Clean up the mounts for Pre-reboot Dexopt on system_server restart.

When there is a system_server restart, it's possible that a previous
Pre-reboot Dexopt job didn't end normally and left over a chroot, so we
need to clean it up, or we may potentially block update_engine (if there
is an OTA).

Bug: 354140992
Test: Run Pre-reboot Dexopt and then kill system_server.
Change-Id: Ieb5ee411d136224e4f1bb50cb1389d2472d27143

4 files changed, 23 insertions, 10 deletions

diff --git a/dexopt_chroot_setup/binder/com/android/server/art/IDexoptChrootSetup.aidl b/dexopt_chroot_setup/binder/com/android/server/art/IDexoptChrootSetup.aidl
index f8770147fc..867fdf9e38 100644
--- a/dexopt_chroot_setup/binder/com/android/server/art/IDexoptChrootSetup.aidl
+++ b/dexopt_chroot_setup/binder/com/android/server/art/IDexoptChrootSetup.aidl
@@ -38,6 +38,12 @@ interface IDexoptChrootSetup {
      */
     void init();
 
-    /** Tears down the chroot environment. */
-    void tearDown();
+    /**
+     * Tears down the chroot environment.
+     *
+     * @param allowConcurrent If true, allows this method to be called concurrently when another
+     * call to the service is still being processed. Note that the service does not process this
+     * call concurrently but waits until the other call is done.
+     */
+    void tearDown(boolean allowConcurrent);
 }
diff --git a/dexopt_chroot_setup/dexopt_chroot_setup.cc b/dexopt_chroot_setup/dexopt_chroot_setup.cc
index ff016d64d5..1710f07b5f 100644
--- a/dexopt_chroot_setup/dexopt_chroot_setup.cc
+++ b/dexopt_chroot_setup/dexopt_chroot_setup.cc
@@ -365,9 +365,16 @@ ScopedAStatus DexoptChrootSetup::init() {
   return ScopedAStatus::ok();
 }
 
-ScopedAStatus DexoptChrootSetup::tearDown() {
-  if (!mu_.try_lock()) {
-    return Fatal("Unexpected concurrent calls");
+ScopedAStatus DexoptChrootSetup::tearDown(bool in_allowConcurrent) {
+  if (in_allowConcurrent) {
+    // Normally, we don't expect concurrent calls, but this method may be called upon system server
+    // restart when another call initiated by the previous system_server instance is still being
+    // processed.
+    mu_.lock();
+  } else {
+    if (!mu_.try_lock()) {
+      return Fatal("Unexpected concurrent calls");
+    }
   }
   std::lock_guard<std::mutex> lock(mu_, std::adopt_lock);
 
diff --git a/dexopt_chroot_setup/dexopt_chroot_setup.h b/dexopt_chroot_setup/dexopt_chroot_setup.h
index de0e35fa4d..3e39be4bb8 100644
--- a/dexopt_chroot_setup/dexopt_chroot_setup.h
+++ b/dexopt_chroot_setup/dexopt_chroot_setup.h
@@ -35,7 +35,7 @@ class DexoptChrootSetup : public aidl::com::android::server::art::BnDexoptChroot
 
   ndk::ScopedAStatus init() override;
 
-  ndk::ScopedAStatus tearDown() override;
+  ndk::ScopedAStatus tearDown(bool in_allowConcurrent) override;
 
   android::base::Result<void> Start();
 
diff --git a/dexopt_chroot_setup/dexopt_chroot_setup_test.cc b/dexopt_chroot_setup/dexopt_chroot_setup_test.cc
index 1b4186f0dd..c5faca7f4e 100644
--- a/dexopt_chroot_setup/dexopt_chroot_setup_test.cc
+++ b/dexopt_chroot_setup/dexopt_chroot_setup_test.cc
@@ -89,7 +89,7 @@ class DexoptChrootSetupTest : public CommonArtTest {
       return;
     }
     scratch_dir_.reset();
-    dexopt_chroot_setup_->tearDown();
+    dexopt_chroot_setup_->tearDown(/*in_allowConcurrent=*/false);
     CommonArtTest::TearDown();
   }
 
@@ -184,17 +184,17 @@ TEST_F(DexoptChrootSetupTest, Run) {
   EXPECT_EQ(status.getExceptionCode(), EX_ILLEGAL_STATE);
   EXPECT_STREQ(status.getMessage(), "init must not be repeatedly called");
 
-  ASSERT_STATUS_OK(dexopt_chroot_setup_->tearDown());
+  ASSERT_STATUS_OK(dexopt_chroot_setup_->tearDown(/*in_allowConcurrent=*/false));
 
   EXPECT_FALSE(std::filesystem::exists(DexoptChrootSetup::CHROOT_DIR));
 
   // Check that `tearDown` can be repeatedly called too.
-  ASSERT_STATUS_OK(dexopt_chroot_setup_->tearDown());
+  ASSERT_STATUS_OK(dexopt_chroot_setup_->tearDown(/*in_allowConcurrent=*/false));
 
   // Check that `setUp` can be followed directly by a `tearDown`.
   ASSERT_STATUS_OK(
       dexopt_chroot_setup_->setUp(/*in_otaSlot=*/std::nullopt, /*in_mapSnapshotsForOta=*/false));
-  ASSERT_STATUS_OK(dexopt_chroot_setup_->tearDown());
+  ASSERT_STATUS_OK(dexopt_chroot_setup_->tearDown(/*in_allowConcurrent=*/false));
   EXPECT_FALSE(std::filesystem::exists(DexoptChrootSetup::CHROOT_DIR));
 }