Implement a tear-down phase in otapreopt_chroot.

Collect the list of APEX packages activated by `otapreopt_chroot` and
deactivate them after executing `otapreopt` (in its own process).

Also share android::installd::Exec between `otapreopt` and
`otapreopt_chroot`.

This tear-down phase ensures loop devices associated during by
`otapreopt_chroot` are detached before `otapreopt_chroot` exits.

Test: m otapreopt_chroot
Test: A/B OTA update test (asit/dexoptota/self_full).
Bug: 113373927
Bug: 120796514
Change-Id: I236ac49bb698fb672e7a4f9de9903229e535e9c6
diff --git a/cmds/installd/Android.bp b/cmds/installd/Android.bp
index 85652b3..95f5efb 100644
--- a/cmds/installd/Android.bp
+++ b/cmds/installd/Android.bp
@@ -136,7 +136,10 @@
     ],
     clang: true,
 
-    srcs: ["otapreopt_chroot.cpp"],
+    srcs: [
+        "otapreopt_chroot.cpp",
+        "otapreopt_utils.cpp",
+    ],
     shared_libs: [
         "libbase",
         "liblog",
@@ -197,6 +200,7 @@
         "dexopt.cpp",
         "globals.cpp",
         "otapreopt.cpp",
+        "otapreopt_utils.cpp",
         "utils.cpp",
     ],
 
diff --git a/cmds/installd/otapreopt.cpp b/cmds/installd/otapreopt.cpp
index d161407..05c8538 100644
--- a/cmds/installd/otapreopt.cpp
+++ b/cmds/installd/otapreopt.cpp
@@ -26,7 +26,6 @@
 #include <sys/capability.h>
 #include <sys/prctl.h>
 #include <sys/stat.h>
-#include <sys/wait.h>
 
 #include <android-base/logging.h>
 #include <android-base/macros.h>
@@ -58,7 +57,6 @@
 #define REPLY_MAX     256   /* largest reply allowed */
 
 using android::base::EndsWith;
-using android::base::Join;
 using android::base::Split;
 using android::base::StartsWith;
 using android::base::StringPrintf;
@@ -619,61 +617,6 @@
     // Helpers, mostly taken from ART //
     ////////////////////////////////////
 
-    // Wrapper on fork/execv to run a command in a subprocess.
-    static bool Exec(const std::vector<std::string>& arg_vector, std::string* error_msg) {
-        const std::string command_line = Join(arg_vector, ' ');
-
-        CHECK_GE(arg_vector.size(), 1U) << command_line;
-
-        // Convert the args to char pointers.
-        const char* program = arg_vector[0].c_str();
-        std::vector<char*> args;
-        for (size_t i = 0; i < arg_vector.size(); ++i) {
-            const std::string& arg = arg_vector[i];
-            char* arg_str = const_cast<char*>(arg.c_str());
-            CHECK(arg_str != nullptr) << i;
-            args.push_back(arg_str);
-        }
-        args.push_back(nullptr);
-
-        // Fork and exec.
-        pid_t pid = fork();
-        if (pid == 0) {
-            // No allocation allowed between fork and exec.
-
-            // Change process groups, so we don't get reaped by ProcessManager.
-            setpgid(0, 0);
-
-            execv(program, &args[0]);
-
-            PLOG(ERROR) << "Failed to execv(" << command_line << ")";
-            // _exit to avoid atexit handlers in child.
-            _exit(1);
-        } else {
-            if (pid == -1) {
-                *error_msg = StringPrintf("Failed to execv(%s) because fork failed: %s",
-                        command_line.c_str(), strerror(errno));
-                return false;
-            }
-
-            // wait for subprocess to finish
-            int status;
-            pid_t got_pid = TEMP_FAILURE_RETRY(waitpid(pid, &status, 0));
-            if (got_pid != pid) {
-                *error_msg = StringPrintf("Failed after fork for execv(%s) because waitpid failed: "
-                        "wanted %d, got %d: %s",
-                        command_line.c_str(), pid, got_pid, strerror(errno));
-                return false;
-            }
-            if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
-                *error_msg = StringPrintf("Failed execv(%s) because non-0 exit status",
-                        command_line.c_str());
-                return false;
-            }
-        }
-        return true;
-    }
-
     // Choose a random relocation offset. Taken from art/runtime/gc/image_space.cc.
     static int32_t ChooseRelocationOffsetDelta(int32_t min_delta, int32_t max_delta) {
         constexpr size_t kPageSize = PAGE_SIZE;
diff --git a/cmds/installd/otapreopt_chroot.cpp b/cmds/installd/otapreopt_chroot.cpp
index ff3ed7e..9965d58 100644
--- a/cmds/installd/otapreopt_chroot.cpp
+++ b/cmds/installd/otapreopt_chroot.cpp
@@ -195,23 +195,43 @@
     // Note that this leaves around the loop devices created and used by
     // libapexd's code, but this is fine, as we expect to reboot soon after.
     apex::scanPackagesDirAndActivate(apex::kApexPackageSystemDir);
+    // Collect activated packages.
+    std::vector<apex::ApexFile> active_packages = apex::getActivePackages();
 
     // Now go on and run otapreopt.
 
-    // Incoming:  cmd + status-fd + target-slot + cmd... + null      | Incoming | = argc + 1
-    // Outgoing:  cmd             + target-slot + cmd... + null      | Outgoing | = argc
-    const char** argv = new const char*[argc];
-
-    argv[0] = "/system/bin/otapreopt";
+    // Incoming:  cmd + status-fd + target-slot + cmd...      | Incoming | = argc
+    // Outgoing:  cmd             + target-slot + cmd...      | Outgoing | = argc - 1
+    std::vector<std::string> cmd;
+    cmd.reserve(argc);
+    cmd.push_back("/system/bin/otapreopt");
 
     // The first parameter is the status file descriptor, skip.
-    for (size_t i = 2; i <= static_cast<size_t>(argc); ++i) {
-        argv[i - 1] = arg[i];
+    for (size_t i = 2; i < static_cast<size_t>(argc); ++i) {
+        cmd.push_back(arg[i]);
     }
 
-    execv(argv[0], static_cast<char * const *>(const_cast<char**>(argv)));
-    PLOG(ERROR) << "execv(OTAPREOPT) failed.";
-    exit(99);
+    // Fork and execute otapreopt in its own process.
+    std::string error_msg;
+    bool exec_result = Exec(cmd, &error_msg);
+    if (!exec_result) {
+        LOG(ERROR) << "Running otapreopt failed: " << error_msg;
+    }
+
+    // Tear down the work down by the apexd logic above (i.e. deactivate packages).
+    for (const apex::ApexFile& apex_file : active_packages) {
+        const std::string& package_path = apex_file.GetPath();
+        apex::Status status = apex::deactivatePackage(package_path);
+        if (!status.Ok()) {
+            LOG(ERROR) << "Failed to deactivate " << package_path << ": " << status.ErrorMessage();
+        }
+    }
+
+    if (!exec_result) {
+        exit(213);
+    }
+
+    return 0;
 }
 
 }  // namespace installd
diff --git a/cmds/installd/otapreopt_utils.cpp b/cmds/installd/otapreopt_utils.cpp
new file mode 100644
index 0000000..124f726
--- /dev/null
+++ b/cmds/installd/otapreopt_utils.cpp
@@ -0,0 +1,88 @@
+/*
+ ** Copyright 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 "otapreopt_utils.h"
+
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#include <android-base/logging.h>
+#include <android-base/stringprintf.h>
+#include <android-base/strings.h>
+
+using android::base::Join;
+using android::base::StringPrintf;
+
+namespace android {
+namespace installd {
+
+bool Exec(const std::vector<std::string>& arg_vector, std::string* error_msg) {
+    const std::string command_line = Join(arg_vector, ' ');
+
+    CHECK_GE(arg_vector.size(), 1U) << command_line;
+
+    // Convert the args to char pointers.
+    const char* program = arg_vector[0].c_str();
+    std::vector<char*> args;
+    for (size_t i = 0; i < arg_vector.size(); ++i) {
+        const std::string& arg = arg_vector[i];
+        char* arg_str = const_cast<char*>(arg.c_str());
+        CHECK(arg_str != nullptr) << i;
+        args.push_back(arg_str);
+    }
+    args.push_back(nullptr);
+
+    // Fork and exec.
+    pid_t pid = fork();
+    if (pid == 0) {
+        // No allocation allowed between fork and exec.
+
+        // Change process groups, so we don't get reaped by ProcessManager.
+        setpgid(0, 0);
+
+        execv(program, &args[0]);
+
+        PLOG(ERROR) << "Failed to execv(" << command_line << ")";
+        // _exit to avoid atexit handlers in child.
+        _exit(1);
+    } else {
+        if (pid == -1) {
+            *error_msg = StringPrintf("Failed to execv(%s) because fork failed: %s",
+                    command_line.c_str(), strerror(errno));
+            return false;
+        }
+
+        // wait for subprocess to finish
+        int status;
+        pid_t got_pid = TEMP_FAILURE_RETRY(waitpid(pid, &status, 0));
+        if (got_pid != pid) {
+            *error_msg = StringPrintf("Failed after fork for execv(%s) because waitpid failed: "
+                    "wanted %d, got %d: %s",
+                    command_line.c_str(), pid, got_pid, strerror(errno));
+            return false;
+        }
+        if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
+            *error_msg = StringPrintf("Failed execv(%s) because non-0 exit status",
+                    command_line.c_str());
+            return false;
+        }
+    }
+    return true;
+}
+
+}  // namespace installd
+}  // namespace android
diff --git a/cmds/installd/otapreopt_utils.h b/cmds/installd/otapreopt_utils.h
index 436e554..03a6d87 100644
--- a/cmds/installd/otapreopt_utils.h
+++ b/cmds/installd/otapreopt_utils.h
@@ -18,6 +18,8 @@
 #define OTAPREOPT_UTILS_H_
 
 #include <regex>
+#include <string>
+#include <vector>
 
 namespace android {
 namespace installd {
@@ -28,6 +30,9 @@
     return std::regex_match(input, slot_suffix_match, slot_suffix_regex);
 }
 
+// Wrapper on fork/execv to run a command in a subprocess.
+bool Exec(const std::vector<std::string>& arg_vector, std::string* error_msg);
+
 }  // namespace installd
 }  // namespace android