Java tutorial
/** * Copyright (C) 2011 Whisper Systems * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ package com.securecomcode.text.service; import android.annotation.TargetApi; import android.app.AlarmManager; import android.app.Notification; import android.app.PendingIntent; import android.app.Service; import android.content.Context; import android.content.Intent; import android.os.AsyncTask; import android.os.Binder; import android.os.Build; import android.os.IBinder; import android.os.SystemClock; import android.support.v4.app.NotificationCompat; import android.util.Log; import android.widget.RemoteViews; import com.securecomcode.text.DatabaseUpgradeActivity; import com.securecomcode.text.DummyActivity; import com.securecomcode.text.R; import com.securecomcode.text.RoutingActivity; import com.securecomcode.text.crypto.DecryptingQueue; import com.securecomcode.text.crypto.InvalidPassphraseException; import org.whispersystems.textsecure.crypto.MasterSecret; import com.securecomcode.text.crypto.MasterSecretUtil; import com.securecomcode.text.notifications.MessageNotifier; import com.securecomcode.text.util.TextSecurePreferences; /** * Small service that stays running to keep a key cached in memory. * * @author Moxie Marlinspike */ public class KeyCachingService extends Service { public static final int SERVICE_RUNNING_ID = 4141; public static final String KEY_PERMISSION = "com.securecomcode.text.ACCESS_SECRETS"; public static final String NEW_KEY_EVENT = "com.securecomcode.text.service.action.NEW_KEY_EVENT"; public static final String CLEAR_KEY_EVENT = "com.securecomcode.text.service.action.CLEAR_KEY_EVENT"; private static final String PASSPHRASE_EXPIRED_EVENT = "com.securecomcode.text.service.action.PASSPHRASE_EXPIRED_EVENT"; public static final String CLEAR_KEY_ACTION = "com.securecomcode.text.service.action.CLEAR_KEY"; public static final String DISABLE_ACTION = "com.securecomcode.text.service.action.DISABLE"; public static final String ACTIVITY_START_EVENT = "com.securecomcode.text.service.action.ACTIVITY_START_EVENT"; public static final String ACTIVITY_STOP_EVENT = "com.securecomcode.text.service.action.ACTIVITY_STOP_EVENT"; private PendingIntent pending; private int activitiesRunning = 0; private final IBinder binder = new KeyCachingBinder(); private MasterSecret masterSecret; public KeyCachingService() { } public synchronized MasterSecret getMasterSecret() { return masterSecret; } public synchronized void setMasterSecret(final MasterSecret masterSecret) { this.masterSecret = masterSecret; foregroundService(); broadcastNewSecret(); startTimeoutIfAppropriate(); new AsyncTask<Void, Void, Void>() { @Override protected Void doInBackground(Void... params) { if (!DatabaseUpgradeActivity.isUpdate(KeyCachingService.this)) { DecryptingQueue.schedulePendingDecrypts(KeyCachingService.this, masterSecret); MessageNotifier.updateNotification(KeyCachingService.this, masterSecret); } return null; } }.execute(); } @Override public int onStartCommand(Intent intent, int flags, int startId) { if (intent == null) return START_NOT_STICKY; if (intent.getAction() != null && intent.getAction().equals(CLEAR_KEY_ACTION)) handleClearKey(); else if (intent.getAction() != null && intent.getAction().equals(ACTIVITY_START_EVENT)) handleActivityStarted(); else if (intent.getAction() != null && intent.getAction().equals(ACTIVITY_STOP_EVENT)) handleActivityStopped(); else if (intent.getAction() != null && intent.getAction().equals(PASSPHRASE_EXPIRED_EVENT)) handleClearKey(); else if (intent.getAction() != null && intent.getAction().equals(DISABLE_ACTION)) handleDisableService(); return START_NOT_STICKY; } @Override public void onCreate() { super.onCreate(); this.pending = PendingIntent.getService(this, 0, new Intent(PASSPHRASE_EXPIRED_EVENT, null, this, KeyCachingService.class), 0); if (TextSecurePreferences.isPasswordDisabled(this)) { try { MasterSecret masterSecret = MasterSecretUtil.getMasterSecret(this, MasterSecretUtil.UNENCRYPTED_PASSPHRASE); setMasterSecret(masterSecret); } catch (InvalidPassphraseException e) { Log.w("KeyCachingService", e); } } } @Override public void onDestroy() { super.onDestroy(); Log.w("KeyCachingService", "KCS Is Being Destroyed!"); handleClearKey(); } /** * Workaround for Android bug: * https://code.google.com/p/android/issues/detail?id=53313 */ @Override public void onTaskRemoved(Intent rootIntent) { Intent intent = new Intent(this, DummyActivity.class); intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK); startActivity(intent); } private void handleActivityStarted() { Log.w("KeyCachingService", "Incrementing activity count..."); AlarmManager alarmManager = (AlarmManager) this.getSystemService(ALARM_SERVICE); alarmManager.cancel(pending); activitiesRunning++; } private void handleActivityStopped() { Log.w("KeyCachingService", "Decrementing activity count..."); activitiesRunning--; startTimeoutIfAppropriate(); } private void handleClearKey() { this.masterSecret = null; stopForeground(true); Intent intent = new Intent(CLEAR_KEY_EVENT); intent.setPackage(getApplicationContext().getPackageName()); sendBroadcast(intent, KEY_PERMISSION); new AsyncTask<Void, Void, Void>() { @Override protected Void doInBackground(Void... params) { MessageNotifier.updateNotification(KeyCachingService.this, null); return null; } }.execute(); } private void handleDisableService() { if (TextSecurePreferences.isPasswordDisabled(this)) stopForeground(true); } private void startTimeoutIfAppropriate() { boolean timeoutEnabled = TextSecurePreferences.isPassphraseTimeoutEnabled(this); if ((activitiesRunning == 0) && (this.masterSecret != null) && timeoutEnabled && !TextSecurePreferences.isPasswordDisabled(this)) { long timeoutMinutes = TextSecurePreferences.getPassphraseTimeoutInterval(this); long timeoutMillis = timeoutMinutes * 60 * 1000; Log.w("KeyCachingService", "Starting timeout: " + timeoutMillis); AlarmManager alarmManager = (AlarmManager) this.getSystemService(ALARM_SERVICE); alarmManager.cancel(pending); alarmManager.set(AlarmManager.ELAPSED_REALTIME, SystemClock.elapsedRealtime() + timeoutMillis, pending); } } @TargetApi(Build.VERSION_CODES.JELLY_BEAN) private void foregroundServiceModern() { NotificationCompat.Builder builder = new NotificationCompat.Builder(this); builder.setContentTitle(getString(R.string.KeyCachingService_passphrase_cached)); builder.setContentText(getString(R.string.KeyCachingService_textsecure_passphrase_cached)); builder.setSmallIcon(R.drawable.icon_cached); builder.setWhen(0); builder.setPriority(Notification.PRIORITY_MIN); builder.addAction(R.drawable.ic_menu_lock_holo_dark, getString(R.string.KeyCachingService_lock), buildLockIntent()); builder.setContentIntent(buildLaunchIntent()); stopForeground(true); startForeground(SERVICE_RUNNING_ID, builder.build()); } private void foregroundServiceICS() { NotificationCompat.Builder builder = new NotificationCompat.Builder(this); RemoteViews remoteViews = new RemoteViews(getPackageName(), R.layout.key_caching_notification); remoteViews.setOnClickPendingIntent(R.id.lock_cache_icon, buildLockIntent()); builder.setSmallIcon(R.drawable.icon_cached); builder.setContent(remoteViews); builder.setContentIntent(buildLaunchIntent()); stopForeground(true); startForeground(SERVICE_RUNNING_ID, builder.build()); } private void foregroundServiceLegacy() { Notification notification = new Notification(R.drawable.icon_cached, getString(R.string.KeyCachingService_textsecure_passphrase_cached), System.currentTimeMillis()); notification.setLatestEventInfo(getApplicationContext(), getString(R.string.KeyCachingService_passphrase_cached), getString(R.string.KeyCachingService_textsecure_passphrase_cached), buildLaunchIntent()); notification.tickerText = null; stopForeground(true); startForeground(SERVICE_RUNNING_ID, notification); } private void foregroundService() { if (TextSecurePreferences.isPasswordDisabled(this)) { stopForeground(true); return; } if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) { foregroundServiceModern(); } else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.ICE_CREAM_SANDWICH) { foregroundServiceICS(); } else { foregroundServiceLegacy(); } } private void broadcastNewSecret() { Log.w("service", "Broadcasting new secret..."); Intent intent = new Intent(NEW_KEY_EVENT); intent.putExtra("master_secret", masterSecret); intent.setPackage(getApplicationContext().getPackageName()); sendBroadcast(intent, KEY_PERMISSION); } private PendingIntent buildLockIntent() { Intent intent = new Intent(this, KeyCachingService.class); intent.setAction(PASSPHRASE_EXPIRED_EVENT); PendingIntent pendingIntent = PendingIntent.getService(getApplicationContext(), 0, intent, 0); return pendingIntent; } private PendingIntent buildLaunchIntent() { Intent intent = new Intent(this, RoutingActivity.class); intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP); PendingIntent launchIntent = PendingIntent.getActivity(getApplicationContext(), 0, intent, 0); return launchIntent; } @Override public IBinder onBind(Intent arg0) { return binder; } public class KeyCachingBinder extends Binder { public KeyCachingService getService() { return KeyCachingService.this; } } public static void registerPassphraseActivityStarted(Context activity) { Intent intent = new Intent(activity, KeyCachingService.class); intent.setAction(KeyCachingService.ACTIVITY_START_EVENT); activity.startService(intent); } public static void registerPassphraseActivityStopped(Context activity) { Intent intent = new Intent(activity, KeyCachingService.class); intent.setAction(KeyCachingService.ACTIVITY_STOP_EVENT); activity.startService(intent); } }