/*
* Copyright (C) 2008 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 com.android.server.am.ActivityManagerService;
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.os.Debug;
import android.os.Handler;
import android.os.Message;
import android.os.Process;
import android.os.ServiceManager;
import android.os.SystemClock;
import android.os.SystemProperties;
import android.provider.Settings;
import android.util.Config;
import android.util.EventLog;
import android.util.Log;
import android.util.Slog;
import java.io.File;
import java.util.ArrayList;
import java.util.Calendar;
/** This class calls its monitor every minute. Killing this process if they don't return **/
public class Watchdog extends Thread {
static final String TAG = "Watchdog";
static final boolean localLOGV = false || Config.LOGV;
// Set this to true to use debug default values.
static final boolean DB = false;
// Set this to true to have the watchdog record kernel thread stacks when it fires
static final boolean RECORD_KERNEL_THREADS = true;
static final int MONITOR = 2718;
static final int TIME_TO_RESTART = DB ? 15*1000 : 60*1000;
static final int TIME_TO_WAIT = TIME_TO_RESTART / 2;
static final int MEMCHECK_DEFAULT_MIN_SCREEN_OFF = DB ? 1*60 : 5*60; // 5 minutes
static final int MEMCHECK_DEFAULT_MIN_ALARM = DB ? 1*60 : 3*60; // 3 minutes
static final int MEMCHECK_DEFAULT_RECHECK_INTERVAL = DB ? 1*60 : 5*60; // 5 minutes
static final int REBOOT_DEFAULT_INTERVAL = DB ? 1 : 0; // never force reboot
static final int REBOOT_DEFAULT_START_TIME = 3*60*60; // 3:00am
static final int REBOOT_DEFAULT_WINDOW = 60*60; // within 1 hour
static final String REBOOT_ACTION = "com.android.service.Watchdog.REBOOT";
static Watchdog sWatchdog;
/* This handler will be used to post message back onto the main thread */
final Handler mHandler;
final ArrayList<Monitor> mMonitors = new ArrayList<Monitor>();
ContentResolver mResolver;
BatteryService mBattery;
PowerManagerService mPower;
AlarmManagerService mAlarm;
ActivityManagerService mActivity;
boolean mCompleted;
boolean mForceKillSystem;
Monitor mCurrentMonitor;
int mPhonePid;
final Calendar mCalendar = Calendar.getInstance();
int mMinScreenOff = MEMCHECK_DEFAULT_MIN_SCREEN_OFF;
int mMinAlarm = MEMCHECK_DEFAULT_MIN_ALARM;
boolean mNeedScheduledCheck;
PendingIntent mCheckupIntent;
PendingIntent mRebootIntent;
long mBootTime;
int mRebootInterval;
boolean mReqRebootNoWait; // should wait for one interval before reboot?
int mReqRebootInterval = -1; // >= 0 if a reboot has been requested
int mReqRebootStartTime = -1; // >= 0 if a specific start time has been requested
int mReqRebootWindow = -1; // >= 0 if a specific window has been requested
int mReqMinScreenOff = -1; // >= 0 if a specific screen off time has been requested
int mReqMinNextAlarm = -1; // >= 0 if specific time to next alarm has been requested
int mReqRecheckInterval= -1; // >= 0 if a specific recheck interval has been requested
/**
* Used for scheduling monitor callbacks and checking memory usage.
*/
final class HeartbeatHandler extends Handler {
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case MONITOR: {
// See if we should force a reboot.
int rebootInterval = mReqRebootInterval >= 0
? mReqRebootInterval : Settings.Secure.getInt(
mResolver, Settings.Secure.REBOOT_INTERVAL,
REBOOT_DEFAULT_INTERVAL);
if (mRebootInterval != rebootInterval) {
mRebootInterval = rebootInterval;
// We have been running long enough that a reboot can
// be considered...
checkReboot(false);
}
final int size = mMonitors.size();
for (int i = 0 ; i < size ; i++) {
mCurrentMonitor = mMonitors.get(i);
mCurrentMonitor.monitor();
}
synchronized (Watchdog.this) {
mCompleted = true;
mCurrentMonitor = null;
}
} break;
}
}
}
final class RebootReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context c, Intent intent) {
if (localLOGV) Slog.v(TAG, "Alarm went off, checking reboot.");
checkReboot(true);
}
}
final class RebootRequestReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context c, Intent intent) {
mReqRebootNoWait = intent.getIntExtra("nowait", 0) != 0;
mReqRebootInterval = intent.getIntExtra("interval", -1);
mReqRebootStartTime = intent.getIntExtra("startTime", -1);
mReqRebootWindow = intent.getIntExtra("window", -1);
mReqMinScreenOff = intent.getIntExtra("minScreenOff", -1);
mReqMinNextAlarm = intent.getIntExtra("minNextAlarm", -1);
mReqRecheckInterval = intent.getIntExtra("recheckInterval", -1);
EventLog.writeEvent(EventLogTags.WATCHDOG_REQUESTED_REBOOT,
mReqRebootNoWait ? 1 : 0, mReqRebootInterval,
mReqRecheckInterval, mReqRebootStartTime,
mReqRebootWindow, mReqMinScreenOff, mReqMinNextAlarm);
checkReboot(true);
}
}
public interface Monitor {
void monitor();
}
public static Watchdog getInstance() {
if (sWatchdog == null) {
sWatchdog = new Watchdog();
}
return sWatchdog;
}
private Watchdog() {
super("watchdog");
mHandler = new HeartbeatHandler();
}
public void init(Context context, BatteryService battery,
PowerManagerService power, AlarmManagerService alarm,
ActivityManagerService activity) {
mResolver = context.getContentResolver();
mBattery = battery;
mPower = power;
mAlarm = alarm;
mActivity = activity;
context.registerReceiver(new RebootReceiver(),
new IntentFilter(REBOOT_ACTION));
mRebootIntent = PendingIntent.getBroadcast(context,
0, new Intent(REBOOT_ACTION), 0);
context.registerReceiver(new RebootRequestReceiver(),
new IntentFilter(Intent.ACTION_REBOOT),
android.Manifest.permission.REBOOT, null);
mBootTime = System.currentTimeMillis();
}
public void processStarted(String name, int pid) {
synchronized (this) {
if ("com.android.phone".equals(name)) {
mPhonePid = pid;
}
}
}
public void addMonitor(Monitor monitor) {
synchronized (this) {
if (isAlive()) {
throw new RuntimeException("Monitors can't be added while the Watchdog is running");
}
mMonitors.add(monitor);
}
}
void checkReboot(boolean fromAlarm) {
int rebootInterval = mReqRebootInterval >= 0 ? mReqRebootInterval
: Settings.Secure.getInt(
mResolver, Settings.Secure.REBOOT_INTERVAL,
REBOOT_DEFAULT_INTERVAL);
mRebootInterval = rebootInterval;
if (rebootInterval <= 0) {
// No reboot interval requested.
if (localLOGV) Slog.v(TAG, "No need to schedule a reboot alarm!");
mAlarm.remove(mRebootIntent);
return;
}
long rebootStartTime = mReqRebootStartTime >= 0 ? mReqRebootStartTime
: Settings.Secure.getLong(
mResolver, Settings.Secure.REBOOT_START_TIME,
REBOOT_DEFAULT_START_TIME);
long rebootWindowMillis = (mReqRebootWindow >= 0 ? mReqRebootWindow
: Settings.Secure.getLong(
mResolver, Settings.Secure.REBOOT_WINDOW,
REBOOT_DEFAULT_WINDOW)) * 1000;
long recheckInterval = (mReqRecheckInterval >= 0 ? mReqRecheckInterval
: Settings.Secure.getLong(
mResolver, Settings.Secure.MEMCHECK_RECHECK_INTERVAL,
MEMCHECK_DEFAULT_RECHECK_INTERVAL)) * 1000;
retrieveBrutalityAmount();
long realStartTime;
long now;
synchronized (this) {
now = System.currentTimeMillis();
realStartTime = computeCalendarTime(mCalendar, now,
rebootStartTime);
long rebootIntervalMillis = rebootInterval*24*60*60*1000;
if (DB || mReqRebootNoWait ||
(now-mBootTime) >= (rebootIntervalMillis-rebootWindowMillis)) {
if (fromAlarm && rebootWindowMillis <= 0) {
// No reboot window -- just immediately reboot.
EventLog.writeEvent(EventLogTags.WATCHDOG_SCHEDULED_REBOOT, now,
(int)rebootIntervalMillis, (int)rebootStartTime*1000,
(int)rebootWindowMillis, "");
rebootSystem("Checkin scheduled forced");
return;
}
// Are we within the reboot window?
if (now < realStartTime) {
// Schedule alarm for next check interval.
realStartTime = computeCalendarTime(mCalendar,
now, rebootStartTime);
} else if (now < (realStartTime+rebootWindowMillis)) {
String doit = shouldWeBeBrutalLocked(now);
EventLog.writeEvent(EventLogTags.WATCHDOG_SCHEDULED_REBOOT, now,
(int)rebootInterval, (int)rebootStartTime*1000,
(int)rebootWindowMillis, doit != null ? doit : "");
if (doit == null) {
rebootSystem("Checked scheduled range");
return;
}
// Schedule next alarm either within the window or in the
// next interval.
if ((now+recheckInterval) >= (realStartTime+rebootWindowMillis)) {
realStartTime = computeCalendarTime(mCalendar,
now + rebootIntervalMillis, rebootStartTime);
} else {
realStartTime = now + recheckInterval;
}
} else {
// Schedule alarm for next check interval.
realStartTime = computeCalendarTime(mCalendar,
now + rebootIntervalMillis, rebootStartTime);
}
}
}
if (localLOGV) Slog.v(TAG, "Scheduling next reboot alarm for "
+ ((realStartTime-now)/1000/60) + "m from now");
mAlarm.remove(mRebootIntent);
mAlarm.set(AlarmManager.RTC_WAKEUP, realStartTime, mRebootIntent);
}
/**
* Perform a full reboot of the system.
*/
void rebootSystem(String reason) {
Slog.i(TAG, "Rebooting system because: " + reason);
PowerManagerService pms = (PowerManagerService) ServiceManager.getService("power");
pms.reboot(reason);
}
/**
* Load the current Gservices settings for when
* {@link #shouldWeBeBrutalLocked} will allow the brutality to happen.
* Must not be called with the lock held.
*/
void retrieveBrutalityAmount() {
mMinScreenOff = (mReqMinScreenOff >= 0 ? mReqMinScreenOff
: Settings.Secure.getInt(
mResolver, Settings.Secure.MEMCHECK_MIN_SCREEN_OFF,
MEMCHECK_DEFAULT_MIN_SCREEN_OFF)) * 1000;
mMinAlarm = (mReqMinNextAlarm >= 0 ? mReqMinNextAlarm
: Settings.Secure.getInt(
mResolver, Settings.Secure.MEMCHECK_MIN_ALARM,
MEMCHECK_DEFAULT_MIN_ALARM)) * 1000;
}
/**
* Determine whether it is a good time to kill, crash, or otherwise
* plunder the current situation for the overall long-term benefit of
* the world.
*
* @param curTime The current system time.
* @return Returns null if this is a good time, else a String with the
* text of why it is not a good time.
*/
String shouldWeBeBrutalLocked(long curTime) {
if (mBattery == null || !mBattery.isPowered()) {
return "battery";
}
if (mMinScreenOff >= 0 && (mPower == null ||
mPower.timeSinceScreenOn() < mMinScreenOff)) {
return "screen";
}
if (mMinAlarm >= 0 && (mAlarm == null ||
mAlarm.timeToNextAlarm() < mMinAlarm)) {
return "alarm";
}
return null;
}
static long computeCalendarTime(Calendar c, long curTime,
long secondsSinceMidnight) {
// start with now
c.setTimeInMillis(curTime);
int val = (int)secondsSinceMidnight / (60*60);
c.set(Calendar.HOUR_OF_DAY, val);
secondsSinceMidnight -= val * (60*60);
val = (int)secondsSinceMidnight / 60;
c.set(Calendar.MINUTE, val);
c.set(Calendar.SECOND, (int)secondsSinceMidnight - (val*60));
c.set(Calendar.MILLISECOND, 0);
long newTime = c.getTimeInMillis();
if (newTime < curTime) {
// The given time (in seconds since midnight) has already passed for today, so advance
// by one day (due to daylight savings, etc., the delta may differ from 24 hours).
c.add(Calendar.DAY_OF_MONTH, 1);
newTime = c.getTimeInMillis();
}
return newTime;
}
@Override
public void run() {
boolean waitedHalf = false;
while (true) {
mCompleted = false;
mHandler.sendEmptyMessage(MONITOR);
synchronized (this) {
long timeout = TIME_TO_WAIT;
// NOTE: We use uptimeMillis() here because we do not want to increment the time we
// wait while asleep. If the device is asleep then the thing that we are waiting
// to timeout on is asleep as well and won't have a chance to run, causing a false
// positive on when to kill things.
long start = SystemClock.uptimeMillis();
while (timeout > 0 && !mForceKillSystem) {
try {
wait(timeout); // notifyAll() is called when mForceKillSystem is set
} catch (InterruptedException e) {
Log.wtf(TAG, e);
}
timeout = TIME_TO_WAIT - (SystemClock.uptimeMillis() - start);
}
if (mCompleted && !mForceKillSystem) {
// The monitors have returned.
waitedHalf = false;
continue;
}
if (!waitedHalf) {
// We've waited half the deadlock-detection interval. Pull a stack
// trace and wait another half.
ArrayList<Integer> pids = new ArrayList<Integer>();
pids.add(Process.myPid());
ActivityManagerService.dumpStackTraces(true, pids, null, null);
waitedHalf = true;
continue;
}
}
// If we got here, that means that the system is most likely hung.
// First collect stack traces from all threads of the system process.
// Then kill this process so that the system will restart.
String name = (mCurrentMonitor != null) ?
mCurrentMonitor.getClass().getName() : "null";
EventLog.writeEvent(EventLogTags.WATCHDOG, name);
ArrayList<Integer> pids = new ArrayList<Integer>();
pids.add(Process.myPid());
if (mPhonePid > 0) pids.add(mPhonePid);
// Pass !waitedHalf so that just in case we somehow wind up here without having
// dumped the halfway stacks, we properly re-initialize the trace file.
File stack = ActivityManagerService.dumpStackTraces(!waitedHalf, pids, null, null);
// Give some extra time to make sure the stack traces get written.
// The system's been hanging for a minute, another second or two won't hurt much.
SystemClock.sleep(2000);
// Pull our own kernel thread stacks as well if we're configured for that
if (RECORD_KERNEL_THREADS) {
dumpKernelStackTraces();
}
mActivity.addErrorToDropBox("watchdog", null, null, null, name, null, stack, null);
// Only kill the process if the debugger is not attached.
if (!Debug.isDebuggerConnected()) {
Slog.w(TAG, "*** WATCHDOG KILLING SYSTEM PROCESS: " + name);
Process.killProcess(Process.myPid());
System.exit(10);
} else {
Slog.w(TAG, "Debugger connected: Watchdog is *not* killing the system process");
}
waitedHalf = false;
}
}
private File dumpKernelStackTraces() {
String tracesPath = SystemProperties.get("dalvik.vm.stack-trace-file", null);
if (tracesPath == null || tracesPath.length() == 0) {
return null;
}
native_dumpKernelStacks(tracesPath);
return new File(tracesPath);
}
private native void native_dumpKernelStacks(String tracesPath);
}