backup: Fix a system server crash

 * If we get into a state where the backup data is null, system server
   will go down in flames. Abort and kill any active agents if this
   happens.

java.lang.NullPointerException: Attempt to invoke virtual method 'java.io.FileDescriptor android.os.ParcelFileDescriptor.getFileDescriptor()' on a null object reference
        at com.android.server.backup.BackupManagerService$PerformBackupTask.operationComplete(BackupManagerService.java:2820)
        at com.android.server.backup.BackupManagerService$BackupHandler.handleMessage(BackupManagerService.java:778)
        at android.os.Handler.dispatchMessage(Handler.java:102)
        at android.os.Looper.loop(Looper.java:135)
        at android.os.HandlerThread.run(HandlerThread.java:61)

Change-Id: I65cb3c7d75a417373e8a59b9150a61b5eb1939af

1 files changed, 6 insertions, 0 deletions

diff --git a/services/backup/java/com/android/server/backup/BackupManagerService.java b/services/backup/java/com/android/server/backup/BackupManagerService.java
index 12003e2..a1ed6e9 100644
--- a/services/backup/java/com/android/server/backup/BackupManagerService.java
+++ b/services/backup/java/com/android/server/backup/BackupManagerService.java
@@ -2931,6 +2931,12 @@ public class BackupManagerService {
 
             final String pkgName = mCurrentPackage.packageName;
             final long filepos = mBackupDataName.length();
+            if (mBackupDataName == null) {
+                failAgent(mAgentBinder, "Backup data was null: " + mBackupDataName);
+                addBackupTrace("backup data was null: " + mBackupDataName);
+                agentErrorCleanup();
+                return;
+            }
             FileDescriptor fd = mBackupData.getFileDescriptor();
             try {
                 // If it's a 3rd party app, see whether they wrote any protected keys