Bluetooth: Thread-safe binder invocation
* Binder object may become null between null check and actual invocation
if using a instance private variable assignable by service connection
callbacks
* The solution to this problem without locking is to assign existing
binder variable to a local final variable before the null check
* Any further invocation to a disconnected binder object will result in
RemoteException that is caught by the try-catch block
* Read and write to volatile variable is always atomic and hence thread-safe
* Removed unnecessary synchronization in BluetoothAdapter constructor
* Private mConnection objects should be final
* Simplfied several return statements where booleans can be returned
directly
* Removed unnecessary catches for NPE since there won't be any
Bug: 64724692
Test: make, pair and use devices, no functional change
Change-Id: Ifc9d6337c0d451a01484b61243230725d5314f8e
diff --git a/core/java/android/bluetooth/BluetoothMap.java b/core/java/android/bluetooth/BluetoothMap.java
index 26a9106..5b55b23 100644
--- a/core/java/android/bluetooth/BluetoothMap.java
+++ b/core/java/android/bluetooth/BluetoothMap.java
@@ -43,7 +43,7 @@
public static final String ACTION_CONNECTION_STATE_CHANGED =
"android.bluetooth.map.profile.action.CONNECTION_STATE_CHANGED";
- private IBluetoothMap mService;
+ private volatile IBluetoothMap mService;
private final Context mContext;
private ServiceListener mServiceListener;
private BluetoothAdapter mAdapter;
@@ -161,9 +161,10 @@
*/
public int getState() {
if (VDBG) log("getState()");
- if (mService != null) {
+ final IBluetoothMap service = mService;
+ if (service != null) {
try {
- return mService.getState();
+ return service.getState();
} catch (RemoteException e) {
Log.e(TAG, e.toString());
}
@@ -182,9 +183,10 @@
*/
public BluetoothDevice getClient() {
if (VDBG) log("getClient()");
- if (mService != null) {
+ final IBluetoothMap service = mService;
+ if (service != null) {
try {
- return mService.getClient();
+ return service.getClient();
} catch (RemoteException e) {
Log.e(TAG, e.toString());
}
@@ -202,9 +204,10 @@
*/
public boolean isConnected(BluetoothDevice device) {
if (VDBG) log("isConnected(" + device + ")");
- if (mService != null) {
+ final IBluetoothMap service = mService;
+ if (service != null) {
try {
- return mService.isConnected(device);
+ return service.isConnected(device);
} catch (RemoteException e) {
Log.e(TAG, e.toString());
}
@@ -232,15 +235,16 @@
*/
public boolean disconnect(BluetoothDevice device) {
if (DBG) log("disconnect(" + device + ")");
- if (mService != null && isEnabled() && isValidDevice(device)) {
+ final IBluetoothMap service = mService;
+ if (service != null && isEnabled() && isValidDevice(device)) {
try {
- return mService.disconnect(device);
+ return service.disconnect(device);
} catch (RemoteException e) {
Log.e(TAG, Log.getStackTraceString(new Throwable()));
return false;
}
}
- if (mService == null) Log.w(TAG, "Proxy not attached to service");
+ if (service == null) Log.w(TAG, "Proxy not attached to service");
return false;
}
@@ -272,15 +276,16 @@
*/
public List<BluetoothDevice> getConnectedDevices() {
if (DBG) log("getConnectedDevices()");
- if (mService != null && isEnabled()) {
+ final IBluetoothMap service = mService;
+ if (service != null && isEnabled()) {
try {
- return mService.getConnectedDevices();
+ return service.getConnectedDevices();
} catch (RemoteException e) {
Log.e(TAG, Log.getStackTraceString(new Throwable()));
return new ArrayList<BluetoothDevice>();
}
}
- if (mService == null) Log.w(TAG, "Proxy not attached to service");
+ if (service == null) Log.w(TAG, "Proxy not attached to service");
return new ArrayList<BluetoothDevice>();
}
@@ -291,15 +296,16 @@
*/
public List<BluetoothDevice> getDevicesMatchingConnectionStates(int[] states) {
if (DBG) log("getDevicesMatchingStates()");
- if (mService != null && isEnabled()) {
+ final IBluetoothMap service = mService;
+ if (service != null && isEnabled()) {
try {
- return mService.getDevicesMatchingConnectionStates(states);
+ return service.getDevicesMatchingConnectionStates(states);
} catch (RemoteException e) {
Log.e(TAG, Log.getStackTraceString(new Throwable()));
return new ArrayList<BluetoothDevice>();
}
}
- if (mService == null) Log.w(TAG, "Proxy not attached to service");
+ if (service == null) Log.w(TAG, "Proxy not attached to service");
return new ArrayList<BluetoothDevice>();
}
@@ -310,15 +316,16 @@
*/
public int getConnectionState(BluetoothDevice device) {
if (DBG) log("getConnectionState(" + device + ")");
- if (mService != null && isEnabled() && isValidDevice(device)) {
+ final IBluetoothMap service = mService;
+ if (service != null && isEnabled() && isValidDevice(device)) {
try {
- return mService.getConnectionState(device);
+ return service.getConnectionState(device);
} catch (RemoteException e) {
Log.e(TAG, Log.getStackTraceString(new Throwable()));
return BluetoothProfile.STATE_DISCONNECTED;
}
}
- if (mService == null) Log.w(TAG, "Proxy not attached to service");
+ if (service == null) Log.w(TAG, "Proxy not attached to service");
return BluetoothProfile.STATE_DISCONNECTED;
}
@@ -335,19 +342,20 @@
*/
public boolean setPriority(BluetoothDevice device, int priority) {
if (DBG) log("setPriority(" + device + ", " + priority + ")");
- if (mService != null && isEnabled() && isValidDevice(device)) {
+ final IBluetoothMap service = mService;
+ if (service != null && isEnabled() && isValidDevice(device)) {
if (priority != BluetoothProfile.PRIORITY_OFF
&& priority != BluetoothProfile.PRIORITY_ON) {
return false;
}
try {
- return mService.setPriority(device, priority);
+ return service.setPriority(device, priority);
} catch (RemoteException e) {
Log.e(TAG, Log.getStackTraceString(new Throwable()));
return false;
}
}
- if (mService == null) Log.w(TAG, "Proxy not attached to service");
+ if (service == null) Log.w(TAG, "Proxy not attached to service");
return false;
}
@@ -363,15 +371,16 @@
*/
public int getPriority(BluetoothDevice device) {
if (VDBG) log("getPriority(" + device + ")");
- if (mService != null && isEnabled() && isValidDevice(device)) {
+ final IBluetoothMap service = mService;
+ if (service != null && isEnabled() && isValidDevice(device)) {
try {
- return mService.getPriority(device);
+ return service.getPriority(device);
} catch (RemoteException e) {
Log.e(TAG, Log.getStackTraceString(new Throwable()));
return PRIORITY_OFF;
}
}
- if (mService == null) Log.w(TAG, "Proxy not attached to service");
+ if (service == null) Log.w(TAG, "Proxy not attached to service");
return PRIORITY_OFF;
}
@@ -403,13 +412,8 @@
log("Bluetooth is Not enabled");
return false;
}
-
- private boolean isValidDevice(BluetoothDevice device) {
- if (device == null) return false;
-
- if (BluetoothAdapter.checkBluetoothAddress(device.getAddress())) return true;
- return false;
+ private static boolean isValidDevice(BluetoothDevice device) {
+ return device != null && BluetoothAdapter.checkBluetoothAddress(device.getAddress());
}
-
}