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Commit 5919ac6b authored by Kenny Root's avatar Kenny Root
Browse files

OBB: track binder death observers 

An incorrect assumption about how death observers were tracked lead to
an IllegalArgumentException in some cases. Make sure the linking and
unlinking of the Binder to its ObbState death observer is symmetric to
avoid this problem.

Bug: 3062360
Change-Id: Idd016db12551c80cd74d00f11cf6569bd3b4ce21
parent a3ee5c03

services/java/com/android/server/MountService.java

+44 −14
Original line number Diff line number Diff line
@@ -170,8 +170,6 @@ class MountService extends IMountService.Stub 
            this.token = token;

            this.callerUid = callerUid;

            mounted = false;



            getBinder().linkToDeath(this, 0);

        }



        // OBB source filename
@@ -196,7 +194,11 @@ class MountService extends IMountService.Stub 
            mObbActionHandler.sendMessage(mObbActionHandler.obtainMessage(OBB_RUN_ACTION, action));

        }



        public void cleanUp() {

        public void link() throws RemoteException {

            getBinder().linkToDeath(this, 0);

        }



        public void unlink() {

            getBinder().unlinkToDeath(this, 0);

        }
@@ -1659,14 +1661,39 @@ class MountService extends IMountService.Stub 
            Slog.i(TAG, "Send to OBB handler: " + action.toString());

    }



    private void addObbState(ObbState obbState) {

    private void addObbState(ObbState obbState) throws RemoteException {

        synchronized (mObbMounts) {

            List<ObbState> obbStates = mObbMounts.get(obbState.getBinder());

            final IBinder binder = obbState.getBinder();

            List<ObbState> obbStates = mObbMounts.get(binder);

            final boolean unique;



            if (obbStates == null) {

                obbStates = new ArrayList<ObbState>();

                mObbMounts.put(obbState.getBinder(), obbStates);

                mObbMounts.put(binder, obbStates);

                unique = true;

            } else {

                unique = obbStates.contains(obbState);

            }



            if (unique) {

                obbStates.add(obbState);

                try {

                    obbState.link();

                } catch (RemoteException e) {

                    /*

                     * The binder died before we could link it, so clean up our

                     * state and return failure.

                     */

                    obbStates.remove(obbState);

                    if (obbStates.isEmpty()) {

                        mObbMounts.remove(binder);

                    }



                    // Rethrow the error so mountObb can get it

                    throw e;

                }

            }



            mObbPathToStateMap.put(obbState.filename, obbState);



            // Track the number of OBBs used by this UID.
@@ -1682,14 +1709,17 @@ class MountService extends IMountService.Stub 


    private void removeObbState(ObbState obbState) {

        synchronized (mObbMounts) {

            final List<ObbState> obbStates = mObbMounts.get(obbState.getBinder());

            final IBinder binder = obbState.getBinder();

            final List<ObbState> obbStates = mObbMounts.get(binder);

            if (obbStates != null) {

                obbStates.remove(obbState);

                if (obbStates.remove(obbState)) {

                    obbState.unlink();

                }

            if (obbStates == null || obbStates.isEmpty()) {

                mObbMounts.remove(obbState.getBinder());

                obbState.cleanUp();

                if (obbStates.isEmpty()) {

                    mObbMounts.remove(binder);

                }

            }



            mObbPathToStateMap.remove(obbState.filename);



            // Track the number of OBBs used by this UID.
@@ -1708,7 +1738,7 @@ class MountService extends IMountService.Stub 
        }

    }



    private void replaceObbState(ObbState oldObbState, ObbState newObbState) {

    private void replaceObbState(ObbState oldObbState, ObbState newObbState) throws RemoteException {

        synchronized (mObbMounts) {

            removeObbState(oldObbState);

            addObbState(newObbState);