installd: Implement support for userdata snapshot and restore.

Adds two binder APIs:
- snapshotAppData: Makes a copy of the apps credential encrypted
  and/or device encrypted data for a given user to one of
  /data/misc_[ce|de]/rollback. This path is writable only by
  installd.
- restoreAppDataSnapshot: Restores a copy of the apps credential
  encrypted and/or device encrypted data from a snapshot, if one
  exists.

Implemented for use from RollbackManagerService, which will make
a transient copy of an app package as well as its data in order to
roll them back within a specified window.

Bug: 112431924
Test: installd_utils_test, installd_service_test

Change-Id: I3e4d36c11e52fb885b585b1946e215cf986206fd
Merged-In: I3e4d36c11e52fb885b585b1946e215cf986206fd
diff --git a/cmds/installd/InstalldNativeService.cpp b/cmds/installd/InstalldNativeService.cpp
index 2439dff..afabbbb 100644
--- a/cmds/installd/InstalldNativeService.cpp
+++ b/cmds/installd/InstalldNativeService.cpp
@@ -41,6 +41,7 @@
 
 #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 <android-base/unique_fd.h>
@@ -745,6 +746,162 @@
     return ok();
 }
 
+static int32_t copy_directory_recursive(const char* from, const char* to) {
+    char *argv[] = {
+        (char*) kCpPath,
+        (char*) "-F", /* delete any existing destination file first (--remove-destination) */
+        (char*) "-p", /* preserve timestamps, ownership, and permissions */
+        (char*) "-R", /* recurse into subdirectories (DEST must be a directory) */
+        (char*) "-P", /* Do not follow symlinks [default] */
+        (char*) "-d", /* don't dereference symlinks */
+        (char*) from,
+        (char*) to
+    };
+
+    LOG(DEBUG) << "Copying " << from << " to " << to;
+    return android_fork_execvp(ARRAY_SIZE(argv), argv, nullptr, false, true);
+}
+
+// TODO(narayan): We should pass through the ceDataInode so that we can call
+// clearAppData(FLAG_CLEAR_CACHE_ONLY | FLAG_CLEAR_CODE_CACHE before we commence
+// the copy.
+//
+// TODO(narayan): For snapshotAppData as well as restoreAppDataSnapshot, we
+// should validate that volumeUuid is either nullptr or TEST, we won't support
+// anything else.
+//
+// TODO(narayan): We need to be clearer about the expected behaviour for the
+// case where a snapshot already exists. We either need to clear the contents
+// of the snapshot directory before we make a copy, or we need to ensure that
+// the caller always clears it before requesting a snapshot.
+binder::Status InstalldNativeService::snapshotAppData(
+        const std::unique_ptr<std::string>& volumeUuid,
+        const std::string& packageName, int32_t user, int32_t storageFlags) {
+    ENFORCE_UID(AID_SYSTEM);
+    CHECK_ARGUMENT_UUID(volumeUuid);
+    CHECK_ARGUMENT_PACKAGE_NAME(packageName);
+    std::lock_guard<std::recursive_mutex> lock(mLock);
+
+    const char* volume_uuid = volumeUuid ? volumeUuid->c_str() : nullptr;
+    const char* package_name = packageName.c_str();
+
+    binder::Status res = ok();
+    bool clear_ce_on_exit = false;
+    bool clear_de_on_exit = false;
+
+    auto deleter = [&clear_ce_on_exit, &clear_de_on_exit, &volume_uuid, &user, &package_name] {
+        if (clear_de_on_exit) {
+            auto to = create_data_misc_de_rollback_package_path(volume_uuid, user, package_name);
+            if (delete_dir_contents(to.c_str(), 1, nullptr) != 0) {
+                LOG(WARNING) << "Failed to delete app data snapshot: " << to;
+            }
+        }
+
+        if (clear_ce_on_exit) {
+            auto to = create_data_misc_ce_rollback_package_path(volume_uuid, user, package_name);
+            if (delete_dir_contents(to.c_str(), 1, nullptr) != 0) {
+                LOG(WARNING) << "Failed to delete app data snapshot: " << to;
+            }
+        }
+    };
+
+    auto scope_guard = android::base::make_scope_guard(deleter);
+
+    // The app may not have any data at all, in which case it's OK to skip here.
+    auto from_ce = create_data_user_ce_package_path(volume_uuid, user, package_name);
+    if (access(from_ce.c_str(), F_OK) != 0) {
+        LOG(INFO) << "Missing source " << from_ce;
+        return ok();
+    }
+
+    if (storageFlags & FLAG_STORAGE_DE) {
+        auto from = create_data_user_de_package_path(volume_uuid, user, package_name);
+        auto to = create_data_misc_de_rollback_path(volume_uuid, user);
+
+        int rc = copy_directory_recursive(from.c_str(), to.c_str());
+        if (rc != 0) {
+            res = error(rc, "Failed copying " + from + " to " + to);
+            clear_de_on_exit = true;
+            return res;
+        }
+    }
+
+    if (storageFlags & FLAG_STORAGE_CE) {
+        auto from = create_data_user_ce_package_path(volume_uuid, user, package_name);
+        auto to = create_data_misc_ce_rollback_path(volume_uuid, user);
+        int rc = copy_directory_recursive(from.c_str(), to.c_str());
+        if (rc != 0) {
+            res = error(rc, "Failed copying " + from + " to " + to);
+            clear_ce_on_exit = true;
+            return res;
+        }
+    }
+
+    return res;
+}
+
+binder::Status InstalldNativeService::restoreAppDataSnapshot(
+        const std::unique_ptr<std::string>& volumeUuid, const std::string& packageName,
+        const int32_t appId, const int64_t ceDataInode, const std::string& seInfo,
+        const int32_t user, int32_t storageFlags) {
+    ENFORCE_UID(AID_SYSTEM);
+    CHECK_ARGUMENT_UUID(volumeUuid);
+    CHECK_ARGUMENT_PACKAGE_NAME(packageName);
+    std::lock_guard<std::recursive_mutex> lock(mLock);
+
+    const char* volume_uuid = volumeUuid ? volumeUuid->c_str() : nullptr;
+    const char* package_name = packageName.c_str();
+
+    auto from_ce = create_data_misc_ce_rollback_package_path(volume_uuid,
+            user, package_name);
+    auto from_de = create_data_misc_de_rollback_package_path(volume_uuid,
+            user, package_name);
+
+    const bool needs_ce_rollback = (storageFlags & FLAG_STORAGE_CE) &&
+        (access(from_ce.c_str(), F_OK) == 0);
+    const bool needs_de_rollback = (storageFlags & FLAG_STORAGE_DE) &&
+        (access(from_de.c_str(), F_OK) == 0);
+
+    if (!needs_ce_rollback && !needs_de_rollback) {
+        return ok();
+    }
+
+    // We know we're going to rollback one of the CE or DE data, so we clear
+    // application data first. Note that it's possible that we're asked to
+    // restore both CE & DE data but that one of the restores fail. Leaving the
+    // app with no data in those cases is arguably better than leaving the app
+    // with mismatched / stale data.
+    LOG(INFO) << "Clearing app data for " << packageName << " to restore snapshot.";
+    binder::Status res = clearAppData(volumeUuid, packageName, user, storageFlags, ceDataInode);
+    if (!res.isOk()) {
+        return res;
+    }
+
+    if (needs_ce_rollback) {
+        auto to_ce = create_data_user_ce_path(volume_uuid, user);
+        int rc = copy_directory_recursive(from_ce.c_str(), to_ce.c_str());
+        if (rc != 0) {
+            res = error(rc, "Failed copying " + from_ce + " to " + to_ce);
+            return res;
+        }
+    }
+
+    if (needs_de_rollback) {
+        auto to_de = create_data_user_de_path(volume_uuid, user);
+        int rc = copy_directory_recursive(from_de.c_str(), to_de.c_str());
+        if (rc != 0) {
+            // TODO(narayan): Should we clear clear the rolled back CE data if
+            // something goes wrong here ? We're choosing between leaving the
+            // app devoid of all its data or with just its ce data installed.
+            res = error(rc, "Failed copying " + from_de + " to " + to_de);
+            return res;
+        }
+    }
+
+    // Finally, restore the SELinux label on the app data.
+    return restoreconAppData(volumeUuid, packageName, user, storageFlags, appId, seInfo);
+}
+
 binder::Status InstalldNativeService::moveCompleteApp(const std::unique_ptr<std::string>& fromUuid,
         const std::unique_ptr<std::string>& toUuid, const std::string& packageName,
         const std::string& dataAppName, int32_t appId, const std::string& seInfo,
@@ -769,19 +926,7 @@
         auto to = create_data_app_package_path(to_uuid, data_app_name);
         auto to_parent = create_data_app_path(to_uuid);
 
-        char *argv[] = {
-            (char*) kCpPath,
-            (char*) "-F", /* delete any existing destination file first (--remove-destination) */
-            (char*) "-p", /* preserve timestamps, ownership, and permissions */
-            (char*) "-R", /* recurse into subdirectories (DEST must be a directory) */
-            (char*) "-P", /* Do not follow symlinks [default] */
-            (char*) "-d", /* don't dereference symlinks */
-            (char*) from.c_str(),
-            (char*) to_parent.c_str()
-        };
-
-        LOG(DEBUG) << "Copying " << from << " to " << to;
-        int rc = android_fork_execvp(ARRAY_SIZE(argv), argv, nullptr, false, true);
+        int rc = copy_directory_recursive(from.c_str(), to_parent.c_str());
         if (rc != 0) {
             res = error(rc, "Failed copying " + from + " to " + to);
             goto fail;
@@ -809,25 +954,11 @@
             goto fail;
         }
 
-        char *argv[] = {
-            (char*) kCpPath,
-            (char*) "-F", /* delete any existing destination file first (--remove-destination) */
-            (char*) "-p", /* preserve timestamps, ownership, and permissions */
-            (char*) "-R", /* recurse into subdirectories (DEST must be a directory) */
-            (char*) "-P", /* Do not follow symlinks [default] */
-            (char*) "-d", /* don't dereference symlinks */
-            nullptr,
-            nullptr
-        };
-
         {
             auto from = create_data_user_de_package_path(from_uuid, user, package_name);
             auto to = create_data_user_de_path(to_uuid, user);
-            argv[6] = (char*) from.c_str();
-            argv[7] = (char*) to.c_str();
 
-            LOG(DEBUG) << "Copying " << from << " to " << to;
-            int rc = android_fork_execvp(ARRAY_SIZE(argv), argv, nullptr, false, true);
+            int rc = copy_directory_recursive(from.c_str(), to.c_str());
             if (rc != 0) {
                 res = error(rc, "Failed copying " + from + " to " + to);
                 goto fail;
@@ -836,11 +967,8 @@
         {
             auto from = create_data_user_ce_package_path(from_uuid, user, package_name);
             auto to = create_data_user_ce_path(to_uuid, user);
-            argv[6] = (char*) from.c_str();
-            argv[7] = (char*) to.c_str();
 
-            LOG(DEBUG) << "Copying " << from << " to " << to;
-            int rc = android_fork_execvp(ARRAY_SIZE(argv), argv, nullptr, false, true);
+            int rc = copy_directory_recursive(from.c_str(), to.c_str());
             if (rc != 0) {
                 res = error(rc, "Failed copying " + from + " to " + to);
                 goto fail;
diff --git a/cmds/installd/InstalldNativeService.h b/cmds/installd/InstalldNativeService.h
index 367f2c1..123859a 100644
--- a/cmds/installd/InstalldNativeService.h
+++ b/cmds/installd/InstalldNativeService.h
@@ -60,6 +60,12 @@
 
     binder::Status fixupAppData(const std::unique_ptr<std::string>& uuid, int32_t flags);
 
+    binder::Status snapshotAppData(const std::unique_ptr<std::string>& volumeUuid,
+            const std::string& packageName, const int32_t user, int32_t storageFlags);
+    binder::Status restoreAppDataSnapshot(const std::unique_ptr<std::string>& volumeUuid,
+            const std::string& packageName, const int32_t appId, const int64_t ceDataInode,
+            const std::string& seInfo, const int32_t user, int32_t storageFlags);
+
     binder::Status getAppSize(const std::unique_ptr<std::string>& uuid,
             const std::vector<std::string>& packageNames, int32_t userId, int32_t flags,
             int32_t appId, const std::vector<int64_t>& ceDataInodes,
diff --git a/cmds/installd/binder/android/os/IInstalld.aidl b/cmds/installd/binder/android/os/IInstalld.aidl
index 91e20b7..13efe13 100644
--- a/cmds/installd/binder/android/os/IInstalld.aidl
+++ b/cmds/installd/binder/android/os/IInstalld.aidl
@@ -102,4 +102,16 @@
     boolean prepareAppProfile(@utf8InCpp String packageName,
         int userId, int appId, @utf8InCpp String profileName, @utf8InCpp String codePath,
         @nullable @utf8InCpp String dexMetadata);
+
+    void snapshotAppData(@nullable @utf8InCpp String uuid, in @utf8InCpp String packageName,
+            int userId, int storageFlags);
+    void restoreAppDataSnapshot(@nullable @utf8InCpp String uuid, in @utf8InCpp String packageName,
+            int appId, long ceDataInode, @utf8InCpp String seInfo, int user, int storageflags);
+
+    // TODO(narayan) we need an API to delete the app data snapshot as well.
+    // void destroyAppDataSnapshot(@nullable @utf8InCpp String uuid,
+    //        in @utf8InCpp String packageName, int userId, int storageFlags);
+
+    const int FLAG_STORAGE_DE = 0x1;
+    const int FLAG_STORAGE_CE = 0x2;
 }
diff --git a/cmds/installd/tests/installd_service_test.cpp b/cmds/installd/tests/installd_service_test.cpp
index a5af5d7..0d46341 100644
--- a/cmds/installd/tests/installd_service_test.cpp
+++ b/cmds/installd/tests/installd_service_test.cpp
@@ -21,6 +21,8 @@
 #include <sys/xattr.h>
 
 #include <android-base/logging.h>
+#include <android-base/file.h>
+#include <android-base/scopeguard.h>
 #include <android-base/stringprintf.h>
 #include <cutils/properties.h>
 #include <gtest/gtest.h>
@@ -240,5 +242,180 @@
     EXPECT_EQ("/data/dalvik-cache/isa/path@to@file.apk@classes.dex", std::string(buf));
 }
 
+static bool mkdirs(const std::string& path, mode_t mode) {
+    struct stat sb;
+    if (stat(path.c_str(), &sb) != -1 && S_ISDIR(sb.st_mode)) {
+        return true;
+    }
+
+    if (!mkdirs(android::base::Dirname(path), mode)) {
+        return false;
+    }
+
+    return (::mkdir(path.c_str(), mode) != -1);
+}
+
+TEST_F(ServiceTest, CreateAppDataSnapshot) {
+  auto rollback_ce_dir = create_data_misc_ce_rollback_path("TEST", 0);
+  auto rollback_de_dir = create_data_misc_de_rollback_path("TEST", 0);
+
+  ASSERT_TRUE(mkdirs(rollback_ce_dir, 700));
+  ASSERT_TRUE(mkdirs(rollback_de_dir, 700));
+
+  auto fake_package_ce_path = create_data_user_ce_package_path("TEST", 0, "com.foo");
+  auto fake_package_de_path = create_data_user_de_package_path("TEST", 0, "com.foo");
+
+  ASSERT_TRUE(mkdirs(fake_package_ce_path, 700));
+  ASSERT_TRUE(mkdirs(fake_package_de_path, 700));
+
+  auto deleter = [&rollback_ce_dir, &rollback_de_dir,
+          &fake_package_ce_path, &fake_package_de_path]() {
+      delete_dir_contents(rollback_ce_dir, true);
+      delete_dir_contents(rollback_de_dir, true);
+      delete_dir_contents(fake_package_ce_path, true);
+      delete_dir_contents(fake_package_de_path, true);
+      rmdir(rollback_ce_dir.c_str());
+      rmdir(rollback_de_dir.c_str());
+  };
+  auto scope_guard = android::base::make_scope_guard(deleter);
+
+  ASSERT_TRUE(android::base::WriteStringToFile(
+          "TEST_CONTENT_CE", fake_package_ce_path + "/file1",
+          0700, 10000, 20000, false /* follow_symlinks */));
+  ASSERT_TRUE(android::base::WriteStringToFile(
+          "TEST_CONTENT_DE", fake_package_de_path + "/file1",
+          0700, 10000, 20000, false /* follow_symlinks */));
+
+  // Request a snapshot of the CE content but not the DE content.
+  ASSERT_TRUE(service->snapshotAppData(std::make_unique<std::string>("TEST"),
+          "com.foo", 0, FLAG_STORAGE_CE).isOk());
+
+  std::string ce_content, de_content;
+  // At this point, we should have the CE content but not the DE content.
+  ASSERT_TRUE(android::base::ReadFileToString(
+      rollback_ce_dir + "/com.foo/file1", &ce_content, false /* follow_symlinks */));
+  ASSERT_FALSE(android::base::ReadFileToString(
+      rollback_de_dir + "/com.foo/file1", &de_content, false /* follow_symlinks */));
+  ASSERT_EQ("TEST_CONTENT_CE", ce_content);
+
+  // Modify the CE content, so we can assert later that it's reflected
+  // in the snapshot.
+  ASSERT_TRUE(android::base::WriteStringToFile(
+          "TEST_CONTENT_CE_MODIFIED", fake_package_ce_path + "/file1",
+          0700, 10000, 20000, false /* follow_symlinks */));
+
+  // Request a snapshot of the DE content but not the CE content.
+  ASSERT_TRUE(service->snapshotAppData(std::make_unique<std::string>("TEST"),
+          "com.foo", 0, FLAG_STORAGE_DE).isOk());
+
+  // At this point, both the CE as well as the DE content should be fully
+  // populated.
+  ASSERT_TRUE(android::base::ReadFileToString(
+      rollback_ce_dir + "/com.foo/file1", &ce_content, false /* follow_symlinks */));
+  ASSERT_TRUE(android::base::ReadFileToString(
+      rollback_de_dir + "/com.foo/file1", &de_content, false /* follow_symlinks */));
+  ASSERT_EQ("TEST_CONTENT_CE", ce_content);
+  ASSERT_EQ("TEST_CONTENT_DE", de_content);
+
+  // Modify the DE content, so we can assert later that it's reflected
+  // in our final snapshot.
+  ASSERT_TRUE(android::base::WriteStringToFile(
+          "TEST_CONTENT_DE_MODIFIED", fake_package_de_path + "/file1",
+          0700, 10000, 20000, false /* follow_symlinks */));
+
+  // Request a snapshot of both the CE as well as the DE content.
+  ASSERT_TRUE(service->snapshotAppData(std::make_unique<std::string>("TEST"),
+          "com.foo", 0, FLAG_STORAGE_DE | FLAG_STORAGE_CE).isOk());
+
+  ASSERT_TRUE(android::base::ReadFileToString(
+      rollback_ce_dir + "/com.foo/file1", &ce_content, false /* follow_symlinks */));
+  ASSERT_TRUE(android::base::ReadFileToString(
+      rollback_de_dir + "/com.foo/file1", &de_content, false /* follow_symlinks */));
+  ASSERT_EQ("TEST_CONTENT_CE_MODIFIED", ce_content);
+  ASSERT_EQ("TEST_CONTENT_DE_MODIFIED", de_content);
+}
+
+TEST_F(ServiceTest, CreateAppDataSnapshot_AppDataAbsent) {
+  auto rollback_ce_dir = create_data_misc_ce_rollback_path("TEST", 0);
+  auto rollback_de_dir = create_data_misc_de_rollback_path("TEST", 0);
+
+  ASSERT_TRUE(mkdirs(rollback_ce_dir, 700));
+  ASSERT_TRUE(mkdirs(rollback_de_dir, 700));
+
+  auto deleter = [&rollback_ce_dir, &rollback_de_dir]() {
+      delete_dir_contents(rollback_ce_dir, true);
+      delete_dir_contents(rollback_de_dir, true);
+      rmdir(rollback_ce_dir.c_str());
+      rmdir(rollback_de_dir.c_str());
+  };
+
+  auto scope_guard = android::base::make_scope_guard(deleter);
+
+  ASSERT_TRUE(service->snapshotAppData(std::make_unique<std::string>("TEST"),
+          "com.foo", 0, FLAG_STORAGE_CE).isOk());
+  ASSERT_TRUE(service->snapshotAppData(std::make_unique<std::string>("TEST"),
+          "com.foo", 0, FLAG_STORAGE_DE).isOk());
+
+  // The snapshot calls must succeed but there should be no snapshot
+  // created.
+  struct stat sb;
+  ASSERT_EQ(-1, stat((rollback_ce_dir + "/com.foo").c_str(), &sb));
+  ASSERT_EQ(-1, stat((rollback_de_dir + "/com.foo").c_str(), &sb));
+}
+
+TEST_F(ServiceTest, RestoreAppDataSnapshot) {
+  auto rollback_ce_dir = create_data_misc_ce_rollback_path("TEST", 0);
+  auto rollback_de_dir = create_data_misc_de_rollback_path("TEST", 0);
+
+  ASSERT_TRUE(mkdirs(rollback_ce_dir, 700));
+  ASSERT_TRUE(mkdirs(rollback_de_dir, 700));
+
+  auto fake_package_ce_path = create_data_user_ce_package_path("TEST", 0, "com.foo");
+  auto fake_package_de_path = create_data_user_de_package_path("TEST", 0, "com.foo");
+
+  ASSERT_TRUE(mkdirs(fake_package_ce_path, 700));
+  ASSERT_TRUE(mkdirs(fake_package_de_path, 700));
+
+  auto deleter = [&rollback_ce_dir, &rollback_de_dir,
+          &fake_package_ce_path, &fake_package_de_path]() {
+      delete_dir_contents(rollback_ce_dir, true);
+      delete_dir_contents(rollback_de_dir, true);
+      delete_dir_contents(fake_package_ce_path, true);
+      delete_dir_contents(fake_package_de_path, true);
+      rmdir(rollback_ce_dir.c_str());
+      rmdir(rollback_de_dir.c_str());
+  };
+  auto scope_guard = android::base::make_scope_guard(deleter);
+
+  // Write contents to the rollback location. We'll write the same files to the
+  // app data location and make sure the restore has overwritten them.
+  ASSERT_TRUE(mkdirs(rollback_ce_dir + "/com.foo/", 700));
+  ASSERT_TRUE(mkdirs(rollback_de_dir + "/com.foo/", 700));
+  ASSERT_TRUE(android::base::WriteStringToFile(
+          "CE_RESTORE_CONTENT", rollback_ce_dir + "/com.foo/file1",
+          0700, 10000, 20000, false /* follow_symlinks */));
+  ASSERT_TRUE(android::base::WriteStringToFile(
+          "DE_RESTORE_CONTENT", rollback_de_dir + "/com.foo/file1",
+          0700, 10000, 20000, false /* follow_symlinks */));
+  ASSERT_TRUE(android::base::WriteStringToFile(
+          "TEST_CONTENT_CE", fake_package_ce_path + "/file1",
+          0700, 10000, 20000, false /* follow_symlinks */));
+  ASSERT_TRUE(android::base::WriteStringToFile(
+          "TEST_CONTENT_DE", fake_package_de_path + "/file1",
+          0700, 10000, 20000, false /* follow_symlinks */));
+
+  ASSERT_TRUE(service->restoreAppDataSnapshot(std::make_unique<std::string>("TEST"),
+          "com.foo", 10000, -1, "", 0, FLAG_STORAGE_DE | FLAG_STORAGE_CE).isOk());
+
+  std::string ce_content, de_content;
+  ASSERT_TRUE(android::base::ReadFileToString(
+      fake_package_ce_path + "/file1", &ce_content, false /* follow_symlinks */));
+  ASSERT_TRUE(android::base::ReadFileToString(
+      fake_package_de_path + "/file1", &de_content, false /* follow_symlinks */));
+  ASSERT_EQ("CE_RESTORE_CONTENT", ce_content);
+  ASSERT_EQ("DE_RESTORE_CONTENT", de_content);
+}
+
+
 }  // namespace installd
 }  // namespace android
diff --git a/cmds/installd/tests/installd_utils_test.cpp b/cmds/installd/tests/installd_utils_test.cpp
index ad7a5ae..ce99fff 100644
--- a/cmds/installd/tests/installd_utils_test.cpp
+++ b/cmds/installd/tests/installd_utils_test.cpp
@@ -544,5 +544,35 @@
     EXPECT_EQ(0, MatchExtension("docx"));
 }
 
+TEST_F(UtilsTest, TestRollbackPaths) {
+    EXPECT_EQ("/data/misc_ce/0/rollback/com.foo",
+            create_data_misc_ce_rollback_package_path(nullptr, 0, "com.foo"));
+    EXPECT_EQ("/data/misc_ce/10/rollback/com.foo",
+            create_data_misc_ce_rollback_package_path(nullptr, 10, "com.foo"));
+
+    EXPECT_EQ("/data/misc_de/0/rollback/com.foo",
+            create_data_misc_de_rollback_package_path(nullptr, 0, "com.foo"));
+    EXPECT_EQ("/data/misc_de/10/rollback/com.foo",
+            create_data_misc_de_rollback_package_path(nullptr, 10, "com.foo"));
+
+    EXPECT_EQ("/data/misc_ce/0/rollback",
+            create_data_misc_ce_rollback_path(nullptr, 0));
+    EXPECT_EQ("/data/misc_ce/10/rollback",
+            create_data_misc_ce_rollback_path(nullptr, 10));
+
+    EXPECT_EQ("/data/misc_de/0/rollback",
+            create_data_misc_de_rollback_path(nullptr, 0));
+    EXPECT_EQ("/data/misc_de/10/rollback",
+            create_data_misc_de_rollback_path(nullptr, 10));
+
+    // These last couple of cases are never exercised in production because we
+    // only snapshot apps in the primary data partition. Exercise them here for
+    // the sake of completeness.
+    EXPECT_EQ("/mnt/expand/57f8f4bc-abf4-655f-bf67-946fc0f9f25b/misc_ce/0/rollback/com.example",
+            create_data_misc_ce_rollback_package_path("57f8f4bc-abf4-655f-bf67-946fc0f9f25b", 0, "com.example"));
+    EXPECT_EQ("/mnt/expand/57f8f4bc-abf4-655f-bf67-946fc0f9f25b/misc_de/0/rollback/com.example",
+            create_data_misc_de_rollback_package_path("57f8f4bc-abf4-655f-bf67-946fc0f9f25b", 0, "com.example"));
+}
+
 }  // namespace installd
 }  // namespace android
diff --git a/cmds/installd/utils.cpp b/cmds/installd/utils.cpp
index 74ad184..6582ba5 100644
--- a/cmds/installd/utils.cpp
+++ b/cmds/installd/utils.cpp
@@ -192,6 +192,27 @@
     return StringPrintf("%s/user_de/%u", data.c_str(), userid);
 }
 
+
+std::string create_data_misc_ce_rollback_path(const char* volume_uuid, userid_t user) {
+    return StringPrintf("%s/misc_ce/%u/rollback", create_data_path(volume_uuid).c_str(), user);
+}
+
+std::string create_data_misc_de_rollback_path(const char* volume_uuid, userid_t user) {
+    return StringPrintf("%s/misc_de/%u/rollback", create_data_path(volume_uuid).c_str(), user);
+}
+
+std::string create_data_misc_ce_rollback_package_path(const char* volume_uuid,
+        userid_t user, const char* package_name) {
+    return StringPrintf("%s/%s",
+           create_data_misc_ce_rollback_path(volume_uuid, user).c_str(), package_name);
+}
+
+std::string create_data_misc_de_rollback_package_path(const char* volume_uuid,
+        userid_t user, const char* package_name) {
+    return StringPrintf("%s/%s",
+           create_data_misc_de_rollback_path(volume_uuid, user).c_str(), package_name);
+}
+
 /**
  * Create the path name for media for a certain userid.
  */
diff --git a/cmds/installd/utils.h b/cmds/installd/utils.h
index d05724a..a36fce1 100644
--- a/cmds/installd/utils.h
+++ b/cmds/installd/utils.h
@@ -61,6 +61,13 @@
 std::string create_data_user_ce_package_path_as_user_link(
         const char* volume_uuid, userid_t userid, const char* package_name);
 
+std::string create_data_misc_ce_rollback_path(const char* volume_uuid, userid_t user);
+std::string create_data_misc_de_rollback_path(const char* volume_uuid, userid_t user);
+std::string create_data_misc_ce_rollback_package_path(const char* volume_uuid,
+        userid_t user, const char* package_name);
+std::string create_data_misc_de_rollback_package_path(const char* volume_uuid,
+        userid_t user, const char* package_name);
+
 std::string create_data_media_path(const char* volume_uuid, userid_t userid);
 std::string create_data_media_obb_path(const char* volume_uuid, const char* package_name);
 std::string create_data_media_package_path(const char* volume_uuid, userid_t userid,