From 8eb67dd5d130952641c01d86c30f1beac2a4d59a Mon Sep 17 00:00:00 2001
From: Kevin Han <kevhan@google.com>
Date: Thu, 11 Nov 2021 14:29:35 -0800
Subject: [PATCH] Add hibernation NPE check and unhibernate only if hibernating

Rather than depend strictly on "leaving" force-stop (i.e. stopped to not
stopped), we unhibernate when setting stopped to false and the app is
hibernating. This prevents situations where an app is not stopped but
hibernating and can never exit hibernation because the app never
"leaves" force-stop.

With this, we can add the NPE check without risk of putting the app into
a permanent hibernation state.

Bug: 205774141
Test: atest AppHibernationIntegrationTest
Test: atest PackageManagerServiceHibernationTests
Merged-In: Ia45d0c9236474841d0ba63b5265b3b835cf9f6f5
Change-Id: Ia45d0c9236474841d0ba63b5265b3b835cf9f6f5
(cherry picked from commit 2e8b4013072f30ee96f77cd691a52a98240c1b71)
---
 .../server/pm/PackageManagerService.java      | 14 ++++----
 .../PackageManagerServiceHibernationTests.kt  | 33 +++++++++++++++++--
 2 files changed, 38 insertions(+), 9 deletions(-)

diff --git a/services/core/java/com/android/server/pm/PackageManagerService.java b/services/core/java/com/android/server/pm/PackageManagerService.java
index 7d68f8dd0d615..da45367767c40 100644
--- a/services/core/java/com/android/server/pm/PackageManagerService.java
+++ b/services/core/java/com/android/server/pm/PackageManagerService.java
@@ -24299,24 +24299,24 @@ public class PackageManagerService extends IPackageManager.Stub
         }
         enforceCrossUserPermission(callingUid, userId, true /* requireFullPermission */,
                 true /* checkShell */, "stop package");
-        boolean shouldUnhibernate = false;
         // writer
         synchronized (mLock) {
             final PackageSetting ps = mSettings.getPackageLPr(packageName);
-            if (ps != null && ps.getStopped(userId) && !stopped) {
-                shouldUnhibernate = true;
-            }
             if (!shouldFilterApplicationLocked(ps, callingUid, userId)
                     && mSettings.setPackageStoppedStateLPw(this, packageName, stopped, userId)) {
                 scheduleWritePackageRestrictionsLocked(userId);
             }
         }
-        if (shouldUnhibernate) {
+        // If this would cause the app to leave force-stop, then also make sure to unhibernate the
+        // app if needed.
+        if (!stopped) {
             mHandler.post(() -> {
                 AppHibernationManagerInternal ah =
                         mInjector.getLocalService(AppHibernationManagerInternal.class);
-                ah.setHibernatingForUser(packageName, userId, false);
-                ah.setHibernatingGlobally(packageName, false);
+                if (ah != null && ah.isHibernatingForUser(packageName, userId)) {
+                    ah.setHibernatingForUser(packageName, userId, false);
+                    ah.setHibernatingGlobally(packageName, false);
+                }
             });
         }
     }
diff --git a/services/tests/mockingservicestests/src/com/android/server/pm/PackageManagerServiceHibernationTests.kt b/services/tests/mockingservicestests/src/com/android/server/pm/PackageManagerServiceHibernationTests.kt
index fd97557480bbf..e053dc3fd32e1 100644
--- a/services/tests/mockingservicestests/src/com/android/server/pm/PackageManagerServiceHibernationTests.kt
+++ b/services/tests/mockingservicestests/src/com/android/server/pm/PackageManagerServiceHibernationTests.kt
@@ -29,6 +29,7 @@ import com.android.server.apphibernation.AppHibernationManagerInternal
 import com.android.server.apphibernation.AppHibernationService
 import com.android.server.extendedtestutils.wheneverStatic
 import com.android.server.testutils.whenever
+import org.junit.Assert
 import org.junit.Assert.assertFalse
 import org.junit.Assert.assertTrue
 import org.junit.Before
@@ -100,8 +101,11 @@ class PackageManagerServiceHibernationTests {
             rule.system().dataAppDirectory)
         val pm = createPackageManagerService()
         rule.system().validateFinalState()
-        val ps = pm.getPackageSetting(TEST_PACKAGE_NAME)
-        ps!!.setStopped(true, TEST_USER_ID)
+
+        TestableLooper.get(this).processAllMessages()
+
+        whenever(appHibernationManager.isHibernatingForUser(TEST_PACKAGE_NAME, TEST_USER_ID))
+            .thenReturn(true)
 
         pm.setPackageStoppedState(TEST_PACKAGE_NAME, false, TEST_USER_ID)
 
@@ -111,6 +115,31 @@ class PackageManagerServiceHibernationTests {
         verify(appHibernationManager).setHibernatingGlobally(TEST_PACKAGE_NAME, false)
     }
 
+    @Test
+    fun testExitForceStop_nonExistingAppHibernationManager_doesNotThrowException() {
+        whenever(rule.mocks().injector.getLocalService(AppHibernationManagerInternal::class.java))
+            .thenReturn(null)
+
+        rule.system().stageScanExistingPackage(
+            TEST_PACKAGE_NAME,
+            1L,
+            rule.system().dataAppDirectory)
+        val pm = createPackageManagerService()
+        rule.system().validateFinalState()
+
+        TestableLooper.get(this).processAllMessages()
+
+        whenever(appHibernationManager.isHibernatingForUser(TEST_PACKAGE_NAME, TEST_USER_ID))
+            .thenReturn(true)
+
+        try {
+            pm.setPackageStoppedState(TEST_PACKAGE_NAME, false, TEST_USER_ID)
+            TestableLooper.get(this).processAllMessages()
+        } catch (e: Exception) {
+            Assert.fail("Method throws exception when AppHibernationManager is not ready.\n$e")
+        }
+    }
+
     @Test
     fun testGetOptimizablePackages_ExcludesGloballyHibernatingPackages() {
         rule.system().stageScanExistingPackage(