From 1f686f645294d624f8b61e4761fd14787a496c75 Mon Sep 17 00:00:00 2001 From: Jack He Date: Thu, 17 Aug 2017 12:11:18 -0700 Subject: 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 --- .../bluetooth/BluetoothAvrcpController.java | 54 +++++++++++----------- 1 file changed, 27 insertions(+), 27 deletions(-) (limited to 'framework/java/android/bluetooth/BluetoothAvrcpController.java') diff --git a/framework/java/android/bluetooth/BluetoothAvrcpController.java b/framework/java/android/bluetooth/BluetoothAvrcpController.java index 7528aa9721..5f0e5d9744 100644 --- a/framework/java/android/bluetooth/BluetoothAvrcpController.java +++ b/framework/java/android/bluetooth/BluetoothAvrcpController.java @@ -81,7 +81,7 @@ public final class BluetoothAvrcpController implements BluetoothProfile { private Context mContext; private ServiceListener mServiceListener; - private IBluetoothAvrcpController mService; + private volatile IBluetoothAvrcpController mService; private BluetoothAdapter mAdapter; private final IBluetoothStateChangeCallback mBluetoothStateChangeCallback = @@ -179,15 +179,16 @@ public final class BluetoothAvrcpController implements BluetoothProfile { @Override public List getConnectedDevices() { if (VDBG) log("getConnectedDevices()"); - if (mService != null && isEnabled()) { + final IBluetoothAvrcpController service = mService; + if (service != null && isEnabled()) { try { - return mService.getConnectedDevices(); + return service.getConnectedDevices(); } catch (RemoteException e) { Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable())); return new ArrayList(); } } - 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(); } @@ -197,15 +198,16 @@ public final class BluetoothAvrcpController implements BluetoothProfile { @Override public List getDevicesMatchingConnectionStates(int[] states) { if (VDBG) log("getDevicesMatchingStates()"); - if (mService != null && isEnabled()) { + final IBluetoothAvrcpController service = mService; + if (service != null && isEnabled()) { try { - return mService.getDevicesMatchingConnectionStates(states); + return service.getDevicesMatchingConnectionStates(states); } catch (RemoteException e) { Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable())); return new ArrayList(); } } - 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(); } @@ -215,16 +217,16 @@ public final class BluetoothAvrcpController implements BluetoothProfile { @Override public int getConnectionState(BluetoothDevice device) { if (VDBG) log("getState(" + device + ")"); - if (mService != null && isEnabled() - && isValidDevice(device)) { + final IBluetoothAvrcpController service = mService; + if (service != null && isEnabled() && isValidDevice(device)) { try { - return mService.getConnectionState(device); + return service.getConnectionState(device); } catch (RemoteException e) { Log.e(TAG, "Stack:" + 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; } @@ -236,9 +238,10 @@ public final class BluetoothAvrcpController implements BluetoothProfile { public BluetoothAvrcpPlayerSettings getPlayerSettings(BluetoothDevice device) { if (DBG) Log.d(TAG, "getPlayerSettings"); BluetoothAvrcpPlayerSettings settings = null; - if (mService != null && isEnabled()) { + final IBluetoothAvrcpController service = mService; + if (service != null && isEnabled()) { try { - settings = mService.getPlayerSettings(device); + settings = service.getPlayerSettings(device); } catch (RemoteException e) { Log.e(TAG, "Error talking to BT service in getMetadata() " + e); return null; @@ -253,15 +256,16 @@ public final class BluetoothAvrcpController implements BluetoothProfile { */ public boolean setPlayerApplicationSetting(BluetoothAvrcpPlayerSettings plAppSetting) { if (DBG) Log.d(TAG, "setPlayerApplicationSetting"); - if (mService != null && isEnabled()) { + final IBluetoothAvrcpController service = mService; + if (service != null && isEnabled()) { try { - return mService.setPlayerApplicationSetting(plAppSetting); + return service.setPlayerApplicationSetting(plAppSetting); } catch (RemoteException e) { Log.e(TAG, "Error talking to BT service in setPlayerApplicationSetting() " + e); 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; } @@ -272,23 +276,23 @@ public final class BluetoothAvrcpController implements BluetoothProfile { public void sendGroupNavigationCmd(BluetoothDevice device, int keyCode, int keyState) { Log.d(TAG, "sendGroupNavigationCmd dev = " + device + " key " + keyCode + " State = " + keyState); - if (mService != null && isEnabled()) { + final IBluetoothAvrcpController service = mService; + if (service != null && isEnabled()) { try { - mService.sendGroupNavigationCmd(device, keyCode, keyState); + service.sendGroupNavigationCmd(device, keyCode, keyState); return; } catch (RemoteException e) { Log.e(TAG, "Error talking to BT service in sendGroupNavigationCmd()", e); return; } } - if (mService == null) Log.w(TAG, "Proxy not attached to service"); + if (service == null) Log.w(TAG, "Proxy not attached to service"); } private final ServiceConnection mConnection = new ServiceConnection() { public void onServiceConnected(ComponentName className, IBinder service) { if (DBG) Log.d(TAG, "Proxy object connected"); mService = IBluetoothAvrcpController.Stub.asInterface(Binder.allowBlocking(service)); - if (mServiceListener != null) { mServiceListener.onServiceConnected(BluetoothProfile.AVRCP_CONTROLLER, BluetoothAvrcpController.this); @@ -305,15 +309,11 @@ public final class BluetoothAvrcpController implements BluetoothProfile { }; private boolean isEnabled() { - if (mAdapter.getState() == BluetoothAdapter.STATE_ON) return true; - return false; + return mAdapter.getState() == BluetoothAdapter.STATE_ON; } - 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()); } private static void log(String msg) { -- cgit v1.2.3