| /* |
| * Copyright (C) 2010 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; |
| |
| import android.app.AlarmManager; |
| import android.app.PendingIntent; |
| import android.content.BroadcastReceiver; |
| import android.content.ContentResolver; |
| import android.content.Context; |
| import android.content.Intent; |
| import android.content.IntentFilter; |
| import android.database.ContentObserver; |
| import android.net.ConnectivityManager; |
| import android.net.ConnectivityManager.NetworkCallback; |
| import android.net.Network; |
| import android.os.Binder; |
| import android.os.Handler; |
| import android.os.HandlerThread; |
| import android.os.Looper; |
| import android.os.Message; |
| import android.os.PowerManager; |
| import android.os.SystemClock; |
| import android.provider.Settings; |
| import android.telephony.TelephonyManager; |
| import android.util.Log; |
| import android.util.NtpTrustedTime; |
| import android.util.TimeUtils; |
| |
| import com.android.internal.util.DumpUtils; |
| |
| import java.io.FileDescriptor; |
| import java.io.PrintWriter; |
| |
| /** |
| * Monitors the network time and updates the system time if it is out of sync |
| * and there hasn't been any NITZ update from the carrier recently. |
| * If looking up the network time fails for some reason, it tries a few times with a short |
| * interval and then resets to checking on longer intervals. |
| * <p> |
| * If the user enables AUTO_TIME, it will check immediately for the network time, if NITZ wasn't |
| * available. |
| * </p> |
| */ |
| public class NetworkTimeUpdateServiceImpl extends Binder implements NetworkTimeUpdateService { |
| |
| private static final String TAG = "NetworkTimeUpdateService"; |
| private static final boolean DBG = false; |
| |
| private static final int EVENT_AUTO_TIME_CHANGED = 1; |
| private static final int EVENT_POLL_NETWORK_TIME = 2; |
| private static final int EVENT_NETWORK_CHANGED = 3; |
| |
| private static final String ACTION_POLL = |
| "com.android.server.NetworkTimeUpdateService.action.POLL"; |
| |
| private static final int POLL_REQUEST = 0; |
| |
| private static final long NOT_SET = -1; |
| private long mNitzTimeSetTime = NOT_SET; |
| private Network mDefaultNetwork = null; |
| |
| private final Context mContext; |
| private final NtpTrustedTime mTime; |
| private final AlarmManager mAlarmManager; |
| private final ConnectivityManager mCM; |
| private final PendingIntent mPendingPollIntent; |
| private final PowerManager.WakeLock mWakeLock; |
| |
| // NTP lookup is done on this thread and handler |
| private Handler mHandler; |
| private SettingsObserver mSettingsObserver; |
| private NetworkTimeUpdateCallback mNetworkTimeUpdateCallback; |
| |
| // Normal polling frequency |
| private final long mPollingIntervalMs; |
| // Try-again polling interval, in case the network request failed |
| private final long mPollingIntervalShorterMs; |
| // Number of times to try again |
| private final int mTryAgainTimesMax; |
| // If the time difference is greater than this threshold, then update the time. |
| private final int mTimeErrorThresholdMs; |
| // Keeps track of how many quick attempts were made to fetch NTP time. |
| // During bootup, the network may not have been up yet, or it's taking time for the |
| // connection to happen. |
| private int mTryAgainCounter; |
| |
| public NetworkTimeUpdateServiceImpl(Context context) { |
| mContext = context; |
| mTime = NtpTrustedTime.getInstance(context); |
| mAlarmManager = mContext.getSystemService(AlarmManager.class); |
| mCM = mContext.getSystemService(ConnectivityManager.class); |
| |
| Intent pollIntent = new Intent(ACTION_POLL, null); |
| mPendingPollIntent = PendingIntent.getBroadcast(mContext, POLL_REQUEST, pollIntent, 0); |
| |
| mPollingIntervalMs = mContext.getResources().getInteger( |
| com.android.internal.R.integer.config_ntpPollingInterval); |
| mPollingIntervalShorterMs = mContext.getResources().getInteger( |
| com.android.internal.R.integer.config_ntpPollingIntervalShorter); |
| mTryAgainTimesMax = mContext.getResources().getInteger( |
| com.android.internal.R.integer.config_ntpRetry); |
| mTimeErrorThresholdMs = mContext.getResources().getInteger( |
| com.android.internal.R.integer.config_ntpThreshold); |
| |
| mWakeLock = context.getSystemService(PowerManager.class).newWakeLock( |
| PowerManager.PARTIAL_WAKE_LOCK, TAG); |
| } |
| |
| @Override |
| public void systemRunning() { |
| registerForTelephonyIntents(); |
| registerForAlarms(); |
| |
| HandlerThread thread = new HandlerThread(TAG); |
| thread.start(); |
| mHandler = new MyHandler(thread.getLooper()); |
| mNetworkTimeUpdateCallback = new NetworkTimeUpdateCallback(); |
| mCM.registerDefaultNetworkCallback(mNetworkTimeUpdateCallback, mHandler); |
| |
| mSettingsObserver = new SettingsObserver(mHandler, EVENT_AUTO_TIME_CHANGED); |
| mSettingsObserver.observe(mContext); |
| } |
| |
| private void registerForTelephonyIntents() { |
| IntentFilter intentFilter = new IntentFilter(); |
| intentFilter.addAction(TelephonyManager.ACTION_NETWORK_SET_TIME); |
| mContext.registerReceiver(mNitzReceiver, intentFilter); |
| } |
| |
| private void registerForAlarms() { |
| mContext.registerReceiver( |
| new BroadcastReceiver() { |
| @Override |
| public void onReceive(Context context, Intent intent) { |
| mHandler.obtainMessage(EVENT_POLL_NETWORK_TIME).sendToTarget(); |
| } |
| }, new IntentFilter(ACTION_POLL)); |
| } |
| |
| private void onPollNetworkTime(int event) { |
| // If Automatic time is not set, don't bother. Similarly, if we don't |
| // have any default network, don't bother. |
| if (mDefaultNetwork == null) return; |
| mWakeLock.acquire(); |
| try { |
| onPollNetworkTimeUnderWakeLock(event); |
| } finally { |
| mWakeLock.release(); |
| } |
| } |
| |
| private void onPollNetworkTimeUnderWakeLock(int event) { |
| // Force an NTP fix when outdated |
| if (mTime.getCacheAge() >= mPollingIntervalMs) { |
| if (DBG) Log.d(TAG, "Stale NTP fix; forcing refresh"); |
| mTime.forceRefresh(); |
| } |
| |
| if (mTime.getCacheAge() < mPollingIntervalMs) { |
| // Obtained fresh fix; schedule next normal update |
| resetAlarm(mPollingIntervalMs); |
| if (isAutomaticTimeRequested()) { |
| updateSystemClock(event); |
| } |
| |
| } else { |
| // No fresh fix; schedule retry |
| mTryAgainCounter++; |
| if (mTryAgainTimesMax < 0 || mTryAgainCounter <= mTryAgainTimesMax) { |
| resetAlarm(mPollingIntervalShorterMs); |
| } else { |
| // Try much later |
| mTryAgainCounter = 0; |
| resetAlarm(mPollingIntervalMs); |
| } |
| } |
| } |
| |
| private long getNitzAge() { |
| if (mNitzTimeSetTime == NOT_SET) { |
| return Long.MAX_VALUE; |
| } else { |
| return SystemClock.elapsedRealtime() - mNitzTimeSetTime; |
| } |
| } |
| |
| /** |
| * Consider updating system clock based on current NTP fix, if requested by |
| * user, significant enough delta, and we don't have a recent NITZ. |
| */ |
| private void updateSystemClock(int event) { |
| final boolean forceUpdate = (event == EVENT_AUTO_TIME_CHANGED); |
| if (!forceUpdate) { |
| if (getNitzAge() < mPollingIntervalMs) { |
| if (DBG) Log.d(TAG, "Ignoring NTP update due to recent NITZ"); |
| return; |
| } |
| |
| final long skew = Math.abs(mTime.currentTimeMillis() - System.currentTimeMillis()); |
| if (skew < mTimeErrorThresholdMs) { |
| if (DBG) Log.d(TAG, "Ignoring NTP update due to low skew"); |
| return; |
| } |
| } |
| |
| SystemClock.setCurrentTimeMillis(mTime.currentTimeMillis()); |
| } |
| |
| /** |
| * Cancel old alarm and starts a new one for the specified interval. |
| * |
| * @param interval when to trigger the alarm, starting from now. |
| */ |
| private void resetAlarm(long interval) { |
| mAlarmManager.cancel(mPendingPollIntent); |
| long now = SystemClock.elapsedRealtime(); |
| long next = now + interval; |
| mAlarmManager.set(AlarmManager.ELAPSED_REALTIME, next, mPendingPollIntent); |
| } |
| |
| /** |
| * Checks if the user prefers to automatically set the time. |
| */ |
| private boolean isAutomaticTimeRequested() { |
| return Settings.Global.getInt( |
| mContext.getContentResolver(), Settings.Global.AUTO_TIME, 0) != 0; |
| } |
| |
| /** Receiver for Nitz time events */ |
| private BroadcastReceiver mNitzReceiver = new BroadcastReceiver() { |
| |
| @Override |
| public void onReceive(Context context, Intent intent) { |
| String action = intent.getAction(); |
| if (DBG) Log.d(TAG, "Received " + action); |
| if (TelephonyManager.ACTION_NETWORK_SET_TIME.equals(action)) { |
| mNitzTimeSetTime = SystemClock.elapsedRealtime(); |
| } |
| } |
| }; |
| |
| /** Handler to do the network accesses on */ |
| private class MyHandler extends Handler { |
| |
| public MyHandler(Looper l) { |
| super(l); |
| } |
| |
| @Override |
| public void handleMessage(Message msg) { |
| switch (msg.what) { |
| case EVENT_AUTO_TIME_CHANGED: |
| case EVENT_POLL_NETWORK_TIME: |
| case EVENT_NETWORK_CHANGED: |
| onPollNetworkTime(msg.what); |
| break; |
| } |
| } |
| } |
| |
| private class NetworkTimeUpdateCallback extends NetworkCallback { |
| @Override |
| public void onAvailable(Network network) { |
| Log.d(TAG, String.format("New default network %s; checking time.", network)); |
| mDefaultNetwork = network; |
| // Running on mHandler so invoke directly. |
| onPollNetworkTime(EVENT_NETWORK_CHANGED); |
| } |
| |
| @Override |
| public void onLost(Network network) { |
| if (network.equals(mDefaultNetwork)) mDefaultNetwork = null; |
| } |
| } |
| |
| /** Observer to watch for changes to the AUTO_TIME setting */ |
| private static class SettingsObserver extends ContentObserver { |
| |
| private int mMsg; |
| private Handler mHandler; |
| |
| SettingsObserver(Handler handler, int msg) { |
| super(handler); |
| mHandler = handler; |
| mMsg = msg; |
| } |
| |
| void observe(Context context) { |
| ContentResolver resolver = context.getContentResolver(); |
| resolver.registerContentObserver(Settings.Global.getUriFor(Settings.Global.AUTO_TIME), |
| false, this); |
| } |
| |
| @Override |
| public void onChange(boolean selfChange) { |
| mHandler.obtainMessage(mMsg).sendToTarget(); |
| } |
| } |
| |
| @Override |
| protected void dump(FileDescriptor fd, PrintWriter pw, String[] args) { |
| if (!DumpUtils.checkDumpPermission(mContext, TAG, pw)) return; |
| pw.print("PollingIntervalMs: "); |
| TimeUtils.formatDuration(mPollingIntervalMs, pw); |
| pw.print("\nPollingIntervalShorterMs: "); |
| TimeUtils.formatDuration(mPollingIntervalShorterMs, pw); |
| pw.println("\nTryAgainTimesMax: " + mTryAgainTimesMax); |
| pw.print("TimeErrorThresholdMs: "); |
| TimeUtils.formatDuration(mTimeErrorThresholdMs, pw); |
| pw.println("\nTryAgainCounter: " + mTryAgainCounter); |
| pw.println("NTP cache age: " + mTime.getCacheAge()); |
| pw.println("NTP cache certainty: " + mTime.getCacheCertainty()); |
| pw.println(); |
| } |
| } |