Ensure synchronized access of JNI callback object

Ensure synchronized access of JNI object using mutex as
the same is accessed from both Application context during
cleanup and from stack call back context during intimating
Apps on stack event update.

CRs-Fixed: 959400

Change-Id: I39f97f1b530086bc446941dde744e43c33b46f81

1 files changed, 53 insertions, 28 deletions

diff --git a/jni/com_android_bluetooth_a2dp.cpp b/jni/com_android_bluetooth_a2dp.cpp
index a9b51f7b9..7c15c37db 100644
--- a/jni/com_android_bluetooth_a2dp.cpp
+++ b/jni/com_android_bluetooth_a2dp.cpp
@@ -27,6 +27,7 @@
 #include "android_runtime/AndroidRuntime.h"
 
 #include <string.h>
+#include <pthread.h>
 
 namespace android {
 static jmethodID method_onConnectionStateChanged;
@@ -39,6 +40,8 @@ static const btav_interface_t *sBluetoothA2dpInterface = NULL;
 static jobject mCallbacksObj = NULL;
 static JNIEnv *sCallbackEnv = NULL;
 
+static pthread_mutex_t mMutex = PTHREAD_MUTEX_INITIALIZER;
+
 static bool checkCallbackThread() {
     // Always fetch the latest callbackEnv from AdapterService.
     // Caching this could cause this sCallbackEnv to go out-of-sync
@@ -58,10 +61,6 @@ static void bta2dp_connection_state_callback(btav_connection_state_t state, bt_b
 
     ALOGI("%s", __FUNCTION__);
 
-    if (mCallbacksObj == NULL) {
-        ALOGE("Callbacks Obj is no more valid: '%s", __FUNCTION__);
-        return;
-    }
     if (!checkCallbackThread()) {                                       \
         ALOGE("Callback: '%s' is not called on the correct thread", __FUNCTION__); \
         return;                                                         \
@@ -75,8 +74,16 @@ static void bta2dp_connection_state_callback(btav_connection_state_t state, bt_b
     }
 
     sCallbackEnv->SetByteArrayRegion(addr, 0, sizeof(bt_bdaddr_t), (jbyte*) bd_addr);
-    sCallbackEnv->CallVoidMethod(mCallbacksObj, method_onConnectionStateChanged, (jint) state,
-                                 addr);
+
+    pthread_mutex_lock(&mMutex);
+    if (mCallbacksObj != NULL) {
+        sCallbackEnv->CallVoidMethod(mCallbacksObj, method_onConnectionStateChanged,
+                        (jint) state, addr);
+    } else {
+        ALOGE("Callbacks Obj is no more valid: '%s", __FUNCTION__);
+    }
+    pthread_mutex_unlock(&mMutex);
+
     checkAndClearExceptionFromCallback(sCallbackEnv, __FUNCTION__);
     sCallbackEnv->DeleteLocalRef(addr);
 }
@@ -86,10 +93,6 @@ static void bta2dp_audio_state_callback(btav_audio_state_t state, bt_bdaddr_t* b
 
     ALOGI("%s", __FUNCTION__);
 
-    if (mCallbacksObj == NULL) {
-        ALOGE("Callbacks Obj is no more valid: '%s", __FUNCTION__);
-        return;
-    }
     if (!checkCallbackThread()) {                                       \
         ALOGE("Callback: '%s' is not called on the correct thread", __FUNCTION__); \
         return;                                                         \
@@ -102,8 +105,16 @@ static void bta2dp_audio_state_callback(btav_audio_state_t state, bt_bdaddr_t* b
     }
 
     sCallbackEnv->SetByteArrayRegion(addr, 0, sizeof(bt_bdaddr_t), (jbyte*) bd_addr);
-    sCallbackEnv->CallVoidMethod(mCallbacksObj, method_onAudioStateChanged, (jint) state,
-                                 addr);
+
+    pthread_mutex_lock(&mMutex);
+    if (mCallbacksObj != NULL) {
+        sCallbackEnv->CallVoidMethod(mCallbacksObj, method_onAudioStateChanged,
+                        (jint) state, addr);
+    } else {
+        ALOGE("Callbacks Obj is no more valid: '%s", __FUNCTION__);
+    }
+    pthread_mutex_unlock(&mMutex);
+
     checkAndClearExceptionFromCallback(sCallbackEnv, __FUNCTION__);
     sCallbackEnv->DeleteLocalRef(addr);
 }
@@ -113,10 +124,6 @@ static void bta2dp_connection_priority_callback(bt_bdaddr_t* bd_addr) {
 
     ALOGI("%s", __FUNCTION__);
 
-    if (mCallbacksObj == NULL) {
-        ALOGE("Callbacks Obj is no more valid: '%s", __FUNCTION__);
-        return;
-    }
     if (!checkCallbackThread()) {                                       \
         ALOGE("Callback: '%s' is not called on the correct thread", __FUNCTION__); \
         return;                                                         \
@@ -129,7 +136,16 @@ static void bta2dp_connection_priority_callback(bt_bdaddr_t* bd_addr) {
     }
 
     sCallbackEnv->SetByteArrayRegion(addr, 0, sizeof(bt_bdaddr_t), (jbyte*) bd_addr);
-    sCallbackEnv->CallVoidMethod(mCallbacksObj, method_onCheckConnectionPriority, addr);
+
+    pthread_mutex_lock(&mMutex);
+    if (mCallbacksObj != NULL) {
+        sCallbackEnv->CallVoidMethod(mCallbacksObj, method_onCheckConnectionPriority,
+                        addr);
+    } else {
+        ALOGE("Callbacks Obj is no more valid: '%s", __FUNCTION__);
+    }
+    pthread_mutex_unlock(&mMutex);
+
     checkAndClearExceptionFromCallback(sCallbackEnv, __FUNCTION__);
     sCallbackEnv->DeleteLocalRef(addr);
 }
@@ -138,16 +154,20 @@ static void bta2dp_multicast_enabled_callback(int state) {
 
     ALOGI("%s", __FUNCTION__);
 
-    if (mCallbacksObj == NULL) {
-        ALOGE("Callbacks Obj is no more valid: '%s", __FUNCTION__);
-        return;
-    }
     if (!checkCallbackThread()) {                                       \
         ALOGE("Callback: '%s' is not called on the correct thread", __FUNCTION__); \
         return;                                                         \
     }
 
-    sCallbackEnv->CallVoidMethod(mCallbacksObj, method_onMulticastStateChanged, state);
+    pthread_mutex_lock(&mMutex);
+    if (mCallbacksObj != NULL) {
+        sCallbackEnv->CallVoidMethod(mCallbacksObj, method_onMulticastStateChanged,
+                        state);
+    } else {
+        ALOGE("Callbacks Obj is no more valid: '%s", __FUNCTION__);
+    }
+    pthread_mutex_unlock(&mMutex);
+
     checkAndClearExceptionFromCallback(sCallbackEnv, __FUNCTION__);
 }
 
@@ -214,30 +234,33 @@ static void initNative(JNIEnv *env, jobject object, jint maxA2dpConnections,
          sBluetoothA2dpInterface = NULL;
     }
 
-    if (mCallbacksObj != NULL) {
-         ALOGW("Cleaning up A2DP callback object");
-         env->DeleteGlobalRef(mCallbacksObj);
-         mCallbacksObj = NULL;
-    }
-
     if ( (sBluetoothA2dpInterface = (btav_interface_t *)
           btInf->get_profile_interface(BT_PROFILE_ADVANCED_AUDIO_ID)) == NULL) {
         ALOGE("Failed to get Bluetooth A2DP Interface");
         return;
     }
 
+    pthread_mutex_lock(&mMutex);
+    if (mCallbacksObj != NULL) {
+         ALOGW("Cleaning up A2DP callback object");
+         env->DeleteGlobalRef(mCallbacksObj);
+         mCallbacksObj = NULL;
+    }
     mCallbacksObj = env->NewGlobalRef(object);
+    pthread_mutex_unlock(&mMutex);
 
     if ( (status = sBluetoothA2dpInterface->init(&sBluetoothA2dpCallbacks,
             maxA2dpConnections, multiCastState,
             offload_capabilities)) != BT_STATUS_SUCCESS) {
         ALOGE("Failed to initialize Bluetooth A2DP, status: %d", status);
         sBluetoothA2dpInterface = NULL;
+        pthread_mutex_lock(&mMutex);
         if (mCallbacksObj != NULL) {
              ALOGW("Clean up A2DP callback object");
              env->DeleteGlobalRef(mCallbacksObj);
              mCallbacksObj = NULL;
         }
+        pthread_mutex_unlock(&mMutex);
         return;
     }
 
@@ -256,10 +279,12 @@ static void cleanupNative(JNIEnv *env, jobject object) {
         sBluetoothA2dpInterface = NULL;
     }
 
+    pthread_mutex_lock(&mMutex);
     if (mCallbacksObj != NULL) {
         env->DeleteGlobalRef(mCallbacksObj);
         mCallbacksObj = NULL;
     }
+    pthread_mutex_unlock(&mMutex);
 }
 
 static jboolean connectA2dpNative(JNIEnv *env, jobject object, jbyteArray address) {