f6438b16ba
This was implemented for 1.0 out of paranoia about the possibility of needing to schedule reboots of the system after it went out in the field, which I am happy to say was never ever used. Let's get rid of it. A small stub is left, to still service the API that allows people to send a reboot broadcast to have the system immediately reboot. Change-Id: I6731b24a28340e50c8015f8cb28e48f74f69f9b7
424 lines
16 KiB
Java
424 lines
16 KiB
Java
/*
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* Copyright (C) 2008 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.android.server;
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import android.app.IActivityController;
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import android.os.Binder;
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import android.os.RemoteException;
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import com.android.server.am.ActivityManagerService;
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import com.android.server.power.PowerManagerService;
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import android.app.AlarmManager;
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import android.app.PendingIntent;
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import android.content.BroadcastReceiver;
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import android.content.ContentResolver;
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import android.content.Context;
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import android.content.Intent;
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import android.content.IntentFilter;
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import android.os.BatteryManager;
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import android.os.Debug;
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import android.os.Handler;
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import android.os.Looper;
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import android.os.Process;
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import android.os.ServiceManager;
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import android.os.SystemClock;
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import android.os.SystemProperties;
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import android.util.EventLog;
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import android.util.Log;
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import android.util.Slog;
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import java.io.File;
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import java.io.FileWriter;
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import java.io.IOException;
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import java.util.ArrayList;
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import java.util.Calendar;
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/** This class calls its monitor every minute. Killing this process if they don't return **/
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public class Watchdog extends Thread {
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static final String TAG = "Watchdog";
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static final boolean localLOGV = false || false;
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// Set this to true to use debug default values.
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static final boolean DB = false;
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// Set this to true to have the watchdog record kernel thread stacks when it fires
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static final boolean RECORD_KERNEL_THREADS = true;
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static final int TIME_TO_WAIT = DB ? 5*1000 : 30*1000;
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static final String[] NATIVE_STACKS_OF_INTEREST = new String[] {
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"/system/bin/mediaserver",
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"/system/bin/sdcard",
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"/system/bin/surfaceflinger"
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};
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static Watchdog sWatchdog;
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/* This handler will be used to post message back onto the main thread */
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final ArrayList<HandlerChecker> mHandlerCheckers = new ArrayList<HandlerChecker>();
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final HandlerChecker mMonitorChecker;
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ContentResolver mResolver;
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BatteryService mBattery;
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PowerManagerService mPower;
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AlarmManagerService mAlarm;
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ActivityManagerService mActivity;
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int mPhonePid;
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IActivityController mController;
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boolean mAllowRestart = true;
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/**
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* Used for checking status of handle threads and scheduling monitor callbacks.
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*/
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public final class HandlerChecker implements Runnable {
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private final Handler mHandler;
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private final String mName;
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private final ArrayList<Monitor> mMonitors = new ArrayList<Monitor>();
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private boolean mCompleted;
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private Monitor mCurrentMonitor;
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HandlerChecker(Handler handler, String name) {
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mHandler = handler;
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mName = name;
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}
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public void addMonitor(Monitor monitor) {
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mMonitors.add(monitor);
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}
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public void scheduleCheckLocked() {
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if (mMonitors.size() == 0 && mHandler.getLooper().isIdling()) {
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// If the target looper is or just recently was idling, then
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// there is no reason to enqueue our checker on it since that
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// is as good as it not being deadlocked. This avoid having
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// to do a context switch to check the thread. Note that we
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// only do this if mCheckReboot is false and we have no
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// monitors, since those would need to be executed at this point.
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mCompleted = true;
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return;
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}
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mCompleted = false;
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mCurrentMonitor = null;
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mHandler.postAtFrontOfQueue(this);
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}
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public boolean isCompletedLocked() {
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return mCompleted;
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}
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public String describeBlockedStateLocked() {
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return mCurrentMonitor == null ? mName : mCurrentMonitor.getClass().getName();
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}
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@Override
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public void run() {
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final int size = mMonitors.size();
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for (int i = 0 ; i < size ; i++) {
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synchronized (Watchdog.this) {
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mCurrentMonitor = mMonitors.get(i);
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}
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mCurrentMonitor.monitor();
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}
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synchronized (Watchdog.this) {
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mCompleted = true;
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mCurrentMonitor = null;
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}
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}
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}
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final class RebootRequestReceiver extends BroadcastReceiver {
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@Override
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public void onReceive(Context c, Intent intent) {
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if (intent.getIntExtra("nowait", 0) != 0) {
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rebootSystem("Received ACTION_REBOOT broadcast");
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return;
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}
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Slog.w(TAG, "Unsupported ACTION_REBOOT broadcast: " + intent);
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}
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}
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public interface Monitor {
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void monitor();
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}
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public static Watchdog getInstance() {
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if (sWatchdog == null) {
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sWatchdog = new Watchdog();
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}
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return sWatchdog;
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}
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private Watchdog() {
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super("watchdog");
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// Initialize handler checkers for each common thread we want to check. Note
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// that we are not currently checking the background thread, since it can
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// potentially hold longer running operations with no guarantees about the timeliness
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// of operations there.
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// The shared foreground thread is the main checker. It is where we
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// will also dispatch monitor checks and do other work.
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mMonitorChecker = new HandlerChecker(FgThread.getHandler(), "foreground thread");
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mHandlerCheckers.add(mMonitorChecker);
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// Add checker for main thread. We only do a quick check since there
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// can be UI running on the thread.
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mHandlerCheckers.add(new HandlerChecker(new Handler(Looper.getMainLooper()),
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"main thread"));
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// Add checker for shared UI thread.
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mHandlerCheckers.add(new HandlerChecker(UiThread.getHandler(), "ui thread"));
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// And also check IO thread.
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mHandlerCheckers.add(new HandlerChecker(IoThread.getHandler(), "i/o thread"));
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}
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public void init(Context context, BatteryService battery,
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PowerManagerService power, AlarmManagerService alarm,
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ActivityManagerService activity) {
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mResolver = context.getContentResolver();
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mBattery = battery;
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mPower = power;
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mAlarm = alarm;
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mActivity = activity;
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context.registerReceiver(new RebootRequestReceiver(),
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new IntentFilter(Intent.ACTION_REBOOT),
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android.Manifest.permission.REBOOT, null);
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}
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public void processStarted(String name, int pid) {
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synchronized (this) {
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if ("com.android.phone".equals(name)) {
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mPhonePid = pid;
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}
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}
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}
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public void setActivityController(IActivityController controller) {
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synchronized (this) {
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mController = controller;
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}
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}
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public void setAllowRestart(boolean allowRestart) {
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synchronized (this) {
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mAllowRestart = allowRestart;
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}
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}
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public void addMonitor(Monitor monitor) {
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synchronized (this) {
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if (isAlive()) {
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throw new RuntimeException("Monitors can't be added once the Watchdog is running");
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}
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mMonitorChecker.addMonitor(monitor);
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}
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}
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public void addThread(Handler thread, String name) {
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synchronized (this) {
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if (isAlive()) {
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throw new RuntimeException("Threads can't be added once the Watchdog is running");
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}
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mHandlerCheckers.add(new HandlerChecker(thread, name));
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}
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}
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/**
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* Perform a full reboot of the system.
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*/
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void rebootSystem(String reason) {
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Slog.i(TAG, "Rebooting system because: " + reason);
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PowerManagerService pms = (PowerManagerService) ServiceManager.getService("power");
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pms.reboot(false, reason, false);
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}
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private boolean haveAllCheckersCompletedLocked() {
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for (int i=0; i<mHandlerCheckers.size(); i++) {
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HandlerChecker hc = mHandlerCheckers.get(i);
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if (!hc.isCompletedLocked()) {
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return false;
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}
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}
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return true;
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}
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private String describeBlockedCheckersLocked() {
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StringBuilder builder = new StringBuilder(128);
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for (int i=0; i<mHandlerCheckers.size(); i++) {
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HandlerChecker hc = mHandlerCheckers.get(i);
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if (!hc.isCompletedLocked()) {
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if (builder.length() > 0) {
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builder.append(", ");
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}
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builder.append(hc.describeBlockedStateLocked());
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}
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}
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return builder.toString();
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}
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@Override
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public void run() {
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boolean waitedHalf = false;
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while (true) {
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final String name;
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final boolean allowRestart;
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synchronized (this) {
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long timeout = TIME_TO_WAIT;
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if (!waitedHalf) {
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// If we are not at the half-point of waiting, perform a
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// new set of checks. Otherwise we are still waiting for a previous set.
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for (int i=0; i<mHandlerCheckers.size(); i++) {
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HandlerChecker hc = mHandlerCheckers.get(i);
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hc.scheduleCheckLocked();
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}
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}
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// NOTE: We use uptimeMillis() here because we do not want to increment the time we
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// wait while asleep. If the device is asleep then the thing that we are waiting
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// to timeout on is asleep as well and won't have a chance to run, causing a false
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// positive on when to kill things.
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long start = SystemClock.uptimeMillis();
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while (timeout > 0) {
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try {
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wait(timeout);
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} catch (InterruptedException e) {
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Log.wtf(TAG, e);
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}
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timeout = TIME_TO_WAIT - (SystemClock.uptimeMillis() - start);
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}
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if (haveAllCheckersCompletedLocked()) {
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// The monitors have returned.
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waitedHalf = false;
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continue;
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}
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if (!waitedHalf) {
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// We've waited half the deadlock-detection interval. Pull a stack
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// trace and wait another half.
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ArrayList<Integer> pids = new ArrayList<Integer>();
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pids.add(Process.myPid());
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ActivityManagerService.dumpStackTraces(true, pids, null, null,
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NATIVE_STACKS_OF_INTEREST);
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waitedHalf = true;
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continue;
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}
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name = describeBlockedCheckersLocked();
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allowRestart = mAllowRestart;
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}
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// If we got here, that means that the system is most likely hung.
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// First collect stack traces from all threads of the system process.
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// Then kill this process so that the system will restart.
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EventLog.writeEvent(EventLogTags.WATCHDOG, name);
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ArrayList<Integer> pids = new ArrayList<Integer>();
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pids.add(Process.myPid());
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if (mPhonePid > 0) pids.add(mPhonePid);
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// Pass !waitedHalf so that just in case we somehow wind up here without having
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// dumped the halfway stacks, we properly re-initialize the trace file.
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final File stack = ActivityManagerService.dumpStackTraces(
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!waitedHalf, pids, null, null, NATIVE_STACKS_OF_INTEREST);
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// Give some extra time to make sure the stack traces get written.
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// The system's been hanging for a minute, another second or two won't hurt much.
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SystemClock.sleep(2000);
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// Pull our own kernel thread stacks as well if we're configured for that
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if (RECORD_KERNEL_THREADS) {
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dumpKernelStackTraces();
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}
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// Trigger the kernel to dump all blocked threads to the kernel log
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try {
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FileWriter sysrq_trigger = new FileWriter("/proc/sysrq-trigger");
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sysrq_trigger.write("w");
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sysrq_trigger.close();
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} catch (IOException e) {
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Slog.e(TAG, "Failed to write to /proc/sysrq-trigger");
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Slog.e(TAG, e.getMessage());
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}
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// Try to add the error to the dropbox, but assuming that the ActivityManager
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// itself may be deadlocked. (which has happened, causing this statement to
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// deadlock and the watchdog as a whole to be ineffective)
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Thread dropboxThread = new Thread("watchdogWriteToDropbox") {
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public void run() {
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mActivity.addErrorToDropBox(
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"watchdog", null, "system_server", null, null,
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name, null, stack, null);
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}
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};
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dropboxThread.start();
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try {
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dropboxThread.join(2000); // wait up to 2 seconds for it to return.
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} catch (InterruptedException ignored) {}
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IActivityController controller;
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synchronized (this) {
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controller = mController;
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}
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if (controller != null) {
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Slog.i(TAG, "Reporting stuck state to activity controller");
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try {
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Binder.setDumpDisabled("Service dumps disabled due to hung system process.");
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// 1 = keep waiting, -1 = kill system
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int res = controller.systemNotResponding(name);
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if (res >= 0) {
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Slog.i(TAG, "Activity controller requested to coninue to wait");
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waitedHalf = false;
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continue;
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}
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} catch (RemoteException e) {
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}
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}
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// Only kill the process if the debugger is not attached.
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if (Debug.isDebuggerConnected()) {
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Slog.w(TAG, "Debugger connected: Watchdog is *not* killing the system process");
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} else if (!allowRestart) {
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Slog.w(TAG, "Restart not allowed: Watchdog is *not* killing the system process");
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} else {
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Slog.w(TAG, "*** WATCHDOG KILLING SYSTEM PROCESS: " + name);
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Slog.w(TAG, "Main thread stack trace:");
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StackTraceElement[] stackTrace = Looper.getMainLooper().getThread().getStackTrace();
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for (StackTraceElement element: stackTrace) {
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Slog.w(TAG, "\tat " + element);
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}
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Slog.w(TAG, "<End of main thread stack trace>");
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Process.killProcess(Process.myPid());
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System.exit(10);
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}
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waitedHalf = false;
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}
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}
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private File dumpKernelStackTraces() {
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String tracesPath = SystemProperties.get("dalvik.vm.stack-trace-file", null);
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if (tracesPath == null || tracesPath.length() == 0) {
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return null;
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}
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native_dumpKernelStacks(tracesPath);
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return new File(tracesPath);
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}
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private native void native_dumpKernelStacks(String tracesPath);
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}
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