android系统关机源码（9.0）流程分析
android系统关机流程分析
- 1.android 系统的关机是从用户按power 键开始的，而每个按键都会在PhoneWindowManager里面被处理
frameworks\base\services\core\java\com\android\server\policy/PhoneWindowManager.java
@Override
public int interceptKeyBeforeQueueing(KeyEvent event, int policyFlags) {
...
case KeyEvent.KEYCODE_POWER: //按下power键
{
// Any activity on the power button stops the accessibility shortcut
cancelPendingAccessibilityShortcutAction();
result &= ~ACTION_PASS_TO_USER;
isWakeKey = false; // wake-up will be handled separately
SystemProperties.set("persist.sys.power","1");
if (down) {
interceptPowerKeyDown(event, interactive); //按下，down 为true，走此方法
} else {
interceptPowerKeyUp(event, interactive, canceled);
}
break;
}
...
}
-
- interceptPowerKeyDown（）方法
private void interceptPowerKeyDown(KeyEvent event, boolean interactive) {
// Hold a wake lock until the power key is released.
if (!mPowerKeyWakeLock.isHeld()) {
mPowerKeyWakeLock.acquire();
}
// Cancel multi-press detection timeout.
if (mPowerKeyPressCounter != 0) {
mHandler.removeMessages(MSG_POWER_DELAYED_PRESS);
}
// Detect user pressing the power button in panic when an application has
// taken over the whole screen.
boolean panic = mImmersiveModeConfirmation.onPowerKeyDown(interactive,
SystemClock.elapsedRealtime(), isImmersiveMode(mLastSystemUiFlags),
isNavBarEmpty(mLastSystemUiFlags));
if (panic) {
mHandler.post(mHiddenNavPanic);
}
// Abort possibly stuck animations.
mHandler.post(mWindowManagerFuncs::triggerAnimationFailsafe);
// Latch power key state to detect screenshot chord. //这段代码实现电源键和音量-键同时按截屏的功能
if (interactive && !mScreenshotChordPowerKeyTriggered
&& (event.getFlags() & KeyEvent.FLAG_FALLBACK) == 0) {
mScreenshotChordPowerKeyTriggered = true;
mScreenshotChordPowerKeyTime = event.getDownTime();
interceptScreenshotChord();
interceptRingerToggleChord();
}
// Stop ringing or end call if configured to do so when power is pressed.
TelecomManager telecomManager = getTelecommService();
boolean hungUp = false;
if (telecomManager != null) {
if (telecomManager.isRinging()) {
// Pressing Power while there's a ringing incoming
// call should silence the ringer.
telecomManager.silenceRinger(); // 如果来电时，则启动静音
} else if ((mIncallPowerBehavior
& Settings.Secure.INCALL_POWER_BUTTON_BEHAVIOR_HANGUP) != 0
&& telecomManager.isInCall() && interactive) {
// Otherwise, if "Power button ends call" is enabled,
// the Power button will hang up any current active call.
hungUp = telecomManager.endCall();
}
}
GestureLauncherService gestureService = LocalServices.getService(
GestureLauncherService.class);
boolean gesturedServiceIntercepted = false;
if (gestureService != null) {
gesturedServiceIntercepted = gestureService.interceptPowerKeyDown(event, interactive,
mTmpBoolean);
if (mTmpBoolean.value && mRequestedOrGoingToSleep) {
mCameraGestureTriggeredDuringGoingToSleep = true;
}
}
// Inform the StatusBar; but do not allow it to consume the event.
sendSystemKeyToStatusBarAsync(event.getKeyCode());
// If the power key has still not yet been handled, then detect short
// press, long press, or multi press and decide what to do.
mPowerKeyHandled = hungUp || mScreenshotChordVolumeDownKeyTriggered
|| mA11yShortcutChordVolumeUpKeyTriggered || gesturedServiceIntercepted;
if (!mPowerKeyHandled) {
if (interactive) {
// When interactive, we're already awake.
// Wait for a long press or for the button to be released to decide what to do.
if (hasLongPressOnPowerBehavior() && fastBootMode) {
if ((event.getFlags() & KeyEvent.FLAG_LONG_PRESS) != 0) {
powerLongPress(); //重点来了，长按power 会走这个方法，下面发消息其实最终也会走这个方法
} else {
Message msg = mHandler.obtainMessage(MSG_POWER_LONG_PRESS);
msg.setAsynchronous(true);
mHandler.sendMessageDelayed(msg,
ViewConfiguration.get(mContext).getDeviceGlobalActionKeyTimeout());
if (hasVeryLongPressOnPowerBehavior()) {
Message longMsg = mHandler.obtainMessage(MSG_POWER_VERY_LONG_PRESS);
longMsg.setAsynchronous(true);
mHandler.sendMessageDelayed(longMsg, mVeryLongPressTimeout);
}
}
}
} else {
wakeUpFromPowerKey(event.getDownTime());
if (mSupportLongPressPowerWhenNonInteractive && hasLongPressOnPowerBehavior() && fastBootMode) {
if ((event.getFlags() & KeyEvent.FLAG_LONG_PRESS) != 0) {
**powerLongPress();** //重点来了，长按power 会走这个方法，下面发消息其实最终也会走这个方法
} else {
Message msg = mHandler.obtainMessage(MSG_POWER_LONG_PRESS);
msg.setAsynchronous(true);
mHandler.sendMessageDelayed(msg,
ViewConfiguration.get(mContext).getDeviceGlobalActionKeyTimeout());
if (hasVeryLongPressOnPowerBehavior()) {
Message longMsg = mHandler.obtainMessage(MSG_POWER_VERY_LONG_PRESS);
longMsg.setAsynchronous(true);
mHandler.sendMessageDelayed(longMsg, mVeryLongPressTimeout);
}
}
mBeganFromNonInteractive = true;
} else {
final int maxCount = getMaxMultiPressPowerCount();
if (maxCount <= 1) {
mPowerKeyHandled = true;
} else {
mBeganFromNonInteractive = true;
}
}
}
}
}
-
- powerLongPress()方法
private void powerLongPress() {
final int behavior = getResolvedLongPressOnPowerBehavior();//得到长按电源键的行为（例如是需要弹出确认对话框呢，还是不需要）
switch (behavior) {
case LONG_PRESS_POWER_NOTHING://0
break;
case LONG_PRESS_POWER_GLOBAL_ACTIONS://1 原生的会走这个case
mPowerKeyHandled = true;
performHapticFeedbackLw(null, HapticFeedbackConstants.LONG_PRESS, false);
showGlobalActionsInternal(); // 所以接下来会走这个方法
break;
case LONG_PRESS_POWER_SHUT_OFF:
case LONG_PRESS_POWER_SHUT_OFF_NO_CONFIRM:
mPowerKeyHandled = true;
performHapticFeedbackLw(null, HapticFeedbackConstants.LONG_PRESS, false);
sendCloseSystemWindows(SYSTEM_DIALOG_REASON_GLOBAL_ACTIONS);
mWindowManagerFuncs.shutdown(behavior == LONG_PRESS_POWER_SHUT_OFF);
break;
case LONG_PRESS_POWER_GO_TO_VOICE_ASSIST:
mPowerKeyHandled = true;
performHapticFeedbackLw(null, HapticFeedbackConstants.LONG_PRESS, false);
final boolean keyguardActive = mKeyguardDelegate == null
? false
: mKeyguardDelegate.isShowing();
if (!keyguardActive) {
Intent intent = new Intent(Intent.ACTION_VOICE_ASSIST);
if (mAllowStartActivityForLongPressOnPowerDuringSetup) {
mContext.startActivityAsUser(intent, UserHandle.CURRENT_OR_SELF);
} else {
startActivityAsUser(intent, UserHandle.CURRENT_OR_SELF);
}
}
break;
}
}
-
- 解析长按电源键行为的方法getResolvedLongPressOnPowerBehavior()
private int getResolvedLongPressOnPowerBehavior() {
if (FactoryTest.isLongPressOnPowerOffEnabled()) {
return LONG_PRESS_POWER_SHUT_OFF_NO_CONFIRM;
}
return mLongPressOnPowerBehavior; // 最后返回这个行为
}
mLongPressOnPowerBehavior 的初始化如下：
mLongPressOnPowerBehavior = mContext.getResources().getInteger(
com.android.internal.R.integer.config_longPressOnPowerBehavior);
由此可见 mLongPressOnPowerBehavior 读取的是 config 中的值。如下：
\frameworks\base\core\res\res\values\config.xml
<!-- Control the behavior when the user long presses the power button.
0 - Nothing // 表示直接关机
1 - Global actions menu //关机要显示Global actions
2 - Power off (with confirmation) // 关机要弹出对话框再次确认
3 - Power off (without confirmation) // 关机不需要弹出对话框
4 - Go to voice assist
-->
<integer name="config_longPressOnPowerBehavior">1</integer> //默认为1
-
- showGlobalActionsInternal() 方法
void showGlobalActionsInternal() {
if (mGlobalActions == null) {
mGlobalActions = new GlobalActions(mContext, mWindowManagerFuncs);
} // 如果mGlobalActions 为空，则创建它
final boolean keyguardShowing = isKeyguardShowingAndNotOccluded();
mGlobalActions.showDialog(keyguardShowing, isDeviceProvisioned()); //然后通过这个showDialog 的方法弹出关机的对话框。
if (keyguardShowing) {
// since it took two seconds of long press to bring this up,
// poke the wake lock so they have some time to see the dialog.
mPowerManager.userActivity(SystemClock.uptimeMillis(), false);
}
}
- 6.showDialog() 方法
\frameworks\base\services\core\java\com\android\server\policy/GlobalActions.java
public void showDialog(boolean keyguardShowing, boolean deviceProvisioned) {
if (DEBUG) Slog.d(TAG, "showDialog " + keyguardShowing + " " + deviceProvisioned);
if (mGlobalActionsProvider != null && mGlobalActionsProvider.isGlobalActionsDisabled()) {
return;
}
mKeyguardShowing = keyguardShowing;
mDeviceProvisioned = deviceProvisioned;
mShowing = true;
if (mGlobalActionsAvailable) {
mHandler.postDelayed(mShowTimeout, 5000);
mGlobalActionsProvider.showGlobalActions();
} else {
// SysUI isn't alive, show legacy menu.
ensureLegacyCreated();
mLegacyGlobalActions.showDialog(mKeyguardShowing, mDeviceProvisioned);
}
\frameworks\base\services\core\java\com\android\server\policy/LegacyGlobalActions.java
/**
* Show the global actions dialog (creating if necessary)
* @param keyguardShowing True if keyguard is showing
*/
public void showDialog(boolean keyguardShowing, boolean isDeviceProvisioned) {
mKeyguardShowing = keyguardShowing;
mDeviceProvisioned = isDeviceProvisioned;
if (mDialog != null) {
mDialog.dismiss();
mDialog = null;
// Show delayed, so that the dismiss of the previous dialog completes
mHandler.sendEmptyMessage(MESSAGE_SHOW);
} else {
handleShow(); // 如果Dialog 不为空，则创建它
}
}
private void handleShow() {
awakenIfNecessary();
mDialog = createDialog();
prepareDialog();
// If we only have 1 item and it's a simple press action, just do this action.
if (mAdapter.getCount() == 1
&& mAdapter.getItem(0) instanceof SinglePressAction
&& !(mAdapter.getItem(0) instanceof LongPressAction)) {
((SinglePressAction) mAdapter.getItem(0)).onPress();
} else {
if (mDialog != null) {
WindowManager.LayoutParams attrs = mDialog.getWindow().getAttributes();
attrs.setTitle("LegacyGlobalActions");
mDialog.getWindow().setAttributes(attrs);
mDialog.show();
mDialog.getWindow().getDecorView().setSystemUiVisibility(
View.STATUS_BAR_DISABLE_EXPAND);
}
}
}
- 当点击 dialog 的power off 时，会调用 PowerAction的onPress方法
@Override
public void onPress() {
// shutdown by making sure radio and power are handled accordingly.
mWindowManagerFuncs.shutdown(false /* confirm */);
}
- mWindowManagerFuncs实则为WindowManagerService的对象。故
frameworks\base\services\core\java\com\android\server\wm/WindowManagerService.java
// Called by window manager policy. Not exposed externally.
@Override
public void shutdown(boolean confirm) {
// Pass in the UI context, since ShutdownThread requires it (to show UI).
ShutdownThread.shutdown(ActivityThread.currentActivityThread().getSystemUiContext(),
PowerManager.SHUTDOWN_USER_REQUESTED, confirm);
}
- ShutdownThread的shutdown方法
frameworks\base\services\core\java\com\android\server\power\ShutdownThread.java
/**
* Request a clean shutdown, waiting for subsystems to clean up their
* state etc. Must be called from a Looper thread in which its UI
* is shown.
*
* @param context Context used to display the shutdown progress dialog. This must be a context
* suitable for displaying UI (aka Themable).
* @param reason code to pass to android_reboot() (e.g. "userrequested"), or null.
* @param confirm true if user confirmation is needed before shutting down.
*/
public static void shutdown(final Context context, String reason, boolean confirm) {
mReboot = false;
mRebootSafeMode = false;
mReason = reason;
shutdownInner(context, confirm);//confirm表示是否弹出确认对话框
}
private static void shutdownInner(final Context context, boolean confirm) {
// ShutdownThread is called from many places, so best to verify here that the context passed
// in is themed.
context.assertRuntimeOverlayThemable();
// ensure that only one thread is trying to power down.
// any additional calls are just returned
synchronized (sIsStartedGuard) {
if (sIsStarted) {
Log.d(TAG, "Request to shutdown already running, returning.");
return;
}
}
final int longPressBehavior = context.getResources().getInteger(
com.android.internal.R.integer.config_longPressOnPowerBehavior);
final int resourceId = mRebootSafeMode
? com.android.internal.R.string.reboot_safemode_confirm
: (longPressBehavior == 2
? com.android.internal.R.string.shutdown_confirm_question
: com.android.internal.R.string.shutdown_confirm);
Log.d(TAG, "Notifying thread to start shutdown longPressBehavior=" + longPressBehavior);
if (confirm) {// 弹出对话框
final CloseDialogReceiver closer = new CloseDialogReceiver(context);
if (sConfirmDialog != null) {
sConfirmDialog.dismiss();
}
sConfirmDialog = new AlertDialog.Builder(context, R.style.Theme_Material_Dialog_Alert)
.setTitle(mRebootSafeMode
? com.android.internal.R.string.reboot_safemode_title
: com.android.internal.R.string.power_off)
.setMessage(resourceId)
.setPositiveButton(com.android.internal.R.string.yes, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
SystemProperties.set("persist.sys.power","0");
beginShutdownSequence(context);
}
})
.setNegativeButton(com.android.internal.R.string.no, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
Log.d(TAG, "Notifying thread to cancle shutdown ");
SystemProperties.set("persist.sys.power","0");
}
})
.create();
closer.dialog = sConfirmDialog;
sConfirmDialog.setOnDismissListener(closer);
sConfirmDialog.getWindow().setType(WindowManager.LayoutParams.TYPE_KEYGUARD_DIALOG);
sConfirmDialog.show();
} else {
beginShutdownSequence(context); // 最终都会走这个方法
}
}
private static void beginShutdownSequence(Context context) { //可以在此方法里面添加关机动画
synchronized (sIsStartedGuard) {
if (sIsStarted) {
Log.d(TAG, "Shutdown sequence already running, returning.");
return;
}
sIsStarted = true;
}
sInstance.mProgressDialog = showShutdownDialog(context);
sInstance.mContext = context;
sInstance.mPowerManager = (PowerManager)context.getSystemService(Context.POWER_SERVICE);
// make sure we never fall asleep again
sInstance.mCpuWakeLock = null;
try {
sInstance.mCpuWakeLock = sInstance.mPowerManager.newWakeLock(
PowerManager.PARTIAL_WAKE_LOCK, TAG + "-cpu");
sInstance.mCpuWakeLock.setReferenceCounted(false);
sInstance.mCpuWakeLock.acquire();
} catch (SecurityException e) {
Log.w(TAG, "No permission to acquire wake lock", e);
sInstance.mCpuWakeLock = null;
}
// also make sure the screen stays on for better user experience
sInstance.mScreenWakeLock = null;
if (sInstance.mPowerManager.isScreenOn()) {
try {
sInstance.mScreenWakeLock = sInstance.mPowerManager.newWakeLock(
PowerManager.FULL_WAKE_LOCK, TAG + "-screen");
sInstance.mScreenWakeLock.setReferenceCounted(false);
sInstance.mScreenWakeLock.acquire();
} catch (SecurityException e) {
Log.w(TAG, "No permission to acquire wake lock", e);
sInstance.mScreenWakeLock = null;
}
}
if (SecurityLog.isLoggingEnabled()) {
SecurityLog.writeEvent(SecurityLog.TAG_OS_SHUTDOWN);
}
// start the thread that initiates shutdown
sInstance.mHandler = new Handler() {
};
sInstance.start(); //进入 ShutdownThread的run方法
}
/**
* Makes sure we handle the shutdown gracefully.
* Shuts off power regardless of radio state if the allotted time has passed.
*/
public void run() {
TimingsTraceLog shutdownTimingLog = newTimingsLog();
shutdownTimingLog.traceBegin("SystemServerShutdown");
metricShutdownStart();
metricStarted(METRIC_SYSTEM_SERVER);
BroadcastReceiver br = new BroadcastReceiver() {
@Override public void onReceive(Context context, Intent intent) {
// We don't allow apps to cancel this, so ignore the result.
actionDone();
}
};
/*
* Write a system property in case the system_server reboots before we
* get to the actual hardware restart. If that happens, we'll retry at
* the beginning of the SystemServer startup.
*/
{
String reason = (mReboot ? "1" : "0") + (mReason != null ? mReason : "");
SystemProperties.set(SHUTDOWN_ACTION_PROPERTY, reason); //保存关机的原因
}
/*
* If we are rebooting into safe mode, write a system property
* indicating so.
*/
if (mRebootSafeMode) {
SystemProperties.set(REBOOT_SAFEMODE_PROPERTY, "1");
}
metricStarted(METRIC_SEND_BROADCAST);
shutdownTimingLog.traceBegin("SendShutdownBroadcast");
Log.i(TAG, "Sending shutdown broadcast...");
//Make ShutDownCamService to front
Intent shutdownIntent = new Intent();
shutdownIntent.setAction("com.mediatek.ShutDownCamService");
shutdownIntent.setPackage("mtktvapi.agent");
mContext.startService(shutdownIntent);
// First send the high-level shut down broadcast.
mActionDone = false;
Intent intent = new Intent(Intent.ACTION_SHUTDOWN);
intent.addFlags(Intent.FLAG_RECEIVER_FOREGROUND | Intent.FLAG_RECEIVER_REGISTERED_ONLY);
mContext.sendOrderedBroadcastAsUser(intent,
UserHandle.ALL, null, br, mHandler, 0, null, null);//发送关机广播
final long endTime = SystemClock.elapsedRealtime() + MAX_BROADCAST_TIME;
synchronized (mActionDoneSync) {
while (!mActionDone) {
long delay = endTime - SystemClock.elapsedRealtime();
if (delay <= 0) {
Log.w(TAG, "Shutdown broadcast timed out");
break;
} else if (mRebootHasProgressBar) {
int status = (int)((MAX_BROADCAST_TIME - delay) * 1.0 *
BROADCAST_STOP_PERCENT / MAX_BROADCAST_TIME);
sInstance.setRebootProgress(status, null);
}
try {
mActionDoneSync.wait(Math.min(delay, ACTION_DONE_POLL_WAIT_MS));
} catch (InterruptedException e) {
}
}
}
if (mRebootHasProgressBar) {
sInstance.setRebootProgress(BROADCAST_STOP_PERCENT, null);
}
shutdownTimingLog.traceEnd(); // SendShutdownBroadcast
metricEnded(METRIC_SEND_BROADCAST);
Log.i(TAG, "Shutting down activity manager...");
shutdownTimingLog.traceBegin("ShutdownActivityManager");
metricStarted(METRIC_AM);
final IActivityManager am =
IActivityManager.Stub.asInterface(ServiceManager.checkService("activity"));
if (am != null) {
try {
am.shutdown(MAX_BROADCAST_TIME); //关闭AMS服务
} catch (RemoteException e) {
}
}
if (mRebootHasProgressBar) {
sInstance.setRebootProgress(ACTIVITY_MANAGER_STOP_PERCENT, null);
}
shutdownTimingLog.traceEnd();// ShutdownActivityManager
metricEnded(METRIC_AM);
Log.i(TAG, "Shutting down package manager...");
shutdownTimingLog.traceBegin("ShutdownPackageManager");
metricStarted(METRIC_PM);
final PackageManagerService pm = (PackageManagerService)
ServiceManager.getService("package");
if (pm != null) {
pm.shutdown(); //关闭pms服务
}
if (mRebootHasProgressBar) {
sInstance.setRebootProgress(PACKAGE_MANAGER_STOP_PERCENT, null);
}
shutdownTimingLog.traceEnd(); // ShutdownPackageManager
metricEnded(METRIC_PM);
// Shutdown radios.
shutdownTimingLog.traceBegin("ShutdownRadios");
metricStarted(METRIC_RADIOS);
shutdownRadios(MAX_RADIO_WAIT_TIME);
if (mRebootHasProgressBar) {
sInstance.setRebootProgress(RADIO_STOP_PERCENT, null);
}
shutdownTimingLog.traceEnd(); // ShutdownRadios
metricEnded(METRIC_RADIOS);
if (mRebootHasProgressBar) {
sInstance.setRebootProgress(MOUNT_SERVICE_STOP_PERCENT, null);
// If it's to reboot to install an update and uncrypt hasn't been
// done yet, trigger it now.
uncrypt();
}
shutdownTimingLog.traceEnd(); // SystemServerShutdown
metricEnded(METRIC_SYSTEM_SERVER);
saveMetrics(mReboot, mReason);
// Remaining work will be done by init, including vold shutdown
rebootOrShutdown(mContext, mReboot, mReason); // 最后调用 这个方法进一步处理
}
/**
* Do not call this directly. Use {@link #reboot(Context, String, boolean)}
* or {@link #shutdown(Context, String, boolean)} instead.
*
* @param context Context used to vibrate or null without vibration
* @param reboot true to reboot or false to shutdown
* @param reason reason for reboot/shutdown
*/
public static void rebootOrShutdown(final Context context, boolean reboot, String reason) {
if (reboot) { //判断是否重启
Log.i(TAG, "Rebooting, reason: " + reason);
PowerManagerService.lowLevelReboot(reason);
Log.e(TAG, "Reboot failed, will attempt shutdown instead");
reason = null;
} else if (SHUTDOWN_VIBRATE_MS > 0 && context != null) {
// vibrate before shutting down
Vibrator vibrator = new SystemVibrator(context); // 关机之前震动一下
try {
vibrator.vibrate(SHUTDOWN_VIBRATE_MS, VIBRATION_ATTRIBUTES);
} catch (Exception e)
// Failure to vibrate shouldn't interrupt shutdown. Just log it.
Log.w(TAG, "Failed to vibrate during shutdown.", e);
}
// vibrator is asynchronous so we need to wait to avoid shutting down too soon.
try {
Thread.sleep(SHUTDOWN_VIBRATE_MS);
} catch (InterruptedException unused) {
}
}
// Shutdown power
Log.i(TAG, "Performing low-level shutdown...");
PowerManagerService.lowLevelShutdown(reason); // 关闭电源
}
/**
* Low-level function turn the device off immediately, without trying
* to be clean. Most people should use {@link ShutdownThread} for a clean shutdown.
*
* @param reason code to pass to android_reboot() (e.g. "userrequested"), or null.
*/
public static void lowLevelShutdown(String reason) {
if (reason == null) {
reason = "";
}
SystemProperties.set("sys.powerctl", "shutdown," + reason); // 最后kernel 会检查此值来 实现真正的关闭。
}