| /* |
| * Copyright (C) 2017 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package com.android.server.am; |
| |
| import android.annotation.NonNull; |
| import android.content.ComponentName; |
| import android.content.Context; |
| import android.content.Intent; |
| import android.content.ServiceConnection; |
| import android.os.Handler; |
| import android.os.IBinder; |
| import android.os.SystemClock; |
| import android.os.UserHandle; |
| import android.util.Slog; |
| import android.util.TimeUtils; |
| |
| import com.android.internal.annotations.GuardedBy; |
| import com.android.internal.annotations.VisibleForTesting; |
| |
| import java.io.PrintWriter; |
| |
| /** |
| * Connects to a given service component on a given user. |
| * |
| * - Call {@link #bind()} to create a connection. |
| * - Call {@link #unbind()} to disconnect. Make sure to disconnect when the user stops. |
| * |
| * Add onConnected/onDisconnected callbacks as needed. |
| * |
| * When the target process gets killed (by OOM-killer, etc), then the activity manager will |
| * re-connect the connection automatically, in which case onServiceDisconnected() gets called |
| * and then onServiceConnected(). |
| * |
| * However sometimes the activity manager just "kills" the connection -- like when the target |
| * package gets updated or the target process crashes multiple times in a row, in which case |
| * onBindingDied() gets called. This class handles this case by re-connecting in the time |
| * {@link #mRebindBackoffMs}. If this happens again, this class increases the back-off time |
| * by {@link #mRebindBackoffIncrease} and retry. The back-off time is capped at |
| * {@link #mRebindMaxBackoffMs}. |
| * |
| * The back-off time will never be reset until {@link #unbind()} and {@link #bind()} are called |
| * explicitly. |
| * |
| * NOTE: This class does *not* handle package-updates -- i.e. even if the binding dies due to |
| * the target package being updated, this class won't reconnect. This is because this class doesn't |
| * know what to do when the service component has gone missing, for example. If the user of this |
| * class wants to restore the connection, then it should call {@link #unbind()} and {@link #bind} |
| * explicitly. |
| */ |
| public abstract class PersistentConnection<T> { |
| private final Object mLock = new Object(); |
| |
| private final static boolean DEBUG = false; |
| |
| private final String mTag; |
| private final Context mContext; |
| private final Handler mHandler; |
| private final int mUserId; |
| private final ComponentName mComponentName; |
| |
| private long mNextBackoffMs; |
| |
| private final long mRebindBackoffMs; |
| private final double mRebindBackoffIncrease; |
| private final long mRebindMaxBackoffMs; |
| |
| private long mReconnectTime; |
| |
| // TODO too many booleans... Should clean up. |
| |
| @GuardedBy("mLock") |
| private boolean mBound; |
| |
| /** |
| * Whether {@link #bind()} has been called and {@link #unbind()} hasn't been yet; meaning this |
| * is the expected bind state from the caller's point of view. |
| */ |
| @GuardedBy("mLock") |
| private boolean mShouldBeBound; |
| |
| @GuardedBy("mLock") |
| private boolean mRebindScheduled; |
| |
| @GuardedBy("mLock") |
| private boolean mIsConnected; |
| |
| @GuardedBy("mLock") |
| private T mService; |
| |
| private final ServiceConnection mServiceConnection = new ServiceConnection() { |
| @Override |
| public void onServiceConnected(ComponentName name, IBinder service) { |
| synchronized (mLock) { |
| if (!mBound) { |
| // Callback came in after PersistentConnection.unbind() was called. |
| // We just ignore this. |
| // (We've already called unbindService() already in unbind) |
| Slog.w(mTag, "Connected: " + mComponentName.flattenToShortString() |
| + " u" + mUserId + " but not bound, ignore."); |
| return; |
| } |
| Slog.i(mTag, "Connected: " + mComponentName.flattenToShortString() |
| + " u" + mUserId); |
| |
| mIsConnected = true; |
| mService = asInterface(service); |
| } |
| } |
| |
| @Override |
| public void onServiceDisconnected(ComponentName name) { |
| synchronized (mLock) { |
| Slog.i(mTag, "Disconnected: " + mComponentName.flattenToShortString() |
| + " u" + mUserId); |
| |
| cleanUpConnectionLocked(); |
| } |
| } |
| |
| @Override |
| public void onBindingDied(ComponentName name) { |
| // Activity manager gave up; we'll schedule a re-connect by ourselves. |
| synchronized (mLock) { |
| if (!mBound) { |
| // Callback came in late? |
| Slog.w(mTag, "Binding died: " + mComponentName.flattenToShortString() |
| + " u" + mUserId + " but not bound, ignore."); |
| return; |
| } |
| |
| Slog.w(mTag, "Binding died: " + mComponentName.flattenToShortString() |
| + " u" + mUserId); |
| scheduleRebindLocked(); |
| } |
| } |
| }; |
| |
| private final Runnable mBindForBackoffRunnable = () -> bindForBackoff(); |
| |
| public PersistentConnection(@NonNull String tag, @NonNull Context context, |
| @NonNull Handler handler, int userId, @NonNull ComponentName componentName, |
| long rebindBackoffSeconds, double rebindBackoffIncrease, long rebindMaxBackoffSeconds) { |
| mTag = tag; |
| mContext = context; |
| mHandler = handler; |
| mUserId = userId; |
| mComponentName = componentName; |
| |
| mRebindBackoffMs = rebindBackoffSeconds * 1000; |
| mRebindBackoffIncrease = rebindBackoffIncrease; |
| mRebindMaxBackoffMs = rebindMaxBackoffSeconds * 1000; |
| |
| mNextBackoffMs = mRebindBackoffMs; |
| } |
| |
| public final ComponentName getComponentName() { |
| return mComponentName; |
| } |
| |
| /** |
| * @return whether {@link #bind()} has been called and {@link #unbind()} hasn't. |
| * |
| * Note when the AM gives up on connection, this class detects it and un-bind automatically, |
| * and schedule rebind, and {@link #isBound} returns false when it's waiting for a retry. |
| */ |
| public final boolean isBound() { |
| synchronized (mLock) { |
| return mBound; |
| } |
| } |
| |
| /** |
| * @return whether re-bind is scheduled after the AM gives up on a connection. |
| */ |
| public final boolean isRebindScheduled() { |
| synchronized (mLock) { |
| return mRebindScheduled; |
| } |
| } |
| |
| /** |
| * @return whether connected. |
| */ |
| public final boolean isConnected() { |
| synchronized (mLock) { |
| return mIsConnected; |
| } |
| } |
| |
| /** |
| * @return the service binder interface. |
| */ |
| public final T getServiceBinder() { |
| synchronized (mLock) { |
| return mService; |
| } |
| } |
| |
| /** |
| * Connects to the service. |
| */ |
| public final void bind() { |
| synchronized (mLock) { |
| mShouldBeBound = true; |
| |
| bindInnerLocked(/* resetBackoff= */ true); |
| } |
| } |
| |
| @GuardedBy("mLock") |
| public final void bindInnerLocked(boolean resetBackoff) { |
| unscheduleRebindLocked(); |
| |
| if (mBound) { |
| return; |
| } |
| mBound = true; |
| |
| if (resetBackoff) { |
| // Note this is the only place we reset the backoff time. |
| mNextBackoffMs = mRebindBackoffMs; |
| } |
| |
| final Intent service = new Intent().setComponent(mComponentName); |
| |
| if (DEBUG) { |
| Slog.d(mTag, "Attempting to connect to " + mComponentName); |
| } |
| |
| final boolean success = mContext.bindServiceAsUser(service, mServiceConnection, |
| Context.BIND_AUTO_CREATE | Context.BIND_FOREGROUND_SERVICE, |
| mHandler, UserHandle.of(mUserId)); |
| |
| if (!success) { |
| Slog.e(mTag, "Binding: " + service.getComponent() + " u" + mUserId |
| + " failed."); |
| } |
| } |
| |
| final void bindForBackoff() { |
| synchronized (mLock) { |
| if (!mShouldBeBound) { |
| // Race condition -- by the time we got here, unbind() has already been called. |
| return; |
| } |
| |
| bindInnerLocked(/* resetBackoff= */ false); |
| } |
| } |
| |
| @GuardedBy("mLock") |
| private void cleanUpConnectionLocked() { |
| mIsConnected = false; |
| mService = null; |
| } |
| |
| /** |
| * Disconnect from the service. |
| */ |
| public final void unbind() { |
| synchronized (mLock) { |
| mShouldBeBound = false; |
| |
| unbindLocked(); |
| } |
| } |
| |
| @GuardedBy("mLock") |
| private final void unbindLocked() { |
| unscheduleRebindLocked(); |
| |
| if (!mBound) { |
| return; |
| } |
| Slog.i(mTag, "Stopping: " + mComponentName.flattenToShortString() + " u" + mUserId); |
| mBound = false; |
| mContext.unbindService(mServiceConnection); |
| |
| cleanUpConnectionLocked(); |
| } |
| |
| @GuardedBy("mLock") |
| void unscheduleRebindLocked() { |
| injectRemoveCallbacks(mBindForBackoffRunnable); |
| mRebindScheduled = false; |
| } |
| |
| @GuardedBy("mLock") |
| void scheduleRebindLocked() { |
| unbindLocked(); |
| |
| if (!mRebindScheduled) { |
| Slog.i(mTag, "Scheduling to reconnect in " + mNextBackoffMs + " ms (uptime)"); |
| |
| mReconnectTime = injectUptimeMillis() + mNextBackoffMs; |
| |
| injectPostAtTime(mBindForBackoffRunnable, mReconnectTime); |
| |
| mNextBackoffMs = Math.min(mRebindMaxBackoffMs, |
| (long) (mNextBackoffMs * mRebindBackoffIncrease)); |
| |
| mRebindScheduled = true; |
| } |
| } |
| |
| /** Must be implemented by a subclass to convert an {@link IBinder} to a stub. */ |
| protected abstract T asInterface(IBinder binder); |
| |
| public void dump(String prefix, PrintWriter pw) { |
| synchronized (mLock) { |
| pw.print(prefix); |
| pw.print(mComponentName.flattenToShortString()); |
| pw.print(mBound ? " [bound]" : " [not bound]"); |
| pw.print(mIsConnected ? " [connected]" : " [not connected]"); |
| if (mRebindScheduled) { |
| pw.print(" reconnect in "); |
| TimeUtils.formatDuration((mReconnectTime - injectUptimeMillis()), pw); |
| } |
| pw.println(); |
| |
| pw.print(prefix); |
| pw.print(" Next backoff(sec): "); |
| pw.print(mNextBackoffMs / 1000); |
| } |
| } |
| |
| @VisibleForTesting |
| void injectRemoveCallbacks(Runnable r) { |
| mHandler.removeCallbacks(r); |
| } |
| |
| @VisibleForTesting |
| void injectPostAtTime(Runnable r, long uptimeMillis) { |
| mHandler.postAtTime(r, uptimeMillis); |
| } |
| |
| @VisibleForTesting |
| long injectUptimeMillis() { |
| return SystemClock.uptimeMillis(); |
| } |
| |
| @VisibleForTesting |
| long getNextBackoffMsForTest() { |
| return mNextBackoffMs; |
| } |
| |
| @VisibleForTesting |
| long getReconnectTimeForTest() { |
| return mReconnectTime; |
| } |
| |
| @VisibleForTesting |
| ServiceConnection getServiceConnectionForTest() { |
| return mServiceConnection; |
| } |
| |
| @VisibleForTesting |
| Runnable getBindForBackoffRunnableForTest() { |
| return mBindForBackoffRunnable; |
| } |
| |
| @VisibleForTesting |
| boolean shouldBeBoundForTest() { |
| return mShouldBeBound; |
| } |
| } |