/endian.h
index 2d0f614..8fa6365 100644
--- a/base/include/android-base/endian.h
+++ b/base/include/android-base/endian.h
@@ -51,8 +51,10 @@
 /* macOS has some of the basics. */
 #include <sys/_endian.h>
 #else
-/* Windows has even less. */
+/* Windows has some of the basics as well. */
 #include <sys/param.h>
+#include <winsock2.h>
+/* winsock2.h *must* be included before the following four macros. */
 #define htons(x) __builtin_bswap16(x)
 #define htonl(x) __builtin_bswap32(x)
 #define ntohs(x) __builtin_bswap16(x)
diff --git a/bootstat/bootstat.cpp b/bootstat/bootstat.cpp
index dd24aac..d08a59f 100644
--- a/bootstat/bootstat.cpp
+++ b/bootstat/bootstat.cpp
@@ -311,6 +311,7 @@
     {"shutdown,userrequested,recovery", 182},
     {"reboot,unknown[0-9]*", 183},
     {"reboot,longkey,.*", 184},
+    {"reboot,boringssl-self-check-failed", 185},
 };
 
 // Converts a string value representing the reason the system booted to an
diff --git a/debuggerd/debuggerd_test.cpp b/debuggerd/debuggerd_test.cpp
index fbc8b97..c9a193c 100644
--- a/debuggerd/debuggerd_test.cpp
+++ b/debuggerd/debuggerd_test.cpp
@@ -176,7 +176,7 @@
   if (crasher_pid != -1) {
     kill(crasher_pid, SIGKILL);
     int status;
-    waitpid(crasher_pid, &status, WUNTRACED);
+    TEMP_FAILURE_RETRY(waitpid(crasher_pid, &status, WUNTRACED));
   }
 
   android::base::SetProperty(kWaitForGdbKey, previous_wait_for_gdb ? "1" : "0");
@@ -195,8 +195,7 @@
 void CrasherTest::FinishIntercept(int* result) {
   InterceptResponse response;
 
-  // Timeout for tombstoned intercept is 10 seconds.
-  ssize_t rc = TIMEOUT(20, read(intercept_fd.get(), &response, sizeof(response)));
+  ssize_t rc = TIMEOUT(30, read(intercept_fd.get(), &response, sizeof(response)));
   if (rc == -1) {
     FAIL() << "failed to read response from tombstoned: " << strerror(errno);
   } else if (rc == 0) {
@@ -233,7 +232,7 @@
     FAIL() << "crasher pipe uninitialized";
   }
 
-  ssize_t rc = write(crasher_pipe.get(), "\n", 1);
+  ssize_t rc = TEMP_FAILURE_RETRY(write(crasher_pipe.get(), "\n", 1));
   if (rc == -1) {
     FAIL() << "failed to write to crasher pipe: " << strerror(errno);
   } else if (rc == 0) {
@@ -243,7 +242,7 @@
 
 void CrasherTest::AssertDeath(int signo) {
   int status;
-  pid_t pid = TIMEOUT(10, waitpid(crasher_pid, &status, 0));
+  pid_t pid = TIMEOUT(30, waitpid(crasher_pid, &status, 0));
   if (pid != crasher_pid) {
     printf("failed to wait for crasher (expected pid %d, return value %d): %s\n", crasher_pid, pid,
            strerror(errno));
@@ -441,7 +440,7 @@
   FinishCrasher();
 
   int status;
-  ASSERT_EQ(crasher_pid, waitpid(crasher_pid, &status, WUNTRACED));
+  ASSERT_EQ(crasher_pid, TEMP_FAILURE_RETRY(waitpid(crasher_pid, &status, WUNTRACED)));
   ASSERT_TRUE(WIFSTOPPED(status));
   ASSERT_EQ(SIGSTOP, WSTOPSIG(status));
 
@@ -603,13 +602,15 @@
   policy += "\nclone: 1";
   policy += "\nsigaltstack: 1";
   policy += "\nnanosleep: 1";
+  policy += "\ngetrlimit: 1";
+  policy += "\nugetrlimit: 1";
 
   FILE* tmp_file = tmpfile();
   if (!tmp_file) {
     PLOG(FATAL) << "tmpfile failed";
   }
 
-  unique_fd tmp_fd(dup(fileno(tmp_file)));
+  unique_fd tmp_fd(TEMP_FAILURE_RETRY(dup(fileno(tmp_file))));
   if (!android::base::WriteStringToFd(policy, tmp_fd.get())) {
     PLOG(FATAL) << "failed to write policy to tmpfile";
   }
@@ -822,7 +823,7 @@
   FinishCrasher();
 
   int status;
-  ASSERT_EQ(crasher_pid, waitpid(crasher_pid, &status, 0));
+  ASSERT_EQ(crasher_pid, TEMP_FAILURE_RETRY(waitpid(crasher_pid, &status, 0)));
   ASSERT_TRUE(WIFSTOPPED(status));
   ASSERT_EQ(SIGABRT, WSTOPSIG(status));
 
@@ -837,7 +838,7 @@
   regex += R"( \(.+debuggerd_test)";
   ASSERT_MATCH(result, regex.c_str());
 
-  ASSERT_EQ(crasher_pid, waitpid(crasher_pid, &status, 0));
+  ASSERT_EQ(crasher_pid, TEMP_FAILURE_RETRY(waitpid(crasher_pid, &status, 0)));
   ASSERT_TRUE(WIFSTOPPED(status));
   ASSERT_EQ(SIGABRT, WSTOPSIG(status));
 
@@ -851,7 +852,7 @@
 
   StartProcess([]() {
     android_fdsan_set_error_level(ANDROID_FDSAN_ERROR_LEVEL_WARN_ONCE);
-    unique_fd fd(open("/dev/null", O_RDONLY | O_CLOEXEC));
+    unique_fd fd(TEMP_FAILURE_RETRY(open("/dev/null", O_RDONLY | O_CLOEXEC)));
     if (fd == -1) {
       abort();
     }
@@ -886,13 +887,13 @@
     raise(DEBUGGER_SIGNAL);
 
     errno = 0;
-    rc = waitpid(-1, &status, __WALL | __WNOTHREAD);
+    rc = TEMP_FAILURE_RETRY(waitpid(-1, &status, __WALL | __WNOTHREAD));
     if (rc != -1 || errno != ECHILD) {
       errx(2, "second waitpid returned %d (%s), expected failure with ECHILD", rc, strerror(errno));
     }
     _exit(0);
   } else {
-    rc = waitpid(forkpid, &status, 0);
+    rc = TEMP_FAILURE_RETRY(waitpid(forkpid, &status, 0));
     ASSERT_EQ(forkpid, rc);
     ASSERT_TRUE(WIFEXITED(status));
     ASSERT_EQ(0, WEXITSTATUS(status));
diff --git a/fastboot/Android.bp b/fastboot/Android.bp
index 978eed0..f452a64 100644
--- a/fastboot/Android.bp
+++ b/fastboot/Android.bp
@@ -143,6 +143,10 @@
     static_libs: [
         "libhealthhalutils",
     ],
+
+    header_libs: [
+        "libsnapshot_headers",
+    ]
 }
 
 cc_defaults {
@@ -185,7 +189,11 @@
     // will violate ODR.
     shared_libs: [],
 
-    header_libs: ["bootimg_headers"],
+    header_libs: [
+        "avb_headers",
+        "bootimg_headers",
+    ],
+
     static_libs: [
         "libziparchive",
         "libsparse",
diff --git a/fastboot/device/flashing.cpp b/fastboot/device/flashing.cpp
index 99854c9..102ebdb 100644
--- a/fastboot/device/flashing.cpp
+++ b/fastboot/device/flashing.cpp
@@ -32,6 +32,7 @@
 #include <fstab/fstab.h>
 #include <liblp/builder.h>
 #include <liblp/liblp.h>
+#include <libsnapshot/snapshot.h>
 #include <sparse/sparse.h>
 
 #include "fastboot_device.h"
@@ -171,6 +172,11 @@
         if (!slot_suffix.empty() && GetPartitionSlotSuffix(partition_name) == slot_suffix) {
             continue;
         }
+        std::string group_name = GetPartitionGroupName(old_metadata->groups[partition.group_index]);
+        // Skip partitions in the COW group
+        if (group_name == android::snapshot::kCowGroupName) {
+            continue;
+        }
         partitions_to_keep.emplace(partition_name);
     }
 
diff --git a/fastboot/fastboot.cpp b/fastboot/fastboot.cpp
index 4737ae4..2fe3b1a 100644
--- a/fastboot/fastboot.cpp
+++ b/fastboot/fastboot.cpp
@@ -51,6 +51,7 @@
 #include <utility>
 #include <vector>
 
+#include <android-base/endian.h>
 #include <android-base/file.h>
 #include <android-base/macros.h>
 #include <android-base/parseint.h>
@@ -59,6 +60,7 @@
 #include <android-base/strings.h>
 #include <android-base/unique_fd.h>
 #include <build/version.h>
+#include <libavb/libavb.h>
 #include <liblp/liblp.h>
 #include <platform_tools_version.h>
 #include <sparse/sparse.h>
@@ -874,7 +876,7 @@
         return false;
     }
 
-    if (sparse_file* s = sparse_file_import_auto(fd, false, false)) {
+    if (sparse_file* s = sparse_file_import(fd, false, false)) {
         buf->image_size = sparse_file_len(s, false, false);
         sparse_file_destroy(s);
     } else {
@@ -919,33 +921,50 @@
     return load_buf_fd(fd.release(), buf);
 }
 
-static void rewrite_vbmeta_buffer(struct fastboot_buffer* buf) {
+static void rewrite_vbmeta_buffer(struct fastboot_buffer* buf, bool vbmeta_in_boot) {
     // Buffer needs to be at least the size of the VBMeta struct which
     // is 256 bytes.
     if (buf->sz < 256) {
         return;
     }
 
-    int fd = make_temporary_fd("vbmeta rewriting");
-
     std::string data;
     if (!android::base::ReadFdToString(buf->fd, &data)) {
         die("Failed reading from vbmeta");
     }
 
+    uint64_t vbmeta_offset = 0;
+    if (vbmeta_in_boot) {
+        // Tries to locate top-level vbmeta from boot.img footer.
+        uint64_t footer_offset = buf->sz - AVB_FOOTER_SIZE;
+        if (0 != data.compare(footer_offset, AVB_FOOTER_MAGIC_LEN, AVB_FOOTER_MAGIC)) {
+            die("Failed to find AVB_FOOTER at offset: %" PRId64, footer_offset);
+        }
+        const AvbFooter* footer = reinterpret_cast<const AvbFooter*>(data.c_str() + footer_offset);
+        vbmeta_offset = be64toh(footer->vbmeta_offset);
+    }
+    // Ensures there is AVB_MAGIC at vbmeta_offset.
+    if (0 != data.compare(vbmeta_offset, AVB_MAGIC_LEN, AVB_MAGIC)) {
+        die("Failed to find AVB_MAGIC at offset: %" PRId64, vbmeta_offset);
+    }
+
+    fprintf(stderr, "Rewriting vbmeta struct at offset: %" PRId64 "\n", vbmeta_offset);
+
     // There's a 32-bit big endian |flags| field at offset 120 where
     // bit 0 corresponds to disable-verity and bit 1 corresponds to
     // disable-verification.
     //
     // See external/avb/libavb/avb_vbmeta_image.h for the layout of
     // the VBMeta struct.
+    uint64_t flags_offset = 123 + vbmeta_offset;
     if (g_disable_verity) {
-        data[123] |= 0x01;
+        data[flags_offset] |= 0x01;
     }
     if (g_disable_verification) {
-        data[123] |= 0x02;
+        data[flags_offset] |= 0x02;
     }
 
+    int fd = make_temporary_fd("vbmeta rewriting");
     if (!android::base::WriteStringToFd(data, fd)) {
         die("Failed writing to modified vbmeta");
     }
@@ -954,14 +973,25 @@
     lseek(fd, 0, SEEK_SET);
 }
 
+static bool has_vbmeta_partition() {
+    std::string partition_type;
+    return fb->GetVar("partition-type:vbmeta", &partition_type) == fastboot::SUCCESS ||
+           fb->GetVar("partition-type:vbmeta_a", &partition_type) == fastboot::SUCCESS ||
+           fb->GetVar("partition-type:vbmeta_b", &partition_type) == fastboot::SUCCESS;
+}
+
 static void flash_buf(const std::string& partition, struct fastboot_buffer *buf)
 {
     sparse_file** s;
 
     // Rewrite vbmeta if that's what we're flashing and modification has been requested.
-    if ((g_disable_verity || g_disable_verification) &&
-        (partition == "vbmeta" || partition == "vbmeta_a" || partition == "vbmeta_b")) {
-        rewrite_vbmeta_buffer(buf);
+    if (g_disable_verity || g_disable_verification) {
+        if (partition == "vbmeta" || partition == "vbmeta_a" || partition == "vbmeta_b") {
+            rewrite_vbmeta_buffer(buf, false /* vbmeta_in_boot */);
+        } else if (!has_vbmeta_partition() &&
+                   (partition == "boot" || partition == "boot_a" || partition == "boot_b")) {
+            rewrite_vbmeta_buffer(buf, true /* vbmeta_in_boot */ );
+        }
     }
 
     switch (buf->type) {
diff --git a/fs_mgr/fs_mgr_dm_linear.cpp b/fs_mgr/fs_mgr_dm_linear.cpp
index ea799ce..0dcb9fe 100644
--- a/fs_mgr/fs_mgr_dm_linear.cpp
+++ b/fs_mgr/fs_mgr_dm_linear.cpp
@@ -79,22 +79,22 @@
     return true;
 }
 
-bool CreateDmTable(const IPartitionOpener& opener, const LpMetadata& metadata,
-                   const LpMetadataPartition& partition, const std::string& super_device,
-                   DmTable* table) {
+bool CreateDmTableInternal(const CreateLogicalPartitionParams& params, DmTable* table) {
+    const auto& super_device = params.block_device;
+
     uint64_t sector = 0;
-    for (size_t i = 0; i < partition.num_extents; i++) {
-        const auto& extent = metadata.extents[partition.first_extent_index + i];
+    for (size_t i = 0; i < params.partition->num_extents; i++) {
+        const auto& extent = params.metadata->extents[params.partition->first_extent_index + i];
         std::unique_ptr<DmTarget> target;
         switch (extent.target_type) {
             case LP_TARGET_TYPE_ZERO:
                 target = std::make_unique<DmTargetZero>(sector, extent.num_sectors);
                 break;
             case LP_TARGET_TYPE_LINEAR: {
-                const auto& block_device = metadata.block_devices[extent.target_source];
+                const auto& block_device = params.metadata->block_devices[extent.target_source];
                 std::string dev_string;
-                if (!GetPhysicalPartitionDevicePath(opener, metadata, block_device, super_device,
-                                                    &dev_string)) {
+                if (!GetPhysicalPartitionDevicePath(*params.partition_opener, *params.metadata,
+                                                    block_device, super_device, &dev_string)) {
                     LOG(ERROR) << "Unable to complete device-mapper table, unknown block device";
                     return false;
                 }
@@ -111,12 +111,21 @@
         }
         sector += extent.num_sectors;
     }
-    if (partition.attributes & LP_PARTITION_ATTR_READONLY) {
+    if (params.partition->attributes & LP_PARTITION_ATTR_READONLY) {
         table->set_readonly(true);
     }
+    if (params.force_writable) {
+        table->set_readonly(false);
+    }
     return true;
 }
 
+bool CreateDmTable(CreateLogicalPartitionParams params, DmTable* table) {
+    CreateLogicalPartitionParams::OwnedData owned_data;
+    if (!params.InitDefaults(&owned_data)) return false;
+    return CreateDmTableInternal(params, table);
+}
+
 bool CreateLogicalPartitions(const std::string& block_device) {
     uint32_t slot = SlotNumberForSlotSuffix(fs_mgr_get_slot_suffix());
     auto metadata = ReadMetadata(block_device.c_str(), slot);
@@ -160,6 +169,11 @@
         return false;
     }
 
+    if (!partition_opener) {
+        owned->partition_opener = std::make_unique<PartitionOpener>();
+        partition_opener = owned->partition_opener.get();
+    }
+
     // Read metadata if needed.
     if (!metadata) {
         if (!metadata_slot) {
@@ -167,7 +181,8 @@
             return false;
         }
         auto slot = *metadata_slot;
-        if (owned->metadata = ReadMetadata(block_device, slot); !owned->metadata) {
+        if (owned->metadata = ReadMetadata(*partition_opener, block_device, slot);
+            !owned->metadata) {
             LOG(ERROR) << "Could not read partition table for: " << block_device;
             return false;
         }
@@ -195,11 +210,6 @@
         return false;
     }
 
-    if (!partition_opener) {
-        owned->partition_opener = std::make_unique<PartitionOpener>();
-        partition_opener = owned->partition_opener.get();
-    }
-
     if (device_name.empty()) {
         device_name = partition_name;
     }
@@ -212,13 +222,9 @@
     if (!params.InitDefaults(&owned_data)) return false;
 
     DmTable table;
-    if (!CreateDmTable(*params.partition_opener, *params.metadata, *params.partition,
-                       params.block_device, &table)) {
+    if (!CreateDmTableInternal(params, &table)) {
         return false;
     }
-    if (params.force_writable) {
-        table.set_readonly(false);
-    }
 
     DeviceMapper& dm = DeviceMapper::Instance();
     if (!dm.CreateDevice(params.device_name, table, path, params.timeout_ms)) {
diff --git a/fs_mgr/fs_mgr_fstab.cpp b/fs_mgr/fs_mgr_fstab.cpp
index 4dbacd7..e50f7c3 100644
--- a/fs_mgr/fs_mgr_fstab.cpp
+++ b/fs_mgr/fs_mgr_fstab.cpp
@@ -36,6 +36,7 @@
 
 #include "fs_mgr_priv.h"
 
+using android::base::EndsWith;
 using android::base::ParseByteCount;
 using android::base::ParseInt;
 using android::base::ReadFileToString;
@@ -598,7 +599,7 @@
     return boot_devices;
 }
 
-FstabEntry BuildGsiUserdataFstabEntry() {
+FstabEntry BuildDsuUserdataFstabEntry() {
     constexpr uint32_t kFlags = MS_NOATIME | MS_NOSUID | MS_NODEV;
 
     FstabEntry userdata = {
@@ -627,7 +628,12 @@
     return false;
 }
 
-void TransformFstabForGsi(Fstab* fstab) {
+}  // namespace
+
+void TransformFstabForDsu(Fstab* fstab, const std::vector<std::string>& dsu_partitions) {
+    static constexpr char kGsiKeys[] =
+            "/avb/q-gsi.avbpubkey:/avb/r-gsi.avbpubkey:/avb/s-gsi.avbpubkey";
+    // Convert userdata
     // Inherit fstab properties for userdata.
     FstabEntry userdata;
     if (FstabEntry* entry = GetEntryForMountPoint(fstab, "/data")) {
@@ -639,19 +645,75 @@
             userdata.key_dir += "/gsi";
         }
     } else {
-        userdata = BuildGsiUserdataFstabEntry();
-    }
-
-    if (EraseFstabEntry(fstab, "/system")) {
-        fstab->emplace_back(BuildGsiSystemFstabEntry());
+        userdata = BuildDsuUserdataFstabEntry();
     }
 
     if (EraseFstabEntry(fstab, "/data")) {
         fstab->emplace_back(userdata);
     }
-}
 
-}  // namespace
+    // Convert others
+    for (auto&& partition : dsu_partitions) {
+        if (!EndsWith(partition, gsi::kDsuPostfix)) {
+            continue;
+        }
+        // userdata has been handled
+        if (StartsWith(partition, "user")) {
+            continue;
+        }
+        // dsu_partition_name = corresponding_partition_name + kDsuPostfix
+        // e.g.
+        //    system_gsi for system
+        //    product_gsi for product
+        //    vendor_gsi for vendor
+        std::string lp_name = partition.substr(0, partition.length() - strlen(gsi::kDsuPostfix));
+        std::string mount_point = "/" + lp_name;
+        std::vector<FstabEntry*> entries = GetEntriesForMountPoint(fstab, mount_point);
+        if (entries.empty()) {
+            FstabEntry entry = {
+                    .blk_device = partition,
+                    .mount_point = mount_point,
+                    .fs_type = "ext4",
+                    .flags = MS_RDONLY,
+                    .fs_options = "barrier=1",
+                    .avb_keys = kGsiKeys,
+                    // .logical_partition_name is required to look up AVB Hashtree descriptors.
+                    .logical_partition_name = "system"};
+            entry.fs_mgr_flags.wait = true;
+            entry.fs_mgr_flags.logical = true;
+            entry.fs_mgr_flags.first_stage_mount = true;
+            // Use the system key which may be in the vbmeta or vbmeta_system
+            // TODO: b/141284191
+            entry.vbmeta_partition = "vbmeta";
+            fstab->emplace_back(entry);
+            entry.vbmeta_partition = "vbmeta_system";
+            fstab->emplace_back(entry);
+        } else {
+            // If the corresponding partition exists, transform all its Fstab
+            // by pointing .blk_device to the DSU partition.
+            for (auto&& entry : entries) {
+                entry->blk_device = partition;
+                if (entry->avb_keys.size() > 0) {
+                    entry->avb_keys += ":";
+                }
+                // If the DSU is signed by OEM, the original Fstab already has the information
+                // required by avb, otherwise the DSU is GSI and will need the avb_keys as listed
+                // below.
+                entry->avb_keys += kGsiKeys;
+            }
+            // Make sure the ext4 is included to support GSI.
+            auto partition_ext4 =
+                    std::find_if(fstab->begin(), fstab->end(), [&](const auto& entry) {
+                        return entry.mount_point == mount_point && entry.fs_type == "ext4";
+                    });
+            if (partition_ext4 == fstab->end()) {
+                auto new_entry = *GetEntryForMountPoint(fstab, mount_point);
+                new_entry.fs_type = "ext4";
+                fstab->emplace_back(new_entry);
+            }
+        }
+    }
+}
 
 bool ReadFstabFromFile(const std::string& path, Fstab* fstab) {
     auto fstab_file = std::unique_ptr<FILE, decltype(&fclose)>{fopen(path.c_str(), "re"), fclose};
@@ -667,7 +729,9 @@
         return false;
     }
     if (!is_proc_mounts && !access(android::gsi::kGsiBootedIndicatorFile, F_OK)) {
-        TransformFstabForGsi(fstab);
+        std::string lp_names;
+        ReadFileToString(gsi::kGsiLpNamesFile, &lp_names);
+        TransformFstabForDsu(fstab, Split(lp_names, ","));
     }
 
     SkipMountingPartitions(fstab);
@@ -779,6 +843,21 @@
     return nullptr;
 }
 
+std::vector<FstabEntry*> GetEntriesForMountPoint(Fstab* fstab, const std::string& path) {
+    std::vector<FstabEntry*> entries;
+    if (fstab == nullptr) {
+        return entries;
+    }
+
+    for (auto& entry : *fstab) {
+        if (entry.mount_point == path) {
+            entries.emplace_back(&entry);
+        }
+    }
+
+    return entries;
+}
+
 std::set<std::string> GetBootDevices() {
     // First check the kernel commandline, then try the device tree otherwise
     std::string dt_file_name = get_android_dt_dir() + "/boot_devices";
@@ -798,23 +877,6 @@
     return ExtraBootDevices(fstab);
 }
 
-FstabEntry BuildGsiSystemFstabEntry() {
-    // .logical_partition_name is required to look up AVB Hashtree descriptors.
-    FstabEntry system = {
-            .blk_device = "system_gsi",
-            .mount_point = "/system",
-            .fs_type = "ext4",
-            .flags = MS_RDONLY,
-            .fs_options = "barrier=1",
-            // could add more keys separated by ':'.
-            .avb_keys = "/avb/q-gsi.avbpubkey:/avb/r-gsi.avbpubkey:/avb/s-gsi.avbpubkey",
-            .logical_partition_name = "system"};
-    system.fs_mgr_flags.wait = true;
-    system.fs_mgr_flags.logical = true;
-    system.fs_mgr_flags.first_stage_mount = true;
-    return system;
-}
-
 std::string GetVerityDeviceName(const FstabEntry& entry) {
     std::string base_device;
     if (entry.mount_point == "/") {
diff --git a/fs_mgr/include/fs_mgr_dm_linear.h b/fs_mgr/include/fs_mgr_dm_linear.h
index a912208..f3d09fb 100644
--- a/fs_mgr/include/fs_mgr_dm_linear.h
+++ b/fs_mgr/include/fs_mgr_dm_linear.h
@@ -105,9 +105,7 @@
 bool DestroyLogicalPartition(const std::string& name);
 
 // Helper for populating a DmTable for a logical partition.
-bool CreateDmTable(const IPartitionOpener& opener, const LpMetadata& metadata,
-                   const LpMetadataPartition& partition, const std::string& super_device,
-                   android::dm::DmTable* table);
+bool CreateDmTable(CreateLogicalPartitionParams params, android::dm::DmTable* table);
 
 }  // namespace fs_mgr
 }  // namespace android
diff --git a/fs_mgr/include_fstab/fstab/fstab.h b/fs_mgr/include_fstab/fstab/fstab.h
index c7193ab..d999ae1 100644
--- a/fs_mgr/include_fstab/fstab/fstab.h
+++ b/fs_mgr/include_fstab/fstab/fstab.h
@@ -101,9 +101,18 @@
 bool SkipMountingPartitions(Fstab* fstab);
 
 FstabEntry* GetEntryForMountPoint(Fstab* fstab, const std::string& path);
+// The Fstab can contain multiple entries for the same mount point with different configurations.
+std::vector<FstabEntry*> GetEntriesForMountPoint(Fstab* fstab, const std::string& path);
 
-// Helper method to build a GSI fstab entry for mounting /system.
-FstabEntry BuildGsiSystemFstabEntry();
+// This method builds DSU fstab entries and transfer the fstab.
+//
+// fstab points to the unmodified fstab.
+//
+// dsu_partitions contains partition names, e.g.
+//     dsu_partitions[0] = "system_gsi"
+//     dsu_partitions[1] = "userdata_gsi"
+//     dsu_partitions[2] = ...
+void TransformFstabForDsu(Fstab* fstab, const std::vector<std::string>& dsu_partitions);
 
 std::set<std::string> GetBootDevices();
 
diff --git a/fs_mgr/libdm/Android.bp b/fs_mgr/libdm/Android.bp
index 4cdea71..449a170 100644
--- a/fs_mgr/libdm/Android.bp
+++ b/fs_mgr/libdm/Android.bp
@@ -44,9 +44,24 @@
     },
 }
 
-cc_test {
-    name: "libdm_test",
-    defaults: ["fs_mgr_defaults"],
+filegroup {
+    name: "libdm_test_srcs",
+    srcs: [
+        "dm_test.cpp",
+        "loop_control_test.cpp",
+        "test_util.cpp",
+    ],
+}
+
+cc_defaults {
+    name: "libdm_defaults",
+    sanitize: {
+        misc_undefined: ["integer"],
+    },
+    cflags: [
+        "-Wall",
+        "-Werror",
+    ],
     static_libs: [
         "libdm",
         "libbase",
@@ -54,9 +69,10 @@
         "libfs_mgr",
         "liblog",
     ],
-    srcs: [
-        "dm_test.cpp",
-        "loop_control_test.cpp",
-        "test_util.cpp",
-    ]
+    srcs: [":libdm_test_srcs"],
+}
+
+cc_test {
+    name: "libdm_test",
+    defaults: ["libdm_defaults"],
 }
diff --git a/fs_mgr/libdm/vts_core/Android.bp b/fs_mgr/libdm/vts_core/Android.bp
new file mode 100644
index 0000000..2eceb28
--- /dev/null
+++ b/fs_mgr/libdm/vts_core/Android.bp
@@ -0,0 +1,23 @@
+//
+// Copyright (C) 2019 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+cc_test {
+    name: "vts_libdm_test",
+    defaults: ["libdm_defaults"],
+    test_suites: ["vts-core"],
+    require_root: true,
+    test_min_api_level: 29,
+}
diff --git a/fs_mgr/liblp/Android.bp b/fs_mgr/liblp/Android.bp
index f0142bb..7fee83c 100644
--- a/fs_mgr/liblp/Android.bp
+++ b/fs_mgr/liblp/Android.bp
@@ -55,19 +55,8 @@
     export_include_dirs: ["include"],
 }
 
-cc_defaults {
-    name: "liblp_test_defaults",
-    defaults: ["fs_mgr_defaults"],
-    cppflags: [
-        "-Wno-unused-parameter",
-    ],
-    static_libs: [
-        "libcutils",
-        "libgmock",
-        "libfs_mgr",
-        "liblp",
-    ] + liblp_lib_deps,
-    stl: "libc++_static",
+filegroup {
+    name: "liblp_test_srcs",
     srcs: [
         "builder_test.cpp",
         "device_test.cpp",
@@ -77,14 +66,36 @@
     ],
 }
 
+cc_defaults {
+    name: "liblp_test_defaults",
+    sanitize: {
+        misc_undefined: ["integer"],
+    },
+    cflags: [
+        "-Wall",
+        "-Werror",
+    ],
+    cppflags: [
+        "-Wno-unused-parameter",
+    ],
+    static_libs: [
+        "libcutils",
+        "libgmock",
+        "libfs_mgr",
+        "liblp",
+    ] + liblp_lib_deps,
+    header_libs: [
+        "libstorage_literals_headers",
+    ],
+    stl: "libc++_static",
+    srcs: [":liblp_test_srcs"],
+}
+
 cc_test {
     name: "liblp_test",
     defaults: ["liblp_test_defaults"],
     test_config: "liblp_test.xml",
-    test_suites: [
-        "device-tests",
-        "vts-core",
-    ],
+    test_suites: ["device-tests"],
 }
 
 cc_test {
diff --git a/fs_mgr/liblp/builder.cpp b/fs_mgr/liblp/builder.cpp
index c5d6a3b..7405039 100644
--- a/fs_mgr/liblp/builder.cpp
+++ b/fs_mgr/liblp/builder.cpp
@@ -40,6 +40,10 @@
     return true;
 }
 
+Interval LinearExtent::AsInterval() const {
+    return Interval(device_index(), physical_sector(), end_sector());
+}
+
 bool ZeroExtent::AddTo(LpMetadata* out) const {
     out->extents.emplace_back(LpMetadataExtent{num_sectors_, LP_TARGET_TYPE_ZERO, 0, 0});
     return true;
@@ -96,6 +100,20 @@
     DCHECK(size_ == aligned_size);
 }
 
+Partition Partition::GetBeginningExtents(uint64_t aligned_size) const {
+    Partition p(name_, group_name_, attributes_);
+    for (const auto& extent : extents_) {
+        auto le = extent->AsLinearExtent();
+        if (le) {
+            p.AddExtent(std::make_unique<LinearExtent>(*le));
+        } else {
+            p.AddExtent(std::make_unique<ZeroExtent>(extent->num_sectors()));
+        }
+    }
+    p.ShrinkTo(aligned_size);
+    return p;
+}
+
 uint64_t Partition::BytesOnDisk() const {
     uint64_t sectors = 0;
     for (const auto& extent : extents_) {
@@ -486,7 +504,7 @@
     return total;
 }
 
-void MetadataBuilder::RemovePartition(const std::string& name) {
+void MetadataBuilder::RemovePartition(std::string_view name) {
     for (auto iter = partitions_.begin(); iter != partitions_.end(); iter++) {
         if ((*iter)->name() == name) {
             partitions_.erase(iter);
@@ -602,6 +620,10 @@
     return ret;
 }
 
+std::unique_ptr<Extent> Interval::AsExtent() const {
+    return std::make_unique<LinearExtent>(length(), device_index, start);
+}
+
 bool MetadataBuilder::GrowPartition(Partition* partition, uint64_t aligned_size,
                                     const std::vector<Interval>& free_region_hint) {
     uint64_t space_needed = aligned_size - partition->size();
@@ -1114,7 +1136,7 @@
     return true;
 }
 
-std::vector<Partition*> MetadataBuilder::ListPartitionsInGroup(const std::string& group_name) {
+std::vector<Partition*> MetadataBuilder::ListPartitionsInGroup(std::string_view group_name) {
     std::vector<Partition*> partitions;
     for (const auto& partition : partitions_) {
         if (partition->group_name() == group_name) {
@@ -1168,5 +1190,9 @@
                    : "";
 }
 
+uint64_t MetadataBuilder::logical_block_size() const {
+    return geometry_.logical_block_size;
+}
+
 }  // namespace fs_mgr
 }  // namespace android
diff --git a/fs_mgr/liblp/builder_test.cpp b/fs_mgr/liblp/builder_test.cpp
index bd41f59..a67ffa7 100644
--- a/fs_mgr/liblp/builder_test.cpp
+++ b/fs_mgr/liblp/builder_test.cpp
@@ -17,11 +17,13 @@
 #include <gmock/gmock.h>
 #include <gtest/gtest.h>
 #include <liblp/builder.h>
+#include <storage_literals/storage_literals.h>
 
 #include "liblp_test.h"
 #include "utility.h"
 
 using namespace std;
+using namespace android::storage_literals;
 using namespace android::fs_mgr;
 using namespace android::fs_mgr::testing;
 using ::testing::_;
@@ -591,13 +593,6 @@
     ASSERT_NE(builder->Export(), nullptr);
 }
 
-constexpr unsigned long long operator"" _GiB(unsigned long long x) {  // NOLINT
-    return x << 30;
-}
-constexpr unsigned long long operator"" _MiB(unsigned long long x) {  // NOLINT
-    return x << 20;
-}
-
 TEST_F(BuilderTest, RemoveAndAddFirstPartition) {
     auto builder = MetadataBuilder::New(10_GiB, 65536, 2);
     ASSERT_NE(nullptr, builder);
diff --git a/fs_mgr/liblp/images.cpp b/fs_mgr/liblp/images.cpp
index 58a88b5..6b842b3 100644
--- a/fs_mgr/liblp/images.cpp
+++ b/fs_mgr/liblp/images.cpp
@@ -17,6 +17,7 @@
 #include "images.h"
 
 #include <limits.h>
+#include <sys/stat.h>
 
 #include <android-base/file.h>
 
@@ -27,12 +28,45 @@
 namespace android {
 namespace fs_mgr {
 
+using android::base::borrowed_fd;
 using android::base::unique_fd;
 
 #if defined(_WIN32)
 static const int O_NOFOLLOW = 0;
 #endif
 
+static bool IsEmptySuperImage(borrowed_fd fd) {
+    struct stat s;
+    if (fstat(fd.get(), &s) < 0) {
+        PERROR << __PRETTY_FUNCTION__ << " fstat failed";
+        return false;
+    }
+    if (s.st_size < LP_METADATA_GEOMETRY_SIZE) {
+        return false;
+    }
+
+    // Rewind back to the start, read the geometry struct.
+    LpMetadataGeometry geometry = {};
+    if (SeekFile64(fd.get(), 0, SEEK_SET) < 0) {
+        PERROR << __PRETTY_FUNCTION__ << " lseek failed";
+        return false;
+    }
+    if (!android::base::ReadFully(fd, &geometry, sizeof(geometry))) {
+        PERROR << __PRETTY_FUNCTION__ << " read failed";
+        return false;
+    }
+    return geometry.magic == LP_METADATA_GEOMETRY_MAGIC;
+}
+
+bool IsEmptySuperImage(const std::string& file) {
+    unique_fd fd = GetControlFileOrOpen(file, O_RDONLY | O_CLOEXEC);
+    if (fd < 0) {
+        PERROR << __PRETTY_FUNCTION__ << " open failed";
+        return false;
+    }
+    return IsEmptySuperImage(fd);
+}
+
 std::unique_ptr<LpMetadata> ReadFromImageFile(int fd) {
     std::unique_ptr<uint8_t[]> buffer = std::make_unique<uint8_t[]>(LP_METADATA_GEOMETRY_SIZE);
     if (SeekFile64(fd, 0, SEEK_SET) < 0) {
diff --git a/fs_mgr/liblp/include/liblp/builder.h b/fs_mgr/liblp/include/liblp/builder.h
index 6f2ab75..b43ccf0 100644
--- a/fs_mgr/liblp/include/liblp/builder.h
+++ b/fs_mgr/liblp/include/liblp/builder.h
@@ -33,10 +33,11 @@
 namespace fs_mgr {
 
 class LinearExtent;
+struct Interval;
 
 // By default, partitions are aligned on a 1MiB boundary.
-static const uint32_t kDefaultPartitionAlignment = 1024 * 1024;
-static const uint32_t kDefaultBlockSize = 4096;
+static constexpr uint32_t kDefaultPartitionAlignment = 1024 * 1024;
+static constexpr uint32_t kDefaultBlockSize = 4096;
 
 // Name of the default group in a metadata.
 static constexpr std::string_view kDefaultGroup = "default";
@@ -74,6 +75,8 @@
         return sector >= physical_sector_ && sector < end_sector();
     }
 
+    Interval AsInterval() const;
+
   private:
     uint32_t device_index_;
     uint64_t physical_sector_;
@@ -127,6 +130,12 @@
     const std::vector<std::unique_ptr<Extent>>& extents() const { return extents_; }
     uint64_t size() const { return size_; }
 
+    // Return a copy of *this, but with extents that includes only the first
+    // |aligned_size| bytes. |aligned_size| should be aligned to
+    // logical_block_size() of the MetadataBuilder that this partition belongs
+    // to.
+    Partition GetBeginningExtents(uint64_t aligned_size) const;
+
   private:
     void ShrinkTo(uint64_t aligned_size);
     void set_group_name(std::string_view group_name) { group_name_ = group_name; }
@@ -156,6 +165,8 @@
         return (start == other.start) ? end < other.end : start < other.start;
     }
 
+    std::unique_ptr<Extent> AsExtent() const;
+
     // Intersect |a| with |b|.
     // If no intersection, result has 0 length().
     static Interval Intersect(const Interval& a, const Interval& b);
@@ -249,7 +260,7 @@
     Partition* AddPartition(const std::string& name, uint32_t attributes);
 
     // Delete a partition by name if it exists.
-    void RemovePartition(const std::string& name);
+    void RemovePartition(std::string_view name);
 
     // Find a partition by name. If no partition is found, nullptr is returned.
     Partition* FindPartition(std::string_view name);
@@ -278,7 +289,7 @@
                          const std::vector<Interval>& free_region_hint = {});
 
     // Return the list of partitions belonging to a group.
-    std::vector<Partition*> ListPartitionsInGroup(const std::string& group_name);
+    std::vector<Partition*> ListPartitionsInGroup(std::string_view group_name);
 
     // Changes a partition's group. Size constraints will not be checked until
     // the metadata is exported, to avoid errors during potential group and
@@ -325,6 +336,8 @@
     // Return the list of free regions not occupied by extents in the metadata.
     std::vector<Interval> GetFreeRegions() const;
 
+    uint64_t logical_block_size() const;
+
   private:
     MetadataBuilder();
     MetadataBuilder(const MetadataBuilder&) = delete;
diff --git a/fs_mgr/liblp/include/liblp/liblp.h b/fs_mgr/liblp/include/liblp/liblp.h
index 135a1b3..cd860cd 100644
--- a/fs_mgr/liblp/include/liblp/liblp.h
+++ b/fs_mgr/liblp/include/liblp/liblp.h
@@ -70,8 +70,15 @@
                           uint32_t slot_number);
 std::unique_ptr<LpMetadata> ReadMetadata(const std::string& super_partition, uint32_t slot_number);
 
+// Returns whether an image is an "empty" image or not. An empty image contains
+// only metadata. Unlike a flashed block device, there are no reserved bytes or
+// backup sections, and only one slot is stored (even if multiple slots are
+// supported). It is a format specifically for storing only metadata.
+bool IsEmptySuperImage(const std::string& file);
+
 // Read/Write logical partition metadata to an image file, for diagnostics or
-// flashing.
+// flashing. If no partition images are specified, the file will be in the
+// empty format.
 bool WriteToImageFile(const std::string& file, const LpMetadata& metadata, uint32_t block_size,
                       const std::map<std::string, std::string>& images, bool sparsify);
 bool WriteToImageFile(const std::string& file, const LpMetadata& metadata);
diff --git a/fs_mgr/liblp/utility.cpp b/fs_mgr/liblp/utility.cpp
index afcce8f..48c5c83 100644
--- a/fs_mgr/liblp/utility.cpp
+++ b/fs_mgr/liblp/utility.cpp
@@ -205,9 +205,9 @@
 #endif
 }
 
-base::unique_fd GetControlFileOrOpen(const char* path, int flags) {
+base::unique_fd GetControlFileOrOpen(std::string_view path, int flags) {
 #if defined(__ANDROID__)
-    int fd = android_get_control_file(path);
+    int fd = android_get_control_file(path.data());
     if (fd >= 0) {
         int newfd = TEMP_FAILURE_RETRY(dup(fd));
         if (newfd >= 0) {
@@ -216,7 +216,7 @@
         PERROR << "Cannot dup fd for already controlled file: " << path << ", reopening...";
     }
 #endif
-    return base::unique_fd(open(path, flags));
+    return base::unique_fd(open(path.data(), flags));
 }
 
 bool UpdateMetadataForInPlaceSnapshot(LpMetadata* metadata, uint32_t source_slot_number,
diff --git a/fs_mgr/liblp/utility.h b/fs_mgr/liblp/utility.h
index 25ab66b..0661769 100644
--- a/fs_mgr/liblp/utility.h
+++ b/fs_mgr/liblp/utility.h
@@ -21,6 +21,9 @@
 #include <stdint.h>
 #include <sys/types.h>
 
+#include <string>
+#include <string_view>
+
 #include <android-base/logging.h>
 #include <android-base/unique_fd.h>
 
@@ -94,7 +97,7 @@
 // Call BLKROSET ioctl on fd so that fd is readonly / read-writable.
 bool SetBlockReadonly(int fd, bool readonly);
 
-::android::base::unique_fd GetControlFileOrOpen(const char* path, int flags);
+::android::base::unique_fd GetControlFileOrOpen(std::string_view path, int flags);
 
 // For Virtual A/B updates, modify |metadata| so that it can be written to |target_slot_number|.
 bool UpdateMetadataForInPlaceSnapshot(LpMetadata* metadata, uint32_t source_slot_number,
diff --git a/fs_mgr/liblp/vts_core/Android.bp b/fs_mgr/liblp/vts_core/Android.bp
new file mode 100644
index 0000000..7af0b9e
--- /dev/null
+++ b/fs_mgr/liblp/vts_core/Android.bp
@@ -0,0 +1,22 @@
+//
+// Copyright (C) 2019 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+cc_test {
+    name: "vts_core_liblp_test",
+    defaults: ["liblp_test_defaults"],
+    test_suites: ["vts-core"],
+    test_min_api_level: 29,
+}
diff --git a/fs_mgr/libsnapshot/Android.bp b/fs_mgr/libsnapshot/Android.bp
index 8df9c52..a012099 100644
--- a/fs_mgr/libsnapshot/Android.bp
+++ b/fs_mgr/libsnapshot/Android.bp
@@ -25,11 +25,14 @@
     shared_libs: [
         "libbase",
         "liblog",
+        "liblp",
     ],
     static_libs: [
         "libdm",
         "libfs_mgr",
+        "libfstab",
         "liblp",
+        "update_metadata-protos",
     ],
     whole_static_libs: [
         "libext2_uuid",
@@ -39,6 +42,9 @@
     header_libs: [
         "libfiemap_headers",
     ],
+    export_static_lib_headers: [
+        "update_metadata-protos",
+    ],
     export_header_lib_headers: [
         "libfiemap_headers",
     ],
@@ -49,10 +55,18 @@
     name: "libsnapshot_sources",
     srcs: [
         "snapshot.cpp",
+        "snapshot_metadata_updater.cpp",
+        "partition_cow_creator.cpp",
         "utility.cpp",
     ],
 }
 
+cc_library_headers {
+    name: "libsnapshot_headers",
+    recovery_available: true,
+    defaults: ["libsnapshot_defaults"],
+}
+
 cc_library_static {
     name: "libsnapshot",
     defaults: ["libsnapshot_defaults"],
@@ -77,10 +91,13 @@
     defaults: ["libsnapshot_defaults"],
     srcs: [
         "snapshot_test.cpp",
+        "partition_cow_creator_test.cpp",
+        "snapshot_metadata_updater_test.cpp",
         "test_helpers.cpp",
     ],
     shared_libs: [
         "libbinder",
+        "libprotobuf-cpp-lite",
         "libutils",
     ],
     static_libs: [
@@ -90,5 +107,36 @@
         "libgmock",
         "liblp",
         "libsnapshot",
+        "libsparse",
+        "libz",
+    ],
+    header_libs: [
+        "libstorage_literals_headers",
+    ],
+}
+
+cc_binary {
+    name: "snapshotctl",
+    srcs: [
+        "snapshotctl.cpp",
+    ],
+    static_libs: [
+        "libdm",
+        "libext2_uuid",
+        "libfiemap_binder",
+        "libfstab",
+        "libsnapshot",
+    ],
+    shared_libs: [
+        "libbase",
+        "libbinder",
+        "libext4_utils",
+        "libfs_mgr",
+        "libutils",
+        "liblog",
+        "liblp",
+    ],
+    init_rc: [
+        "snapshotctl.rc",
     ],
 }
diff --git a/fs_mgr/libsnapshot/include/libsnapshot/snapshot.h b/fs_mgr/libsnapshot/include/libsnapshot/snapshot.h
index c41a951..0dd275a 100644
--- a/fs_mgr/libsnapshot/include/libsnapshot/snapshot.h
+++ b/fs_mgr/libsnapshot/include/libsnapshot/snapshot.h
@@ -17,14 +17,20 @@
 #include <stdint.h>
 
 #include <chrono>
+#include <map>
 #include <memory>
+#include <ostream>
 #include <string>
+#include <string_view>
 #include <vector>
 
 #include <android-base/unique_fd.h>
+#include <fs_mgr_dm_linear.h>
 #include <libdm/dm.h>
 #include <libfiemap/image_manager.h>
+#include <liblp/builder.h>
 #include <liblp/liblp.h>
+#include <update_engine/update_metadata.pb.h>
 
 #ifndef FRIEND_TEST
 #define FRIEND_TEST(test_set_name, individual_test) \
@@ -45,6 +51,13 @@
 
 namespace snapshot {
 
+struct AutoDeleteCowImage;
+struct AutoDeleteSnapshot;
+struct PartitionCowCreator;
+struct AutoDeviceList;
+
+static constexpr const std::string_view kCowGroupName = "cow";
+
 enum class UpdateState : unsigned int {
     // No update or merge is in progress.
     None,
@@ -72,11 +85,14 @@
     // operation via fastboot. This state can only be returned by WaitForMerge.
     Cancelled
 };
+std::ostream& operator<<(std::ostream& os, UpdateState state);
 
 class SnapshotManager final {
     using CreateLogicalPartitionParams = android::fs_mgr::CreateLogicalPartitionParams;
-    using LpMetadata = android::fs_mgr::LpMetadata;
     using IPartitionOpener = android::fs_mgr::IPartitionOpener;
+    using LpMetadata = android::fs_mgr::LpMetadata;
+    using MetadataBuilder = android::fs_mgr::MetadataBuilder;
+    using DeltaArchiveManifest = chromeos_update_engine::DeltaArchiveManifest;
 
   public:
     // Dependency injection for testing.
@@ -86,8 +102,10 @@
         virtual std::string GetGsidDir() const = 0;
         virtual std::string GetMetadataDir() const = 0;
         virtual std::string GetSlotSuffix() const = 0;
+        virtual std::string GetOtherSlotSuffix() const = 0;
         virtual std::string GetSuperDevice(uint32_t slot) const = 0;
         virtual const IPartitionOpener& GetPartitionOpener() const = 0;
+        virtual bool IsOverlayfsSetup() const = 0;
     };
 
     ~SnapshotManager();
@@ -109,8 +127,9 @@
     // will fail if GetUpdateState() != None.
     bool BeginUpdate();
 
-    // Cancel an update; any snapshots will be deleted. This will fail if the
-    // state != Initiated or None.
+    // Cancel an update; any snapshots will be deleted. This is allowed if the
+    // state == Initiated, None, or Unverified (before rebooting to the new
+    // slot).
     bool CancelUpdate();
 
     // Mark snapshot writes as having completed. After this, new snapshots cannot
@@ -153,6 +172,18 @@
     //   Other: 0
     UpdateState GetUpdateState(double* progress = nullptr);
 
+    // Create necessary COW device / files for OTA clients. New logical partitions will be added to
+    // group "cow" in target_metadata. Regions of partitions of current_metadata will be
+    // "write-protected" and snapshotted.
+    bool CreateUpdateSnapshots(const DeltaArchiveManifest& manifest);
+
+    // Map a snapshotted partition for OTA clients to write to. Write-protected regions are
+    // determined previously in CreateSnapshots.
+    bool MapUpdateSnapshot(const CreateLogicalPartitionParams& params, std::string* snapshot_path);
+
+    // Unmap a snapshot device that's previously mapped with MapUpdateSnapshot.
+    bool UnmapUpdateSnapshot(const std::string& target_partition_name);
+
     // If this returns true, first-stage mount must call
     // CreateLogicalAndSnapshotPartitions rather than CreateLogicalPartitions.
     bool NeedSnapshotsInFirstStageMount();
@@ -161,6 +192,9 @@
     // call to CreateLogicalPartitions when snapshots are present.
     bool CreateLogicalAndSnapshotPartitions(const std::string& super_device);
 
+    // Dump debug information.
+    bool Dump(std::ostream& os);
+
   private:
     FRIEND_TEST(SnapshotTest, CleanFirstStageMount);
     FRIEND_TEST(SnapshotTest, CreateSnapshot);
@@ -173,7 +207,12 @@
     FRIEND_TEST(SnapshotTest, Merge);
     FRIEND_TEST(SnapshotTest, MergeCannotRemoveCow);
     FRIEND_TEST(SnapshotTest, NoMergeBeforeReboot);
+    FRIEND_TEST(SnapshotUpdateTest, SnapshotStatusFileWithoutCow);
     friend class SnapshotTest;
+    friend class SnapshotUpdateTest;
+    friend struct AutoDeleteCowImage;
+    friend struct AutoDeleteSnapshot;
+    friend struct PartitionCowCreator;
 
     using DmTargetSnapshot = android::dm::DmTargetSnapshot;
     using IImageManager = android::fiemap::IImageManager;
@@ -241,9 +280,8 @@
     // be mapped with two table entries: a dm-snapshot range covering
     // snapshot_size, and a dm-linear range covering the remainder.
     //
-    // All sizes are specified in bytes, and the device, snapshot and COW partition sizes
-    // must be a multiple of the sector size (512 bytes). COW file size will be rounded up
-    // to the nearest sector.
+    // All sizes are specified in bytes, and the device, snapshot, COW partition and COW file sizes
+    // must be a multiple of the sector size (512 bytes).
     bool CreateSnapshot(LockedFile* lock, const std::string& name, SnapshotStatus status);
 
     // |name| should be the base partition name (e.g. "system_a"). Create the
@@ -262,8 +300,7 @@
                      std::string* dev_path);
 
     // Map a COW image that was previous created with CreateCowImage.
-    bool MapCowImage(const std::string& name, const std::chrono::milliseconds& timeout_ms,
-                     std::string* cow_image_device);
+    bool MapCowImage(const std::string& name, const std::chrono::milliseconds& timeout_ms);
 
     // Remove the backing copy-on-write image and snapshot states for the named snapshot. The
     // caller is responsible for ensuring that the snapshot is unmapped.
@@ -344,6 +381,31 @@
     bool MapPartitionWithSnapshot(LockedFile* lock, CreateLogicalPartitionParams params,
                                   std::string* path);
 
+    // Map the COW devices, including the partition in super and the images.
+    // |params|:
+    //    - |partition_name| should be the name of the top-level partition (e.g. system_b),
+    //            not system_b-cow-img
+    //    - |device_name| and |partition| is ignored
+    //    - |timeout_ms| and the rest is respected
+    // Return the path in |cow_device_path| (e.g. /dev/block/dm-1) and major:minor in
+    // |cow_device_string|
+    bool MapCowDevices(LockedFile* lock, const CreateLogicalPartitionParams& params,
+                       const SnapshotStatus& snapshot_status, AutoDeviceList* created_devices,
+                       std::string* cow_name);
+
+    // The reverse of MapCowDevices.
+    bool UnmapCowDevices(LockedFile* lock, const std::string& name);
+
+    // The reverse of MapPartitionWithSnapshot.
+    bool UnmapPartitionWithSnapshot(LockedFile* lock, const std::string& target_partition_name);
+
+    // If there isn't a previous update, return true. |needs_merge| is set to false.
+    // If there is a previous update but the device has not boot into it, tries to cancel the
+    //   update and delete any snapshots. Return true if successful. |needs_merge| is set to false.
+    // If there is a previous update and the device has boot into it, do nothing and return true.
+    //   |needs_merge| is set to true.
+    bool TryCancelUpdate(bool* needs_merge);
+
     std::string gsid_dir_;
     std::string metadata_dir_;
     std::unique_ptr<IDeviceInfo> device_;
diff --git a/fs_mgr/libsnapshot/partition_cow_creator.cpp b/fs_mgr/libsnapshot/partition_cow_creator.cpp
new file mode 100644
index 0000000..4250d23
--- /dev/null
+++ b/fs_mgr/libsnapshot/partition_cow_creator.cpp
@@ -0,0 +1,180 @@
+// Copyright (C) 2019 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "partition_cow_creator.h"
+
+#include <math.h>
+
+#include <android-base/logging.h>
+
+#include "utility.h"
+
+using android::dm::kSectorSize;
+using android::fs_mgr::Extent;
+using android::fs_mgr::Interval;
+using android::fs_mgr::kDefaultBlockSize;
+using android::fs_mgr::Partition;
+using chromeos_update_engine::InstallOperation;
+template <typename T>
+using RepeatedPtrField = google::protobuf::RepeatedPtrField<T>;
+
+namespace android {
+namespace snapshot {
+
+// Round |d| up to a multiple of |block_size|.
+static uint64_t RoundUp(double d, uint64_t block_size) {
+    uint64_t ret = ((uint64_t)ceil(d) + block_size - 1) / block_size * block_size;
+    CHECK(ret >= d) << "Can't round " << d << " up to a multiple of " << block_size;
+    return ret;
+}
+
+// Intersect two linear extents. If no intersection, return an extent with length 0.
+static std::unique_ptr<Extent> Intersect(Extent* target_extent, Extent* existing_extent) {
+    // Convert target_extent and existing_extent to linear extents. Zero extents
+    // doesn't matter and doesn't result in any intersection.
+    auto existing_linear_extent = existing_extent->AsLinearExtent();
+    if (!existing_linear_extent) return nullptr;
+
+    auto target_linear_extent = target_extent->AsLinearExtent();
+    if (!target_linear_extent) return nullptr;
+
+    return Interval::Intersect(target_linear_extent->AsInterval(),
+                               existing_linear_extent->AsInterval())
+            .AsExtent();
+}
+
+// Check that partition |p| contains |e| fully. Both of them should
+// be from |target_metadata|.
+// Returns true as long as |e| is a subrange of any extent of |p|.
+bool PartitionCowCreator::HasExtent(Partition* p, Extent* e) {
+    for (auto& partition_extent : p->extents()) {
+        auto intersection = Intersect(partition_extent.get(), e);
+        if (intersection != nullptr && intersection->num_sectors() == e->num_sectors()) {
+            return true;
+        }
+    }
+    return false;
+}
+
+// Return the number of sectors, N, where |target_partition|[0..N] (from
+// |target_metadata|) are the sectors that should be snapshotted. N is computed
+// so that this range of sectors are used by partitions in |current_metadata|.
+//
+// The client code (update_engine) should have computed target_metadata by
+// resizing partitions of current_metadata, so only the first N sectors should
+// be snapshotted, not a range with start index != 0.
+//
+// Note that if partition A has shrunk and partition B has grown, the new
+// extents of partition B may use the empty space that was used by partition A.
+// In this case, that new extent cannot be written directly, as it may be used
+// by the running system. Hence, all extents of the new partition B must be
+// intersected with all old partitions (including old partition A and B) to get
+// the region that needs to be snapshotted.
+std::optional<uint64_t> PartitionCowCreator::GetSnapshotSize() {
+    // Compute the number of sectors that needs to be snapshotted.
+    uint64_t snapshot_sectors = 0;
+    std::vector<std::unique_ptr<Extent>> intersections;
+    for (const auto& extent : target_partition->extents()) {
+        for (auto* existing_partition :
+             ListPartitionsWithSuffix(current_metadata, current_suffix)) {
+            for (const auto& existing_extent : existing_partition->extents()) {
+                auto intersection = Intersect(extent.get(), existing_extent.get());
+                if (intersection != nullptr && intersection->num_sectors() > 0) {
+                    snapshot_sectors += intersection->num_sectors();
+                    intersections.emplace_back(std::move(intersection));
+                }
+            }
+        }
+    }
+    uint64_t snapshot_size = snapshot_sectors * kSectorSize;
+
+    // Sanity check that all recorded intersections are indeed within
+    // target_partition[0..snapshot_sectors].
+    Partition target_partition_snapshot = target_partition->GetBeginningExtents(snapshot_size);
+    for (const auto& intersection : intersections) {
+        if (!HasExtent(&target_partition_snapshot, intersection.get())) {
+            auto linear_intersection = intersection->AsLinearExtent();
+            LOG(ERROR) << "Extent "
+                       << (linear_intersection
+                                   ? (std::to_string(linear_intersection->physical_sector()) + "," +
+                                      std::to_string(linear_intersection->end_sector()))
+                                   : "")
+                       << " is not part of Partition " << target_partition->name() << "[0.."
+                       << snapshot_size
+                       << "]. The metadata wasn't constructed correctly. This should not happen.";
+            return std::nullopt;
+        }
+    }
+
+    return snapshot_size;
+}
+
+std::optional<uint64_t> PartitionCowCreator::GetCowSize(uint64_t snapshot_size) {
+    // TODO: Use |operations|. to determine a minimum COW size.
+    // kCowEstimateFactor is good for prototyping but we can't use that in production.
+    static constexpr double kCowEstimateFactor = 1.05;
+    auto cow_size = RoundUp(snapshot_size * kCowEstimateFactor, kDefaultBlockSize);
+    return cow_size;
+}
+
+std::optional<PartitionCowCreator::Return> PartitionCowCreator::Run() {
+    CHECK(current_metadata->GetBlockDevicePartitionName(0) == LP_METADATA_DEFAULT_PARTITION_NAME &&
+          target_metadata->GetBlockDevicePartitionName(0) == LP_METADATA_DEFAULT_PARTITION_NAME);
+
+    uint64_t logical_block_size = current_metadata->logical_block_size();
+    CHECK(logical_block_size != 0 && !(logical_block_size & (logical_block_size - 1)))
+            << "logical_block_size is not power of 2";
+
+    Return ret;
+    ret.snapshot_status.device_size = target_partition->size();
+
+    auto snapshot_size = GetSnapshotSize();
+    if (!snapshot_size.has_value()) return std::nullopt;
+
+    ret.snapshot_status.snapshot_size = *snapshot_size;
+
+    auto cow_size = GetCowSize(*snapshot_size);
+    if (!cow_size.has_value()) return std::nullopt;
+
+    // Compute regions that are free in both current and target metadata. These are the regions
+    // we can use for COW partition.
+    auto target_free_regions = target_metadata->GetFreeRegions();
+    auto current_free_regions = current_metadata->GetFreeRegions();
+    auto free_regions = Interval::Intersect(target_free_regions, current_free_regions);
+    uint64_t free_region_length = 0;
+    for (const auto& interval : free_regions) {
+        free_region_length += interval.length() * kSectorSize;
+    }
+
+    LOG(INFO) << "Remaining free space for COW: " << free_region_length << " bytes";
+
+    // Compute the COW partition size.
+    ret.snapshot_status.cow_partition_size = std::min(*cow_size, free_region_length);
+    // Round it down to the nearest logical block. Logical partitions must be a multiple
+    // of logical blocks.
+    ret.snapshot_status.cow_partition_size &= ~(logical_block_size - 1);
+    // Assign cow_partition_usable_regions to indicate what regions should the COW partition uses.
+    ret.cow_partition_usable_regions = std::move(free_regions);
+
+    // The rest of the COW space is allocated on ImageManager.
+    ret.snapshot_status.cow_file_size = (*cow_size) - ret.snapshot_status.cow_partition_size;
+    // Round it up to the nearest sector.
+    ret.snapshot_status.cow_file_size += kSectorSize - 1;
+    ret.snapshot_status.cow_file_size &= ~(kSectorSize - 1);
+
+    return ret;
+}
+
+}  // namespace snapshot
+}  // namespace android
diff --git a/fs_mgr/libsnapshot/partition_cow_creator.h b/fs_mgr/libsnapshot/partition_cow_creator.h
new file mode 100644
index 0000000..7c81418
--- /dev/null
+++ b/fs_mgr/libsnapshot/partition_cow_creator.h
@@ -0,0 +1,67 @@
+// Copyright (C) 2019 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#pragma once
+
+#include <stdint.h>
+
+#include <optional>
+#include <string>
+
+#include <liblp/builder.h>
+
+#include <libsnapshot/snapshot.h>
+
+namespace android {
+namespace snapshot {
+
+// Helper class that creates COW for a partition.
+struct PartitionCowCreator {
+    using Extent = android::fs_mgr::Extent;
+    using Interval = android::fs_mgr::Interval;
+    using MetadataBuilder = android::fs_mgr::MetadataBuilder;
+    using Partition = android::fs_mgr::Partition;
+    using InstallOperation = chromeos_update_engine::InstallOperation;
+    template <typename T>
+    using RepeatedPtrField = google::protobuf::RepeatedPtrField<T>;
+
+    // The metadata that will be written to target metadata slot.
+    MetadataBuilder* target_metadata = nullptr;
+    // The suffix of the target slot.
+    std::string target_suffix;
+    // The partition in target_metadata that needs to be snapshotted.
+    Partition* target_partition = nullptr;
+    // The metadata at the current slot (that would be used if the device boots
+    // normally). This is used to determine which extents are being used.
+    MetadataBuilder* current_metadata = nullptr;
+    // The suffix of the current slot.
+    std::string current_suffix;
+    // List of operations to be applied on the partition.
+    const RepeatedPtrField<InstallOperation>* operations = nullptr;
+
+    struct Return {
+        SnapshotManager::SnapshotStatus snapshot_status;
+        std::vector<Interval> cow_partition_usable_regions;
+    };
+
+    std::optional<Return> Run();
+
+  private:
+    bool HasExtent(Partition* p, Extent* e);
+    std::optional<uint64_t> GetSnapshotSize();
+    std::optional<uint64_t> GetCowSize(uint64_t snapshot_size);
+};
+
+}  // namespace snapshot
+}  // namespace android
diff --git a/fs_mgr/libsnapshot/partition_cow_creator_test.cpp b/fs_mgr/libsnapshot/partition_cow_creator_test.cpp
new file mode 100644
index 0000000..29d15af
--- /dev/null
+++ b/fs_mgr/libsnapshot/partition_cow_creator_test.cpp
@@ -0,0 +1,87 @@
+// Copyright (C) 2018 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <gmock/gmock.h>
+#include <gtest/gtest.h>
+#include <liblp/builder.h>
+#include <liblp/property_fetcher.h>
+
+#include "partition_cow_creator.h"
+
+using ::android::fs_mgr::MetadataBuilder;
+using ::testing::_;
+using ::testing::AnyNumber;
+using ::testing::Return;
+
+namespace android {
+namespace snapshot {
+
+class MockPropertyFetcher : public fs_mgr::IPropertyFetcher {
+  public:
+    MOCK_METHOD2(GetProperty, std::string(const std::string&, const std::string&));
+    MOCK_METHOD2(GetBoolProperty, bool(const std::string&, bool));
+};
+
+class PartitionCowCreatorTest : ::testing::Test {
+  public:
+    void SetUp() override {
+        fs_mgr::IPropertyFetcher::OverrideForTesting(std::make_unique<MockPropertyFetcher>());
+
+        EXPECT_CALL(fetcher(), GetProperty("ro.boot.slot_suffix", _))
+                .Times(AnyNumber())
+                .WillRepeatedly(Return("_a"));
+        EXPECT_CALL(fetcher(), GetBoolProperty("ro.boot.dynamic_partitions", _))
+                .Times(AnyNumber())
+                .WillRepeatedly(Return(true));
+        EXPECT_CALL(fetcher(), GetBoolProperty("ro.boot.dynamic_partitions_retrofit", _))
+                .Times(AnyNumber())
+                .WillRepeatedly(Return(false));
+        EXPECT_CALL(fetcher(), GetBoolProperty("ro.virtual_ab.enabled", _))
+                .Times(AnyNumber())
+                .WillRepeatedly(Return(true));
+    }
+    void TearDown() override {
+        fs_mgr::IPropertyFetcher::OverrideForTesting(std::make_unique<MockPropertyFetcher>());
+    }
+    MockPropertyFetcher& fetcher() {
+        return *static_cast<MockPropertyFetcher*>(fs_mgr::IPropertyFetcher::GetInstance());
+    }
+};
+
+TEST(PartitionCowCreator, IntersectSelf) {
+    auto builder_a = MetadataBuilder::New(1024 * 1024, 1024, 2);
+    ASSERT_NE(builder_a, nullptr);
+    auto system_a = builder_a->AddPartition("system_a", LP_PARTITION_ATTR_READONLY);
+    ASSERT_NE(system_a, nullptr);
+    ASSERT_TRUE(builder_a->ResizePartition(system_a, 40 * 1024));
+
+    auto builder_b = MetadataBuilder::New(1024 * 1024, 1024, 2);
+    ASSERT_NE(builder_b, nullptr);
+    auto system_b = builder_b->AddPartition("system_b", LP_PARTITION_ATTR_READONLY);
+    ASSERT_NE(system_b, nullptr);
+    ASSERT_TRUE(builder_b->ResizePartition(system_b, 40 * 1024));
+
+    PartitionCowCreator creator{.target_metadata = builder_b.get(),
+                                .target_suffix = "_b",
+                                .target_partition = system_b,
+                                .current_metadata = builder_a.get(),
+                                .current_suffix = "_a"};
+    auto ret = creator.Run();
+    ASSERT_TRUE(ret.has_value());
+    ASSERT_EQ(40 * 1024, ret->snapshot_status.device_size);
+    ASSERT_EQ(40 * 1024, ret->snapshot_status.snapshot_size);
+}
+
+}  // namespace snapshot
+}  // namespace android
diff --git a/fs_mgr/libsnapshot/snapshot.cpp b/fs_mgr/libsnapshot/snapshot.cpp
index f00129a..9d0272b 100644
--- a/fs_mgr/libsnapshot/snapshot.cpp
+++ b/fs_mgr/libsnapshot/snapshot.cpp
@@ -15,6 +15,7 @@
 #include <libsnapshot/snapshot.h>
 
 #include <dirent.h>
+#include <math.h>
 #include <sys/file.h>
 #include <sys/types.h>
 #include <sys/unistd.h>
@@ -31,11 +32,14 @@
 #include <ext4_utils/ext4_utils.h>
 #include <fs_mgr.h>
 #include <fs_mgr_dm_linear.h>
+#include <fs_mgr_overlayfs.h>
 #include <fstab/fstab.h>
 #include <libdm/dm.h>
 #include <libfiemap/image_manager.h>
 #include <liblp/liblp.h>
 
+#include "partition_cow_creator.h"
+#include "snapshot_metadata_updater.h"
 #include "utility.h"
 
 namespace android {
@@ -53,9 +57,15 @@
 using android::fs_mgr::CreateDmTable;
 using android::fs_mgr::CreateLogicalPartition;
 using android::fs_mgr::CreateLogicalPartitionParams;
+using android::fs_mgr::GetPartitionGroupName;
 using android::fs_mgr::GetPartitionName;
 using android::fs_mgr::LpMetadata;
+using android::fs_mgr::MetadataBuilder;
 using android::fs_mgr::SlotNumberForSlotSuffix;
+using chromeos_update_engine::DeltaArchiveManifest;
+using chromeos_update_engine::InstallOperation;
+template <typename T>
+using RepeatedPtrField = google::protobuf::RepeatedPtrField<T>;
 using std::chrono::duration_cast;
 using namespace std::chrono_literals;
 using namespace std::string_literals;
@@ -69,10 +79,12 @@
     std::string GetGsidDir() const override { return "ota"s; }
     std::string GetMetadataDir() const override { return "/metadata/ota"s; }
     std::string GetSlotSuffix() const override { return fs_mgr_get_slot_suffix(); }
+    std::string GetOtherSlotSuffix() const override { return fs_mgr_get_other_slot_suffix(); }
     const android::fs_mgr::IPartitionOpener& GetPartitionOpener() const { return opener_; }
     std::string GetSuperDevice(uint32_t slot) const override {
         return fs_mgr_get_super_partition_name(slot);
     }
+    bool IsOverlayfsSetup() const override { return fs_mgr_overlayfs_is_setup(); }
 
   private:
     android::fs_mgr::PartitionOpener opener_;
@@ -102,7 +114,7 @@
     metadata_dir_ = device_->GetMetadataDir();
 }
 
-[[maybe_unused]] static std::string GetCowName(const std::string& snapshot_name) {
+static std::string GetCowName(const std::string& snapshot_name) {
     return snapshot_name + "-cow";
 }
 
@@ -119,6 +131,16 @@
 }
 
 bool SnapshotManager::BeginUpdate() {
+    bool needs_merge = false;
+    if (!TryCancelUpdate(&needs_merge)) {
+        return false;
+    }
+    if (needs_merge) {
+        LOG(INFO) << "Wait for merge (if any) before beginning a new update.";
+        auto state = ProcessUpdateState();
+        LOG(INFO) << "Merged with state = " << state;
+    }
+
     auto file = LockExclusive();
     if (!file) return false;
 
@@ -131,16 +153,45 @@
 }
 
 bool SnapshotManager::CancelUpdate() {
+    bool needs_merge = false;
+    if (!TryCancelUpdate(&needs_merge)) {
+        return false;
+    }
+    if (needs_merge) {
+        LOG(ERROR) << "Cannot cancel update after it has completed or started merging";
+    }
+    return !needs_merge;
+}
+
+bool SnapshotManager::TryCancelUpdate(bool* needs_merge) {
+    *needs_merge = false;
+
     auto file = LockExclusive();
     if (!file) return false;
 
     UpdateState state = ReadUpdateState(file.get());
     if (state == UpdateState::None) return true;
-    if (state != UpdateState::Initiated) {
-        LOG(ERROR) << "Cannot cancel update after it has completed or started merging";
-        return false;
+
+    if (state == UpdateState::Initiated) {
+        LOG(INFO) << "Update has been initiated, now canceling";
+        return RemoveAllUpdateState(file.get());
     }
-    return RemoveAllUpdateState(file.get());
+
+    if (state == UpdateState::Unverified) {
+        // We completed an update, but it can still be canceled if we haven't booted into it.
+        auto boot_file = GetSnapshotBootIndicatorPath();
+        std::string contents;
+        if (!android::base::ReadFileToString(boot_file, &contents)) {
+            PLOG(WARNING) << "Cannot read " << boot_file << ", proceed to canceling the update:";
+            return RemoveAllUpdateState(file.get());
+        }
+        if (device_->GetSlotSuffix() == contents) {
+            LOG(INFO) << "Canceling a previously completed update";
+            return RemoveAllUpdateState(file.get());
+        }
+    }
+    *needs_merge = true;
+    return true;
 }
 
 bool SnapshotManager::RemoveAllUpdateState(LockedFile* lock) {
@@ -189,7 +240,7 @@
     CHECK(lock->lock_mode() == LOCK_EX);
     // Sanity check these sizes. Like liblp, we guarantee the partition size
     // is respected, which means it has to be sector-aligned. (This guarantee
-    // is useful for locating avb footers correctly). The COW size, however,
+    // is useful for locating avb footers correctly). The COW file size, however,
     // can be arbitrarily larger than specified, so we can safely round it up.
     if (status.device_size % kSectorSize != 0) {
         LOG(ERROR) << "Snapshot " << name
@@ -201,10 +252,17 @@
                    << status.snapshot_size;
         return false;
     }
-
-    // Round the COW size up to the nearest sector.
-    status.cow_file_size += kSectorSize - 1;
-    status.cow_file_size &= ~(kSectorSize - 1);
+    if (status.cow_partition_size % kSectorSize != 0) {
+        LOG(ERROR) << "Snapshot " << name
+                   << " cow partition size is not a multiple of the sector size: "
+                   << status.cow_partition_size;
+        return false;
+    }
+    if (status.cow_file_size % kSectorSize != 0) {
+        LOG(ERROR) << "Snapshot " << name << " cow file size is not a multiple of the sector size: "
+                   << status.cow_partition_size;
+        return false;
+    }
 
     status.state = SnapshotState::Created;
     status.sectors_allocated = 0;
@@ -237,26 +295,7 @@
 
     std::string cow_image_name = GetCowImageDeviceName(name);
     int cow_flags = IImageManager::CREATE_IMAGE_DEFAULT;
-    if (!images_->CreateBackingImage(cow_image_name, status.cow_file_size, cow_flags)) {
-        return false;
-    }
-
-    // when the kernel creates a persistent dm-snapshot, it requires a CoW file
-    // to store the modifications. The kernel interface does not specify how
-    // the CoW is used, and there is no standard associated.
-    // By looking at the current implementation, the CoW file is treated as:
-    // - a _NEW_ snapshot if its first 32 bits are zero, so the newly created
-    // dm-snapshot device will look like a perfect copy of the origin device;
-    // - an _EXISTING_ snapshot if the first 32 bits are equal to a
-    // kernel-specified magic number and the CoW file metadata is set as valid,
-    // so it can be used to resume the last state of a snapshot device;
-    // - an _INVALID_ snapshot otherwise.
-    // To avoid zero-filling the whole CoW file when a new dm-snapshot is
-    // created, here we zero-fill only the first 32 bits. This is a temporary
-    // workaround that will be discussed again when the kernel API gets
-    // consolidated.
-    ssize_t dm_snap_magic_size = 4;  // 32 bit
-    return images_->ZeroFillNewImage(cow_image_name, dm_snap_magic_size);
+    return images_->CreateBackingImage(cow_image_name, status.cow_file_size, cow_flags);
 }
 
 bool SnapshotManager::MapSnapshot(LockedFile* lock, const std::string& name,
@@ -346,12 +385,18 @@
     }
 
     if (linear_sectors) {
+        std::string snap_dev;
+        if (!dm.GetDeviceString(snap_name, &snap_dev)) {
+            LOG(ERROR) << "Cannot determine major/minor for: " << snap_name;
+            return false;
+        }
+
         // Our stacking will looks like this:
         //     [linear, linear] ; to snapshot, and non-snapshot region of base device
         //     [snapshot-inner]
         //     [base device]   [cow]
         DmTable table;
-        table.Emplace<DmTargetLinear>(0, snapshot_sectors, *dev_path, 0);
+        table.Emplace<DmTargetLinear>(0, snapshot_sectors, snap_dev, 0);
         table.Emplace<DmTargetLinear>(snapshot_sectors, linear_sectors, base_device,
                                       snapshot_sectors);
         if (!dm.CreateDevice(name, table, dev_path, timeout_ms)) {
@@ -368,21 +413,24 @@
 }
 
 bool SnapshotManager::MapCowImage(const std::string& name,
-                                  const std::chrono::milliseconds& timeout_ms,
-                                  std::string* cow_dev) {
+                                  const std::chrono::milliseconds& timeout_ms) {
     if (!EnsureImageManager()) return false;
     auto cow_image_name = GetCowImageDeviceName(name);
 
     bool ok;
+    std::string cow_dev;
     if (has_local_image_manager_) {
         // If we forced a local image manager, it means we don't have binder,
         // which means first-stage init. We must use device-mapper.
         const auto& opener = device_->GetPartitionOpener();
-        ok = images_->MapImageWithDeviceMapper(opener, cow_image_name, cow_dev);
+        ok = images_->MapImageWithDeviceMapper(opener, cow_image_name, &cow_dev);
     } else {
-        ok = images_->MapImageDevice(cow_image_name, timeout_ms, cow_dev);
+        ok = images_->MapImageDevice(cow_image_name, timeout_ms, &cow_dev);
     }
-    if (!ok) {
+
+    if (ok) {
+        LOG(INFO) << "Mapped " << cow_image_name << " to " << cow_dev;
+    } else {
         LOG(ERROR) << "Could not map image device: " << cow_image_name;
     }
     return ok;
@@ -391,22 +439,15 @@
 bool SnapshotManager::UnmapSnapshot(LockedFile* lock, const std::string& name) {
     CHECK(lock);
 
-    SnapshotStatus status;
-    if (!ReadSnapshotStatus(lock, name, &status)) {
-        return false;
-    }
-
     auto& dm = DeviceMapper::Instance();
     if (!dm.DeleteDeviceIfExists(name)) {
         LOG(ERROR) << "Could not delete snapshot device: " << name;
         return false;
     }
 
-    // There may be an extra device, since the kernel doesn't let us have a
-    // snapshot and linear target in the same table.
-    auto dm_name = GetSnapshotDeviceName(name, status);
-    if (name != dm_name && !dm.DeleteDeviceIfExists(dm_name)) {
-        LOG(ERROR) << "Could not delete inner snapshot device: " << dm_name;
+    auto snapshot_extra_device = GetSnapshotExtraDeviceName(name);
+    if (!dm.DeleteDeviceIfExists(snapshot_extra_device)) {
+        LOG(ERROR) << "Could not delete snapshot inner device: " << snapshot_extra_device;
         return false;
     }
 
@@ -423,11 +464,12 @@
     CHECK(lock->lock_mode() == LOCK_EX);
     if (!EnsureImageManager()) return false;
 
+    if (!UnmapCowDevices(lock, name)) {
+        return false;
+    }
+
     auto cow_image_name = GetCowImageDeviceName(name);
     if (images_->BackingImageExists(cow_image_name)) {
-        if (!images_->UnmapImageIfExists(cow_image_name)) {
-            return false;
-        }
         if (!images_->DeleteBackingImage(cow_image_name)) {
             return false;
         }
@@ -927,8 +969,8 @@
         return false;
     }
 
-    uint64_t num_sectors = status.snapshot_size / kSectorSize;
-    if (num_sectors * kSectorSize != status.snapshot_size) {
+    uint64_t snapshot_sectors = status.snapshot_size / kSectorSize;
+    if (snapshot_sectors * kSectorSize != status.snapshot_size) {
         LOG(ERROR) << "Snapshot " << name
                    << " size is not sector aligned: " << status.snapshot_size;
         return false;
@@ -956,32 +998,30 @@
                 return false;
             }
         }
-        uint64_t sectors = outer_table[0].spec.length + outer_table[1].spec.length;
-        if (sectors != num_sectors) {
-            LOG(ERROR) << "Outer snapshot " << name << " should have " << num_sectors
-                       << ", got: " << sectors;
+        if (outer_table[0].spec.length != snapshot_sectors) {
+            LOG(ERROR) << "dm-snapshot " << name << " should have " << snapshot_sectors
+                       << " sectors, got: " << outer_table[0].spec.length;
+            return false;
+        }
+        uint64_t expected_device_sectors = status.device_size / kSectorSize;
+        uint64_t actual_device_sectors = outer_table[0].spec.length + outer_table[1].spec.length;
+        if (expected_device_sectors != actual_device_sectors) {
+            LOG(ERROR) << "Outer device " << name << " should have " << expected_device_sectors
+                       << " sectors, got: " << actual_device_sectors;
             return false;
         }
     }
 
-    // Grab the partition metadata for the snapshot.
     uint32_t slot = SlotNumberForSlotSuffix(device_->GetSlotSuffix());
-    auto super_device = device_->GetSuperDevice(slot);
-    const auto& opener = device_->GetPartitionOpener();
-    auto metadata = android::fs_mgr::ReadMetadata(opener, super_device, slot);
-    if (!metadata) {
-        LOG(ERROR) << "Could not read super partition metadata.";
-        return false;
-    }
-    auto partition = android::fs_mgr::FindPartition(*metadata.get(), name);
-    if (!partition) {
-        LOG(ERROR) << "Snapshot does not have a partition in super: " << name;
-        return false;
-    }
-
     // Create a DmTable that is identical to the base device.
+    CreateLogicalPartitionParams base_device_params{
+            .block_device = device_->GetSuperDevice(slot),
+            .metadata_slot = slot,
+            .partition_name = name,
+            .partition_opener = &device_->GetPartitionOpener(),
+    };
     DmTable table;
-    if (!CreateDmTable(opener, *metadata.get(), *partition, super_device, &table)) {
+    if (!CreateDmTable(base_device_params, &table)) {
         LOG(ERROR) << "Could not create a DmTable for partition: " << name;
         return false;
     }
@@ -1058,7 +1098,7 @@
 
     bool ok = true;
     for (const auto& name : snapshots) {
-        ok &= DeleteSnapshot(lock, name);
+        ok &= (UnmapPartitionWithSnapshot(lock, name) && DeleteSnapshot(lock, name));
     }
     return ok;
 }
@@ -1160,6 +1200,12 @@
     }
 
     for (const auto& partition : metadata->partitions) {
+        if (GetPartitionGroupName(metadata->groups[partition.group_index]) == kCowGroupName) {
+            LOG(INFO) << "Skip mapping partition " << GetPartitionName(partition) << " in group "
+                      << kCowGroupName;
+            continue;
+        }
+
         CreateLogicalPartitionParams params = {
                 .block_device = super_device,
                 .metadata = metadata.get(),
@@ -1201,6 +1247,12 @@
     CHECK(lock);
     path->clear();
 
+    if (params.GetPartitionName() != params.GetDeviceName()) {
+        LOG(ERROR) << "Mapping snapshot with a different name is unsupported: partition_name = "
+                   << params.GetPartitionName() << ", device_name = " << params.GetDeviceName();
+        return false;
+    }
+
     // Fill out fields in CreateLogicalPartitionParams so that we have more information (e.g. by
     // reading super partition metadata).
     CreateLogicalPartitionParams::OwnedData params_owned_data;
@@ -1276,22 +1328,20 @@
         return false;
     }
 
-    // If there is a timeout specified, compute the remaining time to call Map* functions.
-    // init calls CreateLogicalAndSnapshotPartitions, which has no timeout specified. Still call
-    // Map* functions in this case.
     auto remaining_time = GetRemainingTime(params.timeout_ms, begin);
     if (remaining_time.count() < 0) return false;
 
-    std::string cow_image_device;
-    if (!MapCowImage(params.GetPartitionName(), remaining_time, &cow_image_device)) {
-        LOG(ERROR) << "Could not map cow image for partition: " << params.GetPartitionName();
+    std::string cow_name;
+    CreateLogicalPartitionParams cow_params = params;
+    cow_params.timeout_ms = remaining_time;
+    if (!MapCowDevices(lock, cow_params, *live_snapshot_status, &created_devices, &cow_name)) {
         return false;
     }
-    created_devices.EmplaceBack<AutoUnmapImage>(images_.get(),
-                                                GetCowImageDeviceName(params.partition_name));
-
-    // TODO: map cow linear device here
-    std::string cow_device = cow_image_device;
+    std::string cow_device;
+    if (!dm.GetDeviceString(cow_name, &cow_device)) {
+        LOG(ERROR) << "Could not determine major/minor for: " << cow_name;
+        return false;
+    }
 
     remaining_time = GetRemainingTime(params.timeout_ms, begin);
     if (remaining_time.count() < 0) return false;
@@ -1310,6 +1360,121 @@
     return true;
 }
 
+bool SnapshotManager::UnmapPartitionWithSnapshot(LockedFile* lock,
+                                                 const std::string& target_partition_name) {
+    CHECK(lock);
+
+    if (!UnmapSnapshot(lock, target_partition_name)) {
+        return false;
+    }
+
+    if (!UnmapCowDevices(lock, target_partition_name)) {
+        return false;
+    }
+
+    auto& dm = DeviceMapper::Instance();
+    std::string base_name = GetBaseDeviceName(target_partition_name);
+    if (!dm.DeleteDeviceIfExists(base_name)) {
+        LOG(ERROR) << "Cannot delete base device: " << base_name;
+        return false;
+    }
+
+    LOG(INFO) << "Successfully unmapped snapshot " << target_partition_name;
+
+    return true;
+}
+
+bool SnapshotManager::MapCowDevices(LockedFile* lock, const CreateLogicalPartitionParams& params,
+                                    const SnapshotStatus& snapshot_status,
+                                    AutoDeviceList* created_devices, std::string* cow_name) {
+    CHECK(lock);
+    if (!EnsureImageManager()) return false;
+    CHECK(snapshot_status.cow_partition_size + snapshot_status.cow_file_size > 0);
+    auto begin = std::chrono::steady_clock::now();
+
+    std::string partition_name = params.GetPartitionName();
+    std::string cow_image_name = GetCowImageDeviceName(partition_name);
+    *cow_name = GetCowName(partition_name);
+
+    auto& dm = DeviceMapper::Instance();
+
+    // Map COW image if necessary.
+    if (snapshot_status.cow_file_size > 0) {
+        auto remaining_time = GetRemainingTime(params.timeout_ms, begin);
+        if (remaining_time.count() < 0) return false;
+
+        if (!MapCowImage(partition_name, remaining_time)) {
+            LOG(ERROR) << "Could not map cow image for partition: " << partition_name;
+            return false;
+        }
+        created_devices->EmplaceBack<AutoUnmapImage>(images_.get(), cow_image_name);
+
+        // If no COW partition exists, just return the image alone.
+        if (snapshot_status.cow_partition_size == 0) {
+            *cow_name = std::move(cow_image_name);
+            LOG(INFO) << "Mapped COW image for " << partition_name << " at " << *cow_name;
+            return true;
+        }
+    }
+
+    auto remaining_time = GetRemainingTime(params.timeout_ms, begin);
+    if (remaining_time.count() < 0) return false;
+
+    CHECK(snapshot_status.cow_partition_size > 0);
+
+    // Create the DmTable for the COW device. It is the DmTable of the COW partition plus
+    // COW image device as the last extent.
+    CreateLogicalPartitionParams cow_partition_params = params;
+    cow_partition_params.partition = nullptr;
+    cow_partition_params.partition_name = *cow_name;
+    cow_partition_params.device_name.clear();
+    DmTable table;
+    if (!CreateDmTable(cow_partition_params, &table)) {
+        return false;
+    }
+    // If the COW image exists, append it as the last extent.
+    if (snapshot_status.cow_file_size > 0) {
+        std::string cow_image_device;
+        if (!dm.GetDeviceString(cow_image_name, &cow_image_device)) {
+            LOG(ERROR) << "Cannot determine major/minor for: " << cow_image_name;
+            return false;
+        }
+        auto cow_partition_sectors = snapshot_status.cow_partition_size / kSectorSize;
+        auto cow_image_sectors = snapshot_status.cow_file_size / kSectorSize;
+        table.Emplace<DmTargetLinear>(cow_partition_sectors, cow_image_sectors, cow_image_device,
+                                      0);
+    }
+
+    // We have created the DmTable now. Map it.
+    std::string cow_path;
+    if (!dm.CreateDevice(*cow_name, table, &cow_path, remaining_time)) {
+        LOG(ERROR) << "Could not create COW device: " << *cow_name;
+        return false;
+    }
+    created_devices->EmplaceBack<AutoUnmapDevice>(&dm, *cow_name);
+    LOG(INFO) << "Mapped COW device for " << params.GetPartitionName() << " at " << cow_path;
+    return true;
+}
+
+bool SnapshotManager::UnmapCowDevices(LockedFile* lock, const std::string& name) {
+    CHECK(lock);
+    if (!EnsureImageManager()) return false;
+
+    auto& dm = DeviceMapper::Instance();
+    auto cow_name = GetCowName(name);
+    if (!dm.DeleteDeviceIfExists(cow_name)) {
+        LOG(ERROR) << "Cannot unmap " << cow_name;
+        return false;
+    }
+
+    std::string cow_image_name = GetCowImageDeviceName(name);
+    if (!images_->UnmapImageIfExists(cow_image_name)) {
+        LOG(ERROR) << "Cannot unmap image " << cow_image_name;
+        return false;
+    }
+    return true;
+}
+
 auto SnapshotManager::OpenFile(const std::string& file, int open_flags, int lock_flags)
         -> std::unique_ptr<LockedFile> {
     unique_fd fd(open(file.c_str(), open_flags | O_CLOEXEC | O_NOFOLLOW | O_SYNC, 0660));
@@ -1317,7 +1482,7 @@
         PLOG(ERROR) << "Open failed: " << file;
         return nullptr;
     }
-    if (flock(fd, lock_flags) < 0) {
+    if (lock_flags != 0 && flock(fd, lock_flags) < 0) {
         PLOG(ERROR) << "Acquire flock failed: " << file;
         return nullptr;
     }
@@ -1384,34 +1549,33 @@
     }
 }
 
-bool SnapshotManager::WriteUpdateState(LockedFile* file, UpdateState state) {
-    std::string contents;
+std::ostream& operator<<(std::ostream& os, UpdateState state) {
     switch (state) {
         case UpdateState::None:
-            contents = "none";
-            break;
+            return os << "none";
         case UpdateState::Initiated:
-            contents = "initiated";
-            break;
+            return os << "initiated";
         case UpdateState::Unverified:
-            contents = "unverified";
-            break;
+            return os << "unverified";
         case UpdateState::Merging:
-            contents = "merging";
-            break;
+            return os << "merging";
         case UpdateState::MergeCompleted:
-            contents = "merge-completed";
-            break;
+            return os << "merge-completed";
         case UpdateState::MergeNeedsReboot:
-            contents = "merge-needs-reboot";
-            break;
+            return os << "merge-needs-reboot";
         case UpdateState::MergeFailed:
-            contents = "merge-failed";
-            break;
+            return os << "merge-failed";
         default:
             LOG(ERROR) << "Unknown update state";
-            return false;
+            return os;
     }
+}
+
+bool SnapshotManager::WriteUpdateState(LockedFile* file, UpdateState state) {
+    std::stringstream ss;
+    ss << state;
+    std::string contents = ss.str();
+    if (contents.empty()) return false;
 
     if (!Truncate(file)) return false;
     if (!android::base::WriteStringToFd(contents, file->fd())) {
@@ -1577,5 +1741,268 @@
     return true;
 }
 
+bool SnapshotManager::CreateUpdateSnapshots(const DeltaArchiveManifest& manifest) {
+    auto lock = LockExclusive();
+    if (!lock) return false;
+
+    const auto& opener = device_->GetPartitionOpener();
+    auto current_suffix = device_->GetSlotSuffix();
+    uint32_t current_slot = SlotNumberForSlotSuffix(current_suffix);
+    auto target_suffix = device_->GetOtherSlotSuffix();
+    uint32_t target_slot = SlotNumberForSlotSuffix(target_suffix);
+    auto current_super = device_->GetSuperDevice(current_slot);
+
+    auto current_metadata = MetadataBuilder::New(opener, current_super, current_slot);
+    auto target_metadata =
+            MetadataBuilder::NewForUpdate(opener, current_super, current_slot, target_slot);
+
+    SnapshotMetadataUpdater metadata_updater(target_metadata.get(), target_slot, manifest);
+    if (!metadata_updater.Update()) {
+        LOG(ERROR) << "Cannot calculate new metadata.";
+        return false;
+    }
+
+    if (!target_metadata->AddGroup(kCowGroupName, 0)) {
+        LOG(ERROR) << "Cannot add group " << kCowGroupName;
+        return false;
+    }
+
+    std::map<std::string, const RepeatedPtrField<InstallOperation>*> install_operation_map;
+    for (const auto& partition_update : manifest.partitions()) {
+        auto suffixed_name = partition_update.partition_name() + target_suffix;
+        auto&& [it, inserted] = install_operation_map.emplace(std::move(suffixed_name),
+                                                              &partition_update.operations());
+        if (!inserted) {
+            LOG(ERROR) << "Duplicated partition " << partition_update.partition_name()
+                       << " in update manifest.";
+            return false;
+        }
+    }
+
+    // TODO(b/134949511): remove this check. Right now, with overlayfs mounted, the scratch
+    // partition takes up a big chunk of space in super, causing COW images to be created on
+    // retrofit Virtual A/B devices.
+    if (device_->IsOverlayfsSetup()) {
+        LOG(ERROR) << "Cannot create update snapshots with overlayfs setup. Run `adb enable-verity`"
+                   << ", reboot, then try again.";
+        return false;
+    }
+
+    // Check that all these metadata is not retrofit dynamic partitions. Snapshots on
+    // devices with retrofit dynamic partitions does not make sense.
+    // This ensures that current_metadata->GetFreeRegions() uses the same device
+    // indices as target_metadata (i.e. 0 -> "super").
+    // This is also assumed in MapCowDevices() call below.
+    CHECK(current_metadata->GetBlockDevicePartitionName(0) == LP_METADATA_DEFAULT_PARTITION_NAME &&
+          target_metadata->GetBlockDevicePartitionName(0) == LP_METADATA_DEFAULT_PARTITION_NAME);
+
+    std::map<std::string, SnapshotStatus> all_snapshot_status;
+
+    // In case of error, automatically delete devices that are created along the way.
+    // Note that "lock" is destroyed after "created_devices", so it is safe to use |lock| for
+    // these devices.
+    AutoDeviceList created_devices;
+
+    for (auto* target_partition : ListPartitionsWithSuffix(target_metadata.get(), target_suffix)) {
+        const RepeatedPtrField<InstallOperation>* operations = nullptr;
+        auto operations_it = install_operation_map.find(target_partition->name());
+        if (operations_it != install_operation_map.end()) {
+            operations = operations_it->second;
+        }
+
+        // Compute the device sizes for the partition.
+        PartitionCowCreator cow_creator{target_metadata.get(),  target_suffix,  target_partition,
+                                        current_metadata.get(), current_suffix, operations};
+        auto cow_creator_ret = cow_creator.Run();
+        if (!cow_creator_ret.has_value()) {
+            return false;
+        }
+
+        LOG(INFO) << "For partition " << target_partition->name()
+                  << ", device size = " << cow_creator_ret->snapshot_status.device_size
+                  << ", snapshot size = " << cow_creator_ret->snapshot_status.snapshot_size
+                  << ", cow partition size = "
+                  << cow_creator_ret->snapshot_status.cow_partition_size
+                  << ", cow file size = " << cow_creator_ret->snapshot_status.cow_file_size;
+
+        // Delete any existing snapshot before re-creating one.
+        if (!DeleteSnapshot(lock.get(), target_partition->name())) {
+            LOG(ERROR) << "Cannot delete existing snapshot before creating a new one for partition "
+                       << target_partition->name();
+            return false;
+        }
+
+        // It is possible that the whole partition uses free space in super, and snapshot / COW
+        // would not be needed. In this case, skip the partition.
+        bool needs_snapshot = cow_creator_ret->snapshot_status.snapshot_size > 0;
+        bool needs_cow = (cow_creator_ret->snapshot_status.cow_partition_size +
+                          cow_creator_ret->snapshot_status.cow_file_size) > 0;
+        CHECK(needs_snapshot == needs_cow);
+
+        if (!needs_snapshot) {
+            LOG(INFO) << "Skip creating snapshot for partition " << target_partition->name()
+                      << "because nothing needs to be snapshotted.";
+            continue;
+        }
+
+        // Store these device sizes to snapshot status file.
+        if (!CreateSnapshot(lock.get(), target_partition->name(),
+                            cow_creator_ret->snapshot_status)) {
+            return false;
+        }
+        created_devices.EmplaceBack<AutoDeleteSnapshot>(this, lock.get(), target_partition->name());
+
+        // Create the COW partition. That is, use any remaining free space in super partition before
+        // creating the COW images.
+        if (cow_creator_ret->snapshot_status.cow_partition_size > 0) {
+            CHECK(cow_creator_ret->snapshot_status.cow_partition_size % kSectorSize == 0)
+                    << "cow_partition_size == "
+                    << cow_creator_ret->snapshot_status.cow_partition_size
+                    << " is not a multiple of sector size " << kSectorSize;
+            auto cow_partition = target_metadata->AddPartition(GetCowName(target_partition->name()),
+                                                               kCowGroupName, 0 /* flags */);
+            if (cow_partition == nullptr) {
+                return false;
+            }
+
+            if (!target_metadata->ResizePartition(
+                        cow_partition, cow_creator_ret->snapshot_status.cow_partition_size,
+                        cow_creator_ret->cow_partition_usable_regions)) {
+                LOG(ERROR) << "Cannot create COW partition on metadata with size "
+                           << cow_creator_ret->snapshot_status.cow_partition_size;
+                return false;
+            }
+            // Only the in-memory target_metadata is modified; nothing to clean up if there is an
+            // error in the future.
+        }
+
+        // Create the backing COW image if necessary.
+        if (cow_creator_ret->snapshot_status.cow_file_size > 0) {
+            if (!CreateCowImage(lock.get(), target_partition->name())) {
+                return false;
+            }
+        }
+
+        all_snapshot_status[target_partition->name()] = std::move(cow_creator_ret->snapshot_status);
+
+        LOG(INFO) << "Successfully created snapshot for " << target_partition->name();
+    }
+
+    auto& dm = DeviceMapper::Instance();
+    auto exported_target_metadata = target_metadata->Export();
+    if (exported_target_metadata == nullptr) {
+        LOG(ERROR) << "Cannot export target metadata";
+        return false;
+    }
+    CreateLogicalPartitionParams cow_params{
+            .block_device = LP_METADATA_DEFAULT_PARTITION_NAME,
+            .metadata = exported_target_metadata.get(),
+            .timeout_ms = std::chrono::milliseconds::max(),
+            .partition_opener = &device_->GetPartitionOpener(),
+    };
+    for (auto* target_partition : ListPartitionsWithSuffix(target_metadata.get(), target_suffix)) {
+        AutoDeviceList created_devices_for_cow;
+
+        if (!UnmapPartitionWithSnapshot(lock.get(), target_partition->name())) {
+            LOG(ERROR) << "Cannot unmap existing COW devices before re-mapping them for zero-fill: "
+                       << target_partition->name();
+            return false;
+        }
+
+        auto it = all_snapshot_status.find(target_partition->name());
+        CHECK(it != all_snapshot_status.end()) << target_partition->name();
+        cow_params.partition_name = target_partition->name();
+        std::string cow_name;
+        if (!MapCowDevices(lock.get(), cow_params, it->second, &created_devices_for_cow,
+                           &cow_name)) {
+            return false;
+        }
+
+        std::string cow_path;
+        if (!dm.GetDmDevicePathByName(cow_name, &cow_path)) {
+            LOG(ERROR) << "Cannot determine path for " << cow_name;
+            return false;
+        }
+
+        if (!InitializeCow(cow_path)) {
+            LOG(ERROR) << "Can't zero-fill COW device for " << target_partition->name() << ": "
+                       << cow_path;
+            return false;
+        }
+        // Let destructor of created_devices_for_cow to unmap the COW devices.
+    };
+
+    if (!UpdatePartitionTable(opener, device_->GetSuperDevice(target_slot),
+                              *exported_target_metadata, target_slot)) {
+        LOG(ERROR) << "Cannot write target metadata";
+        return false;
+    }
+
+    created_devices.Release();
+    LOG(INFO) << "Successfully created all snapshots for target slot " << target_suffix;
+
+    return true;
+}
+
+bool SnapshotManager::MapUpdateSnapshot(const CreateLogicalPartitionParams& params,
+                                        std::string* snapshot_path) {
+    auto lock = LockShared();
+    if (!lock) return false;
+    if (!UnmapPartitionWithSnapshot(lock.get(), params.GetPartitionName())) {
+        LOG(ERROR) << "Cannot unmap existing snapshot before re-mapping it: "
+                   << params.GetPartitionName();
+        return false;
+    }
+    return MapPartitionWithSnapshot(lock.get(), params, snapshot_path);
+}
+
+bool SnapshotManager::UnmapUpdateSnapshot(const std::string& target_partition_name) {
+    auto lock = LockShared();
+    if (!lock) return false;
+    return UnmapPartitionWithSnapshot(lock.get(), target_partition_name);
+}
+
+bool SnapshotManager::Dump(std::ostream& os) {
+    // Don't actually lock. Dump() is for debugging purposes only, so it is okay
+    // if it is racy.
+    auto file = OpenStateFile(O_RDONLY, 0);
+    if (!file) return false;
+
+    std::stringstream ss;
+
+    ss << "Update state: " << ReadUpdateState(file.get()) << std::endl;
+
+    auto boot_file = GetSnapshotBootIndicatorPath();
+    std::string boot_indicator;
+    if (android::base::ReadFileToString(boot_file, &boot_indicator)) {
+        ss << "Boot indicator: old slot = " << boot_indicator << std::endl;
+    }
+
+    bool ok = true;
+    std::vector<std::string> snapshots;
+    if (!ListSnapshots(file.get(), &snapshots)) {
+        LOG(ERROR) << "Could not list snapshots";
+        snapshots.clear();
+        ok = false;
+    }
+    for (const auto& name : snapshots) {
+        ss << "Snapshot: " << name << std::endl;
+        SnapshotStatus status;
+        if (!ReadSnapshotStatus(file.get(), name, &status)) {
+            ok = false;
+            continue;
+        }
+        ss << "    state: " << to_string(status.state) << std::endl;
+        ss << "    device size (bytes): " << status.device_size << std::endl;
+        ss << "    snapshot size (bytes): " << status.snapshot_size << std::endl;
+        ss << "    cow partition size (bytes): " << status.cow_partition_size << std::endl;
+        ss << "    cow file size (bytes): " << status.cow_file_size << std::endl;
+        ss << "    allocated sectors: " << status.sectors_allocated << std::endl;
+        ss << "    metadata sectors: " << status.metadata_sectors << std::endl;
+    }
+    os << ss.rdbuf();
+    return ok;
+}
+
 }  // namespace snapshot
 }  // namespace android
diff --git a/fs_mgr/libsnapshot/snapshot_metadata_updater.cpp b/fs_mgr/libsnapshot/snapshot_metadata_updater.cpp
new file mode 100644
index 0000000..60bf796
--- /dev/null
+++ b/fs_mgr/libsnapshot/snapshot_metadata_updater.cpp
@@ -0,0 +1,273 @@
+//
+// Copyright (C) 2019 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+#include "snapshot_metadata_updater.h"
+
+#include <algorithm>
+#include <map>
+#include <optional>
+#include <set>
+#include <string>
+#include <string_view>
+#include <vector>
+
+#include <android-base/logging.h>
+#include <android-base/strings.h>
+#include <fs_mgr.h>
+#include <libsnapshot/snapshot.h>
+
+using android::fs_mgr::MetadataBuilder;
+using android::fs_mgr::Partition;
+using android::fs_mgr::SlotSuffixForSlotNumber;
+using chromeos_update_engine::DeltaArchiveManifest;
+
+namespace android {
+namespace snapshot {
+SnapshotMetadataUpdater::SnapshotMetadataUpdater(MetadataBuilder* builder, uint32_t target_slot,
+                                                 const DeltaArchiveManifest& manifest)
+    : builder_(builder), target_suffix_(SlotSuffixForSlotNumber(target_slot)) {
+    if (!manifest.has_dynamic_partition_metadata()) {
+        return;
+    }
+
+    // Key: partition name ("system"). Value: group name ("group").
+    // No suffix.
+    std::map<std::string_view, std::string_view> partition_group_map;
+    const auto& metadata_groups = manifest.dynamic_partition_metadata().groups();
+    groups_.reserve(metadata_groups.size());
+    for (const auto& group : metadata_groups) {
+        groups_.emplace_back(Group{group.name() + target_suffix_, &group});
+        for (const auto& partition_name : group.partition_names()) {
+            partition_group_map[partition_name] = group.name();
+        }
+    }
+
+    for (const auto& p : manifest.partitions()) {
+        auto it = partition_group_map.find(p.partition_name());
+        if (it != partition_group_map.end()) {
+            partitions_.emplace_back(Partition{p.partition_name() + target_suffix_,
+                                               std::string(it->second) + target_suffix_, &p});
+        }
+    }
+}
+
+bool SnapshotMetadataUpdater::ShrinkPartitions() const {
+    for (const auto& partition_update : partitions_) {
+        auto* existing_partition = builder_->FindPartition(partition_update.name);
+        if (existing_partition == nullptr) {
+            continue;
+        }
+        auto new_size = partition_update->new_partition_info().size();
+        if (existing_partition->size() <= new_size) {
+            continue;
+        }
+        if (!builder_->ResizePartition(existing_partition, new_size)) {
+            return false;
+        }
+    }
+    return true;
+}
+
+bool SnapshotMetadataUpdater::DeletePartitions() const {
+    std::vector<std::string> partitions_to_delete;
+    // Don't delete partitions in groups where the group name doesn't have target_suffix,
+    // e.g. default.
+    for (auto* existing_partition : ListPartitionsWithSuffix(builder_, target_suffix_)) {
+        auto iter = std::find_if(partitions_.begin(), partitions_.end(),
+                                 [existing_partition](auto&& partition_update) {
+                                     return partition_update.name == existing_partition->name();
+                                 });
+        // Update package metadata doesn't have this partition. Prepare to delete it.
+        // Not deleting from builder_ yet because it may break ListPartitionsWithSuffix if it were
+        // to return an iterable view of builder_.
+        if (iter == partitions_.end()) {
+            partitions_to_delete.push_back(existing_partition->name());
+        }
+    }
+
+    for (const auto& partition_name : partitions_to_delete) {
+        builder_->RemovePartition(partition_name);
+    }
+    return true;
+}
+
+bool SnapshotMetadataUpdater::MovePartitionsToDefault() const {
+    for (const auto& partition_update : partitions_) {
+        auto* existing_partition = builder_->FindPartition(partition_update.name);
+        if (existing_partition == nullptr) {
+            continue;
+        }
+        if (existing_partition->group_name() == partition_update.group_name) {
+            continue;
+        }
+        // Move to "default" group (which doesn't have maximum size constraint)
+        // temporarily.
+        if (!builder_->ChangePartitionGroup(existing_partition, android::fs_mgr::kDefaultGroup)) {
+            return false;
+        }
+    }
+    return true;
+}
+
+bool SnapshotMetadataUpdater::ShrinkGroups() const {
+    for (const auto& group_update : groups_) {
+        auto* existing_group = builder_->FindGroup(group_update.name);
+        if (existing_group == nullptr) {
+            continue;
+        }
+        if (existing_group->maximum_size() <= group_update->size()) {
+            continue;
+        }
+        if (!builder_->ChangeGroupSize(existing_group->name(), group_update->size())) {
+            return false;
+        }
+    }
+    return true;
+}
+
+bool SnapshotMetadataUpdater::DeleteGroups() const {
+    std::vector<std::string> existing_groups = builder_->ListGroups();
+    for (const auto& existing_group_name : existing_groups) {
+        // Don't delete groups without target suffix, e.g. default.
+        if (!android::base::EndsWith(existing_group_name, target_suffix_)) {
+            continue;
+        }
+
+        auto iter = std::find_if(groups_.begin(), groups_.end(),
+                                 [&existing_group_name](auto&& group_update) {
+                                     return group_update.name == existing_group_name;
+                                 });
+        // Update package metadata has this group as well, so not deleting it.
+        if (iter != groups_.end()) {
+            continue;
+        }
+        // Update package metadata doesn't have this group. Before deleting it, sanity check that it
+        // doesn't have any partitions left. Update metadata shouldn't assign any partitions to this
+        // group, so all partitions that originally belong to this group should be moved by
+        // MovePartitionsToDefault at this point.
+        auto existing_partitions_in_group = builder_->ListPartitionsInGroup(existing_group_name);
+        if (!existing_partitions_in_group.empty()) {
+            std::vector<std::string> partition_names_in_group;
+            std::transform(existing_partitions_in_group.begin(), existing_partitions_in_group.end(),
+                           std::back_inserter(partition_names_in_group),
+                           [](auto* p) { return p->name(); });
+            LOG(ERROR)
+                    << "Group " << existing_group_name
+                    << " cannot be deleted because the following partitions are left unassigned: ["
+                    << android::base::Join(partition_names_in_group, ",") << "]";
+            return false;
+        }
+        builder_->RemoveGroupAndPartitions(existing_group_name);
+    }
+    return true;
+}
+
+bool SnapshotMetadataUpdater::AddGroups() const {
+    for (const auto& group_update : groups_) {
+        if (builder_->FindGroup(group_update.name) == nullptr) {
+            if (!builder_->AddGroup(group_update.name, group_update->size())) {
+                return false;
+            }
+        }
+    }
+    return true;
+}
+
+bool SnapshotMetadataUpdater::GrowGroups() const {
+    for (const auto& group_update : groups_) {
+        auto* existing_group = builder_->FindGroup(group_update.name);
+        if (existing_group == nullptr) {
+            continue;
+        }
+        if (existing_group->maximum_size() >= group_update->size()) {
+            continue;
+        }
+        if (!builder_->ChangeGroupSize(existing_group->name(), group_update->size())) {
+            return false;
+        }
+    }
+    return true;
+}
+
+bool SnapshotMetadataUpdater::AddPartitions() const {
+    for (const auto& partition_update : partitions_) {
+        if (builder_->FindPartition(partition_update.name) == nullptr) {
+            auto* p =
+                    builder_->AddPartition(partition_update.name, partition_update.group_name,
+                                           LP_PARTITION_ATTR_READONLY | LP_PARTITION_ATTR_UPDATED);
+            if (p == nullptr) {
+                return false;
+            }
+        }
+    }
+    // Will be resized in GrowPartitions.
+    return true;
+}
+
+bool SnapshotMetadataUpdater::GrowPartitions() const {
+    for (const auto& partition_update : partitions_) {
+        auto* existing_partition = builder_->FindPartition(partition_update.name);
+        if (existing_partition == nullptr) {
+            continue;
+        }
+        auto new_size = partition_update->new_partition_info().size();
+        if (existing_partition->size() >= new_size) {
+            continue;
+        }
+        if (!builder_->ResizePartition(existing_partition, new_size)) {
+            return false;
+        }
+    }
+    return true;
+}
+
+bool SnapshotMetadataUpdater::MovePartitionsToCorrectGroup() const {
+    for (const auto& partition_update : partitions_) {
+        auto* existing_partition = builder_->FindPartition(partition_update.name);
+        if (existing_partition == nullptr) {
+            continue;
+        }
+        if (existing_partition->group_name() == partition_update.group_name) {
+            continue;
+        }
+        if (!builder_->ChangePartitionGroup(existing_partition, partition_update.group_name)) {
+            return false;
+        }
+    }
+    return true;
+}
+
+bool SnapshotMetadataUpdater::Update() const {
+    // Remove extents used by COW devices by removing the COW group completely.
+    builder_->RemoveGroupAndPartitions(android::snapshot::kCowGroupName);
+
+    // The order of these operations are important so that we
+    // always have enough space to grow or add new partitions / groups.
+    // clang-format off
+    return ShrinkPartitions() &&
+           DeletePartitions() &&
+           MovePartitionsToDefault() &&
+           ShrinkGroups() &&
+           DeleteGroups() &&
+           AddGroups() &&
+           GrowGroups() &&
+           AddPartitions() &&
+           GrowPartitions() &&
+           MovePartitionsToCorrectGroup();
+    // clang-format on
+}
+}  // namespace snapshot
+}  // namespace android
diff --git a/fs_mgr/libsnapshot/snapshot_metadata_updater.h b/fs_mgr/libsnapshot/snapshot_metadata_updater.h
new file mode 100644
index 0000000..83c9460
--- /dev/null
+++ b/fs_mgr/libsnapshot/snapshot_metadata_updater.h
@@ -0,0 +1,85 @@
+//
+// Copyright (C) 2019 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+#pragma once
+
+#include <stdint.h>
+
+#include <string>
+#include <vector>
+
+#include <liblp/builder.h>
+#include <update_engine/update_metadata.pb.h>
+
+#include "utility.h"
+
+namespace android {
+namespace snapshot {
+
+// Helper class that modifies a super partition metadata for an update for
+// Virtual A/B devices.
+class SnapshotMetadataUpdater {
+    using DeltaArchiveManifest = chromeos_update_engine::DeltaArchiveManifest;
+    using DynamicPartitionMetadata = chromeos_update_engine::DynamicPartitionMetadata;
+    using DynamicPartitionGroup = chromeos_update_engine::DynamicPartitionGroup;
+    using PartitionUpdate = chromeos_update_engine::PartitionUpdate;
+
+  public:
+    // Caller is responsible for ensuring the lifetime of manifest to be longer
+    // than SnapshotMetadataUpdater.
+    SnapshotMetadataUpdater(android::fs_mgr::MetadataBuilder* builder, uint32_t target_slot,
+                            const DeltaArchiveManifest& manifest);
+    bool Update() const;
+
+  private:
+    bool RenameGroupSuffix() const;
+    bool ShrinkPartitions() const;
+    bool DeletePartitions() const;
+    bool MovePartitionsToDefault() const;
+    bool ShrinkGroups() const;
+    bool DeleteGroups() const;
+    bool AddGroups() const;
+    bool GrowGroups() const;
+    bool AddPartitions() const;
+    bool GrowPartitions() const;
+    bool MovePartitionsToCorrectGroup() const;
+
+    // Wraps a DynamicPartitionGroup with a slot-suffixed name. Always use
+    // .name instead of ->name() because .name has the slot suffix (e.g.
+    // .name is "group_b" and ->name() is "group".)
+    struct Group {
+        std::string name;
+        const DynamicPartitionGroup* group;
+        const DynamicPartitionGroup* operator->() const { return group; }
+    };
+    // Wraps a PartitionUpdate with a slot-suffixed name / group name. Always use
+    // .name instead of ->partition_name() because .name has the slot suffix (e.g.
+    // .name is "system_b" and ->partition_name() is "system".)
+    struct Partition {
+        std::string name;
+        std::string group_name;
+        const PartitionUpdate* partition;
+        const PartitionUpdate* operator->() const { return partition; }
+    };
+
+    android::fs_mgr::MetadataBuilder* const builder_;
+    const std::string target_suffix_;
+    std::vector<Group> groups_;
+    std::vector<Partition> partitions_;
+};
+
+}  // namespace snapshot
+}  // namespace android
diff --git a/fs_mgr/libsnapshot/snapshot_metadata_updater_test.cpp b/fs_mgr/libsnapshot/snapshot_metadata_updater_test.cpp
new file mode 100644
index 0000000..535653a
--- /dev/null
+++ b/fs_mgr/libsnapshot/snapshot_metadata_updater_test.cpp
@@ -0,0 +1,328 @@
+//
+// Copyright (C) 2019 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+#include "snapshot_metadata_updater.h"
+
+#include <memory>
+#include <string>
+
+#include <gmock/gmock.h>
+#include <gtest/gtest.h>
+#include <liblp/builder.h>
+#include <storage_literals/storage_literals.h>
+
+#include "test_helpers.h"
+
+using namespace android::storage_literals;
+using android::fs_mgr::LpMetadata;
+using android::fs_mgr::MetadataBuilder;
+using android::fs_mgr::SlotSuffixForSlotNumber;
+using chromeos_update_engine::DeltaArchiveManifest;
+using chromeos_update_engine::DynamicPartitionGroup;
+using chromeos_update_engine::PartitionUpdate;
+using testing::AssertionFailure;
+using testing::AssertionResult;
+using testing::AssertionSuccess;
+
+namespace android {
+namespace snapshot {
+
+class SnapshotMetadataUpdaterTest : public ::testing::TestWithParam<uint32_t> {
+  public:
+    void SetUp() override {
+        target_slot_ = GetParam();
+        target_suffix_ = SlotSuffixForSlotNumber(target_slot_);
+        builder_ = MetadataBuilder::New(4_GiB + 1_MiB, 4_KiB, 2);
+
+        group_ = manifest_.mutable_dynamic_partition_metadata()->add_groups();
+        group_->set_name("group");
+        group_->set_size(4_GiB);
+        group_->add_partition_names("system");
+        group_->add_partition_names("vendor");
+        system_ = manifest_.add_partitions();
+        system_->set_partition_name("system");
+        SetSize(system_, 2_GiB);
+        vendor_ = manifest_.add_partitions();
+        vendor_->set_partition_name("vendor");
+        SetSize(vendor_, 1_GiB);
+
+        ASSERT_TRUE(FillFakeMetadata(builder_.get(), manifest_, target_suffix_));
+    }
+
+    // Append suffix to name.
+    std::string T(std::string_view name) { return std::string(name) + target_suffix_; }
+
+    AssertionResult UpdateAndExport() {
+        SnapshotMetadataUpdater updater(builder_.get(), target_slot_, manifest_);
+        if (!updater.Update()) {
+            return AssertionFailure() << "Update failed.";
+        }
+
+        exported_ = builder_->Export();
+        if (exported_ == nullptr) {
+            return AssertionFailure() << "Export failed.";
+        }
+        return AssertionSuccess();
+    }
+
+    // Check that in |builder_|, partition |name| + |target_suffix_| has the given |size|.
+    AssertionResult CheckSize(std::string_view name, uint64_t size) {
+        auto p = builder_->FindPartition(T(name));
+        if (p == nullptr) {
+            return AssertionFailure() << "Cannot find partition " << T(name);
+        }
+        if (p->size() != size) {
+            return AssertionFailure() << "Partition " << T(name) << " should be " << size
+                                      << " bytes, but is " << p->size() << " bytes.";
+        }
+        return AssertionSuccess() << "Partition" << T(name) << " is " << size << " bytes.";
+    }
+
+    // Check that in |builder_|, group |name| + |target_suffix_| has the given |size|.
+    AssertionResult CheckGroupSize(std::string_view name, uint64_t size) {
+        auto g = builder_->FindGroup(T(name));
+        if (g == nullptr) {
+            return AssertionFailure() << "Cannot find group " << T(name);
+        }
+        if (g->maximum_size() != size) {
+            return AssertionFailure() << "Group " << T(name) << " should be " << size
+                                      << " bytes, but is " << g->maximum_size() << " bytes.";
+        }
+        return AssertionSuccess() << "Group" << T(name) << " is " << size << " bytes.";
+    }
+
+    // Check that in |builder_|, partition |partition_name| + |target_suffix_| is in group
+    // |group_name| + |target_suffix_|;
+    AssertionResult CheckGroupName(std::string_view partition_name, std::string_view group_name) {
+        auto p = builder_->FindPartition(T(partition_name));
+        if (p == nullptr) {
+            return AssertionFailure() << "Cannot find partition " << T(partition_name);
+        }
+        if (p->group_name() != T(group_name)) {
+            return AssertionFailure() << "Partition " << T(partition_name) << " should be in "
+                                      << T(group_name) << ", but is in " << p->group_name() << ".";
+        }
+        return AssertionSuccess() << "Partition" << T(partition_name) << " is in " << T(group_name)
+                                  << ".";
+    }
+
+    std::unique_ptr<MetadataBuilder> builder_;
+    uint32_t target_slot_;
+    std::string target_suffix_;
+    DeltaArchiveManifest manifest_;
+    std::unique_ptr<LpMetadata> exported_;
+    DynamicPartitionGroup* group_ = nullptr;
+    PartitionUpdate* system_ = nullptr;
+    PartitionUpdate* vendor_ = nullptr;
+};
+
+TEST_P(SnapshotMetadataUpdaterTest, NoChange) {
+    EXPECT_TRUE(UpdateAndExport());
+
+    EXPECT_TRUE(CheckGroupSize("group", 4_GiB));
+    EXPECT_TRUE(CheckSize("system", 2_GiB));
+    EXPECT_TRUE(CheckGroupName("system", "group"));
+    EXPECT_TRUE(CheckSize("vendor", 1_GiB));
+    EXPECT_TRUE(CheckGroupName("vendor", "group"));
+}
+
+TEST_P(SnapshotMetadataUpdaterTest, GrowWithinBounds) {
+    SetSize(system_, 2_GiB + 512_MiB);
+    SetSize(vendor_, 1_GiB + 512_MiB);
+
+    ASSERT_TRUE(UpdateAndExport());
+
+    EXPECT_TRUE(CheckSize("system", 2_GiB + 512_MiB));
+    EXPECT_TRUE(CheckSize("vendor", 1_GiB + 512_MiB));
+}
+
+TEST_P(SnapshotMetadataUpdaterTest, GrowOverSuper) {
+    SetSize(system_, 3_GiB);
+    SetSize(vendor_, 1_GiB + 512_MiB);
+
+    EXPECT_FALSE(UpdateAndExport());
+}
+
+TEST_P(SnapshotMetadataUpdaterTest, GrowOverGroup) {
+    SetSize(system_, 3_GiB);
+    SetSize(vendor_, 1_GiB + 4_KiB);
+
+    EXPECT_FALSE(UpdateAndExport());
+}
+
+TEST_P(SnapshotMetadataUpdaterTest, Add) {
+    group_->add_partition_names("product");
+    auto product = manifest_.add_partitions();
+    product->set_partition_name("product");
+    SetSize(product, 1_GiB);
+
+    EXPECT_TRUE(UpdateAndExport());
+
+    EXPECT_TRUE(CheckSize("system", 2_GiB));
+    EXPECT_TRUE(CheckSize("vendor", 1_GiB));
+    EXPECT_TRUE(CheckSize("product", 1_GiB));
+}
+
+TEST_P(SnapshotMetadataUpdaterTest, AddTooBig) {
+    group_->add_partition_names("product");
+    auto product = manifest_.add_partitions();
+    product->set_partition_name("product");
+    SetSize(product, 1_GiB + 4_KiB);
+
+    EXPECT_FALSE(UpdateAndExport());
+}
+
+TEST_P(SnapshotMetadataUpdaterTest, ShrinkAll) {
+    SetSize(system_, 1_GiB);
+    SetSize(vendor_, 512_MiB);
+
+    ASSERT_TRUE(UpdateAndExport());
+
+    EXPECT_TRUE(CheckSize("system", 1_GiB));
+    EXPECT_TRUE(CheckSize("vendor", 512_MiB));
+}
+
+TEST_P(SnapshotMetadataUpdaterTest, ShrinkAndGrow) {
+    SetSize(system_, 3_GiB + 512_MiB);
+    SetSize(vendor_, 512_MiB);
+
+    ASSERT_TRUE(UpdateAndExport());
+
+    EXPECT_TRUE(CheckSize("system", 3_GiB + 512_MiB));
+    EXPECT_TRUE(CheckSize("vendor", 512_MiB));
+}
+
+TEST_P(SnapshotMetadataUpdaterTest, ShrinkAndAdd) {
+    SetSize(system_, 2_GiB);
+    SetSize(vendor_, 512_MiB);
+    group_->add_partition_names("product");
+    auto product = manifest_.add_partitions();
+    product->set_partition_name("product");
+    SetSize(product, 1_GiB + 512_MiB);
+
+    ASSERT_TRUE(UpdateAndExport());
+
+    EXPECT_TRUE(CheckSize("system", 2_GiB));
+    EXPECT_TRUE(CheckSize("vendor", 512_MiB));
+    EXPECT_TRUE(CheckSize("product", 1_GiB + 512_MiB));
+}
+
+TEST_P(SnapshotMetadataUpdaterTest, Delete) {
+    group_->mutable_partition_names()->RemoveLast();
+    // No need to delete it from manifest.partitions as SnapshotMetadataUpdater
+    // should ignore them (treat them as static partitions).
+
+    EXPECT_TRUE(UpdateAndExport());
+
+    EXPECT_TRUE(CheckSize("system", 2_GiB));
+    EXPECT_EQ(nullptr, builder_->FindPartition(T("vendor")));
+}
+
+TEST_P(SnapshotMetadataUpdaterTest, DeleteAndGrow) {
+    group_->mutable_partition_names()->RemoveLast();
+    SetSize(system_, 4_GiB);
+
+    EXPECT_TRUE(UpdateAndExport());
+
+    EXPECT_TRUE(CheckSize("system", 4_GiB));
+}
+
+TEST_P(SnapshotMetadataUpdaterTest, DeleteAndAdd) {
+    group_->mutable_partition_names()->RemoveLast();
+    group_->add_partition_names("product");
+    auto product = manifest_.add_partitions();
+    product->set_partition_name("product");
+    SetSize(product, 2_GiB);
+
+    EXPECT_TRUE(UpdateAndExport());
+
+    EXPECT_TRUE(CheckSize("system", 2_GiB));
+    EXPECT_EQ(nullptr, builder_->FindPartition(T("vendor")));
+    EXPECT_TRUE(CheckSize("product", 2_GiB));
+}
+
+TEST_P(SnapshotMetadataUpdaterTest, GrowGroup) {
+    group_->set_size(4_GiB + 512_KiB);
+    SetSize(system_, 2_GiB + 256_KiB);
+    SetSize(vendor_, 2_GiB + 256_KiB);
+
+    EXPECT_TRUE(UpdateAndExport());
+
+    EXPECT_TRUE(CheckSize("system", 2_GiB + 256_KiB));
+    EXPECT_TRUE(CheckSize("vendor", 2_GiB + 256_KiB));
+}
+
+TEST_P(SnapshotMetadataUpdaterTest, ShrinkGroup) {
+    group_->set_size(1_GiB);
+    SetSize(system_, 512_MiB);
+    SetSize(vendor_, 512_MiB);
+
+    EXPECT_TRUE(UpdateAndExport());
+
+    EXPECT_TRUE(CheckSize("system", 512_MiB));
+    EXPECT_TRUE(CheckSize("vendor", 512_MiB));
+}
+
+TEST_P(SnapshotMetadataUpdaterTest, MoveToNewGroup) {
+    group_->mutable_partition_names()->RemoveLast();
+    group_->set_size(2_GiB);
+
+    auto another_group = manifest_.mutable_dynamic_partition_metadata()->add_groups();
+    another_group->set_name("another_group");
+    another_group->set_size(2_GiB);
+    another_group->add_partition_names("vendor");
+    SetSize(vendor_, 2_GiB);
+
+    EXPECT_TRUE(UpdateAndExport());
+
+    EXPECT_TRUE(CheckGroupSize("group", 2_GiB));
+    EXPECT_TRUE(CheckGroupSize("another_group", 2_GiB));
+    EXPECT_TRUE(CheckSize("system", 2_GiB));
+    EXPECT_TRUE(CheckGroupName("system", "group"));
+    EXPECT_TRUE(CheckSize("vendor", 2_GiB));
+    EXPECT_TRUE(CheckGroupName("vendor", "another_group"));
+}
+
+TEST_P(SnapshotMetadataUpdaterTest, DeleteAndAddGroup) {
+    manifest_.mutable_dynamic_partition_metadata()->mutable_groups()->RemoveLast();
+    group_ = nullptr;
+
+    auto another_group = manifest_.mutable_dynamic_partition_metadata()->add_groups();
+    another_group->set_name("another_group");
+    another_group->set_size(4_GiB);
+    another_group->add_partition_names("system");
+    another_group->add_partition_names("vendor");
+    another_group->add_partition_names("product");
+    auto product = manifest_.add_partitions();
+    product->set_partition_name("product");
+    SetSize(product, 1_GiB);
+
+    EXPECT_TRUE(UpdateAndExport());
+
+    EXPECT_EQ(nullptr, builder_->FindGroup(T("group")));
+    EXPECT_TRUE(CheckGroupSize("another_group", 4_GiB));
+    EXPECT_TRUE(CheckSize("system", 2_GiB));
+    EXPECT_TRUE(CheckGroupName("system", "another_group"));
+    EXPECT_TRUE(CheckSize("vendor", 1_GiB));
+    EXPECT_TRUE(CheckGroupName("vendor", "another_group"));
+    EXPECT_TRUE(CheckSize("product", 1_GiB));
+    EXPECT_TRUE(CheckGroupName("product", "another_group"));
+}
+
+INSTANTIATE_TEST_SUITE_P(, SnapshotMetadataUpdaterTest, testing::Values(0, 1));
+
+}  // namespace snapshot
+}  // namespace android
diff --git a/fs_mgr/libsnapshot/snapshot_test.cpp b/fs_mgr/libsnapshot/snapshot_test.cpp
index 429fd8e..bc764fd 100644
--- a/fs_mgr/libsnapshot/snapshot_test.cpp
+++ b/fs_mgr/libsnapshot/snapshot_test.cpp
@@ -32,8 +32,10 @@
 #include <libfiemap/image_manager.h>
 #include <liblp/builder.h>
 #include <liblp/mock_property_fetcher.h>
+#include <storage_literals/storage_literals.h>
 
 #include "test_helpers.h"
+#include "utility.h"
 
 namespace android {
 namespace snapshot {
@@ -45,10 +47,14 @@
 using android::fs_mgr::BlockDeviceInfo;
 using android::fs_mgr::CreateLogicalPartitionParams;
 using android::fs_mgr::DestroyLogicalPartition;
+using android::fs_mgr::GetPartitionGroupName;
 using android::fs_mgr::GetPartitionName;
 using android::fs_mgr::MetadataBuilder;
+using chromeos_update_engine::DeltaArchiveManifest;
+using chromeos_update_engine::PartitionUpdate;
 using namespace ::testing;
 using namespace android::fs_mgr::testing;
+using namespace android::storage_literals;
 using namespace std::chrono_literals;
 using namespace std::string_literals;
 
@@ -58,7 +64,8 @@
 TestDeviceInfo* test_device = nullptr;
 std::string fake_super;
 
-static constexpr uint64_t kSuperSize = 16 * 1024 * 1024;
+static constexpr uint64_t kSuperSize = 16_MiB + 4_KiB;
+static constexpr uint64_t kGroupSize = 16_MiB;
 
 class SnapshotTest : public ::testing::Test {
   public:
@@ -105,7 +112,7 @@
         std::vector<std::string> snapshots = {"test-snapshot", "test_partition_a",
                                               "test_partition_b"};
         for (const auto& snapshot : snapshots) {
-            DeleteSnapshotDevice(snapshot);
+            ASSERT_TRUE(DeleteSnapshotDevice(snapshot));
             DeleteBackingImage(image_manager_, snapshot + "-cow-img");
 
             auto status_file = sm->GetSnapshotStatusFilePath(snapshot);
@@ -211,15 +218,52 @@
         return true;
     }
 
-    void DeleteSnapshotDevice(const std::string& snapshot) {
-        DeleteDevice(snapshot);
-        DeleteDevice(snapshot + "-inner");
-        ASSERT_TRUE(image_manager_->UnmapImageIfExists(snapshot + "-cow-img"));
-    }
-    void DeleteDevice(const std::string& device) {
-        if (dm_.GetState(device) != DmDeviceState::INVALID) {
-            ASSERT_TRUE(dm_.DeleteDevice(device));
+    AssertionResult DeleteSnapshotDevice(const std::string& snapshot) {
+        AssertionResult res = AssertionSuccess();
+        if (!(res = DeleteDevice(snapshot))) return res;
+        if (!(res = DeleteDevice(snapshot + "-inner"))) return res;
+        if (!(res = DeleteDevice(snapshot + "-cow"))) return res;
+        if (!image_manager_->UnmapImageIfExists(snapshot + "-cow-img")) {
+            return AssertionFailure() << "Cannot unmap image " << snapshot << "-cow-img";
         }
+        if (!(res = DeleteDevice(snapshot + "-base"))) return res;
+        return AssertionSuccess();
+    }
+
+    AssertionResult DeleteDevice(const std::string& device) {
+        if (!dm_.DeleteDeviceIfExists(device)) {
+            return AssertionFailure() << "Can't delete " << device;
+        }
+        return AssertionSuccess();
+    }
+
+    AssertionResult CreateCowImage(const std::string& name) {
+        if (!sm->CreateCowImage(lock_.get(), name)) {
+            return AssertionFailure() << "Cannot create COW image " << name;
+        }
+        std::string cow_device;
+        auto map_res = MapCowImage(name, 10s, &cow_device);
+        if (!map_res) {
+            return map_res;
+        }
+        if (!InitializeCow(cow_device)) {
+            return AssertionFailure() << "Cannot zero fill " << cow_device;
+        }
+        if (!sm->UnmapCowImage(name)) {
+            return AssertionFailure() << "Cannot unmap " << name << " after zero filling it";
+        }
+        return AssertionSuccess();
+    }
+
+    AssertionResult MapCowImage(const std::string& name,
+                                const std::chrono::milliseconds& timeout_ms, std::string* path) {
+        if (!sm->MapCowImage(name, timeout_ms)) {
+            return AssertionFailure() << "Cannot map cow image " << name;
+        }
+        if (!dm_.GetDmDevicePathByName(name + "-cow-img"s, path)) {
+            return AssertionFailure() << "No path for " << name << "-cow-img";
+        }
+        return AssertionSuccess();
     }
 
     DeviceMapper& dm_;
@@ -236,7 +280,7 @@
                                    {.device_size = kDeviceSize,
                                     .snapshot_size = kDeviceSize,
                                     .cow_file_size = kDeviceSize}));
-    ASSERT_TRUE(sm->CreateCowImage(lock_.get(), "test-snapshot"));
+    ASSERT_TRUE(CreateCowImage("test-snapshot"));
 
     std::vector<std::string> snapshots;
     ASSERT_TRUE(sm->ListSnapshots(lock_.get(), &snapshots));
@@ -265,13 +309,13 @@
                                    {.device_size = kDeviceSize,
                                     .snapshot_size = kDeviceSize,
                                     .cow_file_size = kDeviceSize}));
-    ASSERT_TRUE(sm->CreateCowImage(lock_.get(), "test-snapshot"));
+    ASSERT_TRUE(CreateCowImage("test-snapshot"));
 
     std::string base_device;
     ASSERT_TRUE(CreatePartition("base-device", kDeviceSize, &base_device));
 
     std::string cow_device;
-    ASSERT_TRUE(sm->MapCowImage("test-snapshot", 10s, &cow_device));
+    ASSERT_TRUE(MapCowImage("test-snapshot", 10s, &cow_device));
 
     std::string snap_device;
     ASSERT_TRUE(sm->MapSnapshot(lock_.get(), "test-snapshot", base_device, cow_device, 10s,
@@ -288,13 +332,13 @@
                                    {.device_size = kDeviceSize,
                                     .snapshot_size = kSnapshotSize,
                                     .cow_file_size = kSnapshotSize}));
-    ASSERT_TRUE(sm->CreateCowImage(lock_.get(), "test-snapshot"));
+    ASSERT_TRUE(CreateCowImage("test-snapshot"));
 
     std::string base_device;
     ASSERT_TRUE(CreatePartition("base-device", kDeviceSize, &base_device));
 
     std::string cow_device;
-    ASSERT_TRUE(sm->MapCowImage("test-snapshot", 10s, &cow_device));
+    ASSERT_TRUE(MapCowImage("test-snapshot", 10s, &cow_device));
 
     std::string snap_device;
     ASSERT_TRUE(sm->MapSnapshot(lock_.get(), "test-snapshot", base_device, cow_device, 10s,
@@ -344,8 +388,8 @@
                                    {.device_size = kDeviceSize,
                                     .snapshot_size = kDeviceSize,
                                     .cow_file_size = kDeviceSize}));
-    ASSERT_TRUE(sm->CreateCowImage(lock_.get(), "test_partition_b"));
-    ASSERT_TRUE(sm->MapCowImage("test_partition_b", 10s, &cow_device));
+    ASSERT_TRUE(CreateCowImage("test_partition_b"));
+    ASSERT_TRUE(MapCowImage("test_partition_b", 10s, &cow_device));
     ASSERT_TRUE(sm->MapSnapshot(lock_.get(), "test_partition_b", base_device, cow_device, 10s,
                                 &snap_device));
 
@@ -403,11 +447,11 @@
                                    {.device_size = kDeviceSize,
                                     .snapshot_size = kDeviceSize,
                                     .cow_file_size = kDeviceSize}));
-    ASSERT_TRUE(sm->CreateCowImage(lock_.get(), "test-snapshot"));
+    ASSERT_TRUE(CreateCowImage("test-snapshot"));
 
     std::string base_device, cow_device, snap_device;
     ASSERT_TRUE(CreatePartition("base-device", kDeviceSize, &base_device));
-    ASSERT_TRUE(sm->MapCowImage("test-snapshot", 10s, &cow_device));
+    ASSERT_TRUE(MapCowImage("test-snapshot", 10s, &cow_device));
     ASSERT_TRUE(sm->MapSnapshot(lock_.get(), "test-snapshot", base_device, cow_device, 10s,
                                 &snap_device));
 
@@ -433,11 +477,11 @@
     // Wait 1s, otherwise DeleteSnapshotDevice may fail with EBUSY.
     sleep(1);
     // Forcefully delete the snapshot device, so it looks like we just rebooted.
-    DeleteSnapshotDevice("test-snapshot");
+    ASSERT_TRUE(DeleteSnapshotDevice("test-snapshot"));
 
     // Map snapshot should fail now, because we're in a merge-complete state.
     ASSERT_TRUE(AcquireLock());
-    ASSERT_TRUE(sm->MapCowImage("test-snapshot", 10s, &cow_device));
+    ASSERT_TRUE(MapCowImage("test-snapshot", 10s, &cow_device));
     ASSERT_FALSE(sm->MapSnapshot(lock_.get(), "test-snapshot", base_device, cow_device, 10s,
                                  &snap_device));
 
@@ -462,7 +506,7 @@
                                    {.device_size = kDeviceSize,
                                     .snapshot_size = kDeviceSize,
                                     .cow_file_size = kDeviceSize}));
-    ASSERT_TRUE(sm->CreateCowImage(lock_.get(), "test_partition_b"));
+    ASSERT_TRUE(CreateCowImage("test_partition_b"));
 
     // Simulate a reboot into the new slot.
     lock_ = nullptr;
@@ -504,7 +548,7 @@
                                    {.device_size = kDeviceSize,
                                     .snapshot_size = kDeviceSize,
                                     .cow_file_size = kDeviceSize}));
-    ASSERT_TRUE(sm->CreateCowImage(lock_.get(), "test_partition_b"));
+    ASSERT_TRUE(CreateCowImage("test_partition_b"));
 
     // Simulate a reboot into the new slot.
     lock_ = nullptr;
@@ -552,7 +596,7 @@
                                    {.device_size = kDeviceSize,
                                     .snapshot_size = kDeviceSize,
                                     .cow_file_size = kDeviceSize}));
-    ASSERT_TRUE(sm->CreateCowImage(lock_.get(), "test_partition_b"));
+    ASSERT_TRUE(CreateCowImage("test_partition_b"));
 
     // Simulate a reboot into the new slot.
     lock_ = nullptr;
@@ -570,7 +614,7 @@
 
     // Now, reflash super. Note that we haven't called ProcessUpdateState, so the
     // status is still Merging.
-    DeleteSnapshotDevice("test_partition_b");
+    ASSERT_TRUE(DeleteSnapshotDevice("test_partition_b"));
     ASSERT_TRUE(init->image_manager()->UnmapImageIfExists("test_partition_b-cow-img"));
     FormatFakeSuper();
     ASSERT_TRUE(CreatePartition("test_partition_b", kDeviceSize));
@@ -583,6 +627,378 @@
     ASSERT_EQ(sm->GetUpdateState(), UpdateState::None);
 }
 
+class SnapshotUpdateTest : public SnapshotTest {
+  public:
+    void SetUp() override {
+        SnapshotTest::SetUp();
+        Cleanup();
+
+        // Cleanup() changes slot suffix, so initialize it again.
+        test_device->set_slot_suffix("_a");
+
+        ON_CALL(*GetMockedPropertyFetcher(), GetBoolProperty("ro.virtual_ab.enabled", _))
+                .WillByDefault(Return(true));
+
+        opener_ = std::make_unique<TestPartitionOpener>(fake_super);
+
+        // Create a fake update package metadata.
+        // Not using full name "system", "vendor", "product" because these names collide with the
+        // mapped partitions on the running device.
+        // Each test modifies manifest_ slightly to indicate changes to the partition layout.
+        auto group = manifest_.mutable_dynamic_partition_metadata()->add_groups();
+        group->set_name("group");
+        group->set_size(kGroupSize);
+        group->add_partition_names("sys");
+        group->add_partition_names("vnd");
+        group->add_partition_names("prd");
+        sys_ = manifest_.add_partitions();
+        sys_->set_partition_name("sys");
+        SetSize(sys_, 3_MiB);
+        vnd_ = manifest_.add_partitions();
+        vnd_->set_partition_name("vnd");
+        SetSize(vnd_, 3_MiB);
+        prd_ = manifest_.add_partitions();
+        prd_->set_partition_name("prd");
+        SetSize(prd_, 3_MiB);
+
+        // Initialize source partition metadata using |manifest_|.
+        src_ = MetadataBuilder::New(*opener_, "super", 0);
+        ASSERT_TRUE(FillFakeMetadata(src_.get(), manifest_, "_a"));
+        ASSERT_NE(nullptr, src_);
+        // Add sys_b which is like system_other.
+        auto partition = src_->AddPartition("sys_b", 0);
+        ASSERT_NE(nullptr, partition);
+        ASSERT_TRUE(src_->ResizePartition(partition, 1_MiB));
+        auto metadata = src_->Export();
+        ASSERT_NE(nullptr, metadata);
+        ASSERT_TRUE(UpdatePartitionTable(*opener_, "super", *metadata.get(), 0));
+
+        // Map source partitions. Additionally, map sys_b to simulate system_other after flashing.
+        std::string path;
+        for (const auto& name : {"sys_a", "vnd_a", "prd_a", "sys_b"}) {
+            ASSERT_TRUE(CreateLogicalPartition(
+                    CreateLogicalPartitionParams{
+                            .block_device = fake_super,
+                            .metadata_slot = 0,
+                            .partition_name = name,
+                            .timeout_ms = 1s,
+                            .partition_opener = opener_.get(),
+                    },
+                    &path));
+            ASSERT_TRUE(WriteRandomData(path));
+            auto hash = GetHash(path);
+            ASSERT_TRUE(hash.has_value());
+            hashes_[name] = *hash;
+        }
+    }
+    void TearDown() override {
+        Cleanup();
+        SnapshotTest::TearDown();
+    }
+    void Cleanup() {
+        if (!image_manager_) {
+            InitializeState();
+        }
+        for (const auto& suffix : {"_a", "_b"}) {
+            test_device->set_slot_suffix(suffix);
+            EXPECT_TRUE(sm->CancelUpdate()) << suffix;
+        }
+        EXPECT_TRUE(UnmapAll());
+    }
+
+    AssertionResult IsPartitionUnchanged(const std::string& name) {
+        std::string path;
+        if (!dm_.GetDmDevicePathByName(name, &path)) {
+            return AssertionFailure() << "Path of " << name << " cannot be determined";
+        }
+        auto hash = GetHash(path);
+        if (!hash.has_value()) {
+            return AssertionFailure() << "Cannot read partition " << name << ": " << path;
+        }
+        if (hashes_[name] != *hash) {
+            return AssertionFailure() << "Content of " << name << " has changed after the merge";
+        }
+        return AssertionSuccess();
+    }
+
+    std::optional<uint64_t> GetSnapshotSize(const std::string& name) {
+        if (!AcquireLock()) {
+            return std::nullopt;
+        }
+        auto local_lock = std::move(lock_);
+
+        SnapshotManager::SnapshotStatus status;
+        if (!sm->ReadSnapshotStatus(local_lock.get(), name, &status)) {
+            return std::nullopt;
+        }
+        return status.snapshot_size;
+    }
+
+    AssertionResult UnmapAll() {
+        for (const auto& name : {"sys", "vnd", "prd"}) {
+            if (!dm_.DeleteDeviceIfExists(name + "_a"s)) {
+                return AssertionFailure() << "Cannot unmap " << name << "_a";
+            }
+            if (!DeleteSnapshotDevice(name + "_b"s)) {
+                return AssertionFailure() << "Cannot delete snapshot " << name << "_b";
+            }
+        }
+        return AssertionSuccess();
+    }
+
+    std::unique_ptr<TestPartitionOpener> opener_;
+    DeltaArchiveManifest manifest_;
+    std::unique_ptr<MetadataBuilder> src_;
+    std::map<std::string, std::string> hashes_;
+
+    PartitionUpdate* sys_ = nullptr;
+    PartitionUpdate* vnd_ = nullptr;
+    PartitionUpdate* prd_ = nullptr;
+};
+
+// Test full update flow executed by update_engine. Some partitions uses super empty space,
+// some uses images, and some uses both.
+// Also test UnmapUpdateSnapshot unmaps everything.
+// Also test first stage mount and merge after this.
+TEST_F(SnapshotUpdateTest, FullUpdateFlow) {
+    // OTA client calls BeginUpdate before doing anything.
+    ASSERT_TRUE(sm->BeginUpdate());
+
+    // OTA client blindly unmaps all partitions that are possibly mapped.
+    for (const auto& name : {"sys_b", "vnd_b", "prd_b"}) {
+        ASSERT_TRUE(sm->UnmapUpdateSnapshot(name));
+    }
+
+    // Grow all partitions.
+    SetSize(sys_, 4_MiB);
+    SetSize(vnd_, 4_MiB);
+    SetSize(prd_, 4_MiB);
+
+    ASSERT_TRUE(sm->CreateUpdateSnapshots(manifest_));
+
+    // Test that partitions prioritize using space in super.
+    auto tgt = MetadataBuilder::New(*opener_, "super", 1);
+    ASSERT_NE(nullptr, tgt->FindPartition("sys_b-cow"));
+    ASSERT_NE(nullptr, tgt->FindPartition("vnd_b-cow"));
+    ASSERT_EQ(nullptr, tgt->FindPartition("prd_b-cow"));
+
+    // Write some data to target partitions.
+    for (const auto& name : {"sys_b", "vnd_b", "prd_b"}) {
+        std::string path;
+        ASSERT_TRUE(sm->MapUpdateSnapshot(
+                CreateLogicalPartitionParams{
+                        .block_device = fake_super,
+                        .metadata_slot = 1,
+                        .partition_name = name,
+                        .timeout_ms = 10s,
+                        .partition_opener = opener_.get(),
+                },
+                &path))
+                << name;
+        ASSERT_TRUE(WriteRandomData(path));
+        auto hash = GetHash(path);
+        ASSERT_TRUE(hash.has_value());
+        hashes_[name] = *hash;
+    }
+
+    // Assert that source partitions aren't affected.
+    for (const auto& name : {"sys_a", "vnd_a", "prd_a"}) {
+        ASSERT_TRUE(IsPartitionUnchanged(name));
+    }
+
+    ASSERT_TRUE(sm->FinishedSnapshotWrites());
+
+    // Simulate shutting down the device.
+    ASSERT_TRUE(UnmapAll());
+
+    // After reboot, init does first stage mount.
+    auto rebooted = new TestDeviceInfo(fake_super);
+    rebooted->set_slot_suffix("_b");
+    auto init = SnapshotManager::NewForFirstStageMount(rebooted);
+    ASSERT_NE(init, nullptr);
+    ASSERT_TRUE(init->NeedSnapshotsInFirstStageMount());
+    ASSERT_TRUE(init->CreateLogicalAndSnapshotPartitions("super"));
+
+    // Check that the target partitions have the same content.
+    for (const auto& name : {"sys_b", "vnd_b", "prd_b"}) {
+        ASSERT_TRUE(IsPartitionUnchanged(name));
+    }
+
+    // Initiate the merge and wait for it to be completed.
+    ASSERT_TRUE(init->InitiateMerge());
+    ASSERT_EQ(UpdateState::MergeCompleted, init->ProcessUpdateState());
+
+    // Check that the target partitions have the same content after the merge.
+    for (const auto& name : {"sys_b", "vnd_b", "prd_b"}) {
+        ASSERT_TRUE(IsPartitionUnchanged(name))
+                << "Content of " << name << " changes after the merge";
+    }
+}
+
+// Test that if new system partitions uses empty space in super, that region is not snapshotted.
+TEST_F(SnapshotUpdateTest, DirectWriteEmptySpace) {
+    SetSize(sys_, 4_MiB);
+    // vnd_b and prd_b are unchanged.
+    ASSERT_TRUE(sm->CreateUpdateSnapshots(manifest_));
+    ASSERT_EQ(3_MiB, GetSnapshotSize("sys_b").value_or(0));
+}
+
+// Test that if new system partitions uses space of old vendor partition, that region is
+// snapshotted.
+TEST_F(SnapshotUpdateTest, SnapshotOldPartitions) {
+    SetSize(sys_, 4_MiB);  // grows
+    SetSize(vnd_, 2_MiB);  // shrinks
+    // prd_b is unchanged
+    ASSERT_TRUE(sm->CreateUpdateSnapshots(manifest_));
+    ASSERT_EQ(4_MiB, GetSnapshotSize("sys_b").value_or(0));
+}
+
+// Test that even if there seem to be empty space in target metadata, COW partition won't take
+// it because they are used by old partitions.
+TEST_F(SnapshotUpdateTest, CowPartitionDoNotTakeOldPartitions) {
+    SetSize(sys_, 2_MiB);  // shrinks
+    // vnd_b and prd_b are unchanged.
+    ASSERT_TRUE(sm->CreateUpdateSnapshots(manifest_));
+
+    auto tgt = MetadataBuilder::New(*opener_, "super", 1);
+    ASSERT_NE(nullptr, tgt);
+    auto metadata = tgt->Export();
+    ASSERT_NE(nullptr, metadata);
+    std::vector<std::string> written;
+    // Write random data to all COW partitions in super
+    for (auto p : metadata->partitions) {
+        if (GetPartitionGroupName(metadata->groups[p.group_index]) != kCowGroupName) {
+            continue;
+        }
+        std::string path;
+        ASSERT_TRUE(CreateLogicalPartition(
+                CreateLogicalPartitionParams{
+                        .block_device = fake_super,
+                        .metadata = metadata.get(),
+                        .partition = &p,
+                        .timeout_ms = 1s,
+                        .partition_opener = opener_.get(),
+                },
+                &path));
+        ASSERT_TRUE(WriteRandomData(path));
+        written.push_back(GetPartitionName(p));
+    }
+    ASSERT_FALSE(written.empty())
+            << "No COW partitions are created even if there are empty space in super partition";
+
+    // Make sure source partitions aren't affected.
+    for (const auto& name : {"sys_a", "vnd_a", "prd_a"}) {
+        ASSERT_TRUE(IsPartitionUnchanged(name));
+    }
+}
+
+// Test that it crashes after creating snapshot status file but before creating COW image, then
+// calling CreateUpdateSnapshots again works.
+TEST_F(SnapshotUpdateTest, SnapshotStatusFileWithoutCow) {
+    // Write some trash snapshot files to simulate leftovers from previous runs.
+    {
+        ASSERT_TRUE(AcquireLock());
+        auto local_lock = std::move(lock_);
+        ASSERT_TRUE(sm->WriteSnapshotStatus(local_lock.get(), "sys_b",
+                                            SnapshotManager::SnapshotStatus{}));
+        ASSERT_TRUE(image_manager_->CreateBackingImage("sys_b-cow-img", 1_MiB,
+                                                       IImageManager::CREATE_IMAGE_DEFAULT));
+    }
+
+    // Redo the update.
+    ASSERT_TRUE(sm->BeginUpdate());
+    ASSERT_TRUE(sm->UnmapUpdateSnapshot("sys_b"));
+
+    ASSERT_TRUE(sm->CreateUpdateSnapshots(manifest_));
+
+    // Check that target partitions can be mapped.
+    for (const auto& name : {"sys_b", "vnd_b", "prd_b"}) {
+        std::string path;
+        EXPECT_TRUE(sm->MapUpdateSnapshot(
+                CreateLogicalPartitionParams{
+                        .block_device = fake_super,
+                        .metadata_slot = 1,
+                        .partition_name = name,
+                        .timeout_ms = 10s,
+                        .partition_opener = opener_.get(),
+                },
+                &path))
+                << name;
+    }
+}
+
+// Test that the old partitions are not modified.
+TEST_F(SnapshotUpdateTest, TestRollback) {
+    // Execute the update.
+    ASSERT_TRUE(sm->BeginUpdate());
+    ASSERT_TRUE(sm->UnmapUpdateSnapshot("sys_b"));
+
+    ASSERT_TRUE(sm->CreateUpdateSnapshots(manifest_));
+
+    // Write some data to target partitions.
+    for (const auto& name : {"sys_b", "vnd_b", "prd_b"}) {
+        std::string path;
+        ASSERT_TRUE(sm->MapUpdateSnapshot(
+                CreateLogicalPartitionParams{
+                        .block_device = fake_super,
+                        .metadata_slot = 1,
+                        .partition_name = name,
+                        .timeout_ms = 10s,
+                        .partition_opener = opener_.get(),
+                },
+                &path))
+                << name;
+        ASSERT_TRUE(WriteRandomData(path));
+        auto hash = GetHash(path);
+        ASSERT_TRUE(hash.has_value());
+        hashes_[name] = *hash;
+    }
+
+    // Assert that source partitions aren't affected.
+    for (const auto& name : {"sys_a", "vnd_a", "prd_a"}) {
+        ASSERT_TRUE(IsPartitionUnchanged(name));
+    }
+
+    ASSERT_TRUE(sm->FinishedSnapshotWrites());
+
+    // Simulate shutting down the device.
+    ASSERT_TRUE(UnmapAll());
+
+    // After reboot, init does first stage mount.
+    auto rebooted = new TestDeviceInfo(fake_super);
+    rebooted->set_slot_suffix("_b");
+    auto init = SnapshotManager::NewForFirstStageMount(rebooted);
+    ASSERT_NE(init, nullptr);
+    ASSERT_TRUE(init->NeedSnapshotsInFirstStageMount());
+    ASSERT_TRUE(init->CreateLogicalAndSnapshotPartitions("super"));
+
+    // Check that the target partitions have the same content.
+    for (const auto& name : {"sys_b", "vnd_b", "prd_b"}) {
+        ASSERT_TRUE(IsPartitionUnchanged(name));
+    }
+
+    // Simulate shutting down the device again.
+    ASSERT_TRUE(UnmapAll());
+    rebooted = new TestDeviceInfo(fake_super);
+    rebooted->set_slot_suffix("_a");
+    init = SnapshotManager::NewForFirstStageMount(rebooted);
+    ASSERT_NE(init, nullptr);
+    ASSERT_FALSE(init->NeedSnapshotsInFirstStageMount());
+    ASSERT_TRUE(init->CreateLogicalAndSnapshotPartitions("super"));
+
+    // Assert that the source partitions aren't affected.
+    for (const auto& name : {"sys_a", "vnd_a", "prd_a"}) {
+        ASSERT_TRUE(IsPartitionUnchanged(name));
+    }
+}
+
+// Test that if an update is applied but not booted into, it can be canceled.
+TEST_F(SnapshotUpdateTest, CancelAfterApply) {
+    ASSERT_TRUE(sm->BeginUpdate());
+    ASSERT_TRUE(sm->FinishedSnapshotWrites());
+    ASSERT_TRUE(sm->CancelUpdate());
+}
+
 }  // namespace snapshot
 }  // namespace android
 
@@ -624,6 +1040,7 @@
     }
 
     // Clean up previous run.
+    SnapshotUpdateTest().Cleanup();
     SnapshotTest().Cleanup();
 
     // Use a separate image manager for our fake super partition.
diff --git a/fs_mgr/libsnapshot/snapshotctl.cpp b/fs_mgr/libsnapshot/snapshotctl.cpp
new file mode 100644
index 0000000..d65320c
--- /dev/null
+++ b/fs_mgr/libsnapshot/snapshotctl.cpp
@@ -0,0 +1,115 @@
+//
+// Copyright (C) 2019 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+#include <sysexits.h>
+
+#include <chrono>
+#include <iostream>
+#include <map>
+
+#include <android-base/logging.h>
+#include <libsnapshot/snapshot.h>
+
+using namespace std::string_literals;
+
+int Usage() {
+    std::cerr << "snapshotctl: Control snapshots.\n"
+                 "Usage: snapshotctl [action] [flags]\n"
+                 "Actions:\n"
+                 "  dump\n"
+                 "    Print snapshot states.\n"
+                 "  merge [--logcat]\n"
+                 "    Initialize merge and wait for it to be completed.\n"
+                 "    If --logcat is specified, log to logcat. Otherwise, log to stdout.\n";
+    return EX_USAGE;
+}
+
+namespace android {
+namespace snapshot {
+
+bool DumpCmdHandler(int /*argc*/, char** argv) {
+    android::base::InitLogging(argv, &android::base::StderrLogger);
+    return SnapshotManager::New()->Dump(std::cout);
+}
+
+bool MergeCmdHandler(int argc, char** argv) {
+    auto begin = std::chrono::steady_clock::now();
+
+    bool log_to_logcat = false;
+    for (int i = 2; i < argc; ++i) {
+        if (argv[i] == "--logcat"s) {
+            log_to_logcat = true;
+        }
+    }
+    if (log_to_logcat) {
+        android::base::InitLogging(argv);
+    } else {
+        android::base::InitLogging(argv, &android::base::StdioLogger);
+    }
+
+    auto sm = SnapshotManager::New();
+
+    auto state = sm->GetUpdateState();
+    if (state == UpdateState::None) {
+        LOG(INFO) << "Can't find any snapshot to merge.";
+        return true;
+    }
+    if (state == UpdateState::Unverified) {
+        if (!sm->InitiateMerge()) {
+            LOG(ERROR) << "Failed to initiate merge.";
+            return false;
+        }
+    }
+
+    // All other states can be handled by ProcessUpdateState.
+    LOG(INFO) << "Waiting for any merge to complete. This can take up to 1 minute.";
+    state = SnapshotManager::New()->ProcessUpdateState();
+
+    if (state == UpdateState::MergeCompleted) {
+        auto end = std::chrono::steady_clock::now();
+        auto passed = std::chrono::duration_cast<std::chrono::milliseconds>(end - begin).count();
+        LOG(INFO) << "Snapshot merged in " << passed << " ms.";
+        return true;
+    }
+
+    LOG(ERROR) << "Snapshot failed to merge with state \"" << state << "\".";
+    return false;
+}
+
+static std::map<std::string, std::function<bool(int, char**)>> kCmdMap = {
+        // clang-format off
+        {"dump", DumpCmdHandler},
+        {"merge", MergeCmdHandler},
+        // clang-format on
+};
+
+}  // namespace snapshot
+}  // namespace android
+
+int main(int argc, char** argv) {
+    using namespace android::snapshot;
+    if (argc < 2) {
+        return Usage();
+    }
+
+    for (const auto& cmd : kCmdMap) {
+        if (cmd.first == argv[1]) {
+            return cmd.second(argc, argv) ? EX_OK : EX_SOFTWARE;
+        }
+    }
+
+    return Usage();
+}
diff --git a/fs_mgr/libsnapshot/snapshotctl.rc b/fs_mgr/libsnapshot/snapshotctl.rc
new file mode 100644
index 0000000..29707f1
--- /dev/null
+++ b/fs_mgr/libsnapshot/snapshotctl.rc
@@ -0,0 +1,2 @@
+on property:sys.boot_completed=1
+    exec - root root -- /system/bin/snapshotctl merge --logcat
diff --git a/fs_mgr/libsnapshot/test_helpers.cpp b/fs_mgr/libsnapshot/test_helpers.cpp
index f67dd21..1a6a593 100644
--- a/fs_mgr/libsnapshot/test_helpers.cpp
+++ b/fs_mgr/libsnapshot/test_helpers.cpp
@@ -14,12 +14,21 @@
 
 #include "test_helpers.h"
 
+#include <android-base/file.h>
+#include <android-base/logging.h>
+#include <android-base/unique_fd.h>
 #include <gtest/gtest.h>
+#include <openssl/sha.h>
 
 namespace android {
 namespace snapshot {
 
+using android::base::ReadFully;
+using android::base::unique_fd;
+using android::base::WriteFully;
 using android::fiemap::IImageManager;
+using testing::AssertionFailure;
+using testing::AssertionSuccess;
 
 void DeleteBackingImage(IImageManager* manager, const std::string& name) {
     if (manager->IsImageMapped(name)) {
@@ -53,5 +62,90 @@
     return PartitionOpener::GetDeviceString(partition_name);
 }
 
+bool WriteRandomData(const std::string& path) {
+    unique_fd rand(open("/dev/urandom", O_RDONLY));
+    unique_fd fd(open(path.c_str(), O_WRONLY));
+
+    char buf[4096];
+    while (true) {
+        ssize_t n = TEMP_FAILURE_RETRY(read(rand.get(), buf, sizeof(buf)));
+        if (n <= 0) return false;
+        if (!WriteFully(fd.get(), buf, n)) {
+            if (errno == ENOSPC) {
+                return true;
+            }
+            PLOG(ERROR) << "Cannot write " << path;
+            return false;
+        }
+    }
+}
+
+std::string ToHexString(const uint8_t* buf, size_t len) {
+    char lookup[] = "0123456789abcdef";
+    std::string out(len * 2 + 1, '\0');
+    char* outp = out.data();
+    for (; len > 0; len--, buf++) {
+        *outp++ = (char)lookup[*buf >> 4];
+        *outp++ = (char)lookup[*buf & 0xf];
+    }
+    return out;
+}
+
+std::optional<std::string> GetHash(const std::string& path) {
+    unique_fd fd(open(path.c_str(), O_RDONLY));
+    char buf[4096];
+    SHA256_CTX ctx;
+    SHA256_Init(&ctx);
+    while (true) {
+        ssize_t n = TEMP_FAILURE_RETRY(read(fd.get(), buf, sizeof(buf)));
+        if (n < 0) {
+            PLOG(ERROR) << "Cannot read " << path;
+            return std::nullopt;
+        }
+        if (n == 0) {
+            break;
+        }
+        SHA256_Update(&ctx, buf, n);
+    }
+    uint8_t out[32];
+    SHA256_Final(out, &ctx);
+    return ToHexString(out, sizeof(out));
+}
+
+AssertionResult FillFakeMetadata(MetadataBuilder* builder, const DeltaArchiveManifest& manifest,
+                                 const std::string& suffix) {
+    for (const auto& group : manifest.dynamic_partition_metadata().groups()) {
+        if (!builder->AddGroup(group.name() + suffix, group.size())) {
+            return AssertionFailure()
+                   << "Cannot add group " << group.name() << " with size " << group.size();
+        }
+        for (const auto& partition_name : group.partition_names()) {
+            auto p = builder->AddPartition(partition_name + suffix, group.name() + suffix,
+                                           0 /* attr */);
+            if (!p) {
+                return AssertionFailure() << "Cannot add partition " << partition_name + suffix
+                                          << " to group " << group.name() << suffix;
+            }
+        }
+    }
+    for (const auto& partition : manifest.partitions()) {
+        auto p = builder->FindPartition(partition.partition_name() + suffix);
+        if (!p) {
+            return AssertionFailure() << "Cannot resize partition " << partition.partition_name()
+                                      << suffix << "; it is not found.";
+        }
+        if (!builder->ResizePartition(p, partition.new_partition_info().size())) {
+            return AssertionFailure()
+                   << "Cannot resize partition " << partition.partition_name() << suffix
+                   << " to size " << partition.new_partition_info().size();
+        }
+    }
+    return AssertionSuccess();
+}
+
+void SetSize(PartitionUpdate* partition_update, uint64_t size) {
+    partition_update->mutable_new_partition_info()->set_size(size);
+}
+
 }  // namespace snapshot
 }  // namespace android
diff --git a/fs_mgr/libsnapshot/test_helpers.h b/fs_mgr/libsnapshot/test_helpers.h
index 9f582d9..0303a14 100644
--- a/fs_mgr/libsnapshot/test_helpers.h
+++ b/fs_mgr/libsnapshot/test_helpers.h
@@ -14,15 +14,23 @@
 
 #pragma once
 
+#include <optional>
 #include <string>
 
+#include <gtest/gtest.h>
 #include <libfiemap/image_manager.h>
 #include <liblp/partition_opener.h>
 #include <libsnapshot/snapshot.h>
+#include <update_engine/update_metadata.pb.h>
 
 namespace android {
 namespace snapshot {
 
+using android::fs_mgr::MetadataBuilder;
+using chromeos_update_engine::DeltaArchiveManifest;
+using chromeos_update_engine::PartitionUpdate;
+using testing::AssertionResult;
+
 using namespace std::string_literals;
 
 // Redirect requests for "super" to our fake super partition.
@@ -47,10 +55,12 @@
     std::string GetGsidDir() const override { return "ota/test"s; }
     std::string GetMetadataDir() const override { return "/metadata/ota/test"s; }
     std::string GetSlotSuffix() const override { return slot_suffix_; }
+    std::string GetOtherSlotSuffix() const override { return slot_suffix_ == "_a" ? "_b" : "_a"; }
     std::string GetSuperDevice([[maybe_unused]] uint32_t slot) const override { return "super"; }
     const android::fs_mgr::IPartitionOpener& GetPartitionOpener() const override {
         return *opener_.get();
     }
+    bool IsOverlayfsSetup() const override { return false; }
 
     void set_slot_suffix(const std::string& suffix) { slot_suffix_ = suffix; }
     void set_fake_super(const std::string& path) {
@@ -65,5 +75,17 @@
 // Helper for error-spam-free cleanup.
 void DeleteBackingImage(android::fiemap::IImageManager* manager, const std::string& name);
 
+// Write some random data to the given device. Will write until reaching end of the device.
+bool WriteRandomData(const std::string& device);
+
+std::optional<std::string> GetHash(const std::string& path);
+
+// Add partitions and groups described by |manifest|.
+AssertionResult FillFakeMetadata(MetadataBuilder* builder, const DeltaArchiveManifest& manifest,
+                                 const std::string& suffix);
+
+// In the update package metadata, set a partition with the given size.
+void SetSize(PartitionUpdate* partition_update, uint64_t size);
+
 }  // namespace snapshot
 }  // namespace android
diff --git a/fs_mgr/libsnapshot/utility.cpp b/fs_mgr/libsnapshot/utility.cpp
index 164b472..66629e8 100644
--- a/fs_mgr/libsnapshot/utility.cpp
+++ b/fs_mgr/libsnapshot/utility.cpp
@@ -14,9 +14,13 @@
 
 #include "utility.h"
 
+#include <android-base/file.h>
 #include <android-base/logging.h>
 #include <android-base/strings.h>
 
+using android::fs_mgr::MetadataBuilder;
+using android::fs_mgr::Partition;
+
 namespace android {
 namespace snapshot {
 
@@ -52,5 +56,58 @@
     }
 }
 
+std::vector<Partition*> ListPartitionsWithSuffix(MetadataBuilder* builder,
+                                                 const std::string& suffix) {
+    std::vector<Partition*> ret;
+    for (const auto& group : builder->ListGroups()) {
+        for (auto* partition : builder->ListPartitionsInGroup(group)) {
+            if (!base::EndsWith(partition->name(), suffix)) {
+                continue;
+            }
+            ret.push_back(partition);
+        }
+    }
+    return ret;
+}
+
+AutoDeleteSnapshot::~AutoDeleteSnapshot() {
+    if (!name_.empty() && !manager_->DeleteSnapshot(lock_, name_)) {
+        LOG(ERROR) << "Failed to auto delete snapshot " << name_;
+    }
+}
+
+bool InitializeCow(const std::string& device) {
+    // When the kernel creates a persistent dm-snapshot, it requires a CoW file
+    // to store the modifications. The kernel interface does not specify how
+    // the CoW is used, and there is no standard associated.
+    // By looking at the current implementation, the CoW file is treated as:
+    // - a _NEW_ snapshot if its first 32 bits are zero, so the newly created
+    // dm-snapshot device will look like a perfect copy of the origin device;
+    // - an _EXISTING_ snapshot if the first 32 bits are equal to a
+    // kernel-specified magic number and the CoW file metadata is set as valid,
+    // so it can be used to resume the last state of a snapshot device;
+    // - an _INVALID_ snapshot otherwise.
+    // To avoid zero-filling the whole CoW file when a new dm-snapshot is
+    // created, here we zero-fill only the first 32 bits. This is a temporary
+    // workaround that will be discussed again when the kernel API gets
+    // consolidated.
+    // TODO(b/139202197): Remove this hack once the kernel API is consolidated.
+    constexpr ssize_t kDmSnapZeroFillSize = 4;  // 32-bit
+
+    char zeros[kDmSnapZeroFillSize] = {0};
+    android::base::unique_fd fd(open(device.c_str(), O_WRONLY | O_BINARY));
+    if (fd < 0) {
+        PLOG(ERROR) << "Can't open COW device: " << device;
+        return false;
+    }
+
+    LOG(INFO) << "Zero-filling COW device: " << device;
+    if (!android::base::WriteFully(fd, zeros, kDmSnapZeroFillSize)) {
+        PLOG(ERROR) << "Can't zero-fill COW device for " << device;
+        return false;
+    }
+    return true;
+}
+
 }  // namespace snapshot
 }  // namespace android
diff --git a/fs_mgr/libsnapshot/utility.h b/fs_mgr/libsnapshot/utility.h
index cbab472..75c694c 100644
--- a/fs_mgr/libsnapshot/utility.h
+++ b/fs_mgr/libsnapshot/utility.h
@@ -14,11 +14,15 @@
 
 #pragma once
 
+#include <functional>
 #include <string>
 
 #include <android-base/macros.h>
 #include <libdm/dm.h>
 #include <libfiemap/image_manager.h>
+#include <liblp/builder.h>
+#include <libsnapshot/snapshot.h>
+#include <update_engine/update_metadata.pb.h>
 
 namespace android {
 namespace snapshot {
@@ -81,5 +85,27 @@
     android::fiemap::IImageManager* images_ = nullptr;
 };
 
+// Automatically deletes a snapshot. |name| should be the name of the partition, e.g. "system_a".
+// Client is responsible for maintaining the lifetime of |manager| and |lock|.
+struct AutoDeleteSnapshot : AutoDevice {
+    AutoDeleteSnapshot(SnapshotManager* manager, SnapshotManager::LockedFile* lock,
+                       const std::string& name)
+        : AutoDevice(name), manager_(manager), lock_(lock) {}
+    AutoDeleteSnapshot(AutoDeleteSnapshot&& other);
+    ~AutoDeleteSnapshot();
+
+  private:
+    DISALLOW_COPY_AND_ASSIGN(AutoDeleteSnapshot);
+    SnapshotManager* manager_ = nullptr;
+    SnapshotManager::LockedFile* lock_ = nullptr;
+};
+
+// Return a list of partitions in |builder| with the name ending in |suffix|.
+std::vector<android::fs_mgr::Partition*> ListPartitionsWithSuffix(
+        android::fs_mgr::MetadataBuilder* builder, const std::string& suffix);
+
+// Initialize a device before using it as the COW device for a dm-snapshot device.
+bool InitializeCow(const std::string& device);
+
 }  // namespace snapshot
 }  // namespace android
diff --git a/fs_mgr/libstorage_literals/Android.bp b/fs_mgr/libstorage_literals/Android.bp
new file mode 100644
index 0000000..11611dd
--- /dev/null
+++ b/fs_mgr/libstorage_literals/Android.bp
@@ -0,0 +1,6 @@
+
+cc_library_headers {
+    name: "libstorage_literals_headers",
+    host_supported: true,
+    export_include_dirs: ["."],
+}
diff --git a/fs_mgr/libstorage_literals/storage_literals/storage_literals.h b/fs_mgr/libstorage_literals/storage_literals/storage_literals.h
new file mode 100644
index 0000000..ac0dfbd
--- /dev/null
+++ b/fs_mgr/libstorage_literals/storage_literals/storage_literals.h
@@ -0,0 +1,77 @@
+// Copyright (C) 2019 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#pragma once
+
+#include <stdint.h>
+#include <stdlib.h>
+
+namespace android {
+namespace storage_literals {
+
+template <size_t Power>
+struct Size {
+    static constexpr size_t power = Power;
+    explicit constexpr Size(uint64_t count) : value_(count) {}
+
+    constexpr uint64_t bytes() const { return value_ << power; }
+    constexpr uint64_t count() const { return value_; }
+    constexpr operator uint64_t() const { return bytes(); }
+
+  private:
+    uint64_t value_;
+};
+
+using B = Size<0>;
+using KiB = Size<10>;
+using MiB = Size<20>;
+using GiB = Size<30>;
+
+constexpr B operator""_B(unsigned long long v) {  // NOLINT
+    return B{v};
+}
+
+constexpr KiB operator""_KiB(unsigned long long v) {  // NOLINT
+    return KiB{v};
+}
+
+constexpr MiB operator""_MiB(unsigned long long v) {  // NOLINT
+    return MiB{v};
+}
+
+constexpr GiB operator""_GiB(unsigned long long v) {  // NOLINT
+    return GiB{v};
+}
+
+template <typename Dest, typename Src>
+constexpr Dest size_cast(Src src) {
+    if (Src::power < Dest::power) {
+        return Dest(src.count() >> (Dest::power - Src::power));
+    }
+    if (Src::power > Dest::power) {
+        return Dest(src.count() << (Src::power - Dest::power));
+    }
+    return Dest(src.count());
+}
+
+static_assert(1_B == 1);
+static_assert(1_KiB == 1 << 10);
+static_assert(1_MiB == 1 << 20);
+static_assert(1_GiB == 1 << 30);
+static_assert(size_cast<KiB>(1_B).count() == 0);
+static_assert(size_cast<KiB>(1024_B).count() == 1);
+static_assert(size_cast<KiB>(1_MiB).count() == 1024);
+
+}  // namespace storage_literals
+}  // namespace android
diff --git a/fs_mgr/libvbmeta/Android.bp b/fs_mgr/libvbmeta/Android.bp
new file mode 100644
index 0000000..937e0f3
--- /dev/null
+++ b/fs_mgr/libvbmeta/Android.bp
@@ -0,0 +1,52 @@
+//
+// Copyright (C) 2019 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+libvbmeta_lib_deps = [
+    "libbase",
+    "libcrypto",
+]
+
+cc_library {
+    name: "libvbmeta",
+    host_supported: true,
+    srcs: [
+        "builder.cpp",
+        "reader.cpp",
+        "utility.cpp",
+        "writer.cpp",
+    ],
+    shared_libs: [
+        "liblog",
+    ] + libvbmeta_lib_deps,
+    export_include_dirs: ["include"],
+}
+
+cc_test_host {
+    name: "libvbmeta_test",
+    static_libs: [
+        "libsparse",
+        "libvbmeta",
+        "libz",
+    ] + libvbmeta_lib_deps,
+    srcs: [
+        "builder_test.cpp",
+        "super_vbmeta_test.cpp",
+    ],
+    required: [
+        "avbtool",
+        "vbmake",
+    ],
+}
\ No newline at end of file
diff --git a/fs_mgr/libvbmeta/builder.cpp b/fs_mgr/libvbmeta/builder.cpp
new file mode 100644
index 0000000..a901a4f
--- /dev/null
+++ b/fs_mgr/libvbmeta/builder.cpp
@@ -0,0 +1,214 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "builder.h"
+
+#include <android-base/file.h>
+#include <openssl/sha.h>
+
+#include "reader.h"
+#include "utility.h"
+#include "writer.h"
+
+using android::base::ErrnoError;
+using android::base::Error;
+using android::base::Result;
+using android::base::unique_fd;
+
+namespace android {
+namespace fs_mgr {
+
+SuperVBMetaBuilder::SuperVBMetaBuilder() {}
+
+SuperVBMetaBuilder::SuperVBMetaBuilder(const int super_vbmeta_fd,
+                                       const std::map<std::string, std::string>& images_path)
+    : super_vbmeta_fd_(super_vbmeta_fd), images_path_(images_path) {}
+
+Result<void> SuperVBMetaBuilder::Build() {
+    for (const auto& [vbmeta_name, file_path] : images_path_) {
+        Result<std::string> content = ReadVBMetaImageFromFile(file_path);
+        if (!content) {
+            return content.error();
+        }
+
+        Result<uint8_t> vbmeta_index = AddVBMetaImage(vbmeta_name);
+        if (!vbmeta_index) {
+            return vbmeta_index.error();
+        }
+
+        Result<void> rv_export_vbmeta_image =
+                ExportVBMetaImageToFile(vbmeta_index.value(), content.value());
+        if (!rv_export_vbmeta_image) {
+            return rv_export_vbmeta_image;
+        }
+    }
+    return {};
+}
+
+Result<std::string> SuperVBMetaBuilder::ReadVBMetaImageFromFile(const std::string& file) {
+    unique_fd source_fd(TEMP_FAILURE_RETRY(open(file.c_str(), O_RDONLY | O_CLOEXEC)));
+    if (source_fd < 0) {
+        return ErrnoError() << "Couldn't open vbmeta image file " << file;
+    }
+
+    Result<uint64_t> file_size = GetFileSize(source_fd);
+    if (!file_size) {
+        return file_size.error();
+    }
+
+    if (file_size.value() > VBMETA_IMAGE_MAX_SIZE) {
+        return Error() << "vbmeta image file size " << file_size.value() << " is too large";
+    }
+
+    std::unique_ptr<uint8_t[]> buffer = std::make_unique<uint8_t[]>(VBMETA_IMAGE_MAX_SIZE);
+    if (!android::base::ReadFully(source_fd, buffer.get(), file_size.value())) {
+        return ErrnoError() << "Couldn't read vbmeta image file " << file;
+    }
+
+    return std::string(reinterpret_cast<const char*>(buffer.get()), VBMETA_IMAGE_MAX_SIZE);
+}
+
+Result<uint8_t> SuperVBMetaBuilder::GetEmptySlot() {
+    for (uint8_t i = 0; i < VBMETA_IMAGE_MAX_NUM; ++i) {
+        if ((table_.header.in_use & (1 << i)) == 0) return i;
+    }
+    return Error() << "There isn't empty slot in super vbmeta";
+}
+
+Result<uint8_t> SuperVBMetaBuilder::AddVBMetaImage(const std::string& vbmeta_name) {
+    auto desc = std::find_if(
+            table_.descriptors.begin(), table_.descriptors.end(),
+            [&vbmeta_name](const auto& entry) { return entry.vbmeta_name == vbmeta_name; });
+
+    uint8_t slot_number = 0;
+    if (desc != table_.descriptors.end()) {
+        slot_number = desc->vbmeta_index;
+    } else {
+        Result<uint8_t> new_slot = GetEmptySlot();
+        if (!new_slot) {
+            return new_slot;
+        }
+        slot_number = new_slot.value();
+
+        // insert new descriptor into table
+        InternalVBMetaDescriptor new_desc;
+        new_desc.vbmeta_index = slot_number;
+        new_desc.vbmeta_name_length = vbmeta_name.length();
+        new_desc.vbmeta_name = vbmeta_name;
+        memset(new_desc.reserved, 0, sizeof(new_desc.reserved));
+        table_.descriptors.emplace_back(std::move(new_desc));
+
+        // mark slot as in use
+        table_.header.in_use |= (1 << slot_number);
+    }
+
+    return slot_number;
+}
+
+void SuperVBMetaBuilder::DeleteVBMetaImage(const std::string& vbmeta_name) {
+    auto desc = std::find_if(
+            table_.descriptors.begin(), table_.descriptors.end(),
+            [&vbmeta_name](const auto& entry) { return entry.vbmeta_name == vbmeta_name; });
+
+    if (desc != table_.descriptors.end()) {
+        // mark slot as not in use
+        table_.header.in_use &= ~(1 << desc->vbmeta_index);
+
+        // erase descriptor in table
+        table_.descriptors.erase(desc);
+    }
+}
+
+std::unique_ptr<VBMetaTable> SuperVBMetaBuilder::ExportVBMetaTable() {
+    // calculate descriptors size
+    uint32_t descriptors_size = 0;
+    for (const auto& desc : table_.descriptors) {
+        descriptors_size += SUPER_VBMETA_DESCRIPTOR_SIZE + desc.vbmeta_name_length * sizeof(char);
+    }
+
+    // export header
+    table_.header.magic = SUPER_VBMETA_MAGIC;
+    table_.header.major_version = SUPER_VBMETA_MAJOR_VERSION;
+    table_.header.minor_version = SUPER_VBMETA_MINOR_VERSION;
+    table_.header.header_size = SUPER_VBMETA_HEADER_SIZE;
+    table_.header.total_size = SUPER_VBMETA_HEADER_SIZE + descriptors_size;
+    memset(table_.header.checksum, 0, sizeof(table_.header.checksum));
+    table_.header.descriptors_size = descriptors_size;
+    memset(table_.header.reserved, 0, sizeof(table_.header.reserved));
+    std::string serialized_table = SerializeVBMetaTable(table_);
+    ::SHA256(reinterpret_cast<const uint8_t*>(serialized_table.c_str()), table_.header.total_size,
+             &table_.header.checksum[0]);
+
+    return std::make_unique<VBMetaTable>(table_);
+}
+
+Result<void> SuperVBMetaBuilder::ExportVBMetaTableToFile() {
+    std::unique_ptr<VBMetaTable> table = ExportVBMetaTable();
+
+    std::string serialized_table = SerializeVBMetaTable(*table);
+
+    android::base::Result<void> rv_write_primary_vbmeta_table =
+            WritePrimaryVBMetaTable(super_vbmeta_fd_, serialized_table);
+    if (!rv_write_primary_vbmeta_table) {
+        return rv_write_primary_vbmeta_table;
+    }
+
+    android::base::Result<void> rv_write_backup_vbmeta_table =
+            WriteBackupVBMetaTable(super_vbmeta_fd_, serialized_table);
+    return rv_write_backup_vbmeta_table;
+}
+
+Result<void> SuperVBMetaBuilder::ExportVBMetaImageToFile(const uint8_t vbmeta_index,
+                                                         const std::string& vbmeta_image) {
+    Result<void> rv_write_vbmeta_image =
+            WriteVBMetaImage(super_vbmeta_fd_, vbmeta_index, vbmeta_image);
+    if (!rv_write_vbmeta_image) {
+        return rv_write_vbmeta_image;
+    }
+
+    Result<void> rv_validate_vbmeta_image =
+            ValidateVBMetaImage(super_vbmeta_fd_, vbmeta_index, vbmeta_image);
+    return rv_validate_vbmeta_image;
+}
+
+bool WriteToSuperVBMetaFile(const std::string& super_vbmeta_file,
+                            const std::map<std::string, std::string>& images_path) {
+    unique_fd super_vbmeta_fd(TEMP_FAILURE_RETRY(
+            open(super_vbmeta_file.c_str(), O_CREAT | O_RDWR | O_TRUNC | O_CLOEXEC, 0644)));
+    if (super_vbmeta_fd < 0) {
+        PERROR << "Couldn't open super vbmeta file " << super_vbmeta_file;
+        return false;
+    }
+
+    SuperVBMetaBuilder builder(super_vbmeta_fd, images_path);
+
+    Result<void> rv_build = builder.Build();
+    if (!rv_build) {
+        LERROR << rv_build.error();
+        return false;
+    }
+
+    Result<void> rv_export = builder.ExportVBMetaTableToFile();
+    if (!rv_export) {
+        LERROR << rv_export.error();
+        return false;
+    }
+
+    return true;
+}
+
+}  // namespace fs_mgr
+}  // namespace android
\ No newline at end of file
diff --git a/fs_mgr/libvbmeta/builder.h b/fs_mgr/libvbmeta/builder.h
new file mode 100644
index 0000000..58ea36a
--- /dev/null
+++ b/fs_mgr/libvbmeta/builder.h
@@ -0,0 +1,55 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <map>
+#include <string>
+
+#include <android-base/result.h>
+
+#include "super_vbmeta_format.h"
+
+namespace android {
+namespace fs_mgr {
+
+class SuperVBMetaBuilder {
+  public:
+    SuperVBMetaBuilder();
+    SuperVBMetaBuilder(const int super_vbmeta_fd,
+                       const std::map<std::string, std::string>& images_path);
+    android::base::Result<void> Build();
+    android::base::Result<std::string> ReadVBMetaImageFromFile(const std::string& file);
+    // It adds the vbmeta image in super_vbmeta and returns the index
+    // (which has the same meaning with vbmeta_index of VBMetaDescriptor).
+    android::base::Result<uint8_t> AddVBMetaImage(const std::string& vbmeta_name);
+    void DeleteVBMetaImage(const std::string& vbmeta_name);
+    std::unique_ptr<VBMetaTable> ExportVBMetaTable();
+    android::base::Result<void> ExportVBMetaTableToFile();
+    android::base::Result<void> ExportVBMetaImageToFile(const uint8_t vbmeta_index,
+                                                        const std::string& vbmeta_image);
+
+  private:
+    android::base::Result<uint8_t> GetEmptySlot();
+
+    int super_vbmeta_fd_;
+    VBMetaTable table_;
+    // Maps vbmeta image name to vbmeta image file path.
+    std::map<std::string, std::string> images_path_;
+};
+
+}  // namespace fs_mgr
+}  // namespace android
\ No newline at end of file
diff --git a/fs_mgr/libvbmeta/builder_test.cpp b/fs_mgr/libvbmeta/builder_test.cpp
new file mode 100644
index 0000000..9a015fd
--- /dev/null
+++ b/fs_mgr/libvbmeta/builder_test.cpp
@@ -0,0 +1,80 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <gtest/gtest.h>
+
+#include "builder.h"
+#include "super_vbmeta_format.h"
+
+using android::base::Result;
+using android::fs_mgr::SuperVBMetaBuilder;
+
+TEST(BuilderTest, VBMetaTableBasic) {
+    std::unique_ptr<SuperVBMetaBuilder> builder = std::make_unique<SuperVBMetaBuilder>();
+    ASSERT_NE(builder, nullptr);
+
+    Result<uint8_t> vbmeta_index = builder->AddVBMetaImage("vbmeta" /* vbmeta_name */
+    );
+    EXPECT_TRUE(vbmeta_index);
+
+    Result<uint8_t> vbmeta_system_slot = builder->AddVBMetaImage("vbmeta_system" /* vbmeta_name */
+    );
+    EXPECT_TRUE(vbmeta_system_slot);
+
+    Result<uint8_t> vbmeta_vendor_slot = builder->AddVBMetaImage("vbmeta_vendor" /* vbmeta_name */
+    );
+    EXPECT_TRUE(vbmeta_vendor_slot);
+
+    builder->DeleteVBMetaImage("vbmeta_system" /* vbmeta_name */
+    );
+
+    Result<uint8_t> vbmeta_product_slot = builder->AddVBMetaImage("vbmeta_product" /* vbmeta_name */
+    );
+    EXPECT_TRUE(vbmeta_product_slot);
+
+    std::unique_ptr<VBMetaTable> table = builder->ExportVBMetaTable();
+    ASSERT_NE(table, nullptr);
+
+    // check for vbmeta table header
+    EXPECT_EQ(table->header.magic, SUPER_VBMETA_MAGIC);
+    EXPECT_EQ(table->header.major_version, SUPER_VBMETA_MAJOR_VERSION);
+    EXPECT_EQ(table->header.minor_version, SUPER_VBMETA_MINOR_VERSION);
+    EXPECT_EQ(table->header.header_size, SUPER_VBMETA_HEADER_SIZE);
+    EXPECT_EQ(table->header.total_size,
+              SUPER_VBMETA_HEADER_SIZE + SUPER_VBMETA_DESCRIPTOR_SIZE * 3 + 33);
+    EXPECT_EQ(table->header.descriptors_size, SUPER_VBMETA_DESCRIPTOR_SIZE * 3 + 33);
+
+    // Test for vbmeta table descriptors
+    EXPECT_EQ(table->descriptors.size(), 3);
+
+    EXPECT_EQ(table->descriptors[0].vbmeta_index, 0);
+    EXPECT_EQ(table->descriptors[0].vbmeta_name_length, 6);
+    for (int i = 0; i < sizeof(table->descriptors[0].reserved); i++)
+        EXPECT_EQ(table->descriptors[0].reserved[i], 0);
+    EXPECT_EQ(table->descriptors[0].vbmeta_name, "vbmeta");
+
+    EXPECT_EQ(table->descriptors[1].vbmeta_index, 2);
+    EXPECT_EQ(table->descriptors[1].vbmeta_name_length, 13);
+    for (int i = 0; i < sizeof(table->descriptors[1].reserved); i++)
+        EXPECT_EQ(table->descriptors[1].reserved[i], 0);
+    EXPECT_EQ(table->descriptors[1].vbmeta_name, "vbmeta_vendor");
+
+    EXPECT_EQ(table->descriptors[2].vbmeta_index, 1);
+    EXPECT_EQ(table->descriptors[2].vbmeta_name_length, 14);
+    for (int i = 0; i < sizeof(table->descriptors[2].reserved); i++)
+        EXPECT_EQ(table->descriptors[2].reserved[i], 0);
+    EXPECT_EQ(table->descriptors[2].vbmeta_name, "vbmeta_product");
+}
\ No newline at end of file
diff --git a/fs_mgr/libvbmeta/include/libvbmeta/libvbmeta.h b/fs_mgr/libvbmeta/include/libvbmeta/libvbmeta.h
new file mode 100644
index 0000000..ab7ba73
--- /dev/null
+++ b/fs_mgr/libvbmeta/include/libvbmeta/libvbmeta.h
@@ -0,0 +1,29 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <map>
+#include <string>
+
+namespace android {
+namespace fs_mgr {
+
+bool WriteToSuperVBMetaFile(const std::string& super_vbmeta_file,
+                            const std::map<std::string, std::string>& images_path);
+
+}  // namespace fs_mgr
+}  // namespace android
\ No newline at end of file
diff --git a/fs_mgr/libvbmeta/reader.cpp b/fs_mgr/libvbmeta/reader.cpp
new file mode 100644
index 0000000..212d186
--- /dev/null
+++ b/fs_mgr/libvbmeta/reader.cpp
@@ -0,0 +1,118 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "reader.h"
+
+#include <android-base/file.h>
+
+using android::base::ErrnoError;
+using android::base::Error;
+using android::base::Result;
+
+namespace android {
+namespace fs_mgr {
+
+Result<void> LoadAndVerifySuperVBMetaHeader(const void* buffer, SuperVBMetaHeader* header) {
+    memcpy(header, buffer, sizeof(*header));
+
+    // Do basic validation of super vbmeta.
+    if (header->magic != SUPER_VBMETA_MAGIC) {
+        return Error() << "Super VBMeta has invalid magic value";
+    }
+
+    // Check that the version is compatible.
+    if (header->major_version != SUPER_VBMETA_MAJOR_VERSION ||
+        header->minor_version > SUPER_VBMETA_MINOR_VERSION) {
+        return Error() << "Super VBMeta has incompatible version";
+    }
+    return {};
+}
+
+void LoadVBMetaDescriptors(const void* buffer, uint32_t size,
+                           std::vector<InternalVBMetaDescriptor>* descriptors) {
+    for (int p = 0; p < size;) {
+        InternalVBMetaDescriptor descriptor;
+        memcpy(&descriptor, (char*)buffer + p, SUPER_VBMETA_DESCRIPTOR_SIZE);
+        p += SUPER_VBMETA_DESCRIPTOR_SIZE;
+
+        descriptor.vbmeta_name = std::string((char*)buffer + p, descriptor.vbmeta_name_length);
+        p += descriptor.vbmeta_name_length;
+
+        descriptors->emplace_back(std::move(descriptor));
+    }
+}
+
+Result<void> ReadVBMetaTable(int fd, uint64_t offset, VBMetaTable* table) {
+    std::unique_ptr<uint8_t[]> header_buffer =
+            std::make_unique<uint8_t[]>(SUPER_VBMETA_HEADER_SIZE);
+    if (!android::base::ReadFullyAtOffset(fd, header_buffer.get(), SUPER_VBMETA_HEADER_SIZE,
+                                          offset)) {
+        return ErrnoError() << "Couldn't read super vbmeta header at offset " << offset;
+    }
+
+    Result<void> rv_header = LoadAndVerifySuperVBMetaHeader(header_buffer.get(), &table->header);
+    if (!rv_header) {
+        return rv_header;
+    }
+
+    const uint64_t descriptors_offset = offset + table->header.header_size;
+    std::unique_ptr<uint8_t[]> descriptors_buffer =
+            std::make_unique<uint8_t[]>(table->header.descriptors_size);
+    if (!android::base::ReadFullyAtOffset(fd, descriptors_buffer.get(),
+                                          table->header.descriptors_size, descriptors_offset)) {
+        return ErrnoError() << "Couldn't read super vbmeta descriptors at offset "
+                            << descriptors_offset;
+    }
+
+    LoadVBMetaDescriptors(descriptors_buffer.get(), table->header.descriptors_size,
+                          &table->descriptors);
+    return {};
+}
+
+Result<void> ReadPrimaryVBMetaTable(int fd, VBMetaTable* table) {
+    uint64_t offset = PRIMARY_SUPER_VBMETA_TABLE_OFFSET;
+    return ReadVBMetaTable(fd, offset, table);
+}
+
+Result<void> ReadBackupVBMetaTable(int fd, VBMetaTable* table) {
+    uint64_t offset = BACKUP_SUPER_VBMETA_TABLE_OFFSET;
+    return ReadVBMetaTable(fd, offset, table);
+}
+
+Result<std::string> ReadVBMetaImage(int fd, int slot) {
+    const uint64_t offset = 2 * SUPER_VBMETA_TABLE_MAX_SIZE + slot * VBMETA_IMAGE_MAX_SIZE;
+    std::unique_ptr<uint8_t[]> buffer = std::make_unique<uint8_t[]>(VBMETA_IMAGE_MAX_SIZE);
+    if (!android::base::ReadFullyAtOffset(fd, buffer.get(), VBMETA_IMAGE_MAX_SIZE, offset)) {
+        return ErrnoError() << "Couldn't read vbmeta image at offset " << offset;
+    }
+    return std::string(reinterpret_cast<char*>(buffer.get()), VBMETA_IMAGE_MAX_SIZE);
+}
+
+Result<void> ValidateVBMetaImage(int super_vbmeta_fd, int vbmeta_index,
+                                 const std::string& vbmeta_image) {
+    Result<std::string> content = ReadVBMetaImage(super_vbmeta_fd, vbmeta_index);
+    if (!content) {
+        return content.error();
+    }
+
+    if (vbmeta_image != content.value()) {
+        return Error() << "VBMeta Image in Super VBMeta differ from the original one.";
+    }
+    return {};
+}
+
+}  // namespace fs_mgr
+}  // namespace android
diff --git a/fs_mgr/libvbmeta/reader.h b/fs_mgr/libvbmeta/reader.h
new file mode 100644
index 0000000..f0997ff
--- /dev/null
+++ b/fs_mgr/libvbmeta/reader.h
@@ -0,0 +1,34 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <android-base/result.h>
+
+#include "super_vbmeta_format.h"
+
+namespace android {
+namespace fs_mgr {
+
+android::base::Result<void> ReadPrimaryVBMetaTable(int fd, VBMetaTable* table);
+android::base::Result<void> ReadBackupVBMetaTable(int fd, VBMetaTable* table);
+android::base::Result<std::string> ReadVBMetaImage(int fd, int slot);
+
+android::base::Result<void> ValidateVBMetaImage(int super_vbmeta_fd, int vbmeta_index,
+                                                const std::string& vbmeta_image);
+
+}  // namespace fs_mgr
+}  // namespace android
\ No newline at end of file
diff --git a/fs_mgr/libvbmeta/super_vbmeta_format.h b/fs_mgr/libvbmeta/super_vbmeta_format.h
new file mode 100644
index 0000000..c62a2dd
--- /dev/null
+++ b/fs_mgr/libvbmeta/super_vbmeta_format.h
@@ -0,0 +1,34 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/* This .h file is intended for CPP clients (usually fastbootd, recovery and update_engine)  */
+
+#pragma once
+
+#include <string>
+#include <vector>
+
+#include "super_vbmeta_format_c.h"
+
+struct InternalVBMetaDescriptor : VBMetaDescriptor {
+    /*  64: The vbmeta image's name */
+    std::string vbmeta_name;
+};
+
+struct VBMetaTable {
+    SuperVBMetaHeader header;
+    std::vector<InternalVBMetaDescriptor> descriptors;
+};
\ No newline at end of file
diff --git a/fs_mgr/libvbmeta/super_vbmeta_format_c.h b/fs_mgr/libvbmeta/super_vbmeta_format_c.h
new file mode 100644
index 0000000..6d79801
--- /dev/null
+++ b/fs_mgr/libvbmeta/super_vbmeta_format_c.h
@@ -0,0 +1,122 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/* This .h file is intended for C clients (usually bootloader).  */
+
+#pragma once
+
+#include <stdint.h>
+
+/* Magic signature for super vbmeta. */
+#define SUPER_VBMETA_MAGIC 0x5356424d
+
+/* Current super vbmeta version. */
+#define SUPER_VBMETA_MAJOR_VERSION 1
+#define SUPER_VBMETA_MINOR_VERSION 0
+
+/* super vbmeta size. */
+#define SUPER_VBMETA_HEADER_SIZE sizeof(SuperVBMetaHeader)
+#define SUPER_VBMETA_DESCRIPTOR_SIZE sizeof(VBMetaDescriptor)
+#define SUPER_VBMETA_TABLE_MAX_SIZE 2048
+
+/* super vbmeta offset. */
+#define PRIMARY_SUPER_VBMETA_TABLE_OFFSET 0
+#define BACKUP_SUPER_VBMETA_TABLE_OFFSET SUPER_VBMETA_TABLE_MAX_SIZE
+
+/* restriction of vbmeta image */
+#define VBMETA_IMAGE_MAX_NUM 32
+#define VBMETA_IMAGE_MAX_SIZE 64 * 1024
+
+/* Binary format of the super vbmeta image.
+ *
+ * The super vbmeta image consists of two blocks:
+ *
+ *  +------------------------------------------+
+ *  | Super VBMeta Table - fixed size          |
+ *  +------------------------------------------+
+ *  | Backup Super VBMeta Table - fixed size   |
+ *  +------------------------------------------+
+ *  | VBMeta Images - fixed size               |
+ *  +------------------------------------------+
+ *
+ *  The "Super VBMeta Table" records the offset
+ *  and the size of each vbmeta_partition within
+ *  /super_vbmeta.
+ *
+ *  The "VBMeta Image" is copied from each vbmeta_partition
+ *  and filled with 0 until 64K bytes.
+ *
+ * The super vbmeta table consists of two blocks:
+ *
+ *  +-----------------------------------------+
+ *  | Header data - fixed size                |
+ *  +-----------------------------------------+
+ *  | VBMeta descriptors - variable size      |
+ *  +-----------------------------------------+
+ *
+ * The "Header data" block is described by the following struct and
+ * is always 128 bytes long.
+ *
+ * The "VBMeta descriptor" is |descriptors_size| + |vbmeta_name_length|
+ * bytes long. It contains the offset and size for each vbmeta image
+ * and is followed by |vbmeta_name_length| bytes of the partition name
+ * (UTF-8 encoded).
+ */
+
+typedef struct SuperVBMetaHeader {
+    /*  0: Magic signature (SUPER_VBMETA_MAGIC). */
+    uint32_t magic;
+
+    /*  4: Major version. Version number required to read this super vbmeta. If the version is not
+     * equal to the library version, the super vbmeta should be considered incompatible.
+     */
+    uint16_t major_version;
+
+    /*  6: Minor version. A library supporting newer features should be able to
+     * read super vbmeta with an older minor version. However, an older library
+     * should not support reading super vbmeta if its minor version is higher.
+     */
+    uint16_t minor_version;
+
+    /*  8: The size of this header struct. */
+    uint32_t header_size;
+
+    /*  12: The size of this super vbmeta table. */
+    uint32_t total_size;
+
+    /*  16: SHA256 checksum of this super vbmeta table, with this field set to 0. */
+    uint8_t checksum[32];
+
+    /*  48: The size of the vbmeta table descriptors. */
+    uint32_t descriptors_size;
+
+    /*  52: mark which slot is in use. */
+    uint32_t in_use = 0;
+
+    /*  56: reserved for other usage, filled with 0. */
+    uint8_t reserved[72];
+} __attribute__((packed)) SuperVBMetaHeader;
+
+typedef struct VBMetaDescriptor {
+    /*  0: The slot number of the vbmeta image. */
+    uint8_t vbmeta_index;
+
+    /*  12: The length of the vbmeta image name. */
+    uint32_t vbmeta_name_length;
+
+    /*  16: Space reserved for other usage, filled with 0. */
+    uint8_t reserved[48];
+} __attribute__((packed)) VBMetaDescriptor;
\ No newline at end of file
diff --git a/fs_mgr/libvbmeta/super_vbmeta_test.cpp b/fs_mgr/libvbmeta/super_vbmeta_test.cpp
new file mode 100644
index 0000000..6b4fc5d
--- /dev/null
+++ b/fs_mgr/libvbmeta/super_vbmeta_test.cpp
@@ -0,0 +1,191 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <android-base/file.h>
+#include <gtest/gtest.h>
+#include <openssl/sha.h>
+#include <sparse/sparse.h>
+
+#include "reader.h"
+#include "super_vbmeta_format.h"
+#include "utility.h"
+#include "writer.h"
+
+#define FAKE_DATA_SIZE 40960
+#define FAKE_PARTITION_SIZE FAKE_DATA_SIZE * 25
+
+using android::base::Result;
+using android::fs_mgr::GetFileSize;
+using android::fs_mgr::ReadVBMetaImage;
+using SparsePtr = std::unique_ptr<sparse_file, decltype(&sparse_file_destroy)>;
+
+void GeneratePartitionImage(int fd, const std::string& file_name,
+                            const std::string& partition_name) {
+    std::unique_ptr<uint8_t[]> buffer = std::make_unique<uint8_t[]>(FAKE_DATA_SIZE);
+    for (size_t c = 0; c < FAKE_DATA_SIZE; c++) {
+        buffer[c] = uint8_t(c);
+    }
+
+    SparsePtr file(sparse_file_new(512 /* block size */, FAKE_DATA_SIZE), sparse_file_destroy);
+    EXPECT_TRUE(file);
+    EXPECT_EQ(0, sparse_file_add_data(file.get(), buffer.get(), FAKE_DATA_SIZE,
+                                      0 /* offset in blocks */));
+    EXPECT_EQ(0, sparse_file_write(file.get(), fd, false /* gz */, true /* sparse */,
+                                   false /* crc */));
+
+    std::stringstream cmd;
+    cmd << "avbtool add_hashtree_footer"
+        << " --image " << file_name << " --partition_name " << partition_name
+        << " --partition_size " << FAKE_PARTITION_SIZE << " --algorithm SHA256_RSA2048"
+        << " --key external/avb/test/data/testkey_rsa2048.pem";
+
+    int rc = system(cmd.str().c_str());
+    EXPECT_TRUE(WIFEXITED(rc));
+    EXPECT_EQ(WEXITSTATUS(rc), 0);
+}
+
+void GenerateVBMetaImage(const std::string& vbmeta_file_name,
+                         const std::string& include_file_name) {
+    std::stringstream cmd;
+    cmd << "avbtool make_vbmeta_image"
+        << " --output " << vbmeta_file_name << " --include_descriptors_from_image "
+        << include_file_name;
+
+    int rc = system(cmd.str().c_str());
+    EXPECT_TRUE(WIFEXITED(rc));
+    EXPECT_EQ(WEXITSTATUS(rc), 0);
+}
+
+std::string ReadVBMetaImageFromFile(const std::string& file) {
+    android::base::unique_fd fd(open(file.c_str(), O_RDONLY | O_CLOEXEC));
+    EXPECT_GT(fd, 0);
+    Result<uint64_t> file_size = GetFileSize(fd);
+    EXPECT_TRUE(file_size);
+    std::unique_ptr<uint8_t[]> buffer = std::make_unique<uint8_t[]>(VBMETA_IMAGE_MAX_SIZE);
+    EXPECT_TRUE(android::base::ReadFully(fd, buffer.get(), file_size.value()));
+    return std::string(reinterpret_cast<char*>(buffer.get()), VBMETA_IMAGE_MAX_SIZE);
+}
+
+TEST(VBMetaTableTest, VBMetaTableBasic) {
+    TemporaryDir td;
+
+    // Generate Partition Image
+    TemporaryFile system_tf(std::string(td.path));
+    std::string system_path(system_tf.path);
+    GeneratePartitionImage(system_tf.fd, system_path, "system");
+    system_tf.release();
+
+    TemporaryFile vendor_tf(std::string(td.path));
+    std::string vendor_path(vendor_tf.path);
+    GeneratePartitionImage(vendor_tf.fd, vendor_path, "vendor");
+    vendor_tf.release();
+
+    TemporaryFile product_tf(std::string(td.path));
+    std::string product_path(product_tf.path);
+    GeneratePartitionImage(product_tf.fd, product_path, "product");
+    product_tf.release();
+
+    // Generate VBMeta Image
+    std::string vbmeta_system_path(td.path);
+    vbmeta_system_path.append("/vbmeta_system.img");
+    GenerateVBMetaImage(vbmeta_system_path, system_path);
+
+    std::string vbmeta_vendor_path(td.path);
+    vbmeta_vendor_path.append("/vbmeta_vendor.img");
+    GenerateVBMetaImage(vbmeta_vendor_path, vendor_path);
+
+    std::string vbmeta_product_path(td.path);
+    vbmeta_product_path.append("/vbmeta_product.img");
+    GenerateVBMetaImage(vbmeta_product_path, product_path);
+
+    // Generate Super VBMeta Image
+    std::string super_vbmeta_path(td.path);
+    super_vbmeta_path.append("/super_vbmeta.img");
+
+    std::stringstream cmd;
+    cmd << "vbmake"
+        << " --image "
+        << "vbmeta_system"
+        << "=" << vbmeta_system_path << " --image "
+        << "vbmeta_vendor"
+        << "=" << vbmeta_vendor_path << " --image "
+        << "vbmeta_product"
+        << "=" << vbmeta_product_path << " --output=" << super_vbmeta_path;
+
+    int rc = system(cmd.str().c_str());
+    ASSERT_TRUE(WIFEXITED(rc));
+    ASSERT_EQ(WEXITSTATUS(rc), 0);
+
+    android::base::unique_fd fd(open(super_vbmeta_path.c_str(), O_RDONLY | O_CLOEXEC));
+    EXPECT_GT(fd, 0);
+
+    // Check the size of vbmeta table
+    Result<uint64_t> super_vbmeta_size = GetFileSize(fd);
+    EXPECT_TRUE(super_vbmeta_size);
+    EXPECT_EQ(super_vbmeta_size.value(),
+              SUPER_VBMETA_TABLE_MAX_SIZE * 2 + VBMETA_IMAGE_MAX_SIZE * 3);
+
+    // Check Primary vbmeta table is equal to Backup one
+    VBMetaTable table;
+    EXPECT_TRUE(android::fs_mgr::ReadPrimaryVBMetaTable(fd, &table));
+    VBMetaTable table_backup;
+    EXPECT_TRUE(android::fs_mgr::ReadBackupVBMetaTable(fd, &table_backup));
+    EXPECT_EQ(android::fs_mgr::SerializeVBMetaTable(table),
+              android::fs_mgr::SerializeVBMetaTable(table_backup));
+
+    // Check vbmeta table Header Checksum
+    std::string serial_table = android::fs_mgr::SerializeVBMetaTable(table);
+    std::string serial_removed_checksum(serial_table);
+    // Replace checksum 32 bytes (starts at 16th byte) with 0
+    serial_removed_checksum.replace(16, 32, 32, 0);
+    uint8_t test_checksum[32];
+    ::SHA256(reinterpret_cast<const uint8_t*>(serial_removed_checksum.c_str()),
+             table.header.total_size, &test_checksum[0]);
+    EXPECT_EQ(memcmp(table.header.checksum, test_checksum, 32), 0);
+
+    // Check vbmeta table descriptors and vbmeta images
+    EXPECT_EQ(table.descriptors.size(), 3);
+
+    EXPECT_EQ(table.descriptors[0].vbmeta_index, 0);
+    EXPECT_EQ(table.descriptors[0].vbmeta_name_length, 14);
+    EXPECT_EQ(table.descriptors[0].vbmeta_name, "vbmeta_product");
+    Result<std::string> vbmeta_product_content = ReadVBMetaImage(fd, 0);
+    EXPECT_TRUE(vbmeta_product_content);
+    EXPECT_EQ(ReadVBMetaImageFromFile(vbmeta_product_path), vbmeta_product_content.value());
+
+    EXPECT_EQ(table.descriptors[1].vbmeta_index, 1);
+    EXPECT_EQ(table.descriptors[1].vbmeta_name_length, 13);
+    EXPECT_EQ(table.descriptors[1].vbmeta_name, "vbmeta_system");
+    Result<std::string> vbmeta_system_content = ReadVBMetaImage(fd, 1);
+    EXPECT_TRUE(vbmeta_system_content);
+    EXPECT_EQ(ReadVBMetaImageFromFile(vbmeta_system_path), vbmeta_system_content.value());
+
+    EXPECT_EQ(table.descriptors[2].vbmeta_index, 2);
+    EXPECT_EQ(table.descriptors[2].vbmeta_name_length, 13);
+    EXPECT_EQ(table.descriptors[2].vbmeta_name, "vbmeta_vendor");
+    Result<std::string> vbmeta_vendor_content = ReadVBMetaImage(fd, 2);
+    EXPECT_TRUE(vbmeta_vendor_content);
+    EXPECT_EQ(ReadVBMetaImageFromFile(vbmeta_vendor_path), vbmeta_vendor_content.value());
+}
+
+int main(int argc, char** argv) {
+    ::testing::InitGoogleTest(&argc, argv);
+    return RUN_ALL_TESTS();
+}
\ No newline at end of file
diff --git a/fs_mgr/libvbmeta/utility.cpp b/fs_mgr/libvbmeta/utility.cpp
new file mode 100644
index 0000000..c184227
--- /dev/null
+++ b/fs_mgr/libvbmeta/utility.cpp
@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "utility.h"
+
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "super_vbmeta_format.h"
+
+using android::base::ErrnoError;
+using android::base::Error;
+using android::base::Result;
+
+namespace android {
+namespace fs_mgr {
+
+Result<uint64_t> GetFileSize(int fd) {
+    struct stat sb;
+    if (fstat(fd, &sb) == -1) {
+        return ErrnoError() << "Couldn't get the file size";
+    }
+    return sb.st_size;
+}
+
+uint64_t IndexOffset(const uint8_t vbmeta_index) {
+    /* There are primary and backup vbmeta table in super_vbmeta,
+       so SUPER_VBMETA_TABLE_MAX_SIZE is counted twice. */
+    return 2 * SUPER_VBMETA_TABLE_MAX_SIZE + vbmeta_index * VBMETA_IMAGE_MAX_SIZE;
+}
+
+}  // namespace fs_mgr
+}  // namespace android
diff --git a/fs_mgr/libvbmeta/utility.h b/fs_mgr/libvbmeta/utility.h
new file mode 100644
index 0000000..91db0ad
--- /dev/null
+++ b/fs_mgr/libvbmeta/utility.h
@@ -0,0 +1,37 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <android-base/logging.h>
+#include <android-base/result.h>
+
+#define VBMETA_TAG "[libvbmeta]"
+#define LWARN LOG(WARNING) << VBMETA_TAG
+#define LINFO LOG(INFO) << VBMETA_TAG
+#define LERROR LOG(ERROR) << VBMETA_TAG
+#define PWARNING PLOG(WARNING) << VBMETA_TAG
+#define PERROR PLOG(ERROR) << VBMETA_TAG
+
+namespace android {
+namespace fs_mgr {
+
+android::base::Result<uint64_t> GetFileSize(int fd);
+
+uint64_t IndexOffset(const uint8_t vbmeta_index);
+
+}  // namespace fs_mgr
+}  // namespace android
\ No newline at end of file
diff --git a/fs_mgr/libvbmeta/writer.cpp b/fs_mgr/libvbmeta/writer.cpp
new file mode 100644
index 0000000..fc0e0fb
--- /dev/null
+++ b/fs_mgr/libvbmeta/writer.cpp
@@ -0,0 +1,81 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "writer.h"
+
+#include <android-base/file.h>
+
+#include "utility.h"
+
+using android::base::ErrnoError;
+using android::base::Result;
+
+namespace android {
+namespace fs_mgr {
+
+std::string SerializeVBMetaTable(const VBMetaTable& input) {
+    std::string table;
+    table.append(reinterpret_cast<const char*>(&input.header), SUPER_VBMETA_HEADER_SIZE);
+
+    for (const auto& desc : input.descriptors) {
+        table.append(reinterpret_cast<const char*>(&desc), SUPER_VBMETA_DESCRIPTOR_SIZE);
+        table.append(desc.vbmeta_name);
+    }
+
+    // Ensure the size of vbmeta table is SUPER_VBMETA_TABLE_MAX_SIZE
+    table.resize(SUPER_VBMETA_TABLE_MAX_SIZE, '\0');
+
+    return table;
+}
+
+Result<void> WritePrimaryVBMetaTable(int fd, const std::string& table) {
+    const uint64_t offset = PRIMARY_SUPER_VBMETA_TABLE_OFFSET;
+    if (lseek(fd, offset, SEEK_SET) < 0) {
+        return ErrnoError() << __PRETTY_FUNCTION__ << " lseek failed";
+    }
+
+    if (!android::base::WriteFully(fd, table.data(), table.size())) {
+        return ErrnoError() << "Failed to write primary vbmeta table at offset " << offset;
+    }
+    return {};
+}
+
+Result<void> WriteBackupVBMetaTable(int fd, const std::string& table) {
+    const uint64_t offset = BACKUP_SUPER_VBMETA_TABLE_OFFSET;
+    if (lseek(fd, offset, SEEK_SET) < 0) {
+        return ErrnoError() << __PRETTY_FUNCTION__ << " lseek failed";
+    }
+
+    if (!android::base::WriteFully(fd, table.data(), table.size())) {
+        return ErrnoError() << "Failed to write backup vbmeta table at offset " << offset;
+    }
+    return {};
+}
+
+Result<void> WriteVBMetaImage(int fd, const uint8_t slot_number, const std::string& vbmeta_image) {
+    const uint64_t offset = IndexOffset(slot_number);
+    if (lseek(fd, offset, SEEK_SET) < 0) {
+        return ErrnoError() << __PRETTY_FUNCTION__ << " lseek failed";
+    }
+
+    if (!android::base::WriteFully(fd, vbmeta_image.data(), vbmeta_image.size())) {
+        return ErrnoError() << "Failed to write vbmeta image at offset " << offset;
+    }
+    return {};
+}
+
+}  // namespace fs_mgr
+}  // namespace android
\ No newline at end of file
diff --git a/fs_mgr/libvbmeta/writer.h b/fs_mgr/libvbmeta/writer.h
new file mode 100644
index 0000000..f8eed36
--- /dev/null
+++ b/fs_mgr/libvbmeta/writer.h
@@ -0,0 +1,36 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <string>
+
+#include <android-base/result.h>
+
+#include "super_vbmeta_format.h"
+
+namespace android {
+namespace fs_mgr {
+
+std::string SerializeVBMetaTable(const VBMetaTable& input);
+
+android::base::Result<void> WritePrimaryVBMetaTable(int fd, const std::string& table);
+android::base::Result<void> WriteBackupVBMetaTable(int fd, const std::string& table);
+android::base::Result<void> WriteVBMetaImage(int fd, const uint8_t slot_number,
+                                             const std::string& vbmeta_image);
+
+}  // namespace fs_mgr
+}  // namespace android
\ No newline at end of file
diff --git a/init/Android.bp b/init/Android.bp
index 52cd1ca..b601075 100644
--- a/init/Android.bp
+++ b/init/Android.bp
@@ -62,7 +62,6 @@
         },
     },
     static_libs: [
-        "libseccomp_policy",
         "libavb",
         "libc++fs",
         "libcgrouprc_format",
@@ -129,6 +128,7 @@
         "persistent_properties.cpp",
         "persistent_properties.proto",
         "property_service.cpp",
+        "property_service.proto",
         "property_type.cpp",
         "reboot.cpp",
         "reboot_utils.cpp",
@@ -223,6 +223,7 @@
 
     srcs: [
         "devices_test.cpp",
+        "firmware_handler_test.cpp",
         "init_test.cpp",
         "keychords_test.cpp",
         "persistent_properties_test.cpp",
diff --git a/init/Android.mk b/init/Android.mk
index d7258a7..8f58437 100644
--- a/init/Android.mk
+++ b/init/Android.mk
@@ -92,7 +92,6 @@
     liblogwrap \
     libext4_utils \
     libfscrypt \
-    libseccomp_policy \
     libcrypto_utils \
     libsparse \
     libavb \
@@ -119,6 +118,7 @@
 LOCAL_SANITIZE := signed-integer-overflow
 # First stage init is weird: it may start without stdout/stderr, and no /proc.
 LOCAL_NOSANITIZE := hwaddress
+LOCAL_INJECT_BSSL_HASH := true
 include $(BUILD_EXECUTABLE)
 endif
 
diff --git a/init/README.md b/init/README.md
index 2de76a9..29b972d 100644
--- a/init/README.md
+++ b/init/README.md
@@ -170,6 +170,8 @@
   be changed by setting the "androidboot.console" kernel parameter. In
   all cases the leading "/dev/" should be omitted, so "/dev/tty0" would be
   specified as just "console tty0".
+  This option connects stdin, stdout, and stderr to the console. It is mutually exclusive with the
+  stdio_to_kmsg option, which only connects stdout and stderr to kmsg.
 
 `critical`
 > This is a device-critical service. If it exits more than four times in
@@ -263,6 +265,12 @@
 > Scheduling priority of the service process. This value has to be in range
   -20 to 19. Default priority is 0. Priority is set via setpriority().
 
+`reboot_on_failure <target>`
+> If this process cannot be started or if the process terminates with an exit code other than
+  CLD_EXITED or an status other than '0', reboot the system with the target specified in
+  _target_. _target_ takes the same format as the parameter to sys.powerctl. This is particularly
+  intended to be used with the `exec_start` builtin for any must-have checks during boot.
+
 `restart_period <seconds>`
 > If a non-oneshot service exits, it will be restarted at its start time plus
   this period. It defaults to 5s to rate limit crashing services.
@@ -307,6 +315,13 @@
   seclabel or computed based on the service executable file security context.
   For native executables see libcutils android\_get\_control\_socket().
 
+`stdio_to_kmsg`
+> Redirect stdout and stderr to /dev/kmsg_debug. This is useful for services that do not use native
+  Android logging during early boot and whose logs messages we want to capture. This is only enabled
+  when /dev/kmsg_debug is enabled, which is only enabled on userdebug and eng builds.
+  This is mutually exclusive with the console option, which additionally connects stdin to the
+  given console.
+
 `timeout_period <seconds>`
 > Provide a timeout after which point the service will be killed. The oneshot keyword is respected
   here, so oneshot services do not automatically restart, however all other services will.
diff --git a/init/README.ueventd.md b/init/README.ueventd.md
index c592c37..053ebf8 100644
--- a/init/README.ueventd.md
+++ b/init/README.ueventd.md
@@ -82,7 +82,7 @@
 
 ## Firmware loading
 ----------------
-Ueventd automatically serves firmware requests by searching through a list of firmware directories
+Ueventd by default serves firmware requests by searching through a list of firmware directories
 for a file matching the uevent `FIRMWARE`. It then forks a process to serve this firmware to the
 kernel.
 
@@ -100,6 +100,26 @@
 Ueventd will wait until after `post-fs` in init, to keep retrying before believing the firmwares are
 not present.
 
+The exact firmware file to be served can be customized by running an external program by a
+`external_firmware_handler` line in a ueventd.rc file. This line takes the format of
+
+    external_firmware_handler <devpath> <user name to run as> <path to external program>
+For example
+
+    external_firmware_handler /devices/leds/red/firmware/coeffs.bin system /vendor/bin/led_coeffs.bin
+Will launch `/vendor/bin/led_coeffs.bin` as the system user instead of serving the default firmware
+for `/devices/leds/red/firmware/coeffs.bin`.
+
+Ueventd will provide the uevent `DEVPATH` and `FIRMWARE` to this external program on the environment
+via environment variables with the same names. Ueventd will use the string written to stdout as the
+new name of the firmware to load. It will still look for the new firmware in the list of firmware
+directories stated above. It will also reject file names with `..` in them, to prevent leaving these
+directories. If stdout cannot be read, or the program returns with any exit code other than
+`EXIT_SUCCESS`, or the program crashes, the default firmware from the uevent will be loaded.
+
+Ueventd will additionally log all messages sent to stderr from the external program to the serial
+console after the external program has exited.
+
 ## Coldboot
 --------
 Ueventd must create devices in `/dev` for all devices that have already sent their uevents before
@@ -110,3 +130,9 @@
 
 For boot time purposes, this is done in parallel across a set of child processes. `ueventd.cpp` in
 this directory contains documentation on how the parallelization is done.
+
+There is an option to parallelize the restorecon function during cold boot as well. This should only
+be done for devices that do not use genfscon, which is the recommended method for labeling sysfs
+nodes. To enable this option, use the below line in a ueventd.rc script:
+
+    parallel_restorecon enabled
diff --git a/init/action_parser.cpp b/init/action_parser.cpp
index ff20e43..9736824 100644
--- a/init/action_parser.cpp
+++ b/init/action_parser.cpp
@@ -121,13 +121,8 @@
     }
 
     Subcontext* action_subcontext = nullptr;
-    if (subcontexts_) {
-        for (auto& subcontext : *subcontexts_) {
-            if (StartsWith(filename, subcontext.path_prefix())) {
-                action_subcontext = &subcontext;
-                break;
-            }
-        }
+    if (subcontext_ && subcontext_->PathMatchesSubcontext(filename)) {
+        action_subcontext = subcontext_;
     }
 
     std::string event_trigger;
diff --git a/init/action_parser.h b/init/action_parser.h
index 2fe9983..3000132 100644
--- a/init/action_parser.h
+++ b/init/action_parser.h
@@ -30,8 +30,8 @@
 
 class ActionParser : public SectionParser {
   public:
-    ActionParser(ActionManager* action_manager, std::vector<Subcontext>* subcontexts)
-        : action_manager_(action_manager), subcontexts_(subcontexts), action_(nullptr) {}
+    ActionParser(ActionManager* action_manager, Subcontext* subcontext)
+        : action_manager_(action_manager), subcontext_(subcontext), action_(nullptr) {}
     Result<void> ParseSection(std::vector<std::string>&& args, const std::string& filename,
                               int line) override;
     Result<void> ParseLineSection(std::vector<std::string>&& args, int line) override;
@@ -39,7 +39,7 @@
 
   private:
     ActionManager* action_manager_;
-    std::vector<Subcontext>* subcontexts_;
+    Subcontext* subcontext_;
     std::unique_ptr<Action> action_;
 };
 
diff --git a/init/builtins.cpp b/init/builtins.cpp
index d2c73cb..42211b2 100644
--- a/init/builtins.cpp
+++ b/init/builtins.cpp
@@ -80,6 +80,7 @@
 using namespace std::literals::string_literals;
 
 using android::base::Basename;
+using android::base::StartsWith;
 using android::base::StringPrintf;
 using android::base::unique_fd;
 using android::fs_mgr::Fstab;
@@ -701,6 +702,15 @@
 }
 
 static Result<void> do_setprop(const BuiltinArguments& args) {
+    if (StartsWith(args[1], "ctl.")) {
+        return Error()
+               << "Cannot set ctl. properties from init; call the Service functions directly";
+    }
+    if (args[1] == kRestoreconProperty) {
+        return Error() << "Cannot set '" << kRestoreconProperty
+                       << "' from init; use the restorecon builtin directly";
+    }
+
     property_set(args[1], args[2]);
     return {};
 }
@@ -1016,7 +1026,20 @@
 }
 
 static Result<void> do_load_persist_props(const BuiltinArguments& args) {
-    load_persist_props();
+    // Devices with FDE have load_persist_props called twice; the first time when the temporary
+    // /data partition is mounted and then again once /data is truly mounted.  We do not want to
+    // read persistent properties from the temporary /data partition or mark persistent properties
+    // as having been loaded during the first call, so we return in that case.
+    std::string crypto_state = android::base::GetProperty("ro.crypto.state", "");
+    std::string crypto_type = android::base::GetProperty("ro.crypto.type", "");
+    if (crypto_state == "encrypted" && crypto_type == "block") {
+        static size_t num_calls = 0;
+        if (++num_calls == 1) return {};
+    }
+
+    SendLoadPersistentPropertiesMessage();
+
+    start_waiting_for_property("ro.persistent_properties.ready", "true");
     return {};
 }
 
@@ -1081,20 +1104,6 @@
     return {};
 }
 
-static Result<void> do_exec_reboot_on_failure(const BuiltinArguments& args) {
-    auto reboot_reason = args[1];
-    auto reboot = [reboot_reason](const std::string& message) {
-        property_set(LAST_REBOOT_REASON_PROPERTY, reboot_reason);
-        sync();
-        LOG(FATAL) << message << ": rebooting into bootloader, reason: " << reboot_reason;
-    };
-
-    std::vector<std::string> remaining_args(args.begin() + 1, args.end());
-    remaining_args[0] = args[0];
-
-    return ExecWithFunctionOnFailure(remaining_args, reboot);
-}
-
 static Result<void> ExecVdcRebootOnFailure(const std::string& vdc_arg) {
     auto reboot_reason = vdc_arg + "_failed";
 
@@ -1202,7 +1211,6 @@
         {"enable",                  {1,     1,    {false,  do_enable}}},
         {"exec",                    {1,     kMax, {false,  do_exec}}},
         {"exec_background",         {1,     kMax, {false,  do_exec_background}}},
-        {"exec_reboot_on_failure",  {2,     kMax, {false,  do_exec_reboot_on_failure}}},
         {"exec_start",              {1,     1,    {false,  do_exec_start}}},
         {"export",                  {2,     2,    {false,  do_export}}},
         {"hostname",                {1,     1,    {true,   do_hostname}}},
diff --git a/init/firmware_handler.cpp b/init/firmware_handler.cpp
index c067f6f..1dce2d5 100644
--- a/init/firmware_handler.cpp
+++ b/init/firmware_handler.cpp
@@ -17,6 +17,10 @@
 #include "firmware_handler.h"
 
 #include <fcntl.h>
+#include <pwd.h>
+#include <signal.h>
+#include <stdlib.h>
+#include <string.h>
 #include <sys/sendfile.h>
 #include <sys/wait.h>
 #include <unistd.h>
@@ -26,25 +30,29 @@
 #include <android-base/chrono_utils.h>
 #include <android-base/file.h>
 #include <android-base/logging.h>
+#include <android-base/strings.h>
 #include <android-base/unique_fd.h>
 
+using android::base::ReadFdToString;
+using android::base::Socketpair;
+using android::base::Split;
 using android::base::Timer;
+using android::base::Trim;
 using android::base::unique_fd;
 using android::base::WriteFully;
 
 namespace android {
 namespace init {
 
-static void LoadFirmware(const Uevent& uevent, const std::string& root, int fw_fd, size_t fw_size,
-                         int loading_fd, int data_fd) {
+static void LoadFirmware(const std::string& firmware, const std::string& root, int fw_fd,
+                         size_t fw_size, int loading_fd, int data_fd) {
     // Start transfer.
     WriteFully(loading_fd, "1", 1);
 
     // Copy the firmware.
     int rc = sendfile(data_fd, fw_fd, nullptr, fw_size);
     if (rc == -1) {
-        PLOG(ERROR) << "firmware: sendfile failed { '" << root << "', '" << uevent.firmware
-                    << "' }";
+        PLOG(ERROR) << "firmware: sendfile failed { '" << root << "', '" << firmware << "' }";
     }
 
     // Tell the firmware whether to abort or commit.
@@ -56,36 +64,151 @@
     return access("/dev/.booting", F_OK) == 0;
 }
 
-FirmwareHandler::FirmwareHandler(std::vector<std::string> firmware_directories)
-    : firmware_directories_(std::move(firmware_directories)) {}
+FirmwareHandler::FirmwareHandler(std::vector<std::string> firmware_directories,
+                                 std::vector<ExternalFirmwareHandler> external_firmware_handlers)
+    : firmware_directories_(std::move(firmware_directories)),
+      external_firmware_handlers_(std::move(external_firmware_handlers)) {}
 
-void FirmwareHandler::ProcessFirmwareEvent(const Uevent& uevent) {
-    int booting = IsBooting();
+Result<std::string> FirmwareHandler::RunExternalHandler(const std::string& handler, uid_t uid,
+                                                        const Uevent& uevent) const {
+    unique_fd child_stdout;
+    unique_fd parent_stdout;
+    if (!Socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0, &child_stdout, &parent_stdout)) {
+        return ErrnoError() << "Socketpair() for stdout failed";
+    }
 
+    unique_fd child_stderr;
+    unique_fd parent_stderr;
+    if (!Socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0, &child_stderr, &parent_stderr)) {
+        return ErrnoError() << "Socketpair() for stderr failed";
+    }
+
+    signal(SIGCHLD, SIG_DFL);
+
+    auto pid = fork();
+    if (pid < 0) {
+        return ErrnoError() << "fork() failed";
+    }
+
+    if (pid == 0) {
+        setenv("FIRMWARE", uevent.firmware.c_str(), 1);
+        setenv("DEVPATH", uevent.path.c_str(), 1);
+        parent_stdout.reset();
+        parent_stderr.reset();
+        close(STDOUT_FILENO);
+        close(STDERR_FILENO);
+        dup2(child_stdout.get(), STDOUT_FILENO);
+        dup2(child_stderr.get(), STDERR_FILENO);
+
+        auto args = Split(handler, " ");
+        std::vector<char*> c_args;
+        for (auto& arg : args) {
+            c_args.emplace_back(arg.data());
+        }
+        c_args.emplace_back(nullptr);
+
+        if (setuid(uid) != 0) {
+            fprintf(stderr, "setuid() failed: %s", strerror(errno));
+            _exit(EXIT_FAILURE);
+        }
+
+        execv(c_args[0], c_args.data());
+        fprintf(stderr, "exec() failed: %s", strerror(errno));
+        _exit(EXIT_FAILURE);
+    }
+
+    child_stdout.reset();
+    child_stderr.reset();
+
+    int status;
+    pid_t waited_pid = TEMP_FAILURE_RETRY(waitpid(pid, &status, 0));
+    if (waited_pid == -1) {
+        return ErrnoError() << "waitpid() failed";
+    }
+
+    std::string stdout_content;
+    if (!ReadFdToString(parent_stdout.get(), &stdout_content)) {
+        return ErrnoError() << "ReadFdToString() for stdout failed";
+    }
+
+    std::string stderr_content;
+    if (ReadFdToString(parent_stderr.get(), &stderr_content)) {
+        auto messages = Split(stderr_content, "\n");
+        for (const auto& message : messages) {
+            if (!message.empty()) {
+                LOG(ERROR) << "External Firmware Handler: " << message;
+            }
+        }
+    } else {
+        LOG(ERROR) << "ReadFdToString() for stderr failed";
+    }
+
+    if (WIFEXITED(status)) {
+        if (WEXITSTATUS(status) == EXIT_SUCCESS) {
+            return Trim(stdout_content);
+        } else {
+            return Error() << "exited with status " << WEXITSTATUS(status);
+        }
+    } else if (WIFSIGNALED(status)) {
+        return Error() << "killed by signal " << WTERMSIG(status);
+    }
+
+    return Error() << "unexpected exit status " << status;
+}
+
+std::string FirmwareHandler::GetFirmwarePath(const Uevent& uevent) const {
+    for (const auto& external_handler : external_firmware_handlers_) {
+        if (external_handler.devpath == uevent.path) {
+            LOG(INFO) << "Launching external firmware handler '" << external_handler.handler_path
+                      << "' for devpath: '" << uevent.path << "' firmware: '" << uevent.firmware
+                      << "'";
+
+            auto result =
+                    RunExternalHandler(external_handler.handler_path, external_handler.uid, uevent);
+            if (!result) {
+                LOG(ERROR) << "Using default firmware; External firmware handler failed: "
+                           << result.error();
+                return uevent.firmware;
+            }
+            if (result->find("..") != std::string::npos) {
+                LOG(ERROR) << "Using default firmware; External firmware handler provided an "
+                              "invalid path, '"
+                           << *result << "'";
+                return uevent.firmware;
+            }
+            LOG(INFO) << "Loading firmware '" << *result << "' in place of '" << uevent.firmware
+                      << "'";
+            return *result;
+        }
+    }
     LOG(INFO) << "firmware: loading '" << uevent.firmware << "' for '" << uevent.path << "'";
+    return uevent.firmware;
+}
 
-    std::string root = "/sys" + uevent.path;
+void FirmwareHandler::ProcessFirmwareEvent(const std::string& root,
+                                           const std::string& firmware) const {
     std::string loading = root + "/loading";
     std::string data = root + "/data";
 
     unique_fd loading_fd(open(loading.c_str(), O_WRONLY | O_CLOEXEC));
     if (loading_fd == -1) {
-        PLOG(ERROR) << "couldn't open firmware loading fd for " << uevent.firmware;
+        PLOG(ERROR) << "couldn't open firmware loading fd for " << firmware;
         return;
     }
 
     unique_fd data_fd(open(data.c_str(), O_WRONLY | O_CLOEXEC));
     if (data_fd == -1) {
-        PLOG(ERROR) << "couldn't open firmware data fd for " << uevent.firmware;
+        PLOG(ERROR) << "couldn't open firmware data fd for " << firmware;
         return;
     }
 
     std::vector<std::string> attempted_paths_and_errors;
 
+    int booting = IsBooting();
 try_loading_again:
     attempted_paths_and_errors.clear();
     for (const auto& firmware_directory : firmware_directories_) {
-        std::string file = firmware_directory + uevent.firmware;
+        std::string file = firmware_directory + firmware;
         unique_fd fw_fd(open(file.c_str(), O_RDONLY | O_CLOEXEC));
         if (fw_fd == -1) {
             attempted_paths_and_errors.emplace_back("firmware: attempted " + file +
@@ -98,7 +221,7 @@
                                                     ", fstat failed: " + strerror(errno));
             continue;
         }
-        LoadFirmware(uevent, root, fw_fd, sb.st_size, loading_fd, data_fd);
+        LoadFirmware(firmware, root, fw_fd, sb.st_size, loading_fd, data_fd);
         return;
     }
 
@@ -110,7 +233,7 @@
         goto try_loading_again;
     }
 
-    LOG(ERROR) << "firmware: could not find firmware for " << uevent.firmware;
+    LOG(ERROR) << "firmware: could not find firmware for " << firmware;
     for (const auto& message : attempted_paths_and_errors) {
         LOG(ERROR) << message;
     }
@@ -129,7 +252,8 @@
     }
     if (pid == 0) {
         Timer t;
-        ProcessFirmwareEvent(uevent);
+        auto firmware = GetFirmwarePath(uevent);
+        ProcessFirmwareEvent("/sys" + uevent.path, firmware);
         LOG(INFO) << "loading " << uevent.path << " took " << t;
         _exit(EXIT_SUCCESS);
     }
diff --git a/init/firmware_handler.h b/init/firmware_handler.h
index 3996096..b4138f1 100644
--- a/init/firmware_handler.h
+++ b/init/firmware_handler.h
@@ -14,32 +14,48 @@
  * limitations under the License.
  */
 
-#ifndef _INIT_FIRMWARE_HANDLER_H
-#define _INIT_FIRMWARE_HANDLER_H
+#pragma once
+
+#include <pwd.h>
 
 #include <string>
 #include <vector>
 
+#include "result.h"
 #include "uevent.h"
 #include "uevent_handler.h"
 
 namespace android {
 namespace init {
 
+struct ExternalFirmwareHandler {
+    ExternalFirmwareHandler(std::string devpath, uid_t uid, std::string handler_path)
+        : devpath(std::move(devpath)), uid(uid), handler_path(std::move(handler_path)) {}
+    std::string devpath;
+    uid_t uid;
+    std::string handler_path;
+};
+
 class FirmwareHandler : public UeventHandler {
   public:
-    explicit FirmwareHandler(std::vector<std::string> firmware_directories);
+    FirmwareHandler(std::vector<std::string> firmware_directories,
+                    std::vector<ExternalFirmwareHandler> external_firmware_handlers);
     virtual ~FirmwareHandler() = default;
 
     void HandleUevent(const Uevent& uevent) override;
 
   private:
-    void ProcessFirmwareEvent(const Uevent& uevent);
+    friend void FirmwareTestWithExternalHandler(const std::string& test_name,
+                                                bool expect_new_firmware);
+
+    Result<std::string> RunExternalHandler(const std::string& handler, uid_t uid,
+                                           const Uevent& uevent) const;
+    std::string GetFirmwarePath(const Uevent& uevent) const;
+    void ProcessFirmwareEvent(const std::string& root, const std::string& firmware) const;
 
     std::vector<std::string> firmware_directories_;
+    std::vector<ExternalFirmwareHandler> external_firmware_handlers_;
 };
 
 }  // namespace init
 }  // namespace android
-
-#endif
diff --git a/init/firmware_handler_test.cpp b/init/firmware_handler_test.cpp
new file mode 100644
index 0000000..7bb603c
--- /dev/null
+++ b/init/firmware_handler_test.cpp
@@ -0,0 +1,125 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "firmware_handler.h"
+
+#include <stdlib.h>
+#include <iostream>
+
+#include <android-base/file.h>
+#include <gtest/gtest.h>
+
+#include "uevent.h"
+
+using android::base::GetExecutablePath;
+using namespace std::literals;
+
+namespace android {
+namespace init {
+
+void FirmwareTestWithExternalHandler(const std::string& test_name, bool expect_new_firmware) {
+    auto test_path = GetExecutablePath() + " firmware " + test_name;
+    auto external_firmware_handler = ExternalFirmwareHandler(
+            "/devices/led/firmware/test_firmware001.bin", getuid(), test_path);
+
+    auto firmware_handler = FirmwareHandler({"/test"}, {external_firmware_handler});
+
+    auto uevent = Uevent{
+            .path = "/devices/led/firmware/test_firmware001.bin",
+            .firmware = "test_firmware001.bin",
+    };
+
+    if (expect_new_firmware) {
+        EXPECT_EQ("other_firmware001.bin", firmware_handler.GetFirmwarePath(uevent));
+    } else {
+        EXPECT_EQ("test_firmware001.bin", firmware_handler.GetFirmwarePath(uevent));
+    }
+
+    // Always test the base case that the handler isn't invoked if the devpath doesn't match.
+    auto uevent_different_path = Uevent{
+            .path = "/devices/led/not/mine",
+            .firmware = "test_firmware001.bin",
+    };
+    EXPECT_EQ("test_firmware001.bin", firmware_handler.GetFirmwarePath(uevent_different_path));
+}
+
+TEST(firmware_handler, HandleChange) {
+    FirmwareTestWithExternalHandler("HandleChange", true);
+}
+
+int HandleChange(int argc, char** argv) {
+    // Assert that the environment is set up correctly.
+    if (getenv("DEVPATH") != "/devices/led/firmware/test_firmware001.bin"s) {
+        std::cerr << "$DEVPATH not set correctly" << std::endl;
+        return EXIT_FAILURE;
+    }
+    if (getenv("FIRMWARE") != "test_firmware001.bin"s) {
+        std::cerr << "$FIRMWARE not set correctly" << std::endl;
+        return EXIT_FAILURE;
+    }
+    std::cout << "other_firmware001.bin" << std::endl;
+    return 0;
+}
+
+TEST(firmware_handler, HandleAbort) {
+    FirmwareTestWithExternalHandler("HandleAbort", false);
+}
+
+int HandleAbort(int argc, char** argv) {
+    abort();
+    return 0;
+}
+
+TEST(firmware_handler, HandleFailure) {
+    FirmwareTestWithExternalHandler("HandleFailure", false);
+}
+
+int HandleFailure(int argc, char** argv) {
+    std::cerr << "Failed" << std::endl;
+    return EXIT_FAILURE;
+}
+
+TEST(firmware_handler, HandleBadPath) {
+    FirmwareTestWithExternalHandler("HandleBadPath", false);
+}
+
+int HandleBadPath(int argc, char** argv) {
+    std::cout << "../firmware.bin";
+    return 0;
+}
+
+}  // namespace init
+}  // namespace android
+
+// init_test.cpp contains the main entry point for all init tests.
+int FirmwareTestChildMain(int argc, char** argv) {
+    if (argc < 3) {
+        return 1;
+    }
+
+#define RunTest(testname)                           \
+    if (argv[2] == std::string(#testname)) {        \
+        return android::init::testname(argc, argv); \
+    }
+
+    RunTest(HandleChange);
+    RunTest(HandleAbort);
+    RunTest(HandleFailure);
+    RunTest(HandleBadPath);
+
+#undef RunTest
+    return 1;
+}
diff --git a/init/first_stage_mount.cpp b/init/first_stage_mount.cpp
index 6b4216f..9121bac 100644
--- a/init/first_stage_mount.cpp
+++ b/init/first_stage_mount.cpp
@@ -50,12 +50,13 @@
 using android::fs_mgr::AvbHandleStatus;
 using android::fs_mgr::AvbHashtreeResult;
 using android::fs_mgr::AvbUniquePtr;
-using android::fs_mgr::BuildGsiSystemFstabEntry;
 using android::fs_mgr::Fstab;
 using android::fs_mgr::FstabEntry;
 using android::fs_mgr::ReadDefaultFstab;
 using android::fs_mgr::ReadFstabFromDt;
 using android::fs_mgr::SkipMountingPartitions;
+using android::fs_mgr::TransformFstabForDsu;
+using android::init::WriteFile;
 using android::snapshot::SnapshotManager;
 
 using namespace std::literals;
@@ -77,8 +78,9 @@
     bool InitDevices();
 
   protected:
-    ListenerAction HandleBlockDevice(const std::string& name, const Uevent&);
-    bool InitRequiredDevices();
+    ListenerAction HandleBlockDevice(const std::string& name, const Uevent&,
+                                     std::set<std::string>* required_devices);
+    bool InitRequiredDevices(std::set<std::string> devices);
     bool InitMappedDevice(const std::string& verity_device);
     bool InitDeviceMapper();
     bool CreateLogicalPartitions();
@@ -89,14 +91,14 @@
     bool TrySwitchSystemAsRoot();
     bool TrySkipMountingPartitions();
     bool IsDmLinearEnabled();
-    bool GetDmLinearMetadataDevice();
+    void GetDmLinearMetadataDevice(std::set<std::string>* devices);
     bool InitDmLinearBackingDevices(const android::fs_mgr::LpMetadata& metadata);
     void UseGsiIfPresent();
 
-    ListenerAction UeventCallback(const Uevent& uevent);
+    ListenerAction UeventCallback(const Uevent& uevent, std::set<std::string>* required_devices);
 
     // Pure virtual functions.
-    virtual bool GetDmVerityDevices() = 0;
+    virtual bool GetDmVerityDevices(std::set<std::string>* devices) = 0;
     virtual bool SetUpDmVerity(FstabEntry* fstab_entry) = 0;
 
     bool need_dm_verity_;
@@ -104,7 +106,6 @@
 
     Fstab fstab_;
     std::string lp_metadata_partition_;
-    std::set<std::string> required_devices_partition_names_;
     std::string super_partition_name_;
     std::unique_ptr<DeviceHandler> device_handler_;
     UeventListener uevent_listener_;
@@ -116,7 +117,7 @@
     ~FirstStageMountVBootV1() override = default;
 
   protected:
-    bool GetDmVerityDevices() override;
+    bool GetDmVerityDevices(std::set<std::string>* devices) override;
     bool SetUpDmVerity(FstabEntry* fstab_entry) override;
 };
 
@@ -128,7 +129,7 @@
     ~FirstStageMountVBootV2() override = default;
 
   protected:
-    bool GetDmVerityDevices() override;
+    bool GetDmVerityDevices(std::set<std::string>* devices) override;
     bool SetUpDmVerity(FstabEntry* fstab_entry) override;
     bool InitAvbHandle();
 
@@ -252,7 +253,13 @@
 }
 
 bool FirstStageMount::InitDevices() {
-    return GetDmLinearMetadataDevice() && GetDmVerityDevices() && InitRequiredDevices();
+    std::set<std::string> devices;
+    GetDmLinearMetadataDevice(&devices);
+
+    if (!GetDmVerityDevices(&devices)) {
+        return false;
+    }
+    return InitRequiredDevices(std::move(devices));
 }
 
 bool FirstStageMount::IsDmLinearEnabled() {
@@ -262,45 +269,46 @@
     return false;
 }
 
-bool FirstStageMount::GetDmLinearMetadataDevice() {
+void FirstStageMount::GetDmLinearMetadataDevice(std::set<std::string>* devices) {
     // Add any additional devices required for dm-linear mappings.
     if (!IsDmLinearEnabled()) {
-        return true;
+        return;
     }
 
-    required_devices_partition_names_.emplace(super_partition_name_);
-    return true;
+    devices->emplace(super_partition_name_);
 }
 
-// Creates devices with uevent->partition_name matching one in the member variable
-// required_devices_partition_names_. Found partitions will then be removed from it
-// for the subsequent member function to check which devices are NOT created.
-bool FirstStageMount::InitRequiredDevices() {
+// Creates devices with uevent->partition_name matching ones in the given set.
+// Found partitions will then be removed from it for the subsequent member
+// function to check which devices are NOT created.
+bool FirstStageMount::InitRequiredDevices(std::set<std::string> devices) {
     if (!InitDeviceMapper()) {
         return false;
     }
 
-    if (required_devices_partition_names_.empty()) {
+    if (devices.empty()) {
         return true;
     }
 
-    auto uevent_callback = [this](const Uevent& uevent) { return UeventCallback(uevent); };
+    auto uevent_callback = [&, this](const Uevent& uevent) {
+        return UeventCallback(uevent, &devices);
+    };
     uevent_listener_.RegenerateUevents(uevent_callback);
 
-    // UeventCallback() will remove found partitions from required_devices_partition_names_.
-    // So if it isn't empty here, it means some partitions are not found.
-    if (!required_devices_partition_names_.empty()) {
+    // UeventCallback() will remove found partitions from |devices|. So if it
+    // isn't empty here, it means some partitions are not found.
+    if (!devices.empty()) {
         LOG(INFO) << __PRETTY_FUNCTION__
                   << ": partition(s) not found in /sys, waiting for their uevent(s): "
-                  << android::base::Join(required_devices_partition_names_, ", ");
+                  << android::base::Join(devices, ", ");
         Timer t;
         uevent_listener_.Poll(uevent_callback, 10s);
         LOG(INFO) << "Wait for partitions returned after " << t;
     }
 
-    if (!required_devices_partition_names_.empty()) {
+    if (!devices.empty()) {
         LOG(ERROR) << __PRETTY_FUNCTION__ << ": partition(s) not found after polling timeout: "
-                   << android::base::Join(required_devices_partition_names_, ", ");
+                   << android::base::Join(devices, ", ");
         return false;
     }
 
@@ -333,27 +341,20 @@
 }
 
 bool FirstStageMount::InitDmLinearBackingDevices(const android::fs_mgr::LpMetadata& metadata) {
+    std::set<std::string> devices;
+
     auto partition_names = android::fs_mgr::GetBlockDevicePartitionNames(metadata);
     for (const auto& partition_name : partition_names) {
         // The super partition was found in the earlier pass.
         if (partition_name == super_partition_name_) {
             continue;
         }
-        required_devices_partition_names_.emplace(partition_name);
+        devices.emplace(partition_name);
     }
-    if (required_devices_partition_names_.empty()) {
+    if (devices.empty()) {
         return true;
     }
-
-    auto uevent_callback = [this](const Uevent& uevent) { return UeventCallback(uevent); };
-    uevent_listener_.RegenerateUevents(uevent_callback);
-
-    if (!required_devices_partition_names_.empty()) {
-        LOG(ERROR) << __PRETTY_FUNCTION__ << ": partition(s) not found after polling timeout: "
-                   << android::base::Join(required_devices_partition_names_, ", ");
-        return false;
-    }
-    return true;
+    return InitRequiredDevices(std::move(devices));
 }
 
 bool FirstStageMount::CreateLogicalPartitions() {
@@ -372,6 +373,11 @@
             return false;
         }
         if (sm->NeedSnapshotsInFirstStageMount()) {
+            // When COW images are present for snapshots, they are stored on
+            // the data partition.
+            if (!InitRequiredDevices({"userdata"})) {
+                return false;
+            }
             return sm->CreateLogicalAndSnapshotPartitions(lp_metadata_partition_);
         }
     }
@@ -387,20 +393,21 @@
     return android::fs_mgr::CreateLogicalPartitions(*metadata.get(), lp_metadata_partition_);
 }
 
-ListenerAction FirstStageMount::HandleBlockDevice(const std::string& name, const Uevent& uevent) {
+ListenerAction FirstStageMount::HandleBlockDevice(const std::string& name, const Uevent& uevent,
+                                                  std::set<std::string>* required_devices) {
     // Matches partition name to create device nodes.
     // Both required_devices_partition_names_ and uevent->partition_name have A/B
     // suffix when A/B is used.
-    auto iter = required_devices_partition_names_.find(name);
-    if (iter != required_devices_partition_names_.end()) {
+    auto iter = required_devices->find(name);
+    if (iter != required_devices->end()) {
         LOG(VERBOSE) << __PRETTY_FUNCTION__ << ": found partition: " << *iter;
         if (IsDmLinearEnabled() && name == super_partition_name_) {
             std::vector<std::string> links = device_handler_->GetBlockDeviceSymlinks(uevent);
             lp_metadata_partition_ = links[0];
         }
-        required_devices_partition_names_.erase(iter);
+        required_devices->erase(iter);
         device_handler_->HandleUevent(uevent);
-        if (required_devices_partition_names_.empty()) {
+        if (required_devices->empty()) {
             return ListenerAction::kStop;
         } else {
             return ListenerAction::kContinue;
@@ -409,18 +416,19 @@
     return ListenerAction::kContinue;
 }
 
-ListenerAction FirstStageMount::UeventCallback(const Uevent& uevent) {
+ListenerAction FirstStageMount::UeventCallback(const Uevent& uevent,
+                                               std::set<std::string>* required_devices) {
     // Ignores everything that is not a block device.
     if (uevent.subsystem != "block") {
         return ListenerAction::kContinue;
     }
 
     if (!uevent.partition_name.empty()) {
-        return HandleBlockDevice(uevent.partition_name, uevent);
+        return HandleBlockDevice(uevent.partition_name, uevent, required_devices);
     } else {
         size_t base_idx = uevent.path.rfind('/');
         if (base_idx != std::string::npos) {
-            return HandleBlockDevice(uevent.path.substr(base_idx + 1), uevent);
+            return HandleBlockDevice(uevent.path.substr(base_idx + 1), uevent, required_devices);
         }
     }
     // Not found a partition or find an unneeded partition, continue to find others.
@@ -577,17 +585,7 @@
     const auto devices = fs_mgr_overlayfs_required_devices(&fstab_);
     for (auto const& device : devices) {
         if (android::base::StartsWith(device, "/dev/block/by-name/")) {
-            required_devices_partition_names_.emplace(basename(device.c_str()));
-            auto uevent_callback = [this](const Uevent& uevent) { return UeventCallback(uevent); };
-            uevent_listener_.RegenerateUevents(uevent_callback);
-            if (!required_devices_partition_names_.empty()) {
-                uevent_listener_.Poll(uevent_callback, 10s);
-                if (!required_devices_partition_names_.empty()) {
-                    LOG(ERROR) << __PRETTY_FUNCTION__
-                               << ": partition(s) not found after polling timeout: "
-                               << android::base::Join(required_devices_partition_names_, ", ");
-                }
-            }
+            InitRequiredDevices({basename(device.c_str())});
         } else {
             InitMappedDevice(device);
         }
@@ -599,14 +597,14 @@
 }
 
 void FirstStageMount::UseGsiIfPresent() {
-    std::string metadata_file, error;
+    std::string error;
 
-    if (!android::gsi::CanBootIntoGsi(&metadata_file, &error)) {
+    if (!android::gsi::CanBootIntoGsi(&error)) {
         LOG(INFO) << "GSI " << error << ", proceeding with normal boot";
         return;
     }
 
-    auto metadata = android::fs_mgr::ReadFromImageFile(metadata_file.c_str());
+    auto metadata = android::fs_mgr::ReadFromImageFile(gsi::kDsuLpMetadataFile);
     if (!metadata) {
         LOG(ERROR) << "GSI partition layout could not be read";
         return;
@@ -630,18 +628,20 @@
         return;
     }
 
-    // Replace the existing system fstab entry.
-    auto system_partition = std::find_if(fstab_.begin(), fstab_.end(), [](const auto& entry) {
-        return entry.mount_point == "/system";
-    });
-    if (system_partition != fstab_.end()) {
-        fstab_.erase(system_partition);
+    std::string lp_names = "";
+    std::vector<std::string> dsu_partitions;
+    for (auto&& partition : metadata->partitions) {
+        auto name = fs_mgr::GetPartitionName(partition);
+        dsu_partitions.push_back(name);
+        lp_names += name + ",";
     }
-    fstab_.emplace_back(BuildGsiSystemFstabEntry());
+    // Publish the logical partition names for TransformFstabForDsu
+    WriteFile(gsi::kGsiLpNamesFile, lp_names);
+    TransformFstabForDsu(&fstab_, dsu_partitions);
     gsi_not_on_userdata_ = (super_name != "userdata");
 }
 
-bool FirstStageMountVBootV1::GetDmVerityDevices() {
+bool FirstStageMountVBootV1::GetDmVerityDevices(std::set<std::string>* devices) {
     need_dm_verity_ = false;
 
     for (const auto& fstab_entry : fstab_) {
@@ -660,7 +660,7 @@
     // Notes that fstab_rec->blk_device has A/B suffix updated by fs_mgr when A/B is used.
     for (const auto& fstab_entry : fstab_) {
         if (!fstab_entry.fs_mgr_flags.logical) {
-            required_devices_partition_names_.emplace(basename(fstab_entry.blk_device.c_str()));
+            devices->emplace(basename(fstab_entry.blk_device.c_str()));
         }
     }
 
@@ -711,7 +711,7 @@
     }
 }
 
-bool FirstStageMountVBootV2::GetDmVerityDevices() {
+bool FirstStageMountVBootV2::GetDmVerityDevices(std::set<std::string>* devices) {
     need_dm_verity_ = false;
 
     std::set<std::string> logical_partitions;
@@ -725,7 +725,7 @@
             // Don't try to find logical partitions via uevent regeneration.
             logical_partitions.emplace(basename(fstab_entry.blk_device.c_str()));
         } else {
-            required_devices_partition_names_.emplace(basename(fstab_entry.blk_device.c_str()));
+            devices->emplace(basename(fstab_entry.blk_device.c_str()));
         }
     }
 
@@ -742,11 +742,11 @@
             if (logical_partitions.count(partition_name)) {
                 continue;
             }
-            // required_devices_partition_names_ is of type std::set so it's not an issue
-            // to emplace a partition twice. e.g., /vendor might be in both places:
+            // devices is of type std::set so it's not an issue to emplace a
+            // partition twice. e.g., /vendor might be in both places:
             //   - device_tree_vbmeta_parts_ = "vbmeta,boot,system,vendor"
             //   - mount_fstab_recs_: /vendor_a
-            required_devices_partition_names_.emplace(partition_name);
+            devices->emplace(partition_name);
         }
     }
     return true;
diff --git a/init/fscrypt_init_extensions.cpp b/init/fscrypt_init_extensions.cpp
index 9c2ca75..bd23e31 100644
--- a/init/fscrypt_init_extensions.cpp
+++ b/init/fscrypt_init_extensions.cpp
@@ -38,7 +38,7 @@
 
 #define TAG "fscrypt"
 
-static int set_system_de_policy_on(const std::string& dir);
+static int set_policy_on(const std::string& ref_basename, const std::string& dir);
 
 int fscrypt_install_keyring() {
     key_serial_t device_keyring = add_key("keyring", "fscrypt", 0, 0, KEY_SPEC_SESSION_KEYRING);
@@ -104,7 +104,7 @@
     // Special-case /data/media/obb per b/64566063
     if (dir == "/data/media/obb") {
         // Try to set policy on this directory, but if it is non-empty this may fail.
-        set_system_de_policy_on(dir);
+        set_policy_on(fscrypt_key_ref, dir);
         return 0;
     }
 
@@ -135,7 +135,16 @@
             return 0;
         }
     }
-    int err = set_system_de_policy_on(dir);
+    std::vector<std::string> per_boot_directories = {
+            "per_boot",
+    };
+    for (const auto& d : per_boot_directories) {
+        if ((prefix + d) == dir) {
+            LOG(INFO) << "Setting per_boot key on " << dir;
+            return set_policy_on(fscrypt_key_per_boot_ref, dir);
+        }
+    }
+    int err = set_policy_on(fscrypt_key_ref, dir);
     if (err == 0) {
         return 0;
     }
@@ -147,15 +156,15 @@
         if ((prefix + d) == dir) {
             LOG(ERROR) << "Setting policy failed, deleting: " << dir;
             delete_dir_contents(dir);
-            err = set_system_de_policy_on(dir);
+            err = set_policy_on(fscrypt_key_ref, dir);
             break;
         }
     }
     return err;
 }
 
-static int set_system_de_policy_on(const std::string& dir) {
-    std::string ref_filename = std::string("/data") + fscrypt_key_ref;
+static int set_policy_on(const std::string& ref_basename, const std::string& dir) {
+    std::string ref_filename = std::string("/data") + ref_basename;
     std::string policy;
     if (!android::base::ReadFileToString(ref_filename, &policy)) {
         LOG(ERROR) << "Unable to read system policy to set on " << dir;
diff --git a/init/host_init_stubs.h b/init/host_init_stubs.h
index f9a08a5..e3068b2 100644
--- a/init/host_init_stubs.h
+++ b/init/host_init_stubs.h
@@ -34,6 +34,11 @@
 namespace android {
 namespace init {
 
+// init.h
+inline void EnterShutdown(const std::string&) {
+    abort();
+}
+
 // property_service.h
 inline bool CanReadProperty(const std::string&, const std::string&) {
     return true;
diff --git a/init/init.cpp b/init/init.cpp
index 1f74ab6..ad31fa0 100644
--- a/init/init.cpp
+++ b/init/init.cpp
@@ -19,7 +19,6 @@
 #include <dirent.h>
 #include <fcntl.h>
 #include <pthread.h>
-#include <seccomp_policy.h>
 #include <signal.h>
 #include <stdlib.h>
 #include <string.h>
@@ -28,6 +27,9 @@
 #include <sys/types.h>
 #include <unistd.h>
 
+#define _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_
+#include <sys/_system_properties.h>
+
 #include <functional>
 #include <map>
 #include <memory>
@@ -60,6 +62,7 @@
 #include "mount_handler.h"
 #include "mount_namespace.h"
 #include "property_service.h"
+#include "proto_utils.h"
 #include "reboot.h"
 #include "reboot_utils.h"
 #include "security.h"
@@ -68,6 +71,7 @@
 #include "service.h"
 #include "service_parser.h"
 #include "sigchld_handler.h"
+#include "system/core/init/property_service.pb.h"
 #include "util.h"
 
 using namespace std::chrono_literals;
@@ -89,6 +93,7 @@
 static char qemu[32];
 
 static int signal_fd = -1;
+static int property_fd = -1;
 
 static std::unique_ptr<Timer> waiting_for_prop(nullptr);
 static std::string wait_prop_name;
@@ -98,7 +103,7 @@
 static bool do_shutdown = false;
 static bool load_debug_prop = false;
 
-static std::vector<Subcontext>* subcontexts;
+static std::unique_ptr<Subcontext> subcontext;
 
 void DumpState() {
     ServiceList::GetInstance().DumpState();
@@ -108,9 +113,10 @@
 Parser CreateParser(ActionManager& action_manager, ServiceList& service_list) {
     Parser parser;
 
-    parser.AddSectionParser(
-            "service", std::make_unique<ServiceParser>(&service_list, subcontexts, std::nullopt));
-    parser.AddSectionParser("on", std::make_unique<ActionParser>(&action_manager, subcontexts));
+    parser.AddSectionParser("service", std::make_unique<ServiceParser>(
+                                               &service_list, subcontext.get(), std::nullopt));
+    parser.AddSectionParser("on",
+                            std::make_unique<ActionParser>(&action_manager, subcontext.get()));
     parser.AddSectionParser("import", std::make_unique<ImportParser>(&parser));
 
     return parser;
@@ -120,8 +126,8 @@
 Parser CreateServiceOnlyParser(ServiceList& service_list) {
     Parser parser;
 
-    parser.AddSectionParser(
-            "service", std::make_unique<ServiceParser>(&service_list, subcontexts, std::nullopt));
+    parser.AddSectionParser("service", std::make_unique<ServiceParser>(
+                                               &service_list, subcontext.get(), std::nullopt));
     return parser;
 }
 
@@ -174,6 +180,16 @@
     waiting_for_prop.reset();
 }
 
+void EnterShutdown(const std::string& command) {
+    // We can't call HandlePowerctlMessage() directly in this function,
+    // because it modifies the contents of the action queue, which can cause the action queue
+    // to get into a bad state if this function is called from a command being executed by the
+    // action queue.  Instead we set this flag and ensure that shutdown happens before the next
+    // command is run in the main init loop.
+    shutdown_command = command;
+    do_shutdown = true;
+}
+
 void property_changed(const std::string& name, const std::string& value) {
     // If the property is sys.powerctl, we bypass the event queue and immediately handle it.
     // This is to ensure that init will always and immediately shutdown/reboot, regardless of
@@ -182,16 +198,7 @@
     // In non-thermal-shutdown case, 'shutdown' trigger will be fired to let device specific
     // commands to be executed.
     if (name == "sys.powerctl") {
-        // Despite the above comment, we can't call HandlePowerctlMessage() in this function,
-        // because it modifies the contents of the action queue, which can cause the action queue
-        // to get into a bad state if this function is called from a command being executed by the
-        // action queue.  Instead we set this flag and ensure that shutdown happens before the next
-        // command is run in the main init loop.
-        // TODO: once property service is removed from init, this will never happen from a builtin,
-        // but rather from a callback from the property service socket, in which case this hack can
-        // go away.
-        shutdown_command = value;
-        do_shutdown = true;
+        EnterShutdown(value);
     }
 
     if (property_triggers_enabled) ActionManager::GetInstance().QueuePropertyChange(name, value);
@@ -574,15 +581,6 @@
     }
 }
 
-static void GlobalSeccomp() {
-    import_kernel_cmdline(false, [](const std::string& key, const std::string& value,
-                                    bool in_qemu) {
-        if (key == "androidboot.seccomp" && value == "global" && !set_global_seccomp_filter()) {
-            LOG(FATAL) << "Failed to globally enable seccomp!";
-        }
-    });
-}
-
 static void UmountDebugRamdisk() {
     if (umount("/debug_ramdisk") != 0) {
         LOG(ERROR) << "Failed to umount /debug_ramdisk";
@@ -614,6 +612,60 @@
                                 selinux_start_time_ns));
 }
 
+void SendLoadPersistentPropertiesMessage() {
+    auto init_message = InitMessage{};
+    init_message.set_load_persistent_properties(true);
+    if (auto result = SendMessage(property_fd, init_message); !result) {
+        LOG(ERROR) << "Failed to send load persistent properties message: " << result.error();
+    }
+}
+
+void SendStopSendingMessagesMessage() {
+    auto init_message = InitMessage{};
+    init_message.set_stop_sending_messages(true);
+    if (auto result = SendMessage(property_fd, init_message); !result) {
+        LOG(ERROR) << "Failed to send load persistent properties message: " << result.error();
+    }
+}
+
+static void HandlePropertyFd() {
+    auto message = ReadMessage(property_fd);
+    if (!message) {
+        LOG(ERROR) << "Could not read message from property service: " << message.error();
+        return;
+    }
+
+    auto property_message = PropertyMessage{};
+    if (!property_message.ParseFromString(*message)) {
+        LOG(ERROR) << "Could not parse message from property service";
+        return;
+    }
+
+    switch (property_message.msg_case()) {
+        case PropertyMessage::kControlMessage: {
+            auto& control_message = property_message.control_message();
+            bool success = HandleControlMessage(control_message.msg(), control_message.name(),
+                                                control_message.pid());
+
+            uint32_t response = success ? PROP_SUCCESS : PROP_ERROR_HANDLE_CONTROL_MESSAGE;
+            if (control_message.has_fd()) {
+                int fd = control_message.fd();
+                TEMP_FAILURE_RETRY(send(fd, &response, sizeof(response), 0));
+                close(fd);
+            }
+            break;
+        }
+        case PropertyMessage::kChangedMessage: {
+            auto& changed_message = property_message.changed_message();
+            property_changed(changed_message.name(), changed_message.value());
+            break;
+        }
+        default:
+            LOG(ERROR) << "Unknown message type from property service: "
+                       << property_message.msg_case();
+    }
+}
+
 int SecondStageMain(int argc, char** argv) {
     if (REBOOT_BOOTLOADER_ON_PANIC) {
         InstallRebootSignalHandlers();
@@ -630,9 +682,6 @@
         LOG(ERROR) << "Unable to write -1000 to /proc/1/oom_score_adj: " << result.error();
     }
 
-    // Enable seccomp if global boot option was passed (otherwise it is enabled in zygote).
-    GlobalSeccomp();
-
     // Set up a session keyring that all processes will have access to. It
     // will hold things like FBE encryption keys. No process should override
     // its session keyring.
@@ -685,7 +734,12 @@
     UmountDebugRamdisk();
     fs_mgr_vendor_overlay_mount_all();
     export_oem_lock_status();
-    StartPropertyService(&epoll);
+
+    StartPropertyService(&property_fd);
+    if (auto result = epoll.RegisterHandler(property_fd, HandlePropertyFd); !result) {
+        LOG(FATAL) << "Could not register epoll handler for property fd: " << result.error();
+    }
+
     MountHandler mount_handler(&epoll);
     set_usb_controller();
 
@@ -696,7 +750,7 @@
         PLOG(FATAL) << "SetupMountNamespaces failed";
     }
 
-    subcontexts = InitializeSubcontexts();
+    subcontext = InitializeSubcontext();
 
     ActionManager& am = ActionManager::GetInstance();
     ServiceList& sm = ServiceList::GetInstance();
diff --git a/init/init.h b/init/init.h
index cfc28f1..61fb110 100644
--- a/init/init.h
+++ b/init/init.h
@@ -31,9 +31,7 @@
 Parser CreateParser(ActionManager& action_manager, ServiceList& service_list);
 Parser CreateServiceOnlyParser(ServiceList& service_list);
 
-bool HandleControlMessage(const std::string& msg, const std::string& arg, pid_t pid);
-
-void property_changed(const std::string& name, const std::string& value);
+void EnterShutdown(const std::string& command);
 
 bool start_waiting_for_property(const char *name, const char *value);
 
@@ -41,6 +39,9 @@
 
 void ResetWaitForProp();
 
+void SendLoadPersistentPropertiesMessage();
+void SendStopSendingMessagesMessage();
+
 int SecondStageMain(int argc, char** argv);
 
 }  // namespace init
diff --git a/init/init_test.cpp b/init/init_test.cpp
index 0411214..315d584 100644
--- a/init/init_test.cpp
+++ b/init/init_test.cpp
@@ -221,3 +221,19 @@
 
 }  // namespace init
 }  // namespace android
+
+int SubcontextTestChildMain(int, char**);
+int FirmwareTestChildMain(int, char**);
+
+int main(int argc, char** argv) {
+    if (argc > 1 && !strcmp(argv[1], "subcontext")) {
+        return SubcontextTestChildMain(argc, argv);
+    }
+
+    if (argc > 1 && !strcmp(argv[1], "firmware")) {
+        return FirmwareTestChildMain(argc, argv);
+    }
+
+    testing::InitGoogleTest(&argc, argv);
+    return RUN_ALL_TESTS();
+}
diff --git a/init/interface_utils.cpp b/init/interface_utils.cpp
index a54860f..ddbacd7 100644
--- a/init/interface_utils.cpp
+++ b/init/interface_utils.cpp
@@ -77,6 +77,12 @@
                                                 const InterfaceInheritanceHierarchyMap& hierarchy) {
     std::set<FQName> interface_fqnames;
     for (const std::string& instance : instances) {
+        // There is insufficient build-time information on AIDL interfaces to check them here
+        // TODO(b/139307527): Rework how services store interfaces to avoid excess string parsing
+        if (base::Split(instance, "/")[0] == "aidl") {
+            continue;
+        }
+
         FqInstance fqinstance;
         if (!fqinstance.setTo(instance)) {
             return Error() << "Unable to parse interface instance '" << instance << "'";
diff --git a/init/property_service.cpp b/init/property_service.cpp
index 3408ff3..f5d1143 100644
--- a/init/property_service.cpp
+++ b/init/property_service.cpp
@@ -42,6 +42,7 @@
 #include <map>
 #include <memory>
 #include <mutex>
+#include <optional>
 #include <queue>
 #include <thread>
 #include <vector>
@@ -63,8 +64,10 @@
 #include "init.h"
 #include "persistent_properties.h"
 #include "property_type.h"
+#include "proto_utils.h"
 #include "selinux.h"
 #include "subcontext.h"
+#include "system/core/init/property_service.pb.h"
 #include "util.h"
 
 using namespace std::literals;
@@ -76,6 +79,7 @@
 using android::base::StringPrintf;
 using android::base::Timer;
 using android::base::Trim;
+using android::base::unique_fd;
 using android::base::WriteStringToFile;
 using android::properties::BuildTrie;
 using android::properties::ParsePropertyInfoFile;
@@ -85,18 +89,13 @@
 namespace android {
 namespace init {
 
-static constexpr const char kRestoreconProperty[] = "selinux.restorecon_recursive";
-
 static bool persistent_properties_loaded = false;
 
 static int property_set_fd = -1;
+static int init_socket = -1;
 
 static PropertyInfoAreaFile property_info_area;
 
-uint32_t InitPropertySet(const std::string& name, const std::string& value);
-
-uint32_t (*property_set)(const std::string& name, const std::string& value) = InitPropertySet;
-
 void CreateSerializedPropertyInfo();
 
 struct PropertyAuditData {
@@ -164,6 +163,17 @@
     return has_access;
 }
 
+static void SendPropertyChanged(const std::string& name, const std::string& value) {
+    auto property_msg = PropertyMessage{};
+    auto* changed_message = property_msg.mutable_changed_message();
+    changed_message->set_name(name);
+    changed_message->set_value(value);
+
+    if (auto result = SendMessage(init_socket, property_msg); !result) {
+        LOG(ERROR) << "Failed to send property changed message: " << result.error();
+    }
+}
+
 static uint32_t PropertySet(const std::string& name, const std::string& value, std::string* error) {
     size_t valuelen = value.size();
 
@@ -199,7 +209,11 @@
     if (persistent_properties_loaded && StartsWith(name, "persist.")) {
         WritePersistentProperty(name, value);
     }
-    property_changed(name, value);
+    // If init hasn't started its main loop, then it won't be handling property changed messages
+    // anyway, so there's no need to try to send them.
+    if (init_socket != -1) {
+        SendPropertyChanged(name, value);
+    }
     return PROP_SUCCESS;
 }
 
@@ -239,35 +253,10 @@
     bool thread_started_ = false;
 };
 
-uint32_t InitPropertySet(const std::string& name, const std::string& value) {
-    if (StartsWith(name, "ctl.")) {
-        LOG(ERROR) << "InitPropertySet: Do not set ctl. properties from init; call the Service "
-                      "functions directly";
-        return PROP_ERROR_INVALID_NAME;
-    }
-    if (name == kRestoreconProperty) {
-        LOG(ERROR) << "InitPropertySet: Do not set '" << kRestoreconProperty
-                   << "' from init; use the restorecon builtin directly";
-        return PROP_ERROR_INVALID_NAME;
-    }
-
-    uint32_t result = 0;
-    ucred cr = {.pid = 1, .uid = 0, .gid = 0};
-    std::string error;
-    result = HandlePropertySet(name, value, kInitContext.c_str(), cr, &error);
-    if (result != PROP_SUCCESS) {
-        LOG(ERROR) << "Init cannot set '" << name << "' to '" << value << "': " << error;
-    }
-
-    return result;
-}
-
 class SocketConnection {
   public:
     SocketConnection(int socket, const ucred& cred) : socket_(socket), cred_(cred) {}
 
-    ~SocketConnection() { close(socket_); }
-
     bool RecvUint32(uint32_t* value, uint32_t* timeout_ms) {
         return RecvFully(value, sizeof(*value), timeout_ms);
     }
@@ -304,6 +293,9 @@
     }
 
     bool SendUint32(uint32_t value) {
+        if (!socket_.ok()) {
+            return true;
+        }
         int result = TEMP_FAILURE_RETRY(send(socket_, &value, sizeof(value), 0));
         return result == sizeof(value);
     }
@@ -318,7 +310,7 @@
         return true;
     }
 
-    int socket() { return socket_; }
+    [[nodiscard]] int Release() { return socket_.release(); }
 
     const ucred& cred() { return cred_; }
 
@@ -389,12 +381,46 @@
         return bytes_left == 0;
     }
 
-    int socket_;
+    unique_fd socket_;
     ucred cred_;
 
     DISALLOW_IMPLICIT_CONSTRUCTORS(SocketConnection);
 };
 
+static uint32_t SendControlMessage(const std::string& msg, const std::string& name, pid_t pid,
+                                   SocketConnection* socket, std::string* error) {
+    if (init_socket == -1) {
+        *error = "Received control message after shutdown, ignoring";
+        return PROP_ERROR_HANDLE_CONTROL_MESSAGE;
+    }
+
+    auto property_msg = PropertyMessage{};
+    auto* control_message = property_msg.mutable_control_message();
+    control_message->set_msg(msg);
+    control_message->set_name(name);
+    control_message->set_pid(pid);
+
+    // We must release the fd before sending it to init, otherwise there will be a race with init.
+    // If init calls close() before Release(), then fdsan will see the wrong tag and abort().
+    int fd = -1;
+    if (socket != nullptr) {
+        fd = socket->Release();
+        control_message->set_fd(fd);
+    }
+
+    if (auto result = SendMessage(init_socket, property_msg); !result) {
+        // We've already released the fd above, so if we fail to send the message to init, we need
+        // to manually free it here.
+        if (fd != -1) {
+            close(fd);
+        }
+        *error = "Failed to send control message: " + result.error().message();
+        return PROP_ERROR_HANDLE_CONTROL_MESSAGE;
+    }
+
+    return PROP_SUCCESS;
+}
+
 bool CheckControlPropertyPerms(const std::string& name, const std::string& value,
                                const std::string& source_context, const ucred& cr) {
     // We check the legacy method first but these properties are dontaudit, so we only log an audit
@@ -462,15 +488,14 @@
 
 // This returns one of the enum of PROP_SUCCESS or PROP_ERROR*.
 uint32_t HandlePropertySet(const std::string& name, const std::string& value,
-                           const std::string& source_context, const ucred& cr, std::string* error) {
+                           const std::string& source_context, const ucred& cr,
+                           SocketConnection* socket, std::string* error) {
     if (auto ret = CheckPermissions(name, value, source_context, cr, error); ret != PROP_SUCCESS) {
         return ret;
     }
 
     if (StartsWith(name, "ctl.")) {
-        return HandleControlMessage(name.c_str() + 4, value, cr.pid)
-                       ? PROP_SUCCESS
-                       : PROP_ERROR_HANDLE_CONTROL_MESSAGE;
+        return SendControlMessage(name.c_str() + 4, value, cr.pid, socket, error);
     }
 
     // sys.powerctl is a special property that is used to make the device reboot.  We want to log
@@ -501,6 +526,20 @@
     return PropertySet(name, value, error);
 }
 
+uint32_t InitPropertySet(const std::string& name, const std::string& value) {
+    uint32_t result = 0;
+    ucred cr = {.pid = 1, .uid = 0, .gid = 0};
+    std::string error;
+    result = HandlePropertySet(name, value, kInitContext, cr, nullptr, &error);
+    if (result != PROP_SUCCESS) {
+        LOG(ERROR) << "Init cannot set '" << name << "' to '" << value << "': " << error;
+    }
+
+    return result;
+}
+
+uint32_t (*property_set)(const std::string& name, const std::string& value) = InitPropertySet;
+
 static void handle_property_set_fd() {
     static constexpr uint32_t kDefaultSocketTimeout = 2000; /* ms */
 
@@ -549,7 +588,8 @@
 
         const auto& cr = socket.cred();
         std::string error;
-        uint32_t result = HandlePropertySet(prop_name, prop_value, source_context, cr, &error);
+        uint32_t result =
+                HandlePropertySet(prop_name, prop_value, source_context, cr, nullptr, &error);
         if (result != PROP_SUCCESS) {
             LOG(ERROR) << "Unable to set property '" << prop_name << "' from uid:" << cr.uid
                        << " gid:" << cr.gid << " pid:" << cr.pid << ": " << error;
@@ -577,7 +617,7 @@
 
         const auto& cr = socket.cred();
         std::string error;
-        uint32_t result = HandlePropertySet(name, value, source_context, cr, &error);
+        uint32_t result = HandlePropertySet(name, value, source_context, cr, &socket, &error);
         if (result != PROP_SUCCESS) {
             LOG(ERROR) << "Unable to set property '" << name << "' from uid:" << cr.uid
                        << " gid:" << cr.gid << " pid:" << cr.pid << ": " << error;
@@ -605,11 +645,16 @@
     char *key, *value, *eol, *sol, *tmp, *fn;
     size_t flen = 0;
 
-    const char* context = kInitContext.c_str();
+    static constexpr const char* const kVendorPathPrefixes[2] = {
+            "/vendor",
+            "/odm",
+    };
+
+    const char* context = kInitContext;
     if (SelinuxGetVendorAndroidVersion() >= __ANDROID_API_P__) {
-        for (const auto& [path_prefix, secontext] : paths_and_secontexts) {
-            if (StartsWith(filename, path_prefix)) {
-                context = secontext;
+        for (const auto& vendor_path_prefix : kVendorPathPrefixes) {
+            if (StartsWith(filename, vendor_path_prefix)) {
+                context = kVendorContext;
             }
         }
     }
@@ -741,33 +786,6 @@
     }
 }
 
-/* When booting an encrypted system, /data is not mounted when the
- * property service is started, so any properties stored there are
- * not loaded.  Vold triggers init to load these properties once it
- * has mounted /data.
- */
-void load_persist_props(void) {
-    // Devices with FDE have load_persist_props called twice; the first time when the temporary
-    // /data partition is mounted and then again once /data is truly mounted.  We do not want to
-    // read persistent properties from the temporary /data partition or mark persistent properties
-    // as having been loaded during the first call, so we return in that case.
-    std::string crypto_state = android::base::GetProperty("ro.crypto.state", "");
-    std::string crypto_type = android::base::GetProperty("ro.crypto.type", "");
-    if (crypto_state == "encrypted" && crypto_type == "block") {
-        static size_t num_calls = 0;
-        if (++num_calls == 1) return;
-    }
-
-    load_override_properties();
-    /* Read persistent properties after all default values have been loaded. */
-    auto persistent_properties = LoadPersistentProperties();
-    for (const auto& persistent_property_record : persistent_properties.properties()) {
-        property_set(persistent_property_record.name(), persistent_property_record.value());
-    }
-    persistent_properties_loaded = true;
-    property_set("ro.persistent_properties.ready", "true");
-}
-
 // If the ro.product.[brand|device|manufacturer|model|name] properties have not been explicitly
 // set, derive them from ro.product.${partition}.* properties
 static void property_initialize_ro_product_props() {
@@ -985,21 +1003,92 @@
     selinux_android_restorecon(kPropertyInfosPath, 0);
 }
 
-void StartPropertyService(Epoll* epoll) {
+static void HandleInitSocket() {
+    auto message = ReadMessage(init_socket);
+    if (!message) {
+        LOG(ERROR) << "Could not read message from init_dedicated_recv_socket: " << message.error();
+        return;
+    }
+
+    auto init_message = InitMessage{};
+    if (!init_message.ParseFromString(*message)) {
+        LOG(ERROR) << "Could not parse message from init";
+        return;
+    }
+
+    switch (init_message.msg_case()) {
+        case InitMessage::kLoadPersistentProperties: {
+            load_override_properties();
+            // Read persistent properties after all default values have been loaded.
+            auto persistent_properties = LoadPersistentProperties();
+            for (const auto& persistent_property_record : persistent_properties.properties()) {
+                InitPropertySet(persistent_property_record.name(),
+                                persistent_property_record.value());
+            }
+            InitPropertySet("ro.persistent_properties.ready", "true");
+            persistent_properties_loaded = true;
+            break;
+        }
+        case InitMessage::kStopSendingMessages: {
+            init_socket = -1;
+            break;
+        }
+        default:
+            LOG(ERROR) << "Unknown message type from init: " << init_message.msg_case();
+    }
+}
+
+static void PropertyServiceThread() {
+    Epoll epoll;
+    if (auto result = epoll.Open(); !result) {
+        LOG(FATAL) << result.error();
+    }
+
+    if (auto result = epoll.RegisterHandler(property_set_fd, handle_property_set_fd); !result) {
+        LOG(FATAL) << result.error();
+    }
+
+    if (auto result = epoll.RegisterHandler(init_socket, HandleInitSocket); !result) {
+        LOG(FATAL) << result.error();
+    }
+
+    while (true) {
+        auto pending_functions = epoll.Wait(std::nullopt);
+        if (!pending_functions) {
+            LOG(ERROR) << pending_functions.error();
+        } else {
+            for (const auto& function : *pending_functions) {
+                (*function)();
+            }
+        }
+    }
+}
+
+void StartPropertyService(int* epoll_socket) {
     property_set("ro.property_service.version", "2");
 
+    int sockets[2];
+    if (socketpair(AF_UNIX, SOCK_SEQPACKET | SOCK_CLOEXEC, 0, sockets) != 0) {
+        PLOG(FATAL) << "Failed to socketpair() between property_service and init";
+    }
+    *epoll_socket = sockets[0];
+    init_socket = sockets[1];
+
     if (auto result = CreateSocket(PROP_SERVICE_NAME, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK,
                                    false, 0666, 0, 0, {})) {
         property_set_fd = *result;
     } else {
-        PLOG(FATAL) << "start_property_service socket creation failed: " << result.error();
+        LOG(FATAL) << "start_property_service socket creation failed: " << result.error();
     }
 
     listen(property_set_fd, 8);
 
-    if (auto result = epoll->RegisterHandler(property_set_fd, handle_property_set_fd); !result) {
-        PLOG(FATAL) << result.error();
-    }
+    std::thread{PropertyServiceThread}.detach();
+
+    property_set = [](const std::string& key, const std::string& value) -> uint32_t {
+        android::base::SetProperty(key, value);
+        return 0;
+    };
 }
 
 }  // namespace init
diff --git a/init/property_service.h b/init/property_service.h
index 7f9f844..8f7d8d9 100644
--- a/init/property_service.h
+++ b/init/property_service.h
@@ -25,17 +25,15 @@
 namespace android {
 namespace init {
 
+static constexpr const char kRestoreconProperty[] = "selinux.restorecon_recursive";
+
 bool CanReadProperty(const std::string& source_context, const std::string& name);
 
 extern uint32_t (*property_set)(const std::string& name, const std::string& value);
 
-uint32_t HandlePropertySet(const std::string& name, const std::string& value,
-                           const std::string& source_context, const ucred& cr, std::string* error);
-
 void property_init();
 void property_load_boot_defaults(bool load_debug_prop);
-void load_persist_props();
-void StartPropertyService(Epoll* epoll);
+void StartPropertyService(int* epoll_socket);
 
 }  // namespace init
 }  // namespace android
diff --git a/init/property_service.proto b/init/property_service.proto
new file mode 100644
index 0000000..ea454d4
--- /dev/null
+++ b/init/property_service.proto
@@ -0,0 +1,44 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+syntax = "proto2";
+option optimize_for = LITE_RUNTIME;
+
+message PropertyMessage {
+    message ControlMessage {
+        optional string msg = 1;
+        optional string name = 2;
+        optional int32 pid = 3;
+        optional int32 fd = 4;
+    }
+
+    message ChangedMessage {
+        optional string name = 1;
+        optional string value = 2;
+    }
+
+    oneof msg {
+        ControlMessage control_message = 1;
+        ChangedMessage changed_message = 2;
+    };
+}
+
+message InitMessage {
+    oneof msg {
+        bool load_persistent_properties = 1;
+        bool stop_sending_messages = 2;
+    };
+}
diff --git a/init/proto_utils.h b/init/proto_utils.h
new file mode 100644
index 0000000..93a7d57
--- /dev/null
+++ b/init/proto_utils.h
@@ -0,0 +1,62 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <sys/socket.h>
+#include <unistd.h>
+
+#include <string>
+
+#include "result.h"
+
+namespace android {
+namespace init {
+
+constexpr size_t kBufferSize = 4096;
+
+inline Result<std::string> ReadMessage(int socket) {
+    char buffer[kBufferSize] = {};
+    auto result = TEMP_FAILURE_RETRY(recv(socket, buffer, sizeof(buffer), 0));
+    if (result == 0) {
+        return Error();
+    } else if (result < 0) {
+        return ErrnoError();
+    }
+    return std::string(buffer, result);
+}
+
+template <typename T>
+Result<void> SendMessage(int socket, const T& message) {
+    std::string message_string;
+    if (!message.SerializeToString(&message_string)) {
+        return Error() << "Unable to serialize message";
+    }
+
+    if (message_string.size() > kBufferSize) {
+        return Error() << "Serialized message too long to send";
+    }
+
+    if (auto result =
+                TEMP_FAILURE_RETRY(send(socket, message_string.c_str(), message_string.size(), 0));
+        result != static_cast<long>(message_string.size())) {
+        return ErrnoError() << "send() failed to send message contents";
+    }
+    return {};
+}
+
+}  // namespace init
+}  // namespace android
diff --git a/init/reboot.cpp b/init/reboot.cpp
index b0b5b54..2cf0f5c 100644
--- a/init/reboot.cpp
+++ b/init/reboot.cpp
@@ -60,6 +60,8 @@
 
 #define PROC_SYSRQ "/proc/sysrq-trigger"
 
+using namespace std::literals;
+
 using android::base::GetBoolProperty;
 using android::base::Split;
 using android::base::Timer;
@@ -170,9 +172,23 @@
                  << stat;
 }
 
-/* Find all read+write block devices and emulated devices in /proc/mounts
- * and add them to correpsponding list.
- */
+static bool IsDataMounted() {
+    std::unique_ptr<std::FILE, int (*)(std::FILE*)> fp(setmntent("/proc/mounts", "re"), endmntent);
+    if (fp == nullptr) {
+        PLOG(ERROR) << "Failed to open /proc/mounts";
+        return false;
+    }
+    mntent* mentry;
+    while ((mentry = getmntent(fp.get())) != nullptr) {
+        if (mentry->mnt_dir == "/data"s) {
+            return true;
+        }
+    }
+    return false;
+}
+
+// Find all read+write block devices and emulated devices in /proc/mounts and add them to
+// the correpsponding list.
 static bool FindPartitionsToUmount(std::vector<MountEntry>* blockDevPartitions,
                                    std::vector<MountEntry>* emulatedPartitions, bool dump) {
     std::unique_ptr<std::FILE, int (*)(std::FILE*)> fp(setmntent("/proc/mounts", "re"), endmntent);
@@ -295,12 +311,15 @@
             LOG(ERROR) << "Reboot thread timed out";
 
             if (android::base::GetBoolProperty("ro.debuggable", false) == true) {
-                LOG(INFO) << "Try to dump init process call trace:";
-                const char* vdc_argv[] = {"/system/bin/debuggerd", "-b", "1"};
-                int status;
-                android_fork_execvp_ext(arraysize(vdc_argv), (char**)vdc_argv, &status, true,
-                                        LOG_KLOG, true, nullptr, nullptr, 0);
-
+                if (false) {
+                    // SEPolicy will block debuggerd from running and this is intentional.
+                    // But these lines are left to be enabled during debugging.
+                    LOG(INFO) << "Try to dump init process call trace:";
+                    const char* vdc_argv[] = {"/system/bin/debuggerd", "-b", "1"};
+                    int status;
+                    android_fork_execvp_ext(arraysize(vdc_argv), (char**)vdc_argv, &status, true,
+                                            LOG_KLOG, true, nullptr, nullptr, 0);
+                }
                 LOG(INFO) << "Show stack for all active CPU:";
                 WriteStringToFile("l", PROC_SYSRQ);
 
@@ -436,6 +455,14 @@
     Timer t;
     LOG(INFO) << "Reboot start, reason: " << reason << ", rebootTarget: " << rebootTarget;
 
+    // If /data isn't mounted then we can skip the extra reboot steps below, since we don't need to
+    // worry about unmounting it.
+    if (!IsDataMounted()) {
+        sync();
+        RebootSystem(cmd, rebootTarget);
+        abort();
+    }
+
     // Ensure last reboot reason is reduced to canonical
     // alias reported in bootloader or system boot reason.
     size_t skip = 0;
@@ -730,6 +757,12 @@
         s->UnSetExec();
     }
 
+    // We no longer process messages about properties changing coming from property service, so we
+    // need to tell property service to stop sending us these messages, otherwise it'll fill the
+    // buffers and block indefinitely, causing future property sets, including those that init makes
+    // during shutdown in Service::NotifyStateChange() to also block indefinitely.
+    SendStopSendingMessagesMessage();
+
     return true;
 }
 
diff --git a/init/service.cpp b/init/service.cpp
index 7a20966..e8b75d4 100644
--- a/init/service.cpp
+++ b/init/service.cpp
@@ -29,6 +29,7 @@
 #include <android-base/file.h>
 #include <android-base/logging.h>
 #include <android-base/properties.h>
+#include <android-base/scopeguard.h>
 #include <android-base/stringprintf.h>
 #include <android-base/strings.h>
 #include <cutils/sockets.h>
@@ -41,6 +42,7 @@
 #if defined(__ANDROID__)
 #include <ApexProperties.sysprop.h>
 
+#include "init.h"
 #include "mount_namespace.h"
 #include "property_service.h"
 #else
@@ -50,6 +52,7 @@
 using android::base::boot_clock;
 using android::base::GetProperty;
 using android::base::Join;
+using android::base::make_scope_guard;
 using android::base::StartsWith;
 using android::base::StringPrintf;
 using android::base::WriteStringToFile;
@@ -250,6 +253,11 @@
         f(siginfo);
     }
 
+    if ((siginfo.si_code != CLD_EXITED || siginfo.si_status != 0) && on_failure_reboot_target_) {
+        LOG(ERROR) << "Service with 'reboot_on_failure' option failed, shutting down system.";
+        EnterShutdown(*on_failure_reboot_target_);
+    }
+
     if (flags_ & SVC_EXEC) UnSetExec();
 
     if (flags_ & SVC_TEMPORARY) return;
@@ -325,6 +333,12 @@
 
 
 Result<void> Service::ExecStart() {
+    auto reboot_on_failure = make_scope_guard([this] {
+        if (on_failure_reboot_target_) {
+            EnterShutdown(*on_failure_reboot_target_);
+        }
+    });
+
     if (is_updatable() && !ServiceList::GetInstance().IsServicesUpdated()) {
         // Don't delay the service for ExecStart() as the semantic is that
         // the caller might depend on the side effect of the execution.
@@ -345,10 +359,17 @@
               << " gid " << proc_attr_.gid << "+" << proc_attr_.supp_gids.size() << " context "
               << (!seclabel_.empty() ? seclabel_ : "default") << ") started; waiting...";
 
+    reboot_on_failure.Disable();
     return {};
 }
 
 Result<void> Service::Start() {
+    auto reboot_on_failure = make_scope_guard([this] {
+        if (on_failure_reboot_target_) {
+            EnterShutdown(*on_failure_reboot_target_);
+        }
+    });
+
     if (is_updatable() && !ServiceList::GetInstance().IsServicesUpdated()) {
         ServiceList::GetInstance().DelayService(*this);
         return Error() << "Cannot start an updatable service '" << name_
@@ -371,6 +392,7 @@
             flags_ |= SVC_RESTART;
         }
         // It is not an error to try to start a service that is already running.
+        reboot_on_failure.Disable();
         return {};
     }
 
@@ -419,6 +441,23 @@
 
     LOG(INFO) << "starting service '" << name_ << "'...";
 
+    std::vector<Descriptor> descriptors;
+    for (const auto& socket : sockets_) {
+        if (auto result = socket.Create(scon)) {
+            descriptors.emplace_back(std::move(*result));
+        } else {
+            LOG(INFO) << "Could not create socket '" << socket.name << "': " << result.error();
+        }
+    }
+
+    for (const auto& file : files_) {
+        if (auto result = file.Create()) {
+            descriptors.emplace_back(std::move(*result));
+        } else {
+            LOG(INFO) << "Could not open file '" << file.name << "': " << result.error();
+        }
+    }
+
     pid_t pid = -1;
     if (namespaces_.flags) {
         pid = clone(nullptr, nullptr, namespaces_.flags | SIGCHLD, nullptr);
@@ -438,16 +477,8 @@
             setenv(key.c_str(), value.c_str(), 1);
         }
 
-        for (const auto& socket : sockets_) {
-            if (auto result = socket.CreateAndPublish(scon); !result) {
-                LOG(INFO) << "Could not create socket '" << socket.name << "': " << result.error();
-            }
-        }
-
-        for (const auto& file : files_) {
-            if (auto result = file.CreateAndPublish(); !result) {
-                LOG(INFO) << "Could not open file '" << file.name << "': " << result.error();
-            }
+        for (const auto& descriptor : descriptors) {
+            descriptor.Publish();
         }
 
         if (auto result = WritePidToFiles(&writepid_files_); !result) {
@@ -532,6 +563,7 @@
     }
 
     NotifyStateChange("running");
+    reboot_on_failure.Disable();
     return {};
 }
 
diff --git a/init/service.h b/init/service.h
index ccefc8e..788f792 100644
--- a/init/service.h
+++ b/init/service.h
@@ -196,6 +196,8 @@
     bool post_data_ = false;
 
     bool running_at_post_data_reset_ = false;
+
+    std::optional<std::string> on_failure_reboot_target_;
 };
 
 }  // namespace init
diff --git a/init/service_parser.cpp b/init/service_parser.cpp
index dd552fb..e7808a9 100644
--- a/init/service_parser.cpp
+++ b/init/service_parser.cpp
@@ -83,6 +83,9 @@
 }
 
 Result<void> ServiceParser::ParseConsole(std::vector<std::string>&& args) {
+    if (service_->proc_attr_.stdio_to_kmsg) {
+        return Error() << "'console' and 'stdio_to_kmsg' are mutually exclusive";
+    }
     service_->flags_ |= SVC_CONSOLE;
     service_->proc_attr_.console = args.size() > 1 ? "/dev/" + args[1] : "";
     return {};
@@ -145,17 +148,21 @@
     const std::string& interface_name = args[1];
     const std::string& instance_name = args[2];
 
-    FQName fq_name;
-    if (!FQName::parse(interface_name, &fq_name)) {
-        return Error() << "Invalid fully-qualified name for interface '" << interface_name << "'";
-    }
+    // AIDL services don't use fully qualified names and instead just use "interface aidl <name>"
+    if (interface_name != "aidl") {
+        FQName fq_name;
+        if (!FQName::parse(interface_name, &fq_name)) {
+            return Error() << "Invalid fully-qualified name for interface '" << interface_name
+                           << "'";
+        }
 
-    if (!fq_name.isFullyQualified()) {
-        return Error() << "Interface name not fully-qualified '" << interface_name << "'";
-    }
+        if (!fq_name.isFullyQualified()) {
+            return Error() << "Interface name not fully-qualified '" << interface_name << "'";
+        }
 
-    if (fq_name.isValidValueName()) {
-        return Error() << "Interface name must not be a value name '" << interface_name << "'";
+        if (fq_name.isValidValueName()) {
+            return Error() << "Interface name must not be a value name '" << interface_name << "'";
+        }
     }
 
     const std::string fullname = interface_name + "/" + instance_name;
@@ -306,6 +313,18 @@
     return {};
 }
 
+Result<void> ServiceParser::ParseRebootOnFailure(std::vector<std::string>&& args) {
+    if (service_->on_failure_reboot_target_) {
+        return Error() << "Only one reboot_on_failure command may be specified";
+    }
+    if (!StartsWith(args[1], "shutdown") && !StartsWith(args[1], "reboot")) {
+        return Error()
+               << "reboot_on_failure commands must begin with either 'shutdown' or 'reboot'";
+    }
+    service_->on_failure_reboot_target_ = std::move(args[1]);
+    return {};
+}
+
 Result<void> ServiceParser::ParseRestartPeriod(std::vector<std::string>&& args) {
     int period;
     if (!ParseInt(args[1], &period, 5)) {
@@ -413,6 +432,14 @@
     return {};
 }
 
+Result<void> ServiceParser::ParseStdioToKmsg(std::vector<std::string>&& args) {
+    if (service_->flags_ & SVC_CONSOLE) {
+        return Error() << "'stdio_to_kmsg' and 'console' are mutually exclusive";
+    }
+    service_->proc_attr_.stdio_to_kmsg = true;
+    return {};
+}
+
 // name type
 Result<void> ServiceParser::ParseFile(std::vector<std::string>&& args) {
     if (args[2] != "r" && args[2] != "w" && args[2] != "rw") {
@@ -467,49 +494,42 @@
     constexpr std::size_t kMax = std::numeric_limits<std::size_t>::max();
     // clang-format off
     static const KeywordMap<ServiceParser::OptionParser> parser_map = {
-        {"capabilities",
-                        {0,     kMax, &ServiceParser::ParseCapabilities}},
-        {"class",       {1,     kMax, &ServiceParser::ParseClass}},
-        {"console",     {0,     1,    &ServiceParser::ParseConsole}},
-        {"critical",    {0,     0,    &ServiceParser::ParseCritical}},
-        {"disabled",    {0,     0,    &ServiceParser::ParseDisabled}},
-        {"enter_namespace",
-                        {2,     2,    &ServiceParser::ParseEnterNamespace}},
-        {"file",        {2,     2,    &ServiceParser::ParseFile}},
-        {"group",       {1,     NR_SVC_SUPP_GIDS + 1, &ServiceParser::ParseGroup}},
-        {"interface",   {2,     2,    &ServiceParser::ParseInterface}},
-        {"ioprio",      {2,     2,    &ServiceParser::ParseIoprio}},
-        {"keycodes",    {1,     kMax, &ServiceParser::ParseKeycodes}},
-        {"memcg.limit_in_bytes",
-                        {1,     1,    &ServiceParser::ParseMemcgLimitInBytes}},
-        {"memcg.limit_percent",
-                        {1,     1,    &ServiceParser::ParseMemcgLimitPercent}},
-        {"memcg.limit_property",
-                        {1,     1,    &ServiceParser::ParseMemcgLimitProperty}},
+        {"capabilities",            {0,     kMax, &ServiceParser::ParseCapabilities}},
+        {"class",                   {1,     kMax, &ServiceParser::ParseClass}},
+        {"console",                 {0,     1,    &ServiceParser::ParseConsole}},
+        {"critical",                {0,     0,    &ServiceParser::ParseCritical}},
+        {"disabled",                {0,     0,    &ServiceParser::ParseDisabled}},
+        {"enter_namespace",         {2,     2,    &ServiceParser::ParseEnterNamespace}},
+        {"file",                    {2,     2,    &ServiceParser::ParseFile}},
+        {"group",                   {1,     NR_SVC_SUPP_GIDS + 1, &ServiceParser::ParseGroup}},
+        {"interface",               {2,     2,    &ServiceParser::ParseInterface}},
+        {"ioprio",                  {2,     2,    &ServiceParser::ParseIoprio}},
+        {"keycodes",                {1,     kMax, &ServiceParser::ParseKeycodes}},
+        {"memcg.limit_in_bytes",    {1,     1,    &ServiceParser::ParseMemcgLimitInBytes}},
+        {"memcg.limit_percent",     {1,     1,    &ServiceParser::ParseMemcgLimitPercent}},
+        {"memcg.limit_property",    {1,     1,    &ServiceParser::ParseMemcgLimitProperty}},
         {"memcg.soft_limit_in_bytes",
-                        {1,     1,    &ServiceParser::ParseMemcgSoftLimitInBytes}},
-        {"memcg.swappiness",
-                        {1,     1,    &ServiceParser::ParseMemcgSwappiness}},
-        {"namespace",   {1,     2,    &ServiceParser::ParseNamespace}},
-        {"oneshot",     {0,     0,    &ServiceParser::ParseOneshot}},
-        {"onrestart",   {1,     kMax, &ServiceParser::ParseOnrestart}},
-        {"oom_score_adjust",
-                        {1,     1,    &ServiceParser::ParseOomScoreAdjust}},
-        {"override",    {0,     0,    &ServiceParser::ParseOverride}},
-        {"priority",    {1,     1,    &ServiceParser::ParsePriority}},
-        {"restart_period",
-                        {1,     1,    &ServiceParser::ParseRestartPeriod}},
-        {"rlimit",      {3,     3,    &ServiceParser::ParseProcessRlimit}},
-        {"seclabel",    {1,     1,    &ServiceParser::ParseSeclabel}},
-        {"setenv",      {2,     2,    &ServiceParser::ParseSetenv}},
-        {"shutdown",    {1,     1,    &ServiceParser::ParseShutdown}},
-        {"sigstop",     {0,     0,    &ServiceParser::ParseSigstop}},
-        {"socket",      {3,     6,    &ServiceParser::ParseSocket}},
-        {"timeout_period",
-                        {1,     1,    &ServiceParser::ParseTimeoutPeriod}},
-        {"updatable",   {0,     0,    &ServiceParser::ParseUpdatable}},
-        {"user",        {1,     1,    &ServiceParser::ParseUser}},
-        {"writepid",    {1,     kMax, &ServiceParser::ParseWritepid}},
+                                    {1,     1,    &ServiceParser::ParseMemcgSoftLimitInBytes}},
+        {"memcg.swappiness",        {1,     1,    &ServiceParser::ParseMemcgSwappiness}},
+        {"namespace",               {1,     2,    &ServiceParser::ParseNamespace}},
+        {"oneshot",                 {0,     0,    &ServiceParser::ParseOneshot}},
+        {"onrestart",               {1,     kMax, &ServiceParser::ParseOnrestart}},
+        {"oom_score_adjust",        {1,     1,    &ServiceParser::ParseOomScoreAdjust}},
+        {"override",                {0,     0,    &ServiceParser::ParseOverride}},
+        {"priority",                {1,     1,    &ServiceParser::ParsePriority}},
+        {"reboot_on_failure",       {1,     1,    &ServiceParser::ParseRebootOnFailure}},
+        {"restart_period",          {1,     1,    &ServiceParser::ParseRestartPeriod}},
+        {"rlimit",                  {3,     3,    &ServiceParser::ParseProcessRlimit}},
+        {"seclabel",                {1,     1,    &ServiceParser::ParseSeclabel}},
+        {"setenv",                  {2,     2,    &ServiceParser::ParseSetenv}},
+        {"shutdown",                {1,     1,    &ServiceParser::ParseShutdown}},
+        {"sigstop",                 {0,     0,    &ServiceParser::ParseSigstop}},
+        {"socket",                  {3,     6,    &ServiceParser::ParseSocket}},
+        {"stdio_to_kmsg",           {0,     0,    &ServiceParser::ParseStdioToKmsg}},
+        {"timeout_period",          {1,     1,    &ServiceParser::ParseTimeoutPeriod}},
+        {"updatable",               {0,     0,    &ServiceParser::ParseUpdatable}},
+        {"user",                    {1,     1,    &ServiceParser::ParseUser}},
+        {"writepid",                {1,     kMax, &ServiceParser::ParseWritepid}},
     };
     // clang-format on
     return parser_map;
@@ -529,13 +549,8 @@
     filename_ = filename;
 
     Subcontext* restart_action_subcontext = nullptr;
-    if (subcontexts_) {
-        for (auto& subcontext : *subcontexts_) {
-            if (StartsWith(filename, subcontext.path_prefix())) {
-                restart_action_subcontext = &subcontext;
-                break;
-            }
-        }
+    if (subcontext_ && subcontext_->PathMatchesSubcontext(filename)) {
+        restart_action_subcontext = subcontext_;
     }
 
     std::vector<std::string> str_args(args.begin() + 2, args.end());
diff --git a/init/service_parser.h b/init/service_parser.h
index 4729874..b1281f5 100644
--- a/init/service_parser.h
+++ b/init/service_parser.h
@@ -30,10 +30,10 @@
 class ServiceParser : public SectionParser {
   public:
     ServiceParser(
-            ServiceList* service_list, std::vector<Subcontext>* subcontexts,
+            ServiceList* service_list, Subcontext* subcontext,
             const std::optional<InterfaceInheritanceHierarchyMap>& interface_inheritance_hierarchy)
         : service_list_(service_list),
-          subcontexts_(subcontexts),
+          subcontext_(subcontext),
           interface_inheritance_hierarchy_(interface_inheritance_hierarchy),
           service_(nullptr) {}
     Result<void> ParseSection(std::vector<std::string>&& args, const std::string& filename,
@@ -68,12 +68,14 @@
     Result<void> ParseMemcgSwappiness(std::vector<std::string>&& args);
     Result<void> ParseNamespace(std::vector<std::string>&& args);
     Result<void> ParseProcessRlimit(std::vector<std::string>&& args);
+    Result<void> ParseRebootOnFailure(std::vector<std::string>&& args);
     Result<void> ParseRestartPeriod(std::vector<std::string>&& args);
     Result<void> ParseSeclabel(std::vector<std::string>&& args);
     Result<void> ParseSetenv(std::vector<std::string>&& args);
     Result<void> ParseShutdown(std::vector<std::string>&& args);
     Result<void> ParseSigstop(std::vector<std::string>&& args);
     Result<void> ParseSocket(std::vector<std::string>&& args);
+    Result<void> ParseStdioToKmsg(std::vector<std::string>&& args);
     Result<void> ParseTimeoutPeriod(std::vector<std::string>&& args);
     Result<void> ParseFile(std::vector<std::string>&& args);
     Result<void> ParseUser(std::vector<std::string>&& args);
@@ -83,7 +85,7 @@
     bool IsValidName(const std::string& name) const;
 
     ServiceList* service_list_;
-    std::vector<Subcontext>* subcontexts_;
+    Subcontext* subcontext_;
     std::optional<InterfaceInheritanceHierarchyMap> interface_inheritance_hierarchy_;
     std::unique_ptr<Service> service_;
     std::string filename_;
diff --git a/init/service_utils.cpp b/init/service_utils.cpp
index 836145d..93cffd8 100644
--- a/init/service_utils.cpp
+++ b/init/service_utils.cpp
@@ -16,17 +16,18 @@
 
 #include "service_utils.h"
 
+#include <fcntl.h>
 #include <grp.h>
 #include <sys/mount.h>
 #include <sys/prctl.h>
 #include <sys/wait.h>
+#include <unistd.h>
 
 #include <android-base/file.h>
 #include <android-base/logging.h>
 #include <android-base/properties.h>
 #include <android-base/stringprintf.h>
 #include <android-base/strings.h>
-#include <android-base/unique_fd.h>
 #include <cutils/android_get_control_file.h>
 #include <cutils/sockets.h>
 #include <processgroup/processgroup.h>
@@ -122,11 +123,15 @@
     return {};
 }
 
-void ZapStdio() {
+void SetupStdio(bool stdio_to_kmsg) {
     auto fd = unique_fd{open("/dev/null", O_RDWR | O_CLOEXEC)};
-    dup2(fd, 0);
-    dup2(fd, 1);
-    dup2(fd, 2);
+    dup2(fd, STDIN_FILENO);
+    if (stdio_to_kmsg) {
+        fd.reset(open("/dev/kmsg_debug", O_WRONLY | O_CLOEXEC));
+        if (fd == -1) fd.reset(open("/dev/null", O_WRONLY | O_CLOEXEC));
+    }
+    dup2(fd, STDOUT_FILENO);
+    dup2(fd, STDERR_FILENO);
 }
 
 void OpenConsole(const std::string& console) {
@@ -138,37 +143,44 @@
     dup2(fd, 2);
 }
 
-void PublishDescriptor(const std::string& key, const std::string& name, int fd) {
-    std::string published_name = key + name;
+}  // namespace
+
+void Descriptor::Publish() const {
+    auto published_name = name_;
+
     for (auto& c : published_name) {
         c = isalnum(c) ? c : '_';
     }
 
+    int fd = fd_.get();
+    // For safety, the FD is created as CLOEXEC, so that must be removed before publishing.
+    auto fd_flags = fcntl(fd, F_GETFD);
+    fd_flags &= ~FD_CLOEXEC;
+    if (fcntl(fd, F_SETFD, fd_flags) != 0) {
+        PLOG(ERROR) << "Failed to remove CLOEXEC from '" << published_name << "'";
+    }
+
     std::string val = std::to_string(fd);
     setenv(published_name.c_str(), val.c_str(), 1);
 }
 
-}  // namespace
-
-Result<void> SocketDescriptor::CreateAndPublish(const std::string& global_context) const {
+Result<Descriptor> SocketDescriptor::Create(const std::string& global_context) const {
     const auto& socket_context = context.empty() ? global_context : context;
-    auto result = CreateSocket(name, type, passcred, perm, uid, gid, socket_context);
+    auto result = CreateSocket(name, type | SOCK_CLOEXEC, passcred, perm, uid, gid, socket_context);
     if (!result) {
         return result.error();
     }
 
-    PublishDescriptor(ANDROID_SOCKET_ENV_PREFIX, name, *result);
-
-    return {};
+    return Descriptor(ANDROID_SOCKET_ENV_PREFIX + name, unique_fd(*result));
 }
 
-Result<void> FileDescriptor::CreateAndPublish() const {
+Result<Descriptor> FileDescriptor::Create() const {
     int flags = (type == "r") ? O_RDONLY : (type == "w") ? O_WRONLY : O_RDWR;
 
     // Make sure we do not block on open (eg: devices can chose to block on carrier detect).  Our
     // intention is never to delay launch of a service for such a condition.  The service can
     // perform its own blocking on carrier detect.
-    android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(name.c_str(), flags | O_NONBLOCK)));
+    unique_fd fd(TEMP_FAILURE_RETRY(open(name.c_str(), flags | O_NONBLOCK | O_CLOEXEC)));
 
     if (fd < 0) {
         return ErrnoError() << "Failed to open file '" << name << "'";
@@ -179,9 +191,7 @@
 
     LOG(INFO) << "Opened file '" << name << "', flags " << flags;
 
-    PublishDescriptor(ANDROID_FILE_ENV_PREFIX, name, fd.release());
-
-    return {};
+    return Descriptor(ANDROID_FILE_ENV_PREFIX + name, std::move(fd));
 }
 
 Result<void> EnterNamespaces(const NamespaceInfo& info, const std::string& name, bool pre_apexd) {
@@ -234,7 +244,7 @@
         if (setpgid(0, getpid()) == -1) {
             return ErrnoError() << "setpgid failed";
         }
-        ZapStdio();
+        SetupStdio(attr.stdio_to_kmsg);
     }
 
     for (const auto& rlimit : attr.rlimits) {
diff --git a/init/service_utils.h b/init/service_utils.h
index befce25..3f1071e 100644
--- a/init/service_utils.h
+++ b/init/service_utils.h
@@ -22,6 +22,7 @@
 #include <string>
 #include <vector>
 
+#include <android-base/unique_fd.h>
 #include <cutils/iosched_policy.h>
 
 #include "result.h"
@@ -29,6 +30,18 @@
 namespace android {
 namespace init {
 
+class Descriptor {
+  public:
+    Descriptor(const std::string& name, android::base::unique_fd fd)
+        : name_(name), fd_(std::move(fd)){};
+
+    void Publish() const;
+
+  private:
+    std::string name_;
+    android::base::unique_fd fd_;
+};
+
 struct SocketDescriptor {
     std::string name;
     int type = 0;
@@ -38,14 +51,14 @@
     std::string context;
     bool passcred = false;
 
-    Result<void> CreateAndPublish(const std::string& global_context) const;
+    Result<Descriptor> Create(const std::string& global_context) const;
 };
 
 struct FileDescriptor {
     std::string name;
     std::string type;
 
-    Result<void> CreateAndPublish() const;
+    Result<Descriptor> Create() const;
 };
 
 struct NamespaceInfo {
@@ -64,6 +77,7 @@
     gid_t gid;
     std::vector<gid_t> supp_gids;
     int priority;
+    bool stdio_to_kmsg;
 };
 Result<void> SetProcessAttributes(const ProcessAttributes& attr);
 
diff --git a/init/subcontext.cpp b/init/subcontext.cpp
index 00f91d8..79fc372 100644
--- a/init/subcontext.cpp
+++ b/init/subcontext.cpp
@@ -18,16 +18,17 @@
 
 #include <fcntl.h>
 #include <poll.h>
-#include <sys/socket.h>
 #include <unistd.h>
 
 #include <android-base/file.h>
 #include <android-base/logging.h>
+#include <android-base/properties.h>
 #include <android-base/strings.h>
 #include <selinux/android.h>
 
 #include "action.h"
 #include "builtins.h"
+#include "proto_utils.h"
 #include "util.h"
 
 #if defined(__ANDROID__)
@@ -48,56 +49,8 @@
 
 namespace android {
 namespace init {
-
-const std::string kInitContext = "u:r:init:s0";
-const std::string kVendorContext = "u:r:vendor_init:s0";
-
-const char* const paths_and_secontexts[2][2] = {
-    {"/vendor", kVendorContext.c_str()},
-    {"/odm", kVendorContext.c_str()},
-};
-
 namespace {
 
-constexpr size_t kBufferSize = 4096;
-
-Result<std::string> ReadMessage(int socket) {
-    char buffer[kBufferSize] = {};
-    auto result = TEMP_FAILURE_RETRY(recv(socket, buffer, sizeof(buffer), 0));
-    if (result == 0) {
-        return Error();
-    } else if (result < 0) {
-        return ErrnoError();
-    }
-    return std::string(buffer, result);
-}
-
-template <typename T>
-Result<void> SendMessage(int socket, const T& message) {
-    std::string message_string;
-    if (!message.SerializeToString(&message_string)) {
-        return Error() << "Unable to serialize message";
-    }
-
-    if (message_string.size() > kBufferSize) {
-        return Error() << "Serialized message too long to send";
-    }
-
-    if (auto result =
-            TEMP_FAILURE_RETRY(send(socket, message_string.c_str(), message_string.size(), 0));
-        result != static_cast<long>(message_string.size())) {
-        return ErrnoError() << "send() failed to send message contents";
-    }
-    return {};
-}
-
-std::vector<std::pair<std::string, std::string>> properties_to_set;
-
-uint32_t SubcontextPropertySet(const std::string& name, const std::string& value) {
-    properties_to_set.emplace_back(name, value);
-    return 0;
-}
-
 class SubcontextProcess {
   public:
     SubcontextProcess(const BuiltinFunctionMap* function_map, std::string context, int init_fd)
@@ -131,14 +84,6 @@
         result = RunBuiltinFunction(map_result->function, args, context_);
     }
 
-    for (const auto& [name, value] : properties_to_set) {
-        auto property = reply->add_properties_to_set();
-        property->set_name(name);
-        property->set_value(value);
-    }
-
-    properties_to_set.clear();
-
     if (result) {
         reply->set_success(true);
     } else {
@@ -224,7 +169,10 @@
 
     SelabelInitialize();
 
-    property_set = SubcontextPropertySet;
+    property_set = [](const std::string& key, const std::string& value) -> uint32_t {
+        android::base::SetProperty(key, value);
+        return 0;
+    };
 
     auto subcontext_process = SubcontextProcess(function_map, context, init_fd);
     subcontext_process.MainLoop();
@@ -280,6 +228,15 @@
     Fork();
 }
 
+bool Subcontext::PathMatchesSubcontext(const std::string& path) {
+    for (const auto& prefix : path_prefixes_) {
+        if (StartsWith(path, prefix)) {
+            return true;
+        }
+    }
+    return false;
+}
+
 Result<SubcontextReply> Subcontext::TransmitMessage(const SubcontextCommand& subcontext_command) {
     if (auto result = SendMessage(socket_, subcontext_command); !result) {
         Restart();
@@ -311,15 +268,6 @@
         return subcontext_reply.error();
     }
 
-    for (const auto& property : subcontext_reply->properties_to_set()) {
-        ucred cr = {.pid = pid_, .uid = 0, .gid = 0};
-        std::string error;
-        if (HandlePropertySet(property.name(), property.value(), context_, cr, &error) != 0) {
-            LOG(ERROR) << "Subcontext init could not set '" << property.name() << "' to '"
-                       << property.value() << "': " << error;
-        }
-    }
-
     if (subcontext_reply->reply_case() == SubcontextReply::kFailure) {
         auto& failure = subcontext_reply->failure();
         return ResultError(failure.error_string(), failure.error_errno());
@@ -365,13 +313,12 @@
 static std::vector<Subcontext> subcontexts;
 static bool shutting_down;
 
-std::vector<Subcontext>* InitializeSubcontexts() {
+std::unique_ptr<Subcontext> InitializeSubcontext() {
     if (SelinuxGetVendorAndroidVersion() >= __ANDROID_API_P__) {
-        for (const auto& [path_prefix, secontext] : paths_and_secontexts) {
-            subcontexts.emplace_back(path_prefix, secontext);
-        }
+        return std::make_unique<Subcontext>(std::vector<std::string>{"/vendor", "/odm"},
+                                            kVendorContext);
     }
-    return &subcontexts;
+    return nullptr;
 }
 
 bool SubcontextChildReap(pid_t pid) {
diff --git a/init/subcontext.h b/init/subcontext.h
index 591521f..bcaad29 100644
--- a/init/subcontext.h
+++ b/init/subcontext.h
@@ -14,8 +14,7 @@
  * limitations under the License.
  */
 
-#ifndef _INIT_SUBCONTEXT_H
-#define _INIT_SUBCONTEXT_H
+#pragma once
 
 #include <signal.h>
 
@@ -31,22 +30,21 @@
 namespace android {
 namespace init {
 
-extern const std::string kInitContext;
-extern const std::string kVendorContext;
-extern const char* const paths_and_secontexts[2][2];
+static constexpr const char kInitContext[] = "u:r:init:s0";
+static constexpr const char kVendorContext[] = "u:r:vendor_init:s0";
 
 class Subcontext {
   public:
-    Subcontext(std::string path_prefix, std::string context)
-        : path_prefix_(std::move(path_prefix)), context_(std::move(context)), pid_(0) {
+    Subcontext(std::vector<std::string> path_prefixes, std::string context)
+        : path_prefixes_(std::move(path_prefixes)), context_(std::move(context)), pid_(0) {
         Fork();
     }
 
     Result<void> Execute(const std::vector<std::string>& args);
     Result<std::vector<std::string>> ExpandArgs(const std::vector<std::string>& args);
     void Restart();
+    bool PathMatchesSubcontext(const std::string& path);
 
-    const std::string& path_prefix() const { return path_prefix_; }
     const std::string& context() const { return context_; }
     pid_t pid() const { return pid_; }
 
@@ -54,18 +52,16 @@
     void Fork();
     Result<SubcontextReply> TransmitMessage(const SubcontextCommand& subcontext_command);
 
-    std::string path_prefix_;
+    std::vector<std::string> path_prefixes_;
     std::string context_;
     pid_t pid_;
     android::base::unique_fd socket_;
 };
 
 int SubcontextMain(int argc, char** argv, const BuiltinFunctionMap* function_map);
-std::vector<Subcontext>* InitializeSubcontexts();
+std::unique_ptr<Subcontext> InitializeSubcontext();
 bool SubcontextChildReap(pid_t pid);
 void SubcontextTerminate();
 
 }  // namespace init
 }  // namespace android
-
-#endif
diff --git a/init/subcontext.proto b/init/subcontext.proto
index c31f4fb..e68115e 100644
--- a/init/subcontext.proto
+++ b/init/subcontext.proto
@@ -38,10 +38,4 @@
         Failure failure = 2;
         ExpandArgsReply expand_args_reply = 3;
     }
-
-    message PropertyToSet {
-        optional string name = 1;
-        optional string value = 2;
-    }
-    repeated PropertyToSet properties_to_set = 4;
 }
\ No newline at end of file
diff --git a/init/subcontext_benchmark.cpp b/init/subcontext_benchmark.cpp
index f6fee8a..ccef2f3 100644
--- a/init/subcontext_benchmark.cpp
+++ b/init/subcontext_benchmark.cpp
@@ -33,7 +33,7 @@
         return;
     }
 
-    auto subcontext = Subcontext("path", context);
+    auto subcontext = Subcontext({"path"}, context);
     free(context);
 
     while (state.KeepRunning()) {
diff --git a/init/subcontext_test.cpp b/init/subcontext_test.cpp
index dcbff82..9cac35e 100644
--- a/init/subcontext_test.cpp
+++ b/init/subcontext_test.cpp
@@ -52,7 +52,7 @@
     auto context_string = std::string(context);
     free(context);
 
-    auto subcontext = Subcontext("dummy_path", context_string);
+    auto subcontext = Subcontext({"dummy_path"}, context_string);
     ASSERT_NE(0, subcontext.pid());
 
     test_function(subcontext, context_string);
@@ -224,12 +224,8 @@
 }  // namespace init
 }  // namespace android
 
-int main(int argc, char** argv) {
-    if (argc > 1 && !strcmp(basename(argv[1]), "subcontext")) {
-        auto test_function_map = android::init::BuildTestFunctionMap();
-        return android::init::SubcontextMain(argc, argv, &test_function_map);
-    }
-
-    testing::InitGoogleTest(&argc, argv);
-    return RUN_ALL_TESTS();
+// init_test.cpp contains the main entry point for all init tests.
+int SubcontextTestChildMain(int argc, char** argv) {
+    auto test_function_map = android::init::BuildTestFunctionMap();
+    return android::init::SubcontextMain(argc, argv, &test_function_map);
 }
diff --git a/init/uevent_listener.cpp b/init/uevent_listener.cpp
index ac633776..416d942 100644
--- a/init/uevent_listener.cpp
+++ b/init/uevent_listener.cpp
@@ -171,7 +171,7 @@
     return RegenerateUeventsForDir(d.get(), callback);
 }
 
-static const char* kRegenerationPaths[] = {"/sys/class", "/sys/block", "/sys/devices"};
+static const char* kRegenerationPaths[] = {"/sys/devices"};
 
 void UeventListener::RegenerateUevents(const ListenerCallback& callback) const {
     for (const auto path : kRegenerationPaths) {
diff --git a/init/ueventd.cpp b/init/ueventd.cpp
index cffc1b9..59f91ee 100644
--- a/init/ueventd.cpp
+++ b/init/ueventd.cpp
@@ -113,10 +113,12 @@
 class ColdBoot {
   public:
     ColdBoot(UeventListener& uevent_listener,
-             std::vector<std::unique_ptr<UeventHandler>>& uevent_handlers)
+             std::vector<std::unique_ptr<UeventHandler>>& uevent_handlers,
+             bool enable_parallel_restorecon)
         : uevent_listener_(uevent_listener),
           uevent_handlers_(uevent_handlers),
-          num_handler_subprocesses_(std::thread::hardware_concurrency() ?: 4) {}
+          num_handler_subprocesses_(std::thread::hardware_concurrency() ?: 4),
+          enable_parallel_restorecon_(enable_parallel_restorecon) {}
 
     void Run();
 
@@ -132,6 +134,8 @@
     std::vector<std::unique_ptr<UeventHandler>>& uevent_handlers_;
 
     unsigned int num_handler_subprocesses_;
+    bool enable_parallel_restorecon_;
+
     std::vector<Uevent> uevent_queue_;
 
     std::set<pid_t> subprocess_pids_;
@@ -155,7 +159,6 @@
 
         selinux_android_restorecon(dir.c_str(), SELINUX_ANDROID_RESTORECON_RECURSE);
     }
-    _exit(EXIT_SUCCESS);
 }
 
 void ColdBoot::GenerateRestoreCon(const std::string& directory) {
@@ -195,7 +198,10 @@
 
         if (pid == 0) {
             UeventHandlerMain(i, num_handler_subprocesses_);
-            RestoreConHandler(i, num_handler_subprocesses_);
+            if (enable_parallel_restorecon_) {
+                RestoreConHandler(i, num_handler_subprocesses_);
+            }
+            _exit(EXIT_SUCCESS);
         }
 
         subprocess_pids_.emplace(pid);
@@ -240,14 +246,20 @@
 
     RegenerateUevents();
 
-    selinux_android_restorecon("/sys", 0);
-    selinux_android_restorecon("/sys/devices", 0);
-    GenerateRestoreCon("/sys");
-    // takes long time for /sys/devices, parallelize it
-    GenerateRestoreCon("/sys/devices");
+    if (enable_parallel_restorecon_) {
+        selinux_android_restorecon("/sys", 0);
+        selinux_android_restorecon("/sys/devices", 0);
+        GenerateRestoreCon("/sys");
+        // takes long time for /sys/devices, parallelize it
+        GenerateRestoreCon("/sys/devices");
+    }
 
     ForkSubProcesses();
 
+    if (!enable_parallel_restorecon_) {
+        selinux_android_restorecon("/sys", SELINUX_ANDROID_RESTORECON_RECURSE);
+    }
+
     WaitForSubProcesses();
 
     android::base::SetProperty(kColdBootDoneProp, "true");
@@ -284,7 +296,8 @@
             std::move(ueventd_configuration.sysfs_permissions),
             std::move(ueventd_configuration.subsystems), android::fs_mgr::GetBootDevices(), true));
     uevent_handlers.emplace_back(std::make_unique<FirmwareHandler>(
-            std::move(ueventd_configuration.firmware_directories)));
+            std::move(ueventd_configuration.firmware_directories),
+            std::move(ueventd_configuration.external_firmware_handlers)));
 
     if (ueventd_configuration.enable_modalias_handling) {
         std::vector<std::string> base_paths = {"/odm/lib/modules", "/vendor/lib/modules"};
@@ -293,7 +306,8 @@
     UeventListener uevent_listener(ueventd_configuration.uevent_socket_rcvbuf_size);
 
     if (!android::base::GetBoolProperty(kColdBootDoneProp, false)) {
-        ColdBoot cold_boot(uevent_listener, uevent_handlers);
+        ColdBoot cold_boot(uevent_listener, uevent_handlers,
+                           ueventd_configuration.enable_parallel_restorecon);
         cold_boot.Run();
     }
 
diff --git a/init/ueventd_parser.cpp b/init/ueventd_parser.cpp
index 8ee0cce..a74b247 100644
--- a/init/ueventd_parser.cpp
+++ b/init/ueventd_parser.cpp
@@ -88,18 +88,42 @@
     return {};
 }
 
-Result<void> ParseModaliasHandlingLine(std::vector<std::string>&& args,
-                                       bool* enable_modalias_handling) {
+Result<void> ParseExternalFirmwareHandlerLine(
+        std::vector<std::string>&& args,
+        std::vector<ExternalFirmwareHandler>* external_firmware_handlers) {
+    if (args.size() != 4) {
+        return Error() << "external_firmware_handler lines must have exactly 3 parameters";
+    }
+
+    if (std::find_if(external_firmware_handlers->begin(), external_firmware_handlers->end(),
+                     [&args](const auto& other) { return other.devpath == args[2]; }) !=
+        external_firmware_handlers->end()) {
+        return Error() << "found a previous external_firmware_handler with the same devpath, '"
+                       << args[2] << "'";
+    }
+
+    passwd* pwd = getpwnam(args[2].c_str());
+    if (!pwd) {
+        return ErrnoError() << "invalid handler uid'" << args[2] << "'";
+    }
+
+    ExternalFirmwareHandler handler(std::move(args[1]), pwd->pw_uid, std::move(args[3]));
+    external_firmware_handlers->emplace_back(std::move(handler));
+
+    return {};
+}
+
+Result<void> ParseEnabledDisabledLine(std::vector<std::string>&& args, bool* feature) {
     if (args.size() != 2) {
-        return Error() << "modalias_handling lines take exactly one parameter";
+        return Error() << args[0] << " lines take exactly one parameter";
     }
 
     if (args[1] == "enabled") {
-        *enable_modalias_handling = true;
+        *feature = true;
     } else if (args[1] == "disabled") {
-        *enable_modalias_handling = false;
+        *feature = false;
     } else {
-        return Error() << "modalias_handling takes either 'enabled' or 'disabled' as a parameter";
+        return Error() << args[0] << " takes either 'enabled' or 'disabled' as a parameter";
     }
 
     return {};
@@ -212,12 +236,18 @@
     parser.AddSingleLineParser("firmware_directories",
                                std::bind(ParseFirmwareDirectoriesLine, _1,
                                          &ueventd_configuration.firmware_directories));
+    parser.AddSingleLineParser("external_firmware_handler",
+                               std::bind(ParseExternalFirmwareHandlerLine, _1,
+                                         &ueventd_configuration.external_firmware_handlers));
     parser.AddSingleLineParser("modalias_handling",
-                               std::bind(ParseModaliasHandlingLine, _1,
+                               std::bind(ParseEnabledDisabledLine, _1,
                                          &ueventd_configuration.enable_modalias_handling));
     parser.AddSingleLineParser("uevent_socket_rcvbuf_size",
                                std::bind(ParseUeventSocketRcvbufSizeLine, _1,
                                          &ueventd_configuration.uevent_socket_rcvbuf_size));
+    parser.AddSingleLineParser("parallel_restorecon",
+                               std::bind(ParseEnabledDisabledLine, _1,
+                                         &ueventd_configuration.enable_parallel_restorecon));
 
     for (const auto& config : configs) {
         parser.ParseConfig(config);
diff --git a/init/ueventd_parser.h b/init/ueventd_parser.h
index d476dec..eaafa5a 100644
--- a/init/ueventd_parser.h
+++ b/init/ueventd_parser.h
@@ -14,13 +14,13 @@
  * limitations under the License.
  */
 
-#ifndef _INIT_UEVENTD_PARSER_H
-#define _INIT_UEVENTD_PARSER_H
+#pragma once
 
 #include <string>
 #include <vector>
 
 #include "devices.h"
+#include "firmware_handler.h"
 
 namespace android {
 namespace init {
@@ -30,13 +30,13 @@
     std::vector<SysfsPermissions> sysfs_permissions;
     std::vector<Permissions> dev_permissions;
     std::vector<std::string> firmware_directories;
+    std::vector<ExternalFirmwareHandler> external_firmware_handlers;
     bool enable_modalias_handling = false;
     size_t uevent_socket_rcvbuf_size = 0;
+    bool enable_parallel_restorecon = false;
 };
 
 UeventdConfiguration ParseConfig(const std::vector<std::string>& configs);
 
 }  // namespace init
 }  // namespace android
-
-#endif
diff --git a/init/ueventd_parser_test.cpp b/init/ueventd_parser_test.cpp
index 9c1cedf..172ba0b 100644
--- a/init/ueventd_parser_test.cpp
+++ b/init/ueventd_parser_test.cpp
@@ -20,6 +20,8 @@
 #include <gtest/gtest.h>
 #include <private/android_filesystem_config.h>
 
+#include "firmware_handler.h"
+
 namespace android {
 namespace init {
 
@@ -93,7 +95,7 @@
             {"test_devname2", Subsystem::DEVNAME_UEVENT_DEVNAME, "/dev"},
             {"test_devpath_dirname", Subsystem::DEVNAME_UEVENT_DEVPATH, "/dev/graphics"}};
 
-    TestUeventdFile(ueventd_file, {subsystems, {}, {}, {}});
+    TestUeventdFile(ueventd_file, {subsystems, {}, {}, {}, {}});
 }
 
 TEST(ueventd_parser, Permissions) {
@@ -119,7 +121,7 @@
             {"/sys/devices/virtual/*/input", "poll_delay", 0660, AID_ROOT, AID_INPUT},
     };
 
-    TestUeventdFile(ueventd_file, {{}, sysfs_permissions, permissions, {}});
+    TestUeventdFile(ueventd_file, {{}, sysfs_permissions, permissions, {}, {}});
 }
 
 TEST(ueventd_parser, FirmwareDirectories) {
@@ -135,7 +137,52 @@
             "/more",
     };
 
-    TestUeventdFile(ueventd_file, {{}, {}, {}, firmware_directories});
+    TestUeventdFile(ueventd_file, {{}, {}, {}, firmware_directories, {}});
+}
+
+TEST(ueventd_parser, ExternalFirmwareHandlers) {
+    auto ueventd_file = R"(
+external_firmware_handler devpath root handler_path
+external_firmware_handler /devices/path/firmware/something001.bin system /vendor/bin/firmware_handler.sh
+external_firmware_handler /devices/path/firmware/something001.bin radio "/vendor/bin/firmware_handler.sh --has --arguments"
+)";
+
+    auto external_firmware_handlers = std::vector<ExternalFirmwareHandler>{
+            {
+                    "devpath",
+                    AID_ROOT,
+                    "handler_path",
+            },
+            {
+                    "/devices/path/firmware/something001.bin",
+                    AID_SYSTEM,
+                    "/vendor/bin/firmware_handler.sh",
+            },
+            {
+                    "/devices/path/firmware/something001.bin",
+                    AID_RADIO,
+                    "/vendor/bin/firmware_handler.sh --has --arguments",
+            },
+    };
+
+    TestUeventdFile(ueventd_file, {{}, {}, {}, {}, external_firmware_handlers});
+}
+
+TEST(ueventd_parser, ExternalFirmwareHandlersDuplicate) {
+    auto ueventd_file = R"(
+external_firmware_handler devpath root handler_path
+external_firmware_handler devpath root handler_path2
+)";
+
+    auto external_firmware_handlers = std::vector<ExternalFirmwareHandler>{
+            {
+                    "devpath",
+                    AID_ROOT,
+                    "handler_path",
+            },
+    };
+
+    TestUeventdFile(ueventd_file, {{}, {}, {}, {}, external_firmware_handlers});
 }
 
 TEST(ueventd_parser, UeventSocketRcvbufSize) {
@@ -144,7 +191,25 @@
 uevent_socket_rcvbuf_size 8M
 )";
 
-    TestUeventdFile(ueventd_file, {{}, {}, {}, {}, false, 8 * 1024 * 1024});
+    TestUeventdFile(ueventd_file, {{}, {}, {}, {}, {}, false, 8 * 1024 * 1024});
+}
+
+TEST(ueventd_parser, EnabledDisabledLines) {
+    auto ueventd_file = R"(
+modalias_handling enabled
+parallel_restorecon enabled
+modalias_handling disabled
+)";
+
+    TestUeventdFile(ueventd_file, {{}, {}, {}, {}, {}, false, 0, true});
+
+    auto ueventd_file2 = R"(
+parallel_restorecon enabled
+modalias_handling enabled
+parallel_restorecon disabled
+)";
+
+    TestUeventdFile(ueventd_file2, {{}, {}, {}, {}, {}, true, 0, false});
 }
 
 TEST(ueventd_parser, AllTogether) {
@@ -178,7 +243,11 @@
 /sys/devices/virtual/*/input   poll_delay  0660  root   input
 firmware_directories /more
 
+external_firmware_handler /devices/path/firmware/firmware001.bin root /vendor/bin/touch.sh
+
 uevent_socket_rcvbuf_size 6M
+modalias_handling enabled
+parallel_restorecon enabled
 
 #ending comment
 )";
@@ -208,10 +277,15 @@
             "/more",
     };
 
+    auto external_firmware_handlers = std::vector<ExternalFirmwareHandler>{
+            {"/devices/path/firmware/firmware001.bin", AID_ROOT, "/vendor/bin/touch.sh"},
+    };
+
     size_t uevent_socket_rcvbuf_size = 6 * 1024 * 1024;
 
-    TestUeventdFile(ueventd_file, {subsystems, sysfs_permissions, permissions, firmware_directories,
-                                   false, uevent_socket_rcvbuf_size});
+    TestUeventdFile(ueventd_file,
+                    {subsystems, sysfs_permissions, permissions, firmware_directories,
+                     external_firmware_handlers, true, uevent_socket_rcvbuf_size, true});
 }
 
 // All of these lines are ill-formed, so test that there is 0 output.
@@ -230,6 +304,18 @@
 
 subsystem #no name
 
+modalias_handling
+modalias_handling enabled enabled
+modalias_handling blah
+
+parallel_restorecon
+parallel_restorecon enabled enabled
+parallel_restorecon blah
+
+external_firmware_handler
+external_firmware_handler blah blah
+external_firmware_handler blah blah blah blah
+
 )";
 
     TestUeventdFile(ueventd_file, {});
diff --git a/libbacktrace/include/backtrace/BacktraceMap.h b/libbacktrace/include/backtrace/BacktraceMap.h
index f8d5058..e000a00 100644
--- a/libbacktrace/include/backtrace/BacktraceMap.h
+++ b/libbacktrace/include/backtrace/BacktraceMap.h
@@ -79,7 +79,7 @@
       index_++;
       return *this;
     }
-    iterator& operator++(int increment) {
+    const iterator operator++(int increment) {
       index_ += increment;
       return *this;
     }
@@ -87,7 +87,7 @@
       index_--;
       return *this;
     }
-    iterator& operator--(int decrement) {
+    const iterator operator--(int decrement) {
       index_ -= decrement;
       return *this;
     }
diff --git a/libcutils/fs_config.cpp b/libcutils/fs_config.cpp
index b29638c..d0d83de 100644
--- a/libcutils/fs_config.cpp
+++ b/libcutils/fs_config.cpp
@@ -84,7 +84,7 @@
     { 00755, AID_ROOT,         AID_ROOT,         0, "system/etc/ppp" },
     { 00755, AID_ROOT,         AID_SHELL,        0, "system/vendor" },
     { 00751, AID_ROOT,         AID_SHELL,        0, "system/xbin" },
-    { 00755, AID_ROOT,         AID_SHELL,        0, "system/apex/*/bin" },
+    { 00751, AID_ROOT,         AID_SHELL,        0, "system/apex/*/bin" },
     { 00751, AID_ROOT,         AID_SHELL,        0, "vendor/bin" },
     { 00755, AID_ROOT,         AID_SHELL,        0, "vendor" },
     { 00755, AID_ROOT,         AID_ROOT,         0, 0 },
diff --git a/libcutils/include/private/android_filesystem_config.h b/libcutils/include/private/android_filesystem_config.h
index ae9dab5..e1e8230 100644
--- a/libcutils/include/private/android_filesystem_config.h
+++ b/libcutils/include/private/android_filesystem_config.h
@@ -128,6 +128,7 @@
 #define AID_GPU_SERVICE 1072     /* GPU service daemon */
 #define AID_NETWORK_STACK 1073   /* network stack service */
 #define AID_GSID 1074            /* GSI service daemon */
+#define AID_FSVERITY_CERT 1075   /* fs-verity key ownership in keystore */
 /* Changes to this file must be made in AOSP, *not* in internal branches. */
 
 #define AID_SHELL 2000 /* adb and debug shell user */
diff --git a/libion/tests/Android.bp b/libion/tests/Android.bp
index d3b4688..5600702 100644
--- a/libion/tests/Android.bp
+++ b/libion/tests/Android.bp
@@ -24,7 +24,8 @@
     srcs: [
         "allocate_test.cpp",
         "exit_test.cpp",
-    	"heap_query.cpp",
+        "heap_query.cpp",
+        "system_heap.cpp",
         "invalid_values_test.cpp",
         "ion_test_fixture.cpp",
         "map_test.cpp",
diff --git a/libion/tests/heap_query.cpp b/libion/tests/heap_query.cpp
index bad3bbf..fed8030 100644
--- a/libion/tests/heap_query.cpp
+++ b/libion/tests/heap_query.cpp
@@ -15,6 +15,8 @@
  */
 
 #include <gtest/gtest.h>
+
+#include <ion/ion.h>
 #include "ion_test_fixture.h"
 
 class HeapQuery : public IonTest {};
@@ -23,5 +25,24 @@
     ASSERT_GT(ion_heaps.size(), 0);
 }
 
-// TODO: Check if we expect some of the default
-// heap types to be present on all devices.
+// TODO: Adjust this test to account for the range of valid carveout and DMA heap ids.
+TEST_F(HeapQuery, HeapIdVerify) {
+    for (const auto& heap : ion_heaps) {
+        SCOPED_TRACE(::testing::Message() << "Invalid id for heap:" << heap.name << ":" << heap.type
+                                          << ":" << heap.heap_id);
+        switch (heap.type) {
+            case ION_HEAP_TYPE_SYSTEM:
+                ASSERT_TRUE((1 << heap.heap_id) & ION_HEAP_SYSTEM_MASK);
+                break;
+            case ION_HEAP_TYPE_SYSTEM_CONTIG:
+                ASSERT_TRUE((1 << heap.heap_id) & ION_HEAP_SYSTEM_CONTIG_MASK);
+                break;
+            case ION_HEAP_TYPE_CARVEOUT:
+                ASSERT_TRUE((1 << heap.heap_id) & ION_HEAP_CARVEOUT_MASK);
+                break;
+            case ION_HEAP_TYPE_DMA:
+                ASSERT_TRUE((1 << heap.heap_id) & ION_HEAP_TYPE_DMA_MASK);
+                break;
+        }
+    }
+}
diff --git a/libion/tests/system_heap.cpp b/libion/tests/system_heap.cpp
new file mode 100644
index 0000000..fb63888
--- /dev/null
+++ b/libion/tests/system_heap.cpp
@@ -0,0 +1,44 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <unistd.h>
+
+#include <gtest/gtest.h>
+#include <iostream>
+
+#include <ion/ion.h>
+#include "ion_test_fixture.h"
+
+class SystemHeap : public IonTest {};
+
+TEST_F(SystemHeap, Presence) {
+    bool system_heap_found = false;
+    for (const auto& heap : ion_heaps) {
+        if (heap.type == ION_HEAP_TYPE_SYSTEM) {
+            system_heap_found = true;
+            EXPECT_TRUE((1 << heap.heap_id) & ION_HEAP_SYSTEM_MASK);
+        }
+    }
+    // We now expect the system heap to exist from Android
+    ASSERT_TRUE(system_heap_found);
+}
+
+TEST_F(SystemHeap, Allocate) {
+    int fd;
+    ASSERT_EQ(0, ion_alloc_fd(ionfd, getpagesize(), 0, ION_HEAP_SYSTEM_MASK, 0, &fd));
+    ASSERT_TRUE(fd != 0);
+    ASSERT_EQ(close(fd), 0);  // free the buffer
+}
diff --git a/libmeminfo/libmeminfo_test.cpp b/libmeminfo/libmeminfo_test.cpp
index 4c2be91..cf5341d 100644
--- a/libmeminfo/libmeminfo_test.cpp
+++ b/libmeminfo/libmeminfo_test.cpp
@@ -31,6 +31,7 @@
 #include <android-base/file.h>
 #include <android-base/logging.h>
 #include <android-base/stringprintf.h>
+#include <android-base/strings.h>
 
 using namespace std;
 using namespace android::meminfo;
@@ -334,7 +335,9 @@
     // Check for names
     EXPECT_EQ(vmas[0].name, "[anon:dalvik-zygote-jit-code-cache]");
     EXPECT_EQ(vmas[1].name, "/system/framework/x86_64/boot-framework.art");
-    EXPECT_EQ(vmas[2].name, "[anon:libc_malloc]");
+    EXPECT_TRUE(vmas[2].name == "[anon:libc_malloc]" ||
+                android::base::StartsWith(vmas[2].name, "[anon:scudo:"))
+            << "Unknown map name " << vmas[2].name;
     EXPECT_EQ(vmas[3].name, "/system/priv-app/SettingsProvider/oat/x86_64/SettingsProvider.odex");
     EXPECT_EQ(vmas[4].name, "/system/lib64/libhwui.so");
     EXPECT_EQ(vmas[5].name, "[vsyscall]");
@@ -432,7 +435,9 @@
     // Check for names
     EXPECT_EQ(vmas[0].name, "[anon:dalvik-zygote-jit-code-cache]");
     EXPECT_EQ(vmas[1].name, "/system/framework/x86_64/boot-framework.art");
-    EXPECT_EQ(vmas[2].name, "[anon:libc_malloc]");
+    EXPECT_TRUE(vmas[2].name == "[anon:libc_malloc]" ||
+                android::base::StartsWith(vmas[2].name, "[anon:scudo:"))
+            << "Unknown map name " << vmas[2].name;
     EXPECT_EQ(vmas[3].name, "/system/priv-app/SettingsProvider/oat/x86_64/SettingsProvider.odex");
     EXPECT_EQ(vmas[4].name, "/system/lib64/libhwui.so");
     EXPECT_EQ(vmas[5].name, "[vsyscall]");
diff --git a/libmemunreachable/MemUnreachable.cpp b/libmemunreachable/MemUnreachable.cpp
index ce937fd..c4add19 100644
--- a/libmemunreachable/MemUnreachable.cpp
+++ b/libmemunreachable/MemUnreachable.cpp
@@ -25,6 +25,7 @@
 #include <unordered_map>
 
 #include <android-base/macros.h>
+#include <android-base/strings.h>
 #include <backtrace.h>
 
 #include "Allocator.h"
@@ -250,7 +251,8 @@
     } else if (mapping_name == current_lib) {
       // .rodata or .data section
       globals_mappings.emplace_back(*it);
-    } else if (mapping_name == "[anon:libc_malloc]") {
+    } else if (mapping_name == "[anon:libc_malloc]" ||
+               android::base::StartsWith(mapping_name, "[anon:scudo:")) {
       // named malloc mapping
       heap_mappings.emplace_back(*it);
     } else if (has_prefix(mapping_name, "[anon:dalvik-")) {
diff --git a/libmemunreachable/ScopedDisableMalloc.h b/libmemunreachable/ScopedDisableMalloc.h
index 655e826..dc863c9 100644
--- a/libmemunreachable/ScopedDisableMalloc.h
+++ b/libmemunreachable/ScopedDisableMalloc.h
@@ -34,8 +34,8 @@
 
   void Disable() {
     if (!disabled_) {
-      malloc_disable();
       disabled_ = true;
+      malloc_disable();
     }
   }
 
@@ -71,8 +71,7 @@
 
 class ScopedDisableMallocTimeout {
  public:
-  explicit ScopedDisableMallocTimeout(
-      std::chrono::milliseconds timeout = std::chrono::milliseconds(2000))
+  explicit ScopedDisableMallocTimeout(std::chrono::milliseconds timeout = std::chrono::seconds(10))
       : timeout_(timeout), timed_out_(false), disable_malloc_() {
     Disable();
   }
diff --git a/libnativeloader/Android.bp b/libnativeloader/Android.bp
index b860db9..939bdd7 100644
--- a/libnativeloader/Android.bp
+++ b/libnativeloader/Android.bp
@@ -63,14 +63,6 @@
     export_include_dirs: ["include"],
 }
 
-// TODO(jiyong) Remove this when its use in the internal master is
-// switched to libnativeloader-headers
-cc_library_headers {
-    name: "libnativeloader-dummy-headers",
-    host_supported: true,
-    export_include_dirs: ["include"],
-}
-
 cc_test {
     name: "libnativeloader_test",
     srcs: [
diff --git a/libpackagelistparser/Android.bp b/libpackagelistparser/Android.bp
index 0740e7d..b56dcdb 100644
--- a/libpackagelistparser/Android.bp
+++ b/libpackagelistparser/Android.bp
@@ -19,4 +19,5 @@
         "libpackagelistparser",
     ],
     test_suites: ["device-tests"],
+    require_root: true,
 }
diff --git a/libprocessgroup/OWNERS b/libprocessgroup/OWNERS
index bfa730a..27b9a03 100644
--- a/libprocessgroup/OWNERS
+++ b/libprocessgroup/OWNERS
@@ -1,2 +1,3 @@
 ccross@google.com
+surenb@google.com
 tomcherry@google.com
diff --git a/libunwindstack/Android.bp b/libunwindstack/Android.bp
index da18af6..8d2299f 100644
--- a/libunwindstack/Android.bp
+++ b/libunwindstack/Android.bp
@@ -183,6 +183,7 @@
         "tests/ElfTestUtils.cpp",
         "tests/IsolatedSettings.cpp",
         "tests/JitDebugTest.cpp",
+        "tests/LocalUpdatableMapsTest.cpp",
         "tests/LogFake.cpp",
         "tests/MapInfoCreateMemoryTest.cpp",
         "tests/MapInfoGetBuildIDTest.cpp",
diff --git a/libunwindstack/Maps.cpp b/libunwindstack/Maps.cpp
index 5da73e4..250e600 100644
--- a/libunwindstack/Maps.cpp
+++ b/libunwindstack/Maps.cpp
@@ -149,9 +149,10 @@
       }
 
       // Never delete these maps, they may be in use. The assumption is
-      // that there will only every be a handfull of these so waiting
+      // that there will only every be a handful of these so waiting
       // to destroy them is not too expensive.
       saved_maps_.emplace_back(std::move(info));
+      search_map_idx = old_map_idx + 1;
       maps_[old_map_idx] = nullptr;
       total_entries--;
     }
diff --git a/libunwindstack/include/unwindstack/Maps.h b/libunwindstack/include/unwindstack/Maps.h
index 1784394..e53f367 100644
--- a/libunwindstack/include/unwindstack/Maps.h
+++ b/libunwindstack/include/unwindstack/Maps.h
@@ -105,7 +105,7 @@
 
   const std::string GetMapsFile() const override;
 
- private:
+ protected:
   std::vector<std::unique_ptr<MapInfo>> saved_maps_;
 };
 
diff --git a/libunwindstack/tests/LocalUpdatableMapsTest.cpp b/libunwindstack/tests/LocalUpdatableMapsTest.cpp
new file mode 100644
index 0000000..b816b9a
--- /dev/null
+++ b/libunwindstack/tests/LocalUpdatableMapsTest.cpp
@@ -0,0 +1,274 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdint.h>
+#include <sys/mman.h>
+
+#include <string>
+#include <vector>
+
+#include <gtest/gtest.h>
+
+#include <android-base/file.h>
+#include <unwindstack/Maps.h>
+
+namespace unwindstack {
+
+class TestUpdatableMaps : public LocalUpdatableMaps {
+ public:
+  TestUpdatableMaps() : LocalUpdatableMaps() {}
+  virtual ~TestUpdatableMaps() = default;
+
+  const std::string GetMapsFile() const override { return maps_file_; }
+
+  void TestSetMapsFile(const std::string& maps_file) { maps_file_ = maps_file; }
+
+  const std::vector<std::unique_ptr<MapInfo>>& TestGetSavedMaps() { return saved_maps_; }
+
+ private:
+  std::string maps_file_;
+};
+
+class LocalUpdatableMapsTest : public ::testing::Test {
+ protected:
+  static const std::string GetDefaultMapString() {
+    return "3000-4000 r-xp 00000 00:00 0\n8000-9000 r-xp 00000 00:00 0\n";
+  }
+
+  void SetUp() override {
+    TemporaryFile tf;
+    ASSERT_TRUE(android::base::WriteStringToFile(GetDefaultMapString(), tf.path));
+
+    maps_.TestSetMapsFile(tf.path);
+    ASSERT_TRUE(maps_.Parse());
+    ASSERT_EQ(2U, maps_.Total());
+
+    MapInfo* map_info = maps_.Get(0);
+    ASSERT_TRUE(map_info != nullptr);
+    EXPECT_EQ(0x3000U, map_info->start);
+    EXPECT_EQ(0x4000U, map_info->end);
+    EXPECT_EQ(0U, map_info->offset);
+    EXPECT_EQ(PROT_READ | PROT_EXEC, map_info->flags);
+    EXPECT_TRUE(map_info->name.empty());
+
+    map_info = maps_.Get(1);
+    ASSERT_TRUE(map_info != nullptr);
+    EXPECT_EQ(0x8000U, map_info->start);
+    EXPECT_EQ(0x9000U, map_info->end);
+    EXPECT_EQ(0U, map_info->offset);
+    EXPECT_EQ(PROT_READ | PROT_EXEC, map_info->flags);
+    EXPECT_TRUE(map_info->name.empty());
+  }
+
+  TestUpdatableMaps maps_;
+};
+
+TEST_F(LocalUpdatableMapsTest, same_map) {
+  TemporaryFile tf;
+  ASSERT_TRUE(android::base::WriteStringToFile(GetDefaultMapString(), tf.path));
+
+  maps_.TestSetMapsFile(tf.path);
+  ASSERT_TRUE(maps_.Reparse());
+  ASSERT_EQ(2U, maps_.Total());
+  EXPECT_EQ(0U, maps_.TestGetSavedMaps().size());
+
+  MapInfo* map_info = maps_.Get(0);
+  ASSERT_TRUE(map_info != nullptr);
+  EXPECT_EQ(0x3000U, map_info->start);
+  EXPECT_EQ(0x4000U, map_info->end);
+  EXPECT_EQ(0U, map_info->offset);
+  EXPECT_EQ(PROT_READ | PROT_EXEC, map_info->flags);
+  EXPECT_TRUE(map_info->name.empty());
+
+  map_info = maps_.Get(1);
+  ASSERT_TRUE(map_info != nullptr);
+  EXPECT_EQ(0x8000U, map_info->start);
+  EXPECT_EQ(0x9000U, map_info->end);
+  EXPECT_EQ(0U, map_info->offset);
+  EXPECT_EQ(PROT_READ | PROT_EXEC, map_info->flags);
+  EXPECT_TRUE(map_info->name.empty());
+}
+
+TEST_F(LocalUpdatableMapsTest, same_map_new_perms) {
+  TemporaryFile tf;
+  ASSERT_TRUE(
+      android::base::WriteStringToFile("3000-4000 rwxp 00000 00:00 0\n"
+                                       "8000-9000 r-xp 00000 00:00 0\n",
+                                       tf.path));
+
+  maps_.TestSetMapsFile(tf.path);
+  ASSERT_TRUE(maps_.Reparse());
+  ASSERT_EQ(2U, maps_.Total());
+
+  MapInfo* map_info = maps_.Get(0);
+  ASSERT_TRUE(map_info != nullptr);
+  EXPECT_EQ(0x3000U, map_info->start);
+  EXPECT_EQ(0x4000U, map_info->end);
+  EXPECT_EQ(0U, map_info->offset);
+  EXPECT_EQ(PROT_READ | PROT_WRITE | PROT_EXEC, map_info->flags);
+  EXPECT_TRUE(map_info->name.empty());
+
+  map_info = maps_.Get(1);
+  ASSERT_TRUE(map_info != nullptr);
+  EXPECT_EQ(0x8000U, map_info->start);
+  EXPECT_EQ(0x9000U, map_info->end);
+  EXPECT_EQ(0U, map_info->offset);
+  EXPECT_EQ(PROT_READ | PROT_EXEC, map_info->flags);
+  EXPECT_TRUE(map_info->name.empty());
+
+  auto& saved_maps = maps_.TestGetSavedMaps();
+  ASSERT_EQ(1U, saved_maps.size());
+  map_info = saved_maps[0].get();
+  ASSERT_TRUE(map_info != nullptr);
+  EXPECT_EQ(0x3000U, map_info->start);
+  EXPECT_EQ(0x4000U, map_info->end);
+  EXPECT_EQ(0U, map_info->offset);
+  EXPECT_EQ(PROT_READ | PROT_EXEC, map_info->flags);
+  EXPECT_TRUE(map_info->name.empty());
+}
+
+TEST_F(LocalUpdatableMapsTest, same_map_new_name) {
+  TemporaryFile tf;
+  ASSERT_TRUE(
+      android::base::WriteStringToFile("3000-4000 r-xp 00000 00:00 0 /fake/lib.so\n"
+                                       "8000-9000 r-xp 00000 00:00 0\n",
+                                       tf.path));
+
+  maps_.TestSetMapsFile(tf.path);
+  ASSERT_TRUE(maps_.Reparse());
+  ASSERT_EQ(2U, maps_.Total());
+
+  MapInfo* map_info = maps_.Get(0);
+  ASSERT_TRUE(map_info != nullptr);
+  EXPECT_EQ(0x3000U, map_info->start);
+  EXPECT_EQ(0x4000U, map_info->end);
+  EXPECT_EQ(0U, map_info->offset);
+  EXPECT_EQ(PROT_READ | PROT_EXEC, map_info->flags);
+  EXPECT_EQ("/fake/lib.so", map_info->name);
+
+  map_info = maps_.Get(1);
+  ASSERT_TRUE(map_info != nullptr);
+  EXPECT_EQ(0x8000U, map_info->start);
+  EXPECT_EQ(0x9000U, map_info->end);
+  EXPECT_EQ(0U, map_info->offset);
+  EXPECT_EQ(PROT_READ | PROT_EXEC, map_info->flags);
+  EXPECT_TRUE(map_info->name.empty());
+
+  auto& saved_maps = maps_.TestGetSavedMaps();
+  ASSERT_EQ(1U, saved_maps.size());
+  map_info = saved_maps[0].get();
+  ASSERT_TRUE(map_info != nullptr);
+  EXPECT_EQ(0x3000U, map_info->start);
+  EXPECT_EQ(0x4000U, map_info->end);
+  EXPECT_EQ(0U, map_info->offset);
+  EXPECT_EQ(PROT_READ | PROT_EXEC, map_info->flags);
+  EXPECT_TRUE(map_info->name.empty());
+}
+
+TEST_F(LocalUpdatableMapsTest, only_add_maps) {
+  TemporaryFile tf;
+  ASSERT_TRUE(
+      android::base::WriteStringToFile("1000-2000 r-xp 00000 00:00 0\n"
+                                       "3000-4000 r-xp 00000 00:00 0\n"
+                                       "8000-9000 r-xp 00000 00:00 0\n"
+                                       "a000-f000 r-xp 00000 00:00 0\n",
+                                       tf.path));
+
+  maps_.TestSetMapsFile(tf.path);
+  ASSERT_TRUE(maps_.Reparse());
+  ASSERT_EQ(4U, maps_.Total());
+  EXPECT_EQ(0U, maps_.TestGetSavedMaps().size());
+
+  MapInfo* map_info = maps_.Get(0);
+  ASSERT_TRUE(map_info != nullptr);
+  EXPECT_EQ(0x1000U, map_info->start);
+  EXPECT_EQ(0x2000U, map_info->end);
+  EXPECT_EQ(0U, map_info->offset);
+  EXPECT_EQ(PROT_READ | PROT_EXEC, map_info->flags);
+  EXPECT_TRUE(map_info->name.empty());
+
+  map_info = maps_.Get(1);
+  ASSERT_TRUE(map_info != nullptr);
+  EXPECT_EQ(0x3000U, map_info->start);
+  EXPECT_EQ(0x4000U, map_info->end);
+  EXPECT_EQ(0U, map_info->offset);
+  EXPECT_EQ(PROT_READ | PROT_EXEC, map_info->flags);
+  EXPECT_TRUE(map_info->name.empty());
+
+  map_info = maps_.Get(2);
+  ASSERT_TRUE(map_info != nullptr);
+  EXPECT_EQ(0x8000U, map_info->start);
+  EXPECT_EQ(0x9000U, map_info->end);
+  EXPECT_EQ(0U, map_info->offset);
+  EXPECT_EQ(PROT_READ | PROT_EXEC, map_info->flags);
+  EXPECT_TRUE(map_info->name.empty());
+
+  map_info = maps_.Get(3);
+  ASSERT_TRUE(map_info != nullptr);
+  EXPECT_EQ(0xa000U, map_info->start);
+  EXPECT_EQ(0xf000U, map_info->end);
+  EXPECT_EQ(0U, map_info->offset);
+  EXPECT_EQ(PROT_READ | PROT_EXEC, map_info->flags);
+  EXPECT_TRUE(map_info->name.empty());
+}
+
+TEST_F(LocalUpdatableMapsTest, all_new_maps) {
+  TemporaryFile tf;
+  ASSERT_TRUE(
+      android::base::WriteStringToFile("1000-2000 r-xp 00000 00:00 0\n"
+                                       "a000-f000 r-xp 00000 00:00 0\n",
+                                       tf.path));
+
+  maps_.TestSetMapsFile(tf.path);
+  ASSERT_TRUE(maps_.Reparse());
+  ASSERT_EQ(2U, maps_.Total());
+
+  MapInfo* map_info = maps_.Get(0);
+  ASSERT_TRUE(map_info != nullptr);
+  EXPECT_EQ(0x1000U, map_info->start);
+  EXPECT_EQ(0x2000U, map_info->end);
+  EXPECT_EQ(0U, map_info->offset);
+  EXPECT_EQ(PROT_READ | PROT_EXEC, map_info->flags);
+  EXPECT_TRUE(map_info->name.empty());
+
+  map_info = maps_.Get(1);
+  ASSERT_TRUE(map_info != nullptr);
+  EXPECT_EQ(0xa000U, map_info->start);
+  EXPECT_EQ(0xf000U, map_info->end);
+  EXPECT_EQ(0U, map_info->offset);
+  EXPECT_EQ(PROT_READ | PROT_EXEC, map_info->flags);
+  EXPECT_TRUE(map_info->name.empty());
+
+  auto& saved_maps = maps_.TestGetSavedMaps();
+  ASSERT_EQ(2U, saved_maps.size());
+  map_info = saved_maps[0].get();
+  ASSERT_TRUE(map_info != nullptr);
+  EXPECT_EQ(0x3000U, map_info->start);
+  EXPECT_EQ(0x4000U, map_info->end);
+  EXPECT_EQ(0U, map_info->offset);
+  EXPECT_EQ(PROT_READ | PROT_EXEC, map_info->flags);
+  EXPECT_TRUE(map_info->name.empty());
+
+  map_info = saved_maps[1].get();
+  ASSERT_TRUE(map_info != nullptr);
+  EXPECT_EQ(0x8000U, map_info->start);
+  EXPECT_EQ(0x9000U, map_info->end);
+  EXPECT_EQ(0U, map_info->offset);
+  EXPECT_EQ(PROT_READ | PROT_EXEC, map_info->flags);
+  EXPECT_TRUE(map_info->name.empty());
+}
+
+}  // namespace unwindstack
diff --git a/libutils/Looper_test.cpp b/libutils/Looper_test.cpp
index 6fdc0edc..37bdf05 100644
--- a/libutils/Looper_test.cpp
+++ b/libutils/Looper_test.cpp
@@ -11,8 +11,9 @@
 
 #include <utils/threads.h>
 
+// b/141212746 - increased for virtual platforms with higher volatility
 // # of milliseconds to fudge stopwatch measurements
-#define TIMING_TOLERANCE_MS 25
+#define TIMING_TOLERANCE_MS 100
 
 namespace android {
 
diff --git a/libutils/Timers.cpp b/libutils/Timers.cpp
index c3641ef..1172ae7 100644
--- a/libutils/Timers.cpp
+++ b/libutils/Timers.cpp
@@ -22,7 +22,8 @@
 #include <limits.h>
 #include <time.h>
 
-#if defined(__ANDROID__)
+// host linux support requires Linux 2.6.39+
+#if defined(__linux__)
 nsecs_t systemTime(int clock)
 {
     static const clockid_t clocks[] = {
@@ -41,8 +42,7 @@
 nsecs_t systemTime(int /*clock*/)
 {
     // Clock support varies widely across hosts. Mac OS doesn't support
-    // posix clocks, older glibcs don't support CLOCK_BOOTTIME and Windows
-    // is windows.
+    // CLOCK_BOOTTIME, and Windows is windows.
     struct timeval t;
     t.tv_sec = t.tv_usec = 0;
     gettimeofday(&t, nullptr);
diff --git a/libutils/include/utils/ByteOrder.h b/libutils/include/utils/ByteOrder.h
index 44ea13d..9b940e6 100644
--- a/libutils/include/utils/ByteOrder.h
+++ b/libutils/include/utils/ByteOrder.h
@@ -14,10 +14,17 @@
  * limitations under the License.
  */
 
-//
+#pragma once
 
-#ifndef _LIBS_UTILS_BYTE_ORDER_H
-#define _LIBS_UTILS_BYTE_ORDER_H
+/*
+ * If you're looking for a portable <endian.h> that's available on Android,
+ * Linux, macOS, and Windows, see <android-base/endian.h> instead.
+ *
+ * Nothing in this file is useful because all supported Android ABIs are
+ * little-endian and all our code that runs on the host assumes that the host is
+ * also little-endian. What pretense at big-endian support exists is completely
+ * untested and unlikely to actually work.
+ */
 
 #include <stdint.h>
 #include <sys/types.h>
@@ -27,55 +34,12 @@
 #include <netinet/in.h>
 #endif
 
-/*
- * These macros are like the hton/ntoh byte swapping macros,
- * except they allow you to swap to and from the "device" byte
- * order.  The device byte order is the endianness of the target
- * device -- for the ARM CPUs we use today, this is little endian.
- *
- * Note that the byte swapping functions have not been optimized
- * much; performance is currently not an issue for them since the
- * intent is to allow us to avoid byte swapping on the device.
- */
+/* TODO: move this cruft to frameworks/. */
 
-static inline uint32_t android_swap_long(uint32_t v)
-{
-    return (v<<24) | ((v<<8)&0x00FF0000) | ((v>>8)&0x0000FF00) | (v>>24);
-}
+#define dtohl(x) (x)
+#define dtohs(x) (x)
+#define htodl(x) (x)
+#define htods(x) (x)
 
-static inline uint16_t android_swap_short(uint16_t v)
-{
-    return (v<<8) | (v>>8);
-}
-
-#define DEVICE_BYTE_ORDER LITTLE_ENDIAN
-
-#if BYTE_ORDER == DEVICE_BYTE_ORDER
-
-#define	dtohl(x)	(x)
-#define	dtohs(x)	(x)
-#define	htodl(x)	(x)
-#define	htods(x)	(x)
-
-#else
-
-#define	dtohl(x)	(android_swap_long(x))
-#define	dtohs(x)	(android_swap_short(x))
-#define	htodl(x)	(android_swap_long(x))
-#define	htods(x)	(android_swap_short(x))
-
-#endif
-
-#if BYTE_ORDER == LITTLE_ENDIAN
 #define fromlel(x) (x)
-#define fromles(x) (x)
 #define tolel(x) (x)
-#define toles(x) (x)
-#else
-#define fromlel(x) (android_swap_long(x))
-#define fromles(x) (android_swap_short(x))
-#define tolel(x) (android_swap_long(x))
-#define toles(x) (android_swap_short(x))
-#endif
-
-#endif // _LIBS_UTILS_BYTE_ORDER_H
diff --git a/libutils/include/utils/Trace.h b/libutils/include/utils/Trace.h
index 4b9c91e..fec0ffa 100644
--- a/libutils/include/utils/Trace.h
+++ b/libutils/include/utils/Trace.h
@@ -17,7 +17,12 @@
 #ifndef ANDROID_TRACE_H
 #define ANDROID_TRACE_H
 
-#if defined(__ANDROID__)
+#if defined(_WIN32)
+
+#define ATRACE_NAME(...)
+#define ATRACE_CALL()
+
+#else  // !_WIN32
 
 #include <stdint.h>
 
@@ -51,11 +56,6 @@
 
 }  // namespace android
 
-#else // !__ANDROID__
-
-#define ATRACE_NAME(...)
-#define ATRACE_CALL()
-
-#endif // __ANDROID__
+#endif  // _WIN32
 
 #endif // ANDROID_TRACE_H
diff --git a/logcat/logcat.cpp b/logcat/logcat.cpp
index e2711af..4dcb338 100644
--- a/logcat/logcat.cpp
+++ b/logcat/logcat.cpp
@@ -32,6 +32,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <sys/cdefs.h>
+#include <sys/ioctl.h>
 #include <sys/resource.h>
 #include <sys/socket.h>
 #include <sys/stat.h>
@@ -158,8 +159,22 @@
                          enum helpType showHelp, const char* fmt, ...)
     __printflike(3, 4);
 
-static int openLogFile(const char* pathname) {
-    return open(pathname, O_WRONLY | O_APPEND | O_CREAT, S_IRUSR | S_IWUSR);
+#ifndef F2FS_IOC_SET_PIN_FILE
+#define F2FS_IOCTL_MAGIC       0xf5
+#define F2FS_IOC_SET_PIN_FILE _IOW(F2FS_IOCTL_MAGIC, 13, __u32)
+#endif
+
+static int openLogFile(const char* pathname, size_t sizeKB) {
+    int fd = open(pathname, O_WRONLY | O_APPEND | O_CREAT, S_IRUSR | S_IWUSR);
+    if (fd < 0) {
+        return fd;
+    }
+
+    // no need to check errors
+    __u32 set = 1;
+    ioctl(fd, F2FS_IOC_SET_PIN_FILE, &set);
+    fallocate(fd, FALLOC_FL_KEEP_SIZE, 0, (sizeKB << 10));
+    return fd;
 }
 
 static void close_output(android_logcat_context_internal* context) {
@@ -192,6 +207,7 @@
             if (context->fds[1] == context->output_fd) {
                 context->fds[1] = -1;
             }
+            posix_fadvise(context->output_fd, 0, 0, POSIX_FADV_DONTNEED);
             close(context->output_fd);
         }
         context->output_fd = -1;
@@ -276,7 +292,7 @@
         }
     }
 
-    context->output_fd = openLogFile(context->outputFileName);
+    context->output_fd = openLogFile(context->outputFileName, context->logRotateSizeKBytes);
 
     if (context->output_fd < 0) {
         logcat_panic(context, HELP_FALSE, "couldn't open output file");
@@ -398,7 +414,7 @@
 
     close_output(context);
 
-    context->output_fd = openLogFile(context->outputFileName);
+    context->output_fd = openLogFile(context->outputFileName, context->logRotateSizeKBytes);
 
     if (context->output_fd < 0) {
         logcat_panic(context, HELP_FALSE, "couldn't open output file");
diff --git a/logcat/logcatd.rc b/logcat/logcatd.rc
index 26c9de3..e986184 100644
--- a/logcat/logcatd.rc
+++ b/logcat/logcatd.rc
@@ -52,7 +52,7 @@
     stop logcatd
 
 # logcatd service
-service logcatd /system/bin/logcatd -L -b ${logd.logpersistd.buffer:-all} -v threadtime -v usec -v printable -D -f /data/misc/logd/logcat -r ${logd.logpersistd.rotate_kbytes:-1024} -n ${logd.logpersistd.size:-256} --id=${ro.build.id}
+service logcatd /system/bin/logcatd -L -b ${logd.logpersistd.buffer:-all} -v threadtime -v usec -v printable -D -f /data/misc/logd/logcat -r ${logd.logpersistd.rotate_kbytes:-2048} -n ${logd.logpersistd.size:-256} --id=${ro.build.id}
     class late_start
     disabled
     # logd for write to /data/misc/logd, log group for read from log daemon
diff --git a/logd/LogAudit.cpp b/logd/LogAudit.cpp
index 5a375ec..665bd38 100644
--- a/logd/LogAudit.cpp
+++ b/logd/LogAudit.cpp
@@ -160,7 +160,7 @@
     }
     auto search = denial_to_bug.find(scontext + tcontext + tclass);
     if (search != denial_to_bug.end()) {
-        bug_num->assign(" b/" + search->second);
+        bug_num->assign(" " + search->second);
     } else {
         bug_num->assign("");
     }
diff --git a/property_service/libpropertyinfoserializer/Android.bp b/property_service/libpropertyinfoserializer/Android.bp
index 51c1226..aa02a3a 100644
--- a/property_service/libpropertyinfoserializer/Android.bp
+++ b/property_service/libpropertyinfoserializer/Android.bp
@@ -1,7 +1,6 @@
 cc_defaults {
     name: "propertyinfoserializer_defaults",
     host_supported: true,
-    vendor_available: true,
     cpp_std: "experimental",
     cppflags: [
         "-Wall",
@@ -9,8 +8,8 @@
         "-Werror",
     ],
     static_libs: [
-        "libpropertyinfoparser",
         "libbase",
+        "libpropertyinfoparser",
     ],
 }
 
diff --git a/rootdir/avb/Android.bp b/rootdir/avb/Android.bp
new file mode 100644
index 0000000..85d2786
--- /dev/null
+++ b/rootdir/avb/Android.bp
@@ -0,0 +1,20 @@
+filegroup {
+    name: "q-gsi_avbpubkey",
+    srcs: [
+        "q-gsi.avbpubkey",
+    ],
+}
+
+filegroup {
+    name: "r-gsi_avbpubkey",
+    srcs: [
+        "r-gsi.avbpubkey",
+    ],
+}
+
+filegroup {
+    name: "s-gsi_avbpubkey",
+    srcs: [
+        "s-gsi.avbpubkey",
+    ],
+}
diff --git a/rootdir/etc/ld.config.legacy.txt b/rootdir/etc/ld.config.legacy.txt
index e598f05..bb8d4d0 100644
--- a/rootdir/etc/ld.config.legacy.txt
+++ b/rootdir/etc/ld.config.legacy.txt
@@ -80,16 +80,14 @@
 # This namespace exposes externally accessible libraries from the Runtime APEX.
 # Keep in sync with the "runtime" namespace in art/build/apex/ld.config.txt.
 ###############################################################################
+# TODO(b/139408016): Rename this namespace to "art".
 namespace.runtime.isolated = true
 # Visible to allow links to be created at runtime, e.g. through
 # android_link_namespaces in libnativeloader.
 namespace.runtime.visible = true
 
-# TODO(b/139408016): Split the namespaces for the ART and Runtime APEXes
-namespace.runtime.search.paths  = /apex/com.android.art/${LIB}
-namespace.runtime.search.paths += /apex/com.android.runtime/${LIB}
-namespace.runtime.asan.search.paths  = /apex/com.android.art/${LIB}
-namespace.runtime.asan.search.paths += /apex/com.android.runtime/${LIB}
+namespace.runtime.search.paths = /apex/com.android.art/${LIB}
+namespace.runtime.asan.search.paths = /apex/com.android.art/${LIB}
 namespace.runtime.links = default
 # Need allow_all_shared_libs because libart.so can dlopen oat files in
 # /system/framework and /data.
@@ -181,6 +179,7 @@
 namespace.neuralnetworks.link.default.shared_libs += liblog.so
 namespace.neuralnetworks.link.default.shared_libs += libm.so
 namespace.neuralnetworks.link.default.shared_libs += libnativewindow.so
+namespace.neuralnetworks.link.default.shared_libs += libneuralnetworks_packageinfo.so
 namespace.neuralnetworks.link.default.shared_libs += libsync.so
 namespace.neuralnetworks.link.default.shared_libs += libvndksupport.so
 
diff --git a/rootdir/etc/ld.config.txt b/rootdir/etc/ld.config.txt
index e1da587..60035aa 100644
--- a/rootdir/etc/ld.config.txt
+++ b/rootdir/etc/ld.config.txt
@@ -161,16 +161,14 @@
 # This namespace exposes externally accessible libraries from the Runtime APEX.
 # Keep in sync with the "runtime" namespace in art/build/apex/ld.config.txt.
 ###############################################################################
+# TODO(b/139408016): Rename this namespace to "art".
 namespace.runtime.isolated = true
 # Visible to allow links to be created at runtime, e.g. through
 # android_link_namespaces in libnativeloader.
 namespace.runtime.visible = true
 
-# TODO(b/139408016): Split the namespaces for the ART and Runtime APEXes
-namespace.runtime.search.paths  = /apex/com.android.art/${LIB}
-namespace.runtime.search.paths += /apex/com.android.runtime/${LIB}
-namespace.runtime.asan.search.paths  = /apex/com.android.art/${LIB}
-namespace.runtime.asan.search.paths += /apex/com.android.runtime/${LIB}
+namespace.runtime.search.paths = /apex/com.android.art/${LIB}
+namespace.runtime.asan.search.paths = /apex/com.android.art/${LIB}
 namespace.runtime.links = default
 # Need allow_all_shared_libs because libart.so can dlopen oat files in
 # /system/framework and /data.
@@ -422,6 +420,7 @@
 namespace.neuralnetworks.link.default.shared_libs += liblog.so
 namespace.neuralnetworks.link.default.shared_libs += libm.so
 namespace.neuralnetworks.link.default.shared_libs += libnativewindow.so
+namespace.neuralnetworks.link.default.shared_libs += libneuralnetworks_packageinfo.so
 namespace.neuralnetworks.link.default.shared_libs += libsync.so
 namespace.neuralnetworks.link.default.shared_libs += libvndksupport.so
 
@@ -490,13 +489,11 @@
 # This namespace exposes externally accessible libraries from the Runtime APEX.
 # Keep in sync with the "runtime" namespace in art/build/apex/ld.config.txt.
 ###############################################################################
+# TODO(b/139408016): Rename this namespace to "art".
 namespace.runtime.isolated = true
 
-# TODO(b/139408016): Split the namespaces for the ART and Runtime APEXes
-namespace.runtime.search.paths  = /apex/com.android.art/${LIB}
-namespace.runtime.search.paths += /apex/com.android.runtime/${LIB}
-namespace.runtime.asan.search.paths  = /apex/com.android.art/${LIB}
-namespace.runtime.asan.search.paths += /apex/com.android.runtime/${LIB}
+namespace.runtime.search.paths = /apex/com.android.art/${LIB}
+namespace.runtime.asan.search.paths = /apex/com.android.art/${LIB}
 namespace.runtime.links = system
 # TODO(b/130340935): Use a dynamically created linker namespace similar to
 # classloader-namespace for oat files, and tighten this up.
@@ -645,6 +642,7 @@
 namespace.neuralnetworks.link.system.shared_libs += liblog.so
 namespace.neuralnetworks.link.system.shared_libs += libm.so
 namespace.neuralnetworks.link.system.shared_libs += libnativewindow.so
+namespace.neuralnetworks.link.system.shared_libs += libneuralnetworks_packageinfo.so
 namespace.neuralnetworks.link.system.shared_libs += libsync.so
 namespace.neuralnetworks.link.system.shared_libs += libvndksupport.so
 
@@ -697,16 +695,14 @@
 # This namespace exposes externally accessible libraries from the Runtime APEX.
 # Keep in sync with the "runtime" namespace in art/build/apex/ld.config.txt.
 ###############################################################################
+# TODO(b/139408016): Rename this namespace to "art".
 namespace.runtime.isolated = true
 # Visible to allow links to be created at runtime, e.g. through
 # android_link_namespaces in libnativeloader.
 namespace.runtime.visible = true
 
-# TODO(b/139408016): Split the namespaces for the ART and Runtime APEXes
-namespace.runtime.search.paths  = /apex/com.android.art/${LIB}
-namespace.runtime.search.paths += /apex/com.android.runtime/${LIB}
-namespace.runtime.asan.search.paths  = /apex/com.android.art/${LIB}
-namespace.runtime.asan.search.paths += /apex/com.android.runtime/${LIB}
+namespace.runtime.search.paths = /apex/com.android.art/${LIB}
+namespace.runtime.asan.search.paths = /apex/com.android.art/${LIB}
 namespace.runtime.links = default
 # TODO(b/130340935): Use a dynamically created linker namespace similar to
 # classloader-namespace for oat files, and tighten this up.
@@ -788,6 +784,7 @@
 namespace.neuralnetworks.link.default.shared_libs += liblog.so
 namespace.neuralnetworks.link.default.shared_libs += libm.so
 namespace.neuralnetworks.link.default.shared_libs += libnativewindow.so
+namespace.neuralnetworks.link.default.shared_libs += libneuralnetworks_packageinfo.so
 namespace.neuralnetworks.link.default.shared_libs += libsync.so
 namespace.neuralnetworks.link.default.shared_libs += libvndksupport.so
 
diff --git a/rootdir/etc/ld.config.vndk_lite.txt b/rootdir/etc/ld.config.vndk_lite.txt
index 4beabd6..b9b95a6 100644
--- a/rootdir/etc/ld.config.vndk_lite.txt
+++ b/rootdir/etc/ld.config.vndk_lite.txt
@@ -100,16 +100,14 @@
 # This namespace pulls in externally accessible libs from the Runtime APEX.
 # Keep in sync with the "runtime" namespace in art/build/apex/ld.config.txt.
 ###############################################################################
+# TODO(b/139408016): Rename this namespace to "art".
 namespace.runtime.isolated = true
 # Visible to allow links to be created at runtime, e.g. through
 # android_link_namespaces in libnativeloader.
 namespace.runtime.visible = true
 
-# TODO(b/139408016): Split the namespaces for the ART and Runtime APEXes
-namespace.runtime.search.paths  = /apex/com.android.art/${LIB}
-namespace.runtime.search.paths += /apex/com.android.runtime/${LIB}
-namespace.runtime.asan.search.paths  = /apex/com.android.art/${LIB}
-namespace.runtime.asan.search.paths += /apex/com.android.runtime/${LIB}
+namespace.runtime.search.paths = /apex/com.android.art/${LIB}
+namespace.runtime.asan.search.paths = /apex/com.android.art/${LIB}
 namespace.runtime.links = default
 # Need allow_all_shared_libs because libart.so can dlopen oat files in
 # /system/framework and /data.
@@ -346,6 +344,7 @@
 namespace.neuralnetworks.link.default.shared_libs += liblog.so
 namespace.neuralnetworks.link.default.shared_libs += libm.so
 namespace.neuralnetworks.link.default.shared_libs += libnativewindow.so
+namespace.neuralnetworks.link.default.shared_libs += libneuralnetworks_packageinfo.so
 namespace.neuralnetworks.link.default.shared_libs += libsync.so
 namespace.neuralnetworks.link.default.shared_libs += libvndksupport.so
 
@@ -420,13 +419,11 @@
 # This namespace exposes externally accessible libraries from the Runtime APEX.
 # Keep in sync with the "runtime" namespace in art/build/apex/ld.config.txt.
 ###############################################################################
+# TODO(b/139408016): Rename this namespace to "art".
 namespace.runtime.isolated = true
 
-# TODO(b/139408016): Split the namespaces for the ART and Runtime APEXes
-namespace.runtime.search.paths  = /apex/com.android.art/${LIB}
-namespace.runtime.search.paths += /apex/com.android.runtime/${LIB}
-namespace.runtime.asan.search.paths  = /apex/com.android.art/${LIB}
-namespace.runtime.asan.search.paths += /apex/com.android.runtime/${LIB}
+namespace.runtime.search.paths = /apex/com.android.art/${LIB}
+namespace.runtime.asan.search.paths = /apex/com.android.art/${LIB}
 namespace.runtime.links = default
 # TODO(b/130340935): Use a dynamically created linker namespace similar to
 # classloader-namespace for oat files, and tighten this up.
@@ -449,6 +446,7 @@
 namespace.neuralnetworks.link.default.shared_libs += liblog.so
 namespace.neuralnetworks.link.default.shared_libs += libm.so
 namespace.neuralnetworks.link.default.shared_libs += libnativewindow.so
+namespace.neuralnetworks.link.default.shared_libs += libneuralnetworks_packageinfo.so
 namespace.neuralnetworks.link.default.shared_libs += libsync.so
 namespace.neuralnetworks.link.default.shared_libs += libvndksupport.so
 
@@ -504,16 +502,14 @@
 # This namespace exposes externally accessible libraries from the Runtime APEX.
 # Keep in sync with the "runtime" namespace in art/build/apex/ld.config.txt.
 ###############################################################################
+# TODO(b/139408016): Rename this namespace to "art".
 namespace.runtime.isolated = true
 # Visible to allow links to be created at runtime, e.g. through
 # android_link_namespaces in libnativeloader.
 namespace.runtime.visible = true
 
-# TODO(b/139408016): Split the namespaces for the ART and Runtime APEXes
-namespace.runtime.search.paths  = /apex/com.android.art/${LIB}
-namespace.runtime.search.paths += /apex/com.android.runtime/${LIB}
-namespace.runtime.asan.search.paths  = /apex/com.android.art/${LIB}
-namespace.runtime.asan.search.paths += /apex/com.android.runtime/${LIB}
+namespace.runtime.search.paths = /apex/com.android.art/${LIB}
+namespace.runtime.asan.search.paths = /apex/com.android.art/${LIB}
 namespace.runtime.links = default
 # TODO(b/130340935): Use a dynamically created linker namespace similar to
 # classloader-namespace for oat files, and tighten this up.
@@ -591,6 +587,7 @@
 namespace.neuralnetworks.link.default.shared_libs += liblog.so
 namespace.neuralnetworks.link.default.shared_libs += libm.so
 namespace.neuralnetworks.link.default.shared_libs += libnativewindow.so
+namespace.neuralnetworks.link.default.shared_libs += libneuralnetworks_packageinfo.so
 namespace.neuralnetworks.link.default.shared_libs += libsync.so
 namespace.neuralnetworks.link.default.shared_libs += libvndksupport.so
 
diff --git a/rootdir/init.environ.rc.in b/rootdir/init.environ.rc.in
index 17f6596..50005d9 100644
--- a/rootdir/init.environ.rc.in
+++ b/rootdir/init.environ.rc.in
@@ -5,7 +5,7 @@
     export ANDROID_ASSETS /system/app
     export ANDROID_DATA /data
     export ANDROID_STORAGE /storage
-    export ANDROID_RUNTIME_ROOT /apex/com.android.art
+    export ANDROID_ART_ROOT /apex/com.android.art
     export ANDROID_I18N_ROOT /apex/com.android.i18n
     export ANDROID_TZDATA_ROOT /apex/com.android.tzdata
     export EXTERNAL_STORAGE /sdcard
diff --git a/rootdir/init.rc b/rootdir/init.rc
index 0d3d4db..c61fd90 100644
--- a/rootdir/init.rc
+++ b/rootdir/init.rc
@@ -52,6 +52,40 @@
     # the libraries are available to the processes started after this statement.
     exec_start apexd-bootstrap
 
+    # These must already exist by the time boringssl_self_test32 / boringssl_self_test64 run.
+    mkdir /dev/boringssl 0755 root root
+    mkdir /dev/boringssl/selftest 0755 root root
+
+# Run boringssl self test for each ABI so that later processes can skip it. http://b/139348610
+on early-init && property:ro.product.cpu.abilist32=*
+    exec_start boringssl_self_test32
+on early-init && property:ro.product.cpu.abilist64=*
+    exec_start boringssl_self_test64
+on property:apexd.status=ready && property:ro.product.cpu.abilist32=*
+    exec_start boringssl_self_test_apex32
+on property:apexd.status=ready && property:ro.product.cpu.abilist64=*
+    exec_start boringssl_self_test_apex64
+
+service boringssl_self_test32 /system/bin/boringssl_self_test32
+    setenv BORINGSSL_SELF_TEST_CREATE_FLAG true # Any nonempty value counts as true
+    reboot_on_failure reboot,boringssl-self-check-failed
+    stdio_to_kmsg
+
+service boringssl_self_test64 /system/bin/boringssl_self_test64
+    setenv BORINGSSL_SELF_TEST_CREATE_FLAG true # Any nonempty value counts as true
+    reboot_on_failure reboot,boringssl-self-check-failed
+    stdio_to_kmsg
+
+service boringssl_self_test_apex32 /apex/com.android.conscrypt/bin/boringssl_self_test32
+    setenv BORINGSSL_SELF_TEST_CREATE_FLAG true # Any nonempty value counts as true
+    reboot_on_failure reboot,boringssl-self-check-failed
+    stdio_to_kmsg
+
+service boringssl_self_test_apex64 /apex/com.android.conscrypt/bin/boringssl_self_test64
+    setenv BORINGSSL_SELF_TEST_CREATE_FLAG true # Any nonempty value counts as true
+    reboot_on_failure reboot,boringssl-self-check-failed
+    stdio_to_kmsg
+
 on init
     sysclktz 0
 
@@ -124,13 +158,17 @@
     mkdir /mnt/user/0/self 0755 root root
     mkdir /mnt/user/0/emulated 0755 root root
     mkdir /mnt/user/0/emulated/0 0755 root root
+
+    # Prepare directories for pass through processes
+    mkdir /mnt/pass_through 0755 root root
+    mkdir /mnt/pass_through/0 0755 root root
+    mkdir /mnt/pass_through/0/self 0755 root root
+    mkdir /mnt/pass_through/0/emulated 0755 root root
+    mkdir /mnt/pass_through/0/emulated/0 0755 root root
+
     mkdir /mnt/expand 0771 system system
     mkdir /mnt/appfuse 0711 root root
 
-    # These must already exist by the time boringssl_self_test32 / boringssl_self_test64 run.
-    mkdir /dev/boringssl 0755 root root
-    mkdir /dev/boringssl/selftest 0755 root root
-
     # Storage views to support runtime permissions
     mkdir /mnt/runtime 0700 root root
     mkdir /mnt/runtime/default 0755 root root
@@ -315,16 +353,6 @@
     start hwservicemanager
     start vndservicemanager
 
-# Run boringssl self test for each ABI so that later processes can skip it. http://b/139348610
-on init && property:ro.product.cpu.abilist32=*:
-    exec_reboot_on_failure boringssl-self-check-failed /system/bin/boringssl_self_test32
-on init && property:ro.product.cpu.abilist64=*
-    exec_reboot_on_failure boringssl-self-check-failed /system/bin/boringssl_self_test64
-on property:apexd.status=ready && property:ro.product.cpu.abilist64=*
-    exec_reboot_on_failure boringssl-self-check-failed /apex/com.android.conscrypt/bin/boringssl_self_test64
-on property:apexd.status=ready && property:ro.product.cpu.abilist32=*
-    exec_reboot_on_failure boringssl-self-check-failed /apex/com.android.conscrypt/bin/boringssl_self_test32
-
 # Healthd can trigger a full boot from charger mode by signaling this
 # property when the power button is held.
 on property:sys.boot_from_charger_mode=1
@@ -445,7 +473,6 @@
     mark_post_data
 
     # Start checkpoint before we touch data
-    start vold
     exec - system system -- /system/bin/vdc checkpoint prepareCheckpoint
 
     # We chown/chmod /data again so because mount is run as root + defaults
@@ -663,6 +690,8 @@
   # Mount default storage into root namespace
   mount none /mnt/user/0 /storage bind rec
   mount none none /storage slave rec
+  # Bootstrap the emulated volume for the pass_through directory for user 0
+  mount none /data/media /mnt/pass_through/0/emulated bind rec
 on zygote-start && property:persist.sys.fuse=false
   # Mount default storage into root namespace
   mount none /mnt/runtime/default /storage bind rec
@@ -841,6 +870,9 @@
 
 on property:sys.boot_completed=1
     bootchart stop
+    # Setup per_boot directory so other .rc could start to use it on boot_completed
+    exec - system system -- /bin/rm -rf /data/per_boot
+    mkdir /data/per_boot 0700 system system
 
 # system server cannot write to /proc/sys files,
 # and chown/chmod does not work for /proc/sys/ entries.
diff --git a/rootdir/update_and_install_ld_config.mk b/rootdir/update_and_install_ld_config.mk
index dbe60e5..c4b8e4e 100644
--- a/rootdir/update_and_install_ld_config.mk
+++ b/rootdir/update_and_install_ld_config.mk
@@ -70,19 +70,30 @@
 # /system image.
 llndk_libraries_moved_to_apex_list:=$(LLNDK_MOVED_TO_APEX_LIBRARIES)
 
+# Returns the unique installed basenames of a module, or module.so if there are
+# none.  The guess is to handle cases like libc, where the module itself is
+# marked uninstallable but a symlink is installed with the name libc.so.
 # $(1): list of libraries
-# $(2): output file to write the list of libraries to
-define write-libs-to-file
-$(2): PRIVATE_LIBRARIES := $(1)
-$(2):
-	echo -n > $$@ && $$(foreach lib,$$(PRIVATE_LIBRARIES),echo $$(lib).so >> $$@;)
+# $(2): suffix to to add to each library (not used for guess)
+define module-installed-files-or-guess
+$(foreach lib,$(1),$(or $(strip $(sort $(notdir $(call module-installed-files,$(lib)$(2))))),$(lib).so))
 endef
-$(eval $(call write-libs-to-file,$(llndk_libraries_list),$(llndk_libraries_file)))
-$(eval $(call write-libs-to-file,$(vndksp_libraries_list),$(vndksp_libraries_file)))
-$(eval $(call write-libs-to-file,$(VNDK_CORE_LIBRARIES),$(vndkcore_libraries_file)))
-$(eval $(call write-libs-to-file,$(VNDK_PRIVATE_LIBRARIES),$(vndkprivate_libraries_file)))
+
+# $(1): list of libraries
+# $(2): suffix to add to each library
+# $(3): output file to write the list of libraries to
+define write-libs-to-file
+$(3): PRIVATE_LIBRARIES := $(1)
+$(3): PRIVATE_SUFFIX := $(2)
+$(3):
+	echo -n > $$@ && $$(foreach so,$$(call module-installed-files-or-guess,$$(PRIVATE_LIBRARIES),$$(PRIVATE_SUFFIX)),echo $$(so) >> $$@;)
+endef
+$(eval $(call write-libs-to-file,$(llndk_libraries_list),,$(llndk_libraries_file)))
+$(eval $(call write-libs-to-file,$(vndksp_libraries_list),.vendor,$(vndksp_libraries_file)))
+$(eval $(call write-libs-to-file,$(VNDK_CORE_LIBRARIES),.vendor,$(vndkcore_libraries_file)))
+$(eval $(call write-libs-to-file,$(VNDK_PRIVATE_LIBRARIES),.vendor,$(vndkprivate_libraries_file)))
 ifeq ($(my_vndk_use_core_variant),true)
-$(eval $(call write-libs-to-file,$(VNDK_USING_CORE_VARIANT_LIBRARIES),$(vndk_using_core_variant_libraries_file)))
+$(eval $(call write-libs-to-file,$(VNDK_USING_CORE_VARIANT_LIBRARIES),,$(vndk_using_core_variant_libraries_file)))
 endif
 endif # ifneq ($(lib_list_from_prebuilts),true)
 
@@ -117,7 +128,7 @@
 deps := $(llndk_libraries_file) $(vndksp_libraries_file) $(vndkcore_libraries_file) \
   $(vndkprivate_libraries_file)
 ifeq ($(check_backward_compatibility),true)
-deps += $(compatibility_check_script)
+deps += $(compatibility_check_script) $(wildcard prebuilts/vndk/*/*/configs/ld.config.*.txt)
 endif
 ifeq ($(my_vndk_use_core_variant),true)
 $(LOCAL_BUILT_MODULE): PRIVATE_VNDK_USING_CORE_VARIANT_LIBRARIES_FILE := $(vndk_using_core_variant_libraries_file)
diff --git a/trusty/keymaster/4.0/TrustyKeymaster4Device.cpp b/trusty/keymaster/4.0/TrustyKeymaster4Device.cpp
index b5fc6bf..ec2ba12 100644
--- a/trusty/keymaster/4.0/TrustyKeymaster4Device.cpp
+++ b/trusty/keymaster/4.0/TrustyKeymaster4Device.cpp
@@ -17,6 +17,7 @@
 
 #define LOG_TAG "android.hardware.keymaster@4.0-impl.trusty"
 
+#include <android/hardware/keymaster/3.0/IKeymasterDevice.h>
 #include <authorization_set.h>
 #include <cutils/log.h>
 #include <keymaster/android_keymaster_messages.h>
@@ -46,6 +47,9 @@
 using ::keymaster::UpdateOperationResponse;
 using ::keymaster::ng::Tag;
 
+typedef ::android::hardware::keymaster::V3_0::Tag Tag3;
+using ::android::hardware::keymaster::V4_0::Constants;
+
 namespace keymaster {
 namespace V4_0 {
 namespace {
@@ -79,6 +83,45 @@
     return keymaster_tag_get_type(tag);
 }
 
+/*
+ * injectAuthToken translates a KM4 authToken into a legacy AUTH_TOKEN tag
+ *
+ * Currently, system/keymaster's reference implementation only accepts this
+ * method for passing an auth token, so until that changes we need to
+ * translate to the old format.
+ */
+inline hidl_vec<KeyParameter> injectAuthToken(const hidl_vec<KeyParameter>& keyParamsBase,
+                                              const HardwareAuthToken& authToken) {
+    std::vector<KeyParameter> keyParams(keyParamsBase);
+    const size_t mac_len = static_cast<size_t>(Constants::AUTH_TOKEN_MAC_LENGTH);
+    /*
+     * mac.size() == 0 indicates no token provided, so we should not copy.
+     * mac.size() != mac_len means it is incompatible with the old
+     *   hw_auth_token_t structure. This is forbidden by spec, but to be safe
+     *   we only copy if mac.size() == mac_len, e.g. there is an authToken
+     *   with a hw_auth_token_t compatible MAC.
+     */
+    if (authToken.mac.size() == mac_len) {
+        KeyParameter p;
+        p.tag = static_cast<Tag>(Tag3::AUTH_TOKEN);
+        p.blob.resize(sizeof(hw_auth_token_t));
+
+        hw_auth_token_t* auth_token = reinterpret_cast<hw_auth_token_t*>(p.blob.data());
+        auth_token->version = 0;
+        auth_token->challenge = authToken.challenge;
+        auth_token->user_id = authToken.userId;
+        auth_token->authenticator_id = authToken.authenticatorId;
+        auth_token->authenticator_type =
+                htobe32(static_cast<uint32_t>(authToken.authenticatorType));
+        auth_token->timestamp = htobe64(authToken.timestamp);
+        static_assert(mac_len == sizeof(auth_token->hmac));
+        memcpy(auth_token->hmac, authToken.mac.data(), mac_len);
+        keyParams.push_back(p);
+    }
+
+    return hidl_vec<KeyParameter>(std::move(keyParams));
+}
+
 class KmParamSet : public keymaster_key_param_set_t {
   public:
     KmParamSet(const hidl_vec<KeyParameter>& keyParams) {
@@ -472,11 +515,11 @@
 Return<void> TrustyKeymaster4Device::begin(KeyPurpose purpose, const hidl_vec<uint8_t>& key,
                                            const hidl_vec<KeyParameter>& inParams,
                                            const HardwareAuthToken& authToken, begin_cb _hidl_cb) {
-    (void)authToken;
+    hidl_vec<KeyParameter> extendedParams = injectAuthToken(inParams, authToken);
     BeginOperationRequest request;
     request.purpose = legacy_enum_conversion(purpose);
     request.SetKeyMaterial(key.data(), key.size());
-    request.additional_params.Reinitialize(KmParamSet(inParams));
+    request.additional_params.Reinitialize(KmParamSet(extendedParams));
 
     BeginOperationResponse response;
     impl_->BeginOperation(request, &response);
@@ -496,16 +539,16 @@
                                             const HardwareAuthToken& authToken,
                                             const VerificationToken& verificationToken,
                                             update_cb _hidl_cb) {
-    (void)authToken;
     (void)verificationToken;
     UpdateOperationRequest request;
     UpdateOperationResponse response;
     hidl_vec<KeyParameter> resultParams;
     hidl_vec<uint8_t> resultBlob;
+    hidl_vec<KeyParameter> extendedParams = injectAuthToken(inParams, authToken);
     uint32_t resultConsumed = 0;
 
     request.op_handle = operationHandle;
-    request.additional_params.Reinitialize(KmParamSet(inParams));
+    request.additional_params.Reinitialize(KmParamSet(extendedParams));
 
     size_t inp_size = input.size();
     size_t ser_size = request.SerializedSize();
@@ -537,13 +580,13 @@
                                             const HardwareAuthToken& authToken,
                                             const VerificationToken& verificationToken,
                                             finish_cb _hidl_cb) {
-    (void)authToken;
     (void)verificationToken;
     FinishOperationRequest request;
+    hidl_vec<KeyParameter> extendedParams = injectAuthToken(inParams, authToken);
     request.op_handle = operationHandle;
     request.input.Reinitialize(input.data(), input.size());
     request.signature.Reinitialize(signature.data(), signature.size());
-    request.additional_params.Reinitialize(KmParamSet(inParams));
+    request.additional_params.Reinitialize(KmParamSet(extendedParams));
 
     FinishOperationResponse response;
     impl_->FinishOperation(request, &response);
diff --git a/trusty/keymaster/4.0/android.hardware.keymaster@4.0-service.trusty.xml b/trusty/keymaster/4.0/android.hardware.keymaster@4.0-service.trusty.xml
new file mode 100644
index 0000000..aa30707
--- /dev/null
+++ b/trusty/keymaster/4.0/android.hardware.keymaster@4.0-service.trusty.xml
@@ -0,0 +1,11 @@
+<manifest version="1.0" type="device">
+    <hal format="hidl">
+        <name>android.hardware.keymaster</name>
+        <transport>hwbinder</transport>
+        <version>4.0</version>
+        <interface>
+        <name>IKeymasterDevice</name>
+            <instance>default</instance>
+        </interface>
+    </hal>
+</manifest>
diff --git a/trusty/keymaster/Android.bp b/trusty/keymaster/Android.bp
index 3a9beaf..f32a69e 100644
--- a/trusty/keymaster/Android.bp
+++ b/trusty/keymaster/Android.bp
@@ -136,4 +136,6 @@
         "libkeymaster4",
         "android.hardware.keymaster@4.0"
     ],
+
+    vintf_fragments: ["4.0/android.hardware.keymaster@4.0-service.trusty.xml"],
 }