| /** |
| * Copyright (c) 2016, 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.utils; |
| |
| import android.annotation.NonNull; |
| import android.annotation.Nullable; |
| import android.app.PendingIntent; |
| 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.IBinder.DeathRecipient; |
| import android.os.IInterface; |
| import android.os.RemoteException; |
| import android.os.SystemClock; |
| import android.os.UserHandle; |
| import android.util.Slog; |
| |
| import java.text.SimpleDateFormat; |
| import java.util.Objects; |
| import java.util.Date; |
| |
| /** |
| * Manages the lifecycle of an application-provided service bound from system server. |
| * |
| * @hide |
| */ |
| public class ManagedApplicationService { |
| private final String TAG = getClass().getSimpleName(); |
| |
| /** |
| * Attempt to reconnect service forever if an onBindingDied or onServiceDisconnected event |
| * is received. |
| */ |
| public static final int RETRY_FOREVER = 1; |
| |
| /** |
| * Never attempt to reconnect the service - a single onBindingDied or onServiceDisconnected |
| * event will cause this to fully unbind the service and never attempt to reconnect. |
| */ |
| public static final int RETRY_NEVER = 2; |
| |
| /** |
| * Attempt to reconnect the service until the maximum number of retries is reached, then stop. |
| * |
| * The first retry will occur MIN_RETRY_DURATION_MS after the disconnection, and each |
| * subsequent retry will occur after 2x the duration used for the previous retry up to the |
| * MAX_RETRY_DURATION_MS duration. |
| * |
| * In this case, retries mean a full unbindService/bindService pair to handle cases when the |
| * usual service re-connection logic in ActiveServices has very high backoff times or when the |
| * serviceconnection has fully died due to a package update or similar. |
| */ |
| public static final int RETRY_BEST_EFFORT = 3; |
| |
| // Maximum number of retries before giving up (for RETRY_BEST_EFFORT). |
| private static final int MAX_RETRY_COUNT = 4; |
| // Max time between retry attempts. |
| private static final long MAX_RETRY_DURATION_MS = 16000; |
| // Min time between retry attempts. |
| private static final long MIN_RETRY_DURATION_MS = 2000; |
| // Time since the last retry attempt after which to clear the retry attempt counter. |
| private static final long RETRY_RESET_TIME_MS = MAX_RETRY_DURATION_MS * 4; |
| |
| private final Context mContext; |
| private final int mUserId; |
| private final ComponentName mComponent; |
| private final int mClientLabel; |
| private final String mSettingsAction; |
| private final BinderChecker mChecker; |
| private final boolean mIsImportant; |
| private final int mRetryType; |
| private final Handler mHandler; |
| private final Runnable mRetryRunnable = this::doRetry; |
| private final EventCallback mEventCb; |
| |
| private final Object mLock = new Object(); |
| |
| // State protected by mLock |
| private ServiceConnection mConnection; |
| private IInterface mBoundInterface; |
| private PendingEvent mPendingEvent; |
| private int mRetryCount; |
| private long mLastRetryTimeMs; |
| private long mNextRetryDurationMs = MIN_RETRY_DURATION_MS; |
| private boolean mRetrying; |
| |
| public static interface LogFormattable { |
| String toLogString(SimpleDateFormat dateFormat); |
| } |
| |
| /** |
| * Lifecycle event of this managed service. |
| */ |
| public static class LogEvent implements LogFormattable { |
| public static final int EVENT_CONNECTED = 1; |
| public static final int EVENT_DISCONNECTED = 2; |
| public static final int EVENT_BINDING_DIED = 3; |
| public static final int EVENT_STOPPED_PERMANENTLY = 4; |
| |
| // Time of the events in "current time ms" timebase. |
| public final long timestamp; |
| // Name of the component for this system service. |
| public final ComponentName component; |
| // ID of the event that occurred. |
| public final int event; |
| |
| public LogEvent(long timestamp, ComponentName component, int event) { |
| this.timestamp = timestamp; |
| this.component = component; |
| this.event = event; |
| } |
| |
| @Override |
| public String toLogString(SimpleDateFormat dateFormat) { |
| return dateFormat.format(new Date(timestamp)) + " " + eventToString(event) |
| + " Managed Service: " |
| + ((component == null) ? "None" : component.flattenToString()); |
| } |
| |
| public static String eventToString(int event) { |
| switch (event) { |
| case EVENT_CONNECTED: |
| return "Connected"; |
| case EVENT_DISCONNECTED: |
| return "Disconnected"; |
| case EVENT_BINDING_DIED: |
| return "Binding Died For"; |
| case EVENT_STOPPED_PERMANENTLY: |
| return "Permanently Stopped"; |
| default: |
| return "Unknown Event Occurred"; |
| } |
| } |
| } |
| |
| private ManagedApplicationService(final Context context, final ComponentName component, |
| final int userId, int clientLabel, String settingsAction, |
| BinderChecker binderChecker, boolean isImportant, int retryType, Handler handler, |
| EventCallback eventCallback) { |
| mContext = context; |
| mComponent = component; |
| mUserId = userId; |
| mClientLabel = clientLabel; |
| mSettingsAction = settingsAction; |
| mChecker = binderChecker; |
| mIsImportant = isImportant; |
| mRetryType = retryType; |
| mHandler = handler; |
| mEventCb = eventCallback; |
| } |
| |
| /** |
| * Implement to validate returned IBinder instance. |
| */ |
| public interface BinderChecker { |
| IInterface asInterface(IBinder binder); |
| boolean checkType(IInterface service); |
| } |
| |
| /** |
| * Implement to call IInterface methods after service is connected. |
| */ |
| public interface PendingEvent { |
| void runEvent(IInterface service) throws RemoteException; |
| } |
| |
| /** |
| * Implement to be notified about any problems with remote service. |
| */ |
| public interface EventCallback { |
| /** |
| * Called when an sevice lifecycle event occurs. |
| */ |
| void onServiceEvent(LogEvent event); |
| } |
| |
| /** |
| * Create a new ManagedApplicationService object but do not yet bind to the user service. |
| * |
| * @param context a Context to use for binding the application service. |
| * @param component the {@link ComponentName} of the application service to bind. |
| * @param userId the user ID of user to bind the application service as. |
| * @param clientLabel the resource ID of a label displayed to the user indicating the |
| * binding service, or 0 if none is desired. |
| * @param settingsAction an action that can be used to open the Settings UI to enable/disable |
| * binding to these services, or null if none is desired. |
| * @param binderChecker an interface used to validate the returned binder object, or null if |
| * this interface is unchecked. |
| * @param isImportant bind the user service with BIND_IMPORTANT. |
| * @param retryType reconnect behavior to have when bound service is disconnected. |
| * @param handler the Handler to use for retries and delivering EventCallbacks. |
| * @param eventCallback a callback used to deliver disconnection events, or null if you |
| * don't care. |
| * @return a ManagedApplicationService instance. |
| */ |
| public static ManagedApplicationService build(@NonNull final Context context, |
| @NonNull final ComponentName component, final int userId, int clientLabel, |
| @Nullable String settingsAction, @Nullable BinderChecker binderChecker, |
| boolean isImportant, int retryType, @NonNull Handler handler, |
| @Nullable EventCallback eventCallback) { |
| return new ManagedApplicationService(context, component, userId, clientLabel, |
| settingsAction, binderChecker, isImportant, retryType, handler, eventCallback); |
| } |
| |
| |
| /** |
| * @return the user ID of the user that owns the bound service. |
| */ |
| public int getUserId() { |
| return mUserId; |
| } |
| |
| /** |
| * @return the component of the bound service. |
| */ |
| public ComponentName getComponent() { |
| return mComponent; |
| } |
| |
| /** |
| * Asynchronously unbind from the application service if the bound service component and user |
| * does not match the given signature. |
| * |
| * @param componentName the component that must match. |
| * @param userId the user ID that must match. |
| * @return {@code true} if not matching. |
| */ |
| public boolean disconnectIfNotMatching(final ComponentName componentName, final int userId) { |
| if (matches(componentName, userId)) { |
| return false; |
| } |
| disconnect(); |
| return true; |
| } |
| |
| /** |
| * Send an event to run as soon as the binder interface is available. |
| * |
| * @param event a {@link PendingEvent} to send. |
| */ |
| public void sendEvent(@NonNull PendingEvent event) { |
| IInterface iface; |
| synchronized (mLock) { |
| iface = mBoundInterface; |
| if (iface == null) { |
| mPendingEvent = event; |
| } |
| } |
| |
| if (iface != null) { |
| try { |
| event.runEvent(iface); |
| } catch (RuntimeException | RemoteException ex) { |
| Slog.e(TAG, "Received exception from user service: ", ex); |
| } |
| } |
| } |
| |
| /** |
| * Asynchronously unbind from the application service if bound. |
| */ |
| public void disconnect() { |
| synchronized (mLock) { |
| // Unbind existing connection, if it exists |
| if (mConnection == null) { |
| return; |
| } |
| |
| mContext.unbindService(mConnection); |
| mConnection = null; |
| mBoundInterface = null; |
| } |
| } |
| |
| /** |
| * Asynchronously bind to the application service if not bound. |
| */ |
| public void connect() { |
| synchronized (mLock) { |
| if (mConnection != null) { |
| // We're already connected or are trying to connect |
| return; |
| } |
| |
| Intent intent = new Intent().setComponent(mComponent); |
| if (mClientLabel != 0) { |
| intent.putExtra(Intent.EXTRA_CLIENT_LABEL, mClientLabel); |
| } |
| if (mSettingsAction != null) { |
| intent.putExtra(Intent.EXTRA_CLIENT_INTENT, |
| PendingIntent.getActivity(mContext, 0, new Intent(mSettingsAction), 0)); |
| } |
| |
| mConnection = new ServiceConnection() { |
| @Override |
| public void onBindingDied(ComponentName componentName) { |
| final long timestamp = System.currentTimeMillis(); |
| Slog.w(TAG, "Service binding died: " + componentName); |
| synchronized (mLock) { |
| if (mConnection != this) { |
| return; |
| } |
| mHandler.post(() -> { |
| mEventCb.onServiceEvent(new LogEvent(timestamp, mComponent, |
| LogEvent.EVENT_BINDING_DIED)); |
| }); |
| |
| mBoundInterface = null; |
| startRetriesLocked(); |
| } |
| } |
| |
| @Override |
| public void onServiceConnected(ComponentName componentName, IBinder iBinder) { |
| final long timestamp = System.currentTimeMillis(); |
| Slog.i(TAG, "Service connected: " + componentName); |
| IInterface iface = null; |
| PendingEvent pendingEvent = null; |
| synchronized (mLock) { |
| if (mConnection != this) { |
| // Must've been unbound. |
| return; |
| } |
| mHandler.post(() -> { |
| mEventCb.onServiceEvent(new LogEvent(timestamp, mComponent, |
| LogEvent.EVENT_CONNECTED)); |
| }); |
| |
| stopRetriesLocked(); |
| |
| mBoundInterface = null; |
| if (mChecker != null) { |
| mBoundInterface = mChecker.asInterface(iBinder); |
| if (!mChecker.checkType(mBoundInterface)) { |
| // Received an invalid binder, disconnect. |
| mBoundInterface = null; |
| Slog.w(TAG, "Invalid binder from " + componentName); |
| startRetriesLocked(); |
| return; |
| } |
| iface = mBoundInterface; |
| pendingEvent = mPendingEvent; |
| mPendingEvent = null; |
| } |
| } |
| if (iface != null && pendingEvent != null) { |
| try { |
| pendingEvent.runEvent(iface); |
| } catch (RuntimeException | RemoteException ex) { |
| Slog.e(TAG, "Received exception from user service: ", ex); |
| startRetriesLocked(); |
| } |
| } |
| } |
| |
| @Override |
| public void onServiceDisconnected(ComponentName componentName) { |
| final long timestamp = System.currentTimeMillis(); |
| Slog.w(TAG, "Service disconnected: " + componentName); |
| synchronized (mLock) { |
| if (mConnection != this) { |
| return; |
| } |
| |
| mHandler.post(() -> { |
| mEventCb.onServiceEvent(new LogEvent(timestamp, mComponent, |
| LogEvent.EVENT_DISCONNECTED)); |
| }); |
| |
| mBoundInterface = null; |
| startRetriesLocked(); |
| } |
| } |
| }; |
| |
| int flags = Context.BIND_AUTO_CREATE | Context.BIND_FOREGROUND_SERVICE; |
| if (mIsImportant) { |
| flags |= Context.BIND_IMPORTANT; |
| } |
| try { |
| if (!mContext.bindServiceAsUser(intent, mConnection, flags, |
| new UserHandle(mUserId))) { |
| Slog.w(TAG, "Unable to bind service: " + intent); |
| startRetriesLocked(); |
| } |
| } catch (SecurityException e) { |
| Slog.w(TAG, "Unable to bind service: " + intent, e); |
| startRetriesLocked(); |
| } |
| } |
| } |
| |
| private boolean matches(final ComponentName component, final int userId) { |
| return Objects.equals(mComponent, component) && mUserId == userId; |
| } |
| |
| private void startRetriesLocked() { |
| if (checkAndDeliverServiceDiedCbLocked()) { |
| // If we delivered the service callback, disconnect and stop retrying. |
| disconnect(); |
| return; |
| } |
| |
| if (mRetrying) { |
| // Retry already queued, don't queue a new one. |
| return; |
| } |
| mRetrying = true; |
| queueRetryLocked(); |
| } |
| |
| private void stopRetriesLocked() { |
| mRetrying = false; |
| mHandler.removeCallbacks(mRetryRunnable); |
| } |
| |
| private void queueRetryLocked() { |
| long now = SystemClock.uptimeMillis(); |
| if ((now - mLastRetryTimeMs) > RETRY_RESET_TIME_MS) { |
| // It's been longer than the reset time since we last had to retry. Re-initialize. |
| mNextRetryDurationMs = MIN_RETRY_DURATION_MS; |
| mRetryCount = 0; |
| } |
| mLastRetryTimeMs = now; |
| mHandler.postDelayed(mRetryRunnable, mNextRetryDurationMs); |
| mNextRetryDurationMs = Math.min(2 * mNextRetryDurationMs, MAX_RETRY_DURATION_MS); |
| mRetryCount++; |
| } |
| |
| private boolean checkAndDeliverServiceDiedCbLocked() { |
| |
| if (mRetryType == RETRY_NEVER || (mRetryType == RETRY_BEST_EFFORT |
| && mRetryCount >= MAX_RETRY_COUNT)) { |
| // If we never retry, or we've exhausted our retries, post the onServiceDied callback. |
| Slog.e(TAG, "Service " + mComponent + " has died too much, not retrying."); |
| if (mEventCb != null) { |
| final long timestamp = System.currentTimeMillis(); |
| mHandler.post(() -> { |
| mEventCb.onServiceEvent(new LogEvent(timestamp, mComponent, |
| LogEvent.EVENT_STOPPED_PERMANENTLY)); |
| }); |
| } |
| return true; |
| } |
| return false; |
| } |
| |
| private void doRetry() { |
| synchronized (mLock) { |
| if (mConnection == null) { |
| // We disconnected for good. Don't attempt to retry. |
| return; |
| } |
| if (!mRetrying) { |
| // We successfully connected. Don't attempt to retry. |
| return; |
| } |
| Slog.i(TAG, "Attempting to reconnect " + mComponent + "..."); |
| // While frameworks may restart the remote Service if we stay bound, we have little |
| // control of the backoff timing for reconnecting the service. In the event of a |
| // process crash, the backoff time can be very large (1-30 min), which is not |
| // acceptable for the types of services this is used for. Instead force an unbind/bind |
| // sequence to cause a more immediate retry. |
| disconnect(); |
| if (checkAndDeliverServiceDiedCbLocked()) { |
| // No more retries. |
| return; |
| } |
| queueRetryLocked(); |
| connect(); |
| } |
| } |
| } |