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@guhuizaifeiyang 2017-09-04T17:46:21.000000Z 字数 10737 阅读 3177

Android7.0 关机流程分析

开关机流程

Android7.0关机流程分析
android L 关机流程图

关机流程的时序图

PhoneWindowManager

当长按电源键时，按键消息被分发到PhoneWindowManager的interceptKeyBeforeQueueing函数中处理：

Step 1. interceptKeyBeforeDispatching

PhoneWindowManager.java->interceptKeyBeforeDispatching

  1. public long interceptKeyBeforeDispatching(WindowState win, KeyEvent event, int policyFlags) {
  2.     case KeyEvent.KEYCODE_POWER: {
  3.         result &= ~ACTION_PASS_TO_USER;
  4.         isWakeKey = false; // wake-up will be handled separately
  5.         if (down) {
  6.             interceptPowerKeyDown(event, interactive);
  7.         } else {
  8.             interceptPowerKeyUp(event, interactive, canceled);
  9.         }
  10.         break;
  11.     }
  12. }

Step 2. interceptPowerKeyDown

PhoneWindowManager.java->interceptPowerKeyDown

  1. private void interceptPowerKeyDown(KeyEvent event, boolean interactive) {  
  2.     //..........  
  3.     // When interactive, we're already awake.  
  4.     // Wait for a long press or for the button to be released to decide what to do.  
  5.     if (hasLongPressOnPowerBehavior()) {     
  6.     // 如果存在长按事件，就发送MSG_POWER_LONG_PRESS。
  7.         Message msg = mHandler.obtainMessage(MSG_POWER_LONG_PRESS);  
  8.         msg.setAsynchronous(true);     
  9.         mHandler.sendMessageDelayed(msg, ViewConfiguration.get(mContext).getDeviceGlobalActionKeyTimeout());  
  10.     }  
  11.     //........  
  12. }

Step 3. powerLongPress

MSG_POWER_LONG_PRESS消息最终在PolicyHandler中被处理：
PhoneWindowManager$PolicyHandler->handleMessage

  1. private class PolicyHandler extends Handler {  
  2.     @Override  
  3.     public void handleMessage(Message msg) {  
  4.         // ......  
  5.             case MSG_POWER_LONG_PRESS:  
  6.                 powerLongPress();    //处理长按事件  
  7.                 break;  
  8.         // ......
  9.         }  
  10.     }  
  11. }

PhoneWindowManager.java->powerLongPress

  1. static final int LONG_PRESS_POWER_NOTHING = 0;       //长按power键什么都不做  
  2. static final int LONG_PRESS_POWER_GLOBAL_ACTIONS = 1;     //为全局动作, 显示关机dialog  
  3. static final int LONG_PRESS_POWER_SHUT_OFF = 2;    //只有关机一个选项  
  4. static final int LONG_PRESS_POWER_SHUT_OFF_NO_CONFIRM = 3;   //直接关机不用确认 
  6. private void powerLongPress() {
  7.     final int behavior = getResolvedLongPressOnPowerBehavior();
  8.     switch (behavior) {
  9.     case LONG_PRESS_POWER_NOTHING:
  10.         break;
  11.     case LONG_PRESS_POWER_GLOBAL_ACTIONS:
  12.         mPowerKeyHandled = true;
  13.         if (!performHapticFeedbackLw(null, HapticFeedbackConstants.LONG_PRESS, false)) {
  14.             performAuditoryFeedbackForAccessibilityIfNeed();
  15.         }
  16.         // 我们直接看显示Dialog这一条分支
  17.         showGlobalActionsInternal();
  18.         break;
  19.     case LONG_PRESS_POWER_SHUT_OFF:
  20.     case LONG_PRESS_POWER_SHUT_OFF_NO_CONFIRM:
  21.         mPowerKeyHandled = true;
  22.         performHapticFeedbackLw(null, HapticFeedbackConstants.LONG_PRESS, false);
  23.         sendCloseSystemWindows(SYSTEM_DIALOG_REASON_GLOBAL_ACTIONS);
  24.         mWindowManagerFuncs.shutdown(behavior == LONG_PRESS_POWER_SHUT_OFF);
  25.         break;
  26.     }
  27. }

Step 4. showGlobalActionsInternal

PhoneWindowManager.java->showGlobalActionsInternal

  1. void showGlobalActionsInternal() {  
  2.     // 关闭系统dialogs
  3.     sendCloseSystemWindows(SYSTEM_DIALOG_REASON_GLOBAL_ACTIONS);
  4.     if (mGlobalActions == null) {  
  5.         // 创建GlobalActions 
  6.         mGlobalActions = new GlobalActions(mContext, mWindowManagerFuncs);   
  7.     }  
  8.     final boolean keyguardShowing = isKeyguardShowingAndNotOccluded();
  9.     // 重点看showDialog
  10.     mGlobalActions.showDialog(keyguardShowing, isDeviceProvisioned()); 
  11.     if (keyguardShowing) {  
  12.         // since it took two seconds of long press to bring this up,  
  13.         // poke the wake lock so they have some time to see the dialog.  
  14.         mPowerManager.userActivity(SystemClock.uptimeMillis(), false);   
  15.     }  
  16. }

GlobalActions

Step 5. showDialog

  1. /**
  2.  * Show the global actions dialog (creating if necessary)
  3.  * @param keyguardShowing True if keyguard is showing
  4.  */
  5. public void showDialog(boolean keyguardShowing, boolean isDeviceProvisioned) {
  6.     mKeyguardShowing = keyguardShowing;
  7.     mDeviceProvisioned = isDeviceProvisioned;
  8.     if (mDialog != null) {
  9.         mDialog.dismiss();
  10.         mDialog = null;
  11.         // Show delayed, so that the dismiss of the previous dialog completes
  12.         mHandler.sendEmptyMessage(MESSAGE_SHOW);
  13.     } else {
  14.         handleShow();
  15.     }
  16.     // 最后都会调用handleShow()
  17. }

Step 6. handleShow

  1. private void handleShow() {  
  2.     awakenIfNecessary();  
  3.     mDialog = createDialog();   //创建mDialog对象  
  4.     prepareDialog();   //准备dialog  
  6.     // If we only have 1 item and it's a simple press action, just do this action.  
  7.     if (mAdapter.getCount() == 1  
  8.             && mAdapter.getItem(0) instanceof SinglePressAction  
  9.             && !(mAdapter.getItem(0) instanceof LongPressAction)) {  
  10.         ((SinglePressAction) mAdapter.getItem(0)).onPress();    //调用onPress函数  
  11.     } else {  
  12.         WindowManager.LayoutParams attrs = mDialog.getWindow().getAttributes();  
  13.         attrs.setTitle("GlobalActions");  
  14.         mDialog.getWindow().setAttributes(attrs);  
  15.         mDialog.show();     //显示dialog  
  16.         mDialog.getWindow().getDecorView().setSystemUiVisibility(View.STATUS_BAR_DISABLE_EXPAND);  
  17.     }  
  18. }

PowerAction

Step 7. onPress

  1. @Override  
  2. public void onPress() {  
  3.     // shutdown by making sure radio and power are handled accordingly.  
  4.     mWindowManagerFuncs.shutdown(false /* confirm */);    //关机  
  5. }

WindowManagerService

Step 8. shutdown

由于WindowManagerService实现了接口WindowManagerFuncs, 所以就会调用到WMS中的shutdown函数. 进而调用ShutdownThread中去实现关机功能.

  1. @Override
  2. public void shutdown(boolean confirm) {
  3.     ShutdownThread.shutdown(mContext, PowerManager.SHUTDOWN_USER_REQUESTED, confirm);
  4. }

关机过程的主要实现在ShutdownThread.java中

ShutdownThread

Step 9. shutdown

  1. public static void shutdown(final Context context, String reason, boolean confirm) {  
  2.     mReboot = false;  
  3.     mRebootSafeMode = false;   //不是重启  
  4.     mReason = reason;   //记录关机的原因  
  5.     shutdownInner(context, confirm);  
  6. }  
  8. static void shutdownInner(final Context context, boolean confirm) {  
  9.     // ensure that only one thread is trying to power down.  
  10.     // any additional calls are just returned   
  11.     synchronized (sIsStartedGuard) {   //保证只有一个关机线程  
  12.         if (sIsStarted) {  
  13.             Log.d(TAG, "Request to shutdown already running, returning.");  
  14.             return;  
  15.         }  
  16.     }  
  18.     final int longPressBehavior = context.getResources().getInteger(  
  19.                     com.android.internal.R.integer.config_longPressOnPowerBehavior);   //获取长按资源id  
  20.     final int resourceId = mRebootSafeMode  
  21.             ? com.android.internal.R.string.reboot_safemode_confirm  
  22.             : (longPressBehavior == 2         //关机确认信息  
  23.                     ? com.android.internal.R.string.shutdown_confirm_question  
  24.                     : com.android.internal.R.string.shutdown_confirm);  
  26.     Log.d(TAG, "Notifying thread to start shutdown longPressBehavior=" + longPressBehavior);  
  28.     if (confirm) {      
  29.         final CloseDialogReceiver closer = new CloseDialogReceiver(context);  
  30.         if (sConfirmDialog != null) {      
  31.             sConfirmDialog.dismiss();  
  32.         }  
  33.         sConfirmDialog = new AlertDialog.Builder(context)//需要再次确认关机, 创建dialog  
  34.                 .setTitle(mRebootSafeMode  
  35.                         ? com.android.internal.R.string.reboot_safemode_title  
  36.                         : com.android.internal.R.string.power_off)  
  37.                 .setMessage(resourceId)  
  38.                 .setPositiveButton(com.android.internal.R.string.yes, new DialogInterface.OnClickListener() {  
  39.                     public void onClick(DialogInterface dialog, int which) {  
  40.                         beginShutdownSequence(context);     //确认关机  
  41.                     }  
  42.                 })  
  43.                 .setNegativeButton(com.android.internal.R.string.no, null)  //不关机了  
  44.                 .create();  
  45.         closer.dialog = sConfirmDialog;  
  46.         sConfirmDialog.setOnDismissListener(closer);  
  47.         sConfirmDialog.getWindow().setType(WindowManager.LayoutParams.TYPE_KEYGUARD_DIALOG);  
  48.         sConfirmDialog.show();  
  49.     } else {  
  50.         beginShutdownSequence(context);   //如果不需要确认就直接关机  
  51.     }  
  52. }

Step 10. beginShutdownSequence

  1. private static void beginShutdownSequence(Context context) {
  2.     // ...
  3.     if (PowerManager.REBOOT_RECOVERY_UPDATE.equals(mReason)) {
  4.         // ...
  5.     } else if (PowerManager.REBOOT_RECOVERY.equals(mReason)) {
  6.         // ...
  7.     } else {
  8.          pd.setTitle(context.getText(com.android.internal.R.string.power_off));
  9.             pd.setMessage(context.getText(com.android.internal.R.string.shutdown_progress));
  11.         pd.setIndeterminate(true);
  12.     }
  13.     pd.setCancelable(false);
  14.     pd.getWindow().setType(WindowManager.LayoutParams.TYPE_KEYGUARD_DIALOG);
  16.     pd.show();
  18.     sInstance.mProgressDialog = pd;
  19.     sInstance.mContext = context;
  20.     sInstance.mPowerManager = (PowerManager)context.getSystemService(Context.POWER_SERVICE);
  22.     // make sure we never fall asleep again
  23.     sInstance.mCpuWakeLock = null;
  24.     try {
  25.         sInstance.mCpuWakeLock = sInstance.mPowerManager.newWakeLock(
  26.                 PowerManager.PARTIAL_WAKE_LOCK, TAG + "-cpu");
  27.         sInstance.mCpuWakeLock.setReferenceCounted(false);
  28.         sInstance.mCpuWakeLock.acquire();
  29.     } catch (SecurityException e) {
  30.         Log.w(TAG, "No permission to acquire wake lock", e);
  31.         sInstance.mCpuWakeLock = null;
  32.     }
  34.     // also make sure the screen stays on for better user experience
  35.     sInstance.mScreenWakeLock = null;
  36.     if (sInstance.mPowerManager.isScreenOn()) {
  37.         try {
  38.             sInstance.mScreenWakeLock = sInstance.mPowerManager.newWakeLock(
  39.                     PowerManager.FULL_WAKE_LOCK, TAG + "-screen");
  40.             sInstance.mScreenWakeLock.setReferenceCounted(false);
  41.             sInstance.mScreenWakeLock.acquire();
  42.         } catch (SecurityException e) {
  43.             Log.w(TAG, "No permission to acquire wake lock", e);
  44.             sInstance.mScreenWakeLock = null;
  45.         }
  46.     }
  48.     // start the thread that initiates shutdown
  49.     sInstance.mHandler = new Handler() {
  50.     };
  51.     // 开始启动ShutdownThread
  52.     sInstance.start();
  53. }

Step 11. run

  1. public void run() {
  2.     // ...
  3.     // First send the high-level shut down broadcast.
  4.     // (1) 启动PowerOffHandlerActivity，显示关机动画。
  5.     mActionDone = false;
  6.     Intent intent = new Intent(Intent.ACTION_SHUTDOWN);
  7.     intent.addFlags(Intent.FLAG_RECEIVER_FOREGROUND);
  8.     mContext.sendOrderedBroadcastAsUser(intent,
  9.             UserHandle.ALL, null, br, mHandler, 0, null, null);
  11.     // (2) 关闭activity manager
  12.     Log.i(TAG, "Shutting down activity manager...");
  14.     final IActivityManager am =
  15.         ActivityManagerNative.asInterface(ServiceManager.checkService("activity"));
  16.     if (am != null) {
  17.         try {
  18.             am.shutdown(MAX_BROADCAST_TIME);
  19.         } catch (RemoteException e) {
  20.         }
  21.     }
  22.     // ...
  23.     // (3) 关闭package manager
  24.     Log.i(TAG, "Shutting down package manager...");
  26.     final PackageManagerService pm = (PackageManagerService)
  27.         ServiceManager.getService("package");
  28.     if (pm != null) {
  29.         pm.shutdown();
  30.     }
  31.     if (mRebootHasProgressBar) {
  32.         sInstance.setRebootProgress(PACKAGE_MANAGER_STOP_PERCENT, null);
  33.     }
  35.     // (4) 关闭radios.
  36.     shutdownRadios(MAX_RADIO_WAIT_TIME);
  37.     if (mRebootHasProgressBar) {
  38.         sInstance.setRebootProgress(RADIO_STOP_PERCENT, null);
  39.     }
  41.     // (5) 关闭MountService
  42.     // Shutdown MountService to ensure media is in a safe state
  43.     IMountShutdownObserver observer = new IMountShutdownObserver.Stub() {
  44.         public void onShutDownComplete(int statusCode) throws RemoteException {
  45.             Log.w(TAG, "Result code " + statusCode + " from MountService.shutdown");
  46.             actionDone();
  47.         }
  48.     };
  50.     Log.i(TAG, "Shutting down MountService");
  52.     // ...
  54.     // (6) 处理关机闹钟和加密
  55.     // If it is alarm boot and encryption status, power off alarm status will
  56.     // be set to handled when device go to shutdown or reboot.
  57.     boolean isAlarmBoot = SystemProperties.getBoolean("ro.alarm_boot", false);
  58.     String cryptState = SystemProperties.get("vold.decrypt");
  60.     if (isAlarmBoot &&
  61.             ("trigger_restart_min_framework".equals(cryptState) ||
  62.             "1".equals(cryptState))) {
  63.         AlarmManager.writePowerOffAlarmFile(AlarmManager.POWER_OFF_ALARM_HANDLE_FILE,
  64.                 AlarmManager.POWER_OFF_ALARM_HANDLED);
  65.     }
  67.     // ...
  68.     // (7) 重启或关机
  69.     rebootOrShutdown(mContext, mReboot, mReason);
  70. }

这个步骤处理的任务主要是：
1. 发送关机广播Intent.ACTION_SHUTDOWN
2. 关闭activity manager
3. 关闭package manager
4. 关闭radios
5. 关闭MountService
6. 处理关机闹钟

Step 12. rebootOrShutdown

  1. public static void rebootOrShutdown(final Context context, boolean reboot, String reason) {
  2.     // Call oem shutdown handler
  3.     deviceRebootOrShutdown(reboot, reason);
  4.     if (reboot) {
  5.         // 重启
  6.         // 如果是重启，就不会走到后面lowLevelShutdown
  7.         Log.i(TAG, "Rebooting, reason: " + reason);
  8.         PowerManagerService.lowLevelReboot(reason);
  9.         Log.e(TAG, "Reboot failed, will attempt shutdown instead");
  10.         reason = null;
  11.     } else if (SHUTDOWN_VIBRATE_MS > 0 && context != null) {
  12.         // 关机
  13.         // vibrate before shutting down
  14.         Vibrator vibrator = new SystemVibrator(context);
  15.         try {
  16.             vibrator.vibrate(SHUTDOWN_VIBRATE_MS, VIBRATION_ATTRIBUTES);
  17.         } catch (Exception e) {
  18.             // Failure to vibrate shouldn't interrupt shutdown.  Just log it.
  19.             Log.w(TAG, "Failed to vibrate during shutdown.", e);
  20.         }
  22.         // vibrator is asynchronous so we need to wait to avoid shutting down too soon.
  23.         try {
  24.             Thread.sleep(SHUTDOWN_VIBRATE_MS);
  25.         } catch (InterruptedException unused) {
  26.         }
  27.     }
  29.     // 关闭电源
  30.     // Shutdown power
  31.     Log.i(TAG, "Performing low-level shutdown...");
  32.     PowerManagerService.lowLevelShutdown(reason);
  33. }

Step 13. lowLevelShutdown

  1. public static void lowLevelShutdown(String reason) {
  2.     if (reason == null) {
  3.         reason = "";
  4.     }
  5.     SystemProperties.set("sys.powerctl", "shutdown," + reason);
  6. }

正是这个动作触发关机流程往下走，执行Builtins.c的do_powerctl函数，最终通过bionic的reboot.cpp，调用kernel中kernel_power_off进行关机。
// TODO
该部分后续再补充

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