Fix issue 2678048: binder death detection in AudioFlinger is broken.

There is a bug in the way notification client list is managed when the client binder
interface dies that makes that the dead client is not removed from the list: the week
reference passed by binderDied() cannot be promoted and compared to the strong
references in the list.

The fix consists in creating a new NotificationClient class that implements the
binder DeathRecipient and holds a strong reference to the IAudioFlingerClient interface.
A new instance of this class is created for each cient and a strong reference to this
object is added to the notification client list maintained by AudioFlinger.
When binderDied() is called on this object, it is removed from the list preventing
AudioFlinger to notify this client for further io changes.

Also added code to disable LifeVibes effects when the client that has enabled the
enhancements dies.

Change-Id: Icedc4af171759e9ae9a575d82d44784b4e8267e8

2 files changed, 89 insertions, 35 deletions

diff --git a/libs/audioflinger/AudioFlinger.cpp b/libs/audioflinger/AudioFlinger.cpp
index 2414e8dc5e03..06443ef6712a 100644
--- a/libs/audioflinger/AudioFlinger.cpp
+++ b/libs/audioflinger/AudioFlinger.cpp
@@ -142,6 +142,7 @@ AudioFlinger::AudioFlinger()
     }
 #ifdef LVMX
     LifeVibes::init();
+    mLifeVibesClientPid = -1;
 #endif
 }
 
@@ -596,8 +597,10 @@ status_t AudioFlinger::setParameters(int ioHandle, const String8& keyValuePairs)
     int musicEnabled = -1;
     if (NO_ERROR == param.get(key, value)) {
         if (value == LifevibesEnable) {
+            mLifeVibesClientPid = IPCThreadState::self()->getCallingPid();
             musicEnabled = 1;
         } else if (value == LifevibesDisable) {
+            mLifeVibesClientPid = -1;
             musicEnabled = 0;
         }
     }
@@ -609,7 +612,7 @@ status_t AudioFlinger::setParameters(int ioHandle, const String8& keyValuePairs)
         mHardwareStatus = AUDIO_SET_PARAMETER;
         result = mAudioHardware->setParameters(keyValuePairs);
 #ifdef LVMX
-        if ((NO_ERROR == result) && (musicEnabled != -1)) {
+        if (musicEnabled != -1) {
             LifeVibes::enableMusic((bool) musicEnabled);
         }
 #endif
@@ -713,51 +716,57 @@ status_t AudioFlinger::getRenderPosition(uint32_t *halFrames, uint32_t *dspFrame
 void AudioFlinger::registerClient(const sp<IAudioFlingerClient>& client)
 {
 
-    LOGV("registerClient() %p, tid %d, calling tid %d", client.get(), gettid(), IPCThreadState::self()->getCallingPid());
     Mutex::Autolock _l(mLock);
 
-    sp<IBinder> binder = client->asBinder();
-    if (mNotificationClients.indexOf(binder) < 0) {
-        LOGV("Adding notification client %p", binder.get());
-        binder->linkToDeath(this);
-        mNotificationClients.add(binder);
-    }
+    int pid = IPCThreadState::self()->getCallingPid();
+    if (mNotificationClients.indexOfKey(pid) < 0) {
+        sp<NotificationClient> notificationClient = new NotificationClient(this,
+                                                                            client,
+                                                                            pid);
+        LOGV("registerClient() client %p, pid %d", notificationClient.get(), pid);
 
-    // the config change is always sent from playback or record threads to avoid deadlock
-    // with AudioSystem::gLock
-    for (size_t i = 0; i < mPlaybackThreads.size(); i++) {
-        mPlaybackThreads.valueAt(i)->sendConfigEvent(AudioSystem::OUTPUT_OPENED);
-    }
+        mNotificationClients.add(pid, notificationClient);
+
+        sp<IBinder> binder = client->asBinder();
+        binder->linkToDeath(notificationClient);
 
-    for (size_t i = 0; i < mRecordThreads.size(); i++) {
-        mRecordThreads.valueAt(i)->sendConfigEvent(AudioSystem::INPUT_OPENED);
+        // the config change is always sent from playback or record threads to avoid deadlock
+        // with AudioSystem::gLock
+        for (size_t i = 0; i < mPlaybackThreads.size(); i++) {
+            mPlaybackThreads.valueAt(i)->sendConfigEvent(AudioSystem::OUTPUT_OPENED);
+        }
+
+        for (size_t i = 0; i < mRecordThreads.size(); i++) {
+            mRecordThreads.valueAt(i)->sendConfigEvent(AudioSystem::INPUT_OPENED);
+        }
     }
 }
 
-void AudioFlinger::binderDied(const wp<IBinder>& who) {
-
-    LOGV("binderDied() %p, tid %d, calling tid %d", who.unsafe_get(), gettid(), IPCThreadState::self()->getCallingPid());
+void AudioFlinger::removeNotificationClient(pid_t pid)
+{
     Mutex::Autolock _l(mLock);
 
-    IBinder *binder = who.unsafe_get();
-
-    if (binder != NULL) {
-        int index = mNotificationClients.indexOf(binder);
-        if (index >= 0) {
-            LOGV("Removing notification client %p", binder);
-            mNotificationClients.removeAt(index);
+    int index = mNotificationClients.indexOfKey(pid);
+    if (index >= 0) {
+        sp <NotificationClient> client = mNotificationClients.valueFor(pid);
+        LOGV("removeNotificationClient() %p, pid %d", client.get(), pid);
+#ifdef LVMX
+        if (pid == mLifeVibesClientPid) {
+            LOGV("Disabling lifevibes");
+            LifeVibes::enableMusic(false);
+            mLifeVibesClientPid = -1;
         }
+#endif
+        mNotificationClients.removeItem(pid);
     }
 }
 
 // audioConfigChanged_l() must be called with AudioFlinger::mLock held
-void AudioFlinger::audioConfigChanged_l(int event, int ioHandle, void *param2) {
+void AudioFlinger::audioConfigChanged_l(int event, int ioHandle, void *param2)
+{
     size_t size = mNotificationClients.size();
     for (size_t i = 0; i < size; i++) {
-        sp<IBinder> binder = mNotificationClients.itemAt(i);
-        LOGV("audioConfigChanged_l() Notifying change to client %p", binder.get());
-        sp<IAudioFlingerClient> client = interface_cast<IAudioFlingerClient> (binder);
-        client->ioConfigChanged(event, ioHandle, param2);
+        mNotificationClients.valueAt(i)->client()->ioConfigChanged(event, ioHandle, param2);
     }
 }
 
@@ -768,6 +777,7 @@ void AudioFlinger::removeClient_l(pid_t pid)
     mClients.removeItem(pid);
 }
 
+
 // ----------------------------------------------------------------------------
 
 AudioFlinger::ThreadBase::ThreadBase(const sp<AudioFlinger>& audioFlinger, int id)
@@ -3086,6 +3096,28 @@ const sp<MemoryDealer>& AudioFlinger::Client::heap() const
 
 // ----------------------------------------------------------------------------
 
+AudioFlinger::NotificationClient::NotificationClient(const sp<AudioFlinger>& audioFlinger,
+                                                     const sp<IAudioFlingerClient>& client,
+                                                     pid_t pid)
+    : mAudioFlinger(audioFlinger), mPid(pid), mClient(client)
+{
+}
+
+AudioFlinger::NotificationClient::~NotificationClient()
+{
+    mClient.clear();
+}
+
+void AudioFlinger::NotificationClient::binderDied(const wp<IBinder>& who)
+{
+    sp<NotificationClient> keep(this);
+    {
+        mAudioFlinger->removeNotificationClient(mPid);
+    }
+}
+
+// ----------------------------------------------------------------------------
+
 AudioFlinger::TrackHandle::TrackHandle(const sp<AudioFlinger::PlaybackThread::Track>& track)
     : BnAudioTrack(),
       mTrack(track)
diff --git a/libs/audioflinger/AudioFlinger.h b/libs/audioflinger/AudioFlinger.h
index 739ec3331165..13aac8b96f8c 100644
--- a/libs/audioflinger/AudioFlinger.h
+++ b/libs/audioflinger/AudioFlinger.h
@@ -57,7 +57,7 @@ class AudioResampler;
 
 static const nsecs_t kStandbyTimeInNsecs = seconds(3);
 
-class AudioFlinger : public BnAudioFlinger, public IBinder::DeathRecipient
+class AudioFlinger : public BnAudioFlinger
 {
 public:
     static void instantiate();
@@ -139,9 +139,6 @@ public:
 
     virtual status_t getRenderPosition(uint32_t *halFrames, uint32_t *dspFrames, int output);
 
-    // IBinder::DeathRecipient
-    virtual     void        binderDied(const wp<IBinder>& who);
-
     enum hardware_call_state {
         AUDIO_HW_IDLE = 0,
         AUDIO_HW_INIT,
@@ -205,6 +202,27 @@ private:
         pid_t               mPid;
     };
 
+    // --- Notification Client ---
+    class NotificationClient : public IBinder::DeathRecipient {
+    public:
+                            NotificationClient(const sp<AudioFlinger>& audioFlinger,
+                                                const sp<IAudioFlingerClient>& client,
+                                                pid_t pid);
+        virtual             ~NotificationClient();
+
+                sp<IAudioFlingerClient>    client() { return mClient; }
+
+                // IBinder::DeathRecipient
+                virtual     void        binderDied(const wp<IBinder>& who);
+
+    private:
+                            NotificationClient(const NotificationClient&);
+                            NotificationClient& operator = (const NotificationClient&);
+
+        sp<AudioFlinger>        mAudioFlinger;
+        pid_t                   mPid;
+        sp<IAudioFlingerClient> mClient;
+    };
 
     class TrackHandle;
     class RecordHandle;
@@ -685,6 +703,7 @@ private:
 
 
                 void        removeClient_l(pid_t pid);
+                void        removeNotificationClient(pid_t pid);
 
 
     // record thread
@@ -796,8 +815,11 @@ private:
 
                 DefaultKeyedVector< int, sp<RecordThread> >    mRecordThreads;
 
-                SortedVector< sp<IBinder> >         mNotificationClients;
+                DefaultKeyedVector< pid_t, sp<NotificationClient> >    mNotificationClients;
                 int                                 mNextThreadId;
+#ifdef LVMX
+                int mLifeVibesClientPid;
+#endif
 };
 
 // ----------------------------------------------------------------------------