Attribute alarm broadcast wakelocks to the sender

Wakelock usage for the purpose of sending an alarm broadcast is now
attributed to the application which posted the alarm, not to the OS.

Bug 5911317

Change-Id: I8cb79c3bd5db467388716ab68285f4ab0bfe468b

Author: Christopher Tate

core/java/android/app/ActivityManagerNative.java

@@ -867,6 +867,16 @@ public boolean onTransact(int code, Parcel data, Parcel reply, int flags)
             return true;
         }
 
+        case GET_UID_FOR_INTENT_SENDER_TRANSACTION: {
+            data.enforceInterface(IActivityManager.descriptor);
+            IIntentSender r = IIntentSender.Stub.asInterface(
+                data.readStrongBinder());
+            int res = getUidForIntentSender(r);
+            reply.writeNoException();
+            reply.writeInt(res);
+            return true;
+        }
+
         case SET_PROCESS_LIMIT_TRANSACTION: {
             data.enforceInterface(IActivityManager.descriptor);
             int max = data.readInt();
@@ -2714,6 +2724,18 @@ public String getPackageForIntentSender(IIntentSender sender) throws RemoteExcep
         reply.recycle();
         return res;
     }
+    public int getUidForIntentSender(IIntentSender sender) throws RemoteException {
+        Parcel data = Parcel.obtain();
+        Parcel reply = Parcel.obtain();
+        data.writeInterfaceToken(IActivityManager.descriptor);
+        data.writeStrongBinder(sender.asBinder());
+        mRemote.transact(GET_UID_FOR_INTENT_SENDER_TRANSACTION, data, reply, 0);
+        reply.readException();
+        int res = reply.readInt();
+        data.recycle();
+        reply.recycle();
+        return res;
+    }
     public void setProcessLimit(int max) throws RemoteException
     {
         Parcel data = Parcel.obtain();

core/java/android/app/IActivityManager.java

@@ -175,6 +175,7 @@ public IIntentSender getIntentSender(int type,
     public boolean clearApplicationUserData(final String packageName,
             final IPackageDataObserver observer, int userId) throws RemoteException;
     public String getPackageForIntentSender(IIntentSender sender) throws RemoteException;
+    public int getUidForIntentSender(IIntentSender sender) throws RemoteException;
 
     public void setProcessLimit(int max) throws RemoteException;
     public int getProcessLimit() throws RemoteException;
@@ -531,6 +532,7 @@ private WaitResult(Parcel source) {
     int START_BACKUP_AGENT_TRANSACTION = IBinder.FIRST_CALL_TRANSACTION+89;
     int BACKUP_AGENT_CREATED_TRANSACTION = IBinder.FIRST_CALL_TRANSACTION+90;
     int UNBIND_BACKUP_AGENT_TRANSACTION = IBinder.FIRST_CALL_TRANSACTION+91;
+    int GET_UID_FOR_INTENT_SENDER_TRANSACTION = IBinder.FIRST_CALL_TRANSACTION+92;
 
 
     int START_ACTIVITY_IN_PACKAGE_TRANSACTION = IBinder.FIRST_CALL_TRANSACTION+94;

services/java/com/android/server/AlarmManagerService.java

@@ -34,9 +34,9 @@
 import android.os.PowerManager;
 import android.os.SystemClock;
 import android.os.SystemProperties;
+import android.os.WorkSource;
 import android.text.TextUtils;
 import android.text.format.Time;
-import android.util.EventLog;
 import android.util.Slog;
 import android.util.TimeUtils;
 
@@ -50,6 +50,7 @@
 import java.util.Date;
 import java.util.HashMap;
 import java.util.Iterator;
+import java.util.LinkedList;
 import java.util.Map;
 import java.util.TimeZone;
 
@@ -89,6 +90,7 @@ class AlarmManagerService extends IAlarmManager.Stub {
     private int mDescriptor;
     private int mBroadcastRefCount = 0;
     private PowerManager.WakeLock mWakeLock;
+    private LinkedList<PendingIntent> mInFlight = new LinkedList<PendingIntent>();
     private final AlarmThread mWaitThread = new AlarmThread();
     private final AlarmHandler mHandler = new AlarmHandler();
     private ClockReceiver mClockReceiver;
@@ -668,10 +670,12 @@ public void run()
                                             Intent.EXTRA_ALARM_COUNT, alarm.count),
                                     mResultReceiver, mHandler);
 
-                            // we have an active broadcast so stay awake. 
+                            // we have an active broadcast so stay awake.
                             if (mBroadcastRefCount == 0) {
+                                setWakelockWorkSource(alarm.operation);
                                 mWakeLock.acquire();
                             }
+                            mInFlight.add(alarm.operation);
                             mBroadcastRefCount++;
 
                             BroadcastStats bs = getStatsLocked(alarm.operation);
@@ -700,7 +704,22 @@ public void run()
             }
         }
     }
-    
+
+    void setWakelockWorkSource(PendingIntent pi) {
+        try {
+            final int uid = ActivityManagerNative.getDefault()
+                    .getUidForIntentSender(pi.getTarget());
+            if (uid >= 0) {
+                mWakeLock.setWorkSource(new WorkSource(uid));
+                return;
+            }
+        } catch (Exception e) {
+        }
+
+        // Something went wrong; fall back to attributing the lock to the OS
+        mWakeLock.setWorkSource(null);
+    }
+
     private class AlarmHandler extends Handler {
         public static final int ALARM_EVENT = 1;
         public static final int MINUTE_CHANGE_EVENT = 2;
@@ -876,9 +895,20 @@ public void onSendFinished(PendingIntent pi, Intent intent, int resultCode,
                         fs.count++;
                     }
                 }
+                mInFlight.removeFirst();
                 mBroadcastRefCount--;
                 if (mBroadcastRefCount == 0) {
                     mWakeLock.release();
+                } else {
+                    // the next of our alarms is now in flight.  reattribute the wakelock.
+                    final PendingIntent nowInFlight = mInFlight.peekFirst();
+                    if (nowInFlight != null) {
+                        setWakelockWorkSource(nowInFlight);
+                    } else {
+                        // should never happen
+                        Slog.e(TAG, "Alarm wakelock still held but sent queue empty");
+                        mWakeLock.setWorkSource(null);
+                    }
                 }
             }
         }

services/java/com/android/server/am/ActivityManagerService.java

@@ -4444,6 +4444,17 @@ public String getPackageForIntentSender(IIntentSender pendingResult) {
         return null;
     }
 
+    public int getUidForIntentSender(IIntentSender sender) {
+        if (sender instanceof PendingIntentRecord) {
+            try {
+                PendingIntentRecord res = (PendingIntentRecord)sender;
+                return res.uid;
+            } catch (ClassCastException e) {
+            }
+        }
+        return -1;
+    }
+
     public boolean isIntentSenderTargetedToPackage(IIntentSender pendingResult) {
         if (!(pendingResult instanceof PendingIntentRecord)) {
             return false;