Merge "Avoid NPE when quickly toggling USB debugging state"

1 files changed, 123 insertions, 69 deletions

diff --git a/services/usb/java/com/android/server/usb/UsbDebuggingManager.java b/services/usb/java/com/android/server/usb/UsbDebuggingManager.java
index e489279..6fcd1eb 100644
--- a/services/usb/java/com/android/server/usb/UsbDebuggingManager.java
+++ b/services/usb/java/com/android/server/usb/UsbDebuggingManager.java
@@ -35,6 +35,7 @@ import android.os.SystemProperties;
 import android.os.UserHandle;
 import android.util.Slog;
 import android.util.Base64;
+
 import com.android.server.FgThread;
 
 import java.lang.Thread;
@@ -48,7 +49,7 @@ import java.io.PrintWriter;
 import java.security.MessageDigest;
 import java.util.Arrays;
 
-public class UsbDebuggingManager implements Runnable {
+public class UsbDebuggingManager {
     private static final String TAG = "UsbDebuggingManager";
     private static final boolean DEBUG = false;
 
@@ -59,86 +60,135 @@ public class UsbDebuggingManager implements Runnable {
 
     private final Context mContext;
     private final Handler mHandler;
-    private Thread mThread;
+    private UsbDebuggingThread mThread;
     private boolean mAdbEnabled = false;
     private String mFingerprints;
-    private LocalSocket mSocket = null;
-    private OutputStream mOutputStream = null;
 
     public UsbDebuggingManager(Context context) {
         mHandler = new UsbDebuggingHandler(FgThread.get().getLooper());
         mContext = context;
     }
 
-    private void listenToSocket() throws IOException {
-        try {
-            byte[] buffer = new byte[BUFFER_SIZE];
-            LocalSocketAddress address = new LocalSocketAddress(ADBD_SOCKET,
-                                         LocalSocketAddress.Namespace.RESERVED);
-            InputStream inputStream = null;
-
-            mSocket = new LocalSocket();
-            mSocket.connect(address);
+    class UsbDebuggingThread extends Thread {
+        private boolean mStopped;
+        private LocalSocket mSocket;
+        private OutputStream mOutputStream;
+        private InputStream mInputStream;
 
-            mOutputStream = mSocket.getOutputStream();
-            inputStream = mSocket.getInputStream();
+        UsbDebuggingThread() {
+            super(TAG);
+        }
 
+        @Override
+        public void run() {
+            if (DEBUG) Slog.d(TAG, "Entering thread");
             while (true) {
-                int count = inputStream.read(buffer);
-                if (count < 0) {
-                    break;
-                }
-
-                if (buffer[0] == 'P' && buffer[1] == 'K') {
-                    String key = new String(Arrays.copyOfRange(buffer, 2, count));
-                    Slog.d(TAG, "Received public key: " + key);
-                    Message msg = mHandler.obtainMessage(UsbDebuggingHandler.MESSAGE_ADB_CONFIRM);
-                    msg.obj = key;
-                    mHandler.sendMessage(msg);
+                synchronized (this) {
+                    if (mStopped) {
+                        if (DEBUG) Slog.d(TAG, "Exiting thread");
+                        return;
+                    }
+                    try {
+                        openSocketLocked();
+                    } catch (Exception e) {
+                        /* Don't loop too fast if adbd dies, before init restarts it */
+                        SystemClock.sleep(1000);
+                    }
                 }
-                else {
-                    Slog.e(TAG, "Wrong message: " + (new String(Arrays.copyOfRange(buffer, 0, 2))));
-                    break;
+                try {
+                    listenToSocket();
+                } catch (IOException e) {
+                    /* Don't loop too fast if adbd dies, before init restarts it */
+                    SystemClock.sleep(1000);
                 }
             }
-        } finally {
-            closeSocket();
         }
-    }
 
-    @Override
-    public void run() {
-        while (mAdbEnabled) {
+        private void openSocketLocked() throws IOException {
             try {
-                listenToSocket();
-            } catch (Exception e) {
-                /* Don't loop too fast if adbd dies, before init restarts it */
-                SystemClock.sleep(1000);
+                LocalSocketAddress address = new LocalSocketAddress(ADBD_SOCKET,
+                        LocalSocketAddress.Namespace.RESERVED);
+                mInputStream = null;
+
+                if (DEBUG) Slog.d(TAG, "Creating socket");
+                mSocket = new LocalSocket();
+                mSocket.connect(address);
+
+                mOutputStream = mSocket.getOutputStream();
+                mInputStream = mSocket.getInputStream();
+            } catch (IOException ioe) {
+                closeSocketLocked();
+                throw ioe;
             }
         }
-    }
 
-    private void closeSocket() {
-        try {
-            mOutputStream.close();
-        } catch (IOException e) {
-            Slog.e(TAG, "Failed closing output stream: " + e);
-        }
+        private void listenToSocket() throws IOException {
+            try {
+                byte[] buffer = new byte[BUFFER_SIZE];
+                while (true) {
+                    int count = mInputStream.read(buffer);
+                    if (count < 0) {
+                        break;
+                    }
 
-        try {
-            mSocket.close();
-        } catch (IOException ex) {
-            Slog.e(TAG, "Failed closing socket: " + ex);
+                    if (buffer[0] == 'P' && buffer[1] == 'K') {
+                        String key = new String(Arrays.copyOfRange(buffer, 2, count));
+                        Slog.d(TAG, "Received public key: " + key);
+                        Message msg = mHandler.obtainMessage(UsbDebuggingHandler.MESSAGE_ADB_CONFIRM);
+                        msg.obj = key;
+                        mHandler.sendMessage(msg);
+                    } else {
+                        Slog.e(TAG, "Wrong message: "
+                                + (new String(Arrays.copyOfRange(buffer, 0, 2))));
+                        break;
+                    }
+                }
+            } finally {
+                synchronized (this) {
+                    closeSocketLocked();
+                }
+            }
         }
-    }
 
-    private void sendResponse(String msg) {
-        if (mOutputStream != null) {
+        private void closeSocketLocked() {
+            if (DEBUG) Slog.d(TAG, "Closing socket");
+            try {
+                if (mOutputStream != null) {
+                    mOutputStream.close();
+                    mOutputStream = null;
+                }
+            } catch (IOException e) {
+                Slog.e(TAG, "Failed closing output stream: " + e);
+            }
+
             try {
-                mOutputStream.write(msg.getBytes());
+                if (mSocket != null) {
+                    mSocket.close();
+                    mSocket = null;
+                }
+            } catch (IOException ex) {
+                Slog.e(TAG, "Failed closing socket: " + ex);
             }
-            catch (IOException ex) {
-                Slog.e(TAG, "Failed to write response:", ex);
+        }
+
+        /** Call to stop listening on the socket and exit the thread. */
+        void stopListening() {
+            synchronized (this) {
+                mStopped = true;
+                closeSocketLocked();
+            }
+        }
+
+        void sendResponse(String msg) {
+            synchronized (this) {
+                if (!mStopped && mOutputStream != null) {
+                    try {
+                        mOutputStream.write(msg.getBytes());
+                    }
+                    catch (IOException ex) {
+                        Slog.e(TAG, "Failed to write response:", ex);
+                    }
+                }
             }
         }
     }
@@ -163,7 +213,7 @@ public class UsbDebuggingManager implements Runnable {
 
                     mAdbEnabled = true;
 
-                    mThread = new Thread(UsbDebuggingManager.this, TAG);
+                    mThread = new UsbDebuggingThread();
                     mThread.start();
 
                     break;
@@ -173,16 +223,12 @@ public class UsbDebuggingManager implements Runnable {
                         break;
 
                     mAdbEnabled = false;
-                    closeSocket();
 
-                    try {
-                        mThread.join();
-                    } catch (Exception ex) {
+                    if (mThread != null) {
+                        mThread.stopListening();
+                        mThread = null;
                     }
 
-                    mThread = null;
-                    mOutputStream = null;
-                    mSocket = null;
                     break;
 
                 case MESSAGE_ADB_ALLOW: {
@@ -199,25 +245,33 @@ public class UsbDebuggingManager implements Runnable {
                         writeKey(key);
                     }
 
-                    sendResponse("OK");
+                    if (mThread != null) {
+                        mThread.sendResponse("OK");
+                    }
                     break;
                 }
 
                 case MESSAGE_ADB_DENY:
-                    sendResponse("NO");
+                    if (mThread != null) {
+                        mThread.sendResponse("NO");
+                    }
                     break;
 
                 case MESSAGE_ADB_CONFIRM: {
                     if ("trigger_restart_min_framework".equals(
                             SystemProperties.get("vold.decrypt"))) {
                         Slog.d(TAG, "Deferring adb confirmation until after vold decrypt");
-                        sendResponse("NO");
+                        if (mThread != null) {
+                            mThread.sendResponse("NO");
+                        }
                         break;
                     }
                     String key = (String)msg.obj;
                     String fingerprints = getFingerprints(key);
                     if ("".equals(fingerprints)) {
-                        sendResponse("NO");
+                        if (mThread != null) {
+                            mThread.sendResponse("NO");
+                        }
                         break;
                     }
                     mFingerprints = fingerprints;
@@ -387,7 +441,7 @@ public class UsbDebuggingManager implements Runnable {
 
     public void dump(FileDescriptor fd, PrintWriter pw) {
         pw.println("  USB Debugging State:");
-        pw.println("    Connected to adbd: " + (mOutputStream != null));
+        pw.println("    Connected to adbd: " + (mThread != null));
         pw.println("    Last key received: " + mFingerprints);
         pw.println("    User keys:");
         try {