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Android N运行于一个安全的模式,也就是Dierect Boot模式(具体可参照)
当手机开机,首先进入一个Dierect Boot的模式,
1、在这个模式下只可以访问device-encrypted store下的数据, 无法访问credential-encrypted store下的数据。当用户解锁后就都可以访问了。
2、一般情况下,应用是无法在Direct Boot模式下运行的
3、如果需要某个app能够在Direct Boot模式下运行,需要注册相关APP的组件。
应用组件申请在Direct Boot模式下运行:在AndroidManinfest.xml中设置 android:directBootAware="true"。(可参照gms包里的开机向导)
首次开机进入开机向导前出现黑屏的原因是:
开机向导没有设置过android:directBootAware="true"属性,因此它必须要等动画结束,ACTION_USER_UNLOCKED发送后,fallbackhome才能退出并加载启动开机向导,这样就会引起黑屏现象
在开机向导的<applicatio里加了android:directBootAware="true"属性后,问题不存在了
可以参考gms包里开机向导,有多个activity设置了directBootAware属性
https://blog.csdn.net/fu_kevin0606/article/details/65437594 这篇文档
以下为转载内容
DirectBoot功能介绍
DirectBoot功能介绍
当手机已经通电开机但是用户并有解锁锁屏的时候,Android N运行于一个安全的模式,也就是Dierect Boot模式。
为了支持Dierect Boot模式,系统提供了两个存储数据的地方:
1.Credential encrypted storage,默认存储数据的地方,仅在用户解锁手机后可用。
2.Device encrypted storage,主要对应的就是Direct Boot使用的存储空间。在Direct Boot模式下和用户解锁手机后都可以使用的存储空间。
系统把部分系统数据和已经注册了相关权限的Apps的数据保存在device-encrypted store 。其他的数据默认保存到credential-encrypted store。
当手机开机,首先进入一个Dierect Boot的模式,在这个模式下只可以访问device-encrypted store下的数据,无法访问credential-encrypted store下的数据。当用户解锁后就都可以访问了。
一般情况下,应用是无法在Direct Boot模式下运行的
如果需要某个app能够在Direct Boot模式下运行,需要注册相关APP的组件。通常需要在这个模式下运行的app:
1.计划通知的应用,例如Clock
2.重要的用户通知的应用,例如sms
3.提供无障碍服务的应用,例如Talkback
应用组件申请在Direct Boot模式下运行:在AndroidManinfest.xml中设置 android:directBootAware="true"。
应用访问device encrypted storage:
创建Context.createDeviceEncryptedStorageContext().然后通过这个Context来使用device encrypted storage 的存储空间。
-
- Context directBootContext = Context.createDeviceEncryptedStorageContext();
-
- // Access appDataFilename that lives in device encrypted storage
-
- FileInputStream inStream = directBootContext.openFileInput(appDataFilename);
-
- // Use inStream to read content...
应用获取解锁的通知:
监听广播ACTION_USER_UNLOCKED 。
或者接收ACTION_BOOT_COMPLETED ,这个广播的意思是手机开机并且用户解锁。
也可调用UserManager.isUserUnlocked()方法来查询。
应用迁移已经存在的数据:
Context.migrateSharedPreferencesFrom()
Context.migrateDatabaseFrom()
两种方法在credential encrypted storage 和device encrypted storage存储空间之间去迁移preference 和database的数据.
启动FallbackHome流程
在分析7.0过程中发现在启动Launcher之前会先启动一个FallbackHome,之后才会启动Launcher,通过调查发现FallbackHome属于Settings中的一个activity,Settings的android:directBootAware为true,并且FallbackHome在category中配置了Home属性,而Launcher的android:directBootAware为false,所有只有FallbackHome可以在direct boot模式下启动。
- <application android:label="@string/settings_label"
-
- android:icon="@mipmap/ic_launcher_settings"
-
- ............
-
- android:directBootAware="true">
-
-
- <!-- Triggered when user-selected home app isn't encryption aware -->
-
- <activity android:name=".FallbackHome"
-
- android:excludeFromRecents="true"
-
- android:theme="@style/FallbackHome">
-
- <intent-filter android:priority="-1000">
-
- <action android:name="android.intent.action.MAIN" />
-
- <category android:name="android.intent.category.HOME" />
-
- <category android:name="android.intent.category.DEFAULT" />
-
- </intent-filter>
-
- </activity>
所以在ActivityManagerService启动Home界面时,从PackageManagerService中获取到的Home界面就是FallbackHome
-
- Intent getHomeIntent() {
-
- Intent intent = new Intent(mTopAction, mTopData != null ? Uri.parse(mTopData) : null);
-
- intent.setComponent(mTopComponent);
-
- intent.addFlags(Intent.FLAG_DEBUG_TRIAGED_MISSING);
-
- if (mFactoryTest != FactoryTest.FACTORY_TEST_LOW_LEVEL) {
-
- intent.addCategory(Intent.CATEGORY_HOME);
-
- }
-
- return intent;
-
- }
-
-
- boolean startHomeActivityLocked(int userId, String reason) {
-
- if (mFactoryTest == FactoryTest.FACTORY_TEST_LOW_LEVEL
-
- && mTopAction == null) {
-
- // We are running in factory test mode, but unable to find
-
- // the factory test app, so just sit around displaying the
-
- // error message and don't try to start anything.
- return false;
- }
- Intent intent = getHomeIntent();
- ActivityInfo aInfo = resolveActivityInfo(intent, STOCK_PM_FLAGS, userId); //获取Home activity信息
- if (aInfo != null) {
- intent.setComponent(new ComponentName(aInfo.applicationInfo.packageName, aInfo.name));
- // Don't do this if the home app is currently being
-
- // instrumented.
-
- aInfo = new ActivityInfo(aInfo);
-
- aInfo.applicationInfo = getAppInfoForUser(aInfo.applicationInfo, userId);
-
- ProcessRecord app = getProcessRecordLocked(aInfo.processName,
-
- aInfo.applicationInfo.uid, true);
-
- if (app == null || app.instrumentationClass == null) {
-
- intent.setFlags(intent.getFlags() | Intent.FLAG_ACTIVITY_NEW_TASK);
-
- mActivityStarter.startHomeActivityLocked(intent, aInfo, reason); //启动FallbackHome
-
- }
-
- } else {
-
- Slog.wtf(TAG, "No home screen found for " + intent, new Throwable());
-
- }
-
-
- return true;
-
- }
接着就会将FallbackHome启动起来,其实这个activity的代码非常简单不到100行,是个透明的activity,创建FallbackHome时注册ACTION_USER_UNLOCKED广播,然后进行判断用户是否都已经解锁,如果没有就结束执行。之后就会等待接收ACTION_USER_UNLOCKED广播,继续判断用户是否已经解锁,如果此时已经解锁,就找Home界面,如果没有找到就发延迟消息500ms再找一次,如果找到Launcher就会将FallbackHome finish掉。
下面就要看具体什么时候发送ACTION_USER_UNLOCKED广播了。
代码位置packages/apps/Settings/src/com/android/settings/FallbackHome.java
- * Copyright (C) 2015 The Android Open Source Project
-
-
- package com.android.settings;
-
-
- import android.app.Activity;
-
-
- public class FallbackHome extends Activity {
-
- private static final String TAG = "FallbackHome";
-
-
- @Override
-
- protected void onCreate(Bundle savedInstanceState) {
-
- super.onCreate(savedInstanceState);
-
-
- // Set ourselves totally black before the device is provisioned so that
-
- // we don't flash the wallpaper before SUW
-
- if (Settings.Global.getInt(getContentResolver(),
-
- Settings.Global.DEVICE_PROVISIONED, 0) == 0) {
-
- setTheme(android.R.style.Theme_Black_NoTitleBar_Fullscreen);
-
- }
-
-
- registerReceiver(mReceiver, new IntentFilter(Intent.ACTION_USER_UNLOCKED));
-
- maybeFinish();
-
- }
-
-
- @Override
-
- protected void onDestroy() {
-
- super.onDestroy();
-
- unregisterReceiver(mReceiver);
-
- }
-
-
- private BroadcastReceiver mReceiver = new BroadcastReceiver() {
-
- @Override
-
- public void onReceive(Context context, Intent intent) {
-
- maybeFinish();
-
- }
-
- };
-
-
- private void maybeFinish() {
-
- if (getSystemService(UserManager.class).isUserUnlocked()) {
-
- final Intent homeIntent = new Intent(Intent.ACTION_MAIN)
-
- .addCategory(Intent.CATEGORY_HOME);
-
- final ResolveInfo homeInfo = getPackageManager().resolveActivity(homeIntent, 0);
-
- if (Objects.equals(getPackageName(), homeInfo.activityInfo.packageName)) {
-
- Log.d(TAG, "User unlocked but no home; let's hope someone enables one soon?");
-
- mHandler.sendEmptyMessageDelayed(0, 500);
-
- } else {
-
- Log.d(TAG, "User unlocked and real home found; let's go!");
-
- finish();
-
- }
-
- }
-
- }
-
-
- private Handler mHandler = new Handler() {
-
- @Override
-
- public void handleMessage(Message msg) {
-
- maybeFinish();
-
- }
-
- };
-
- }
发送ACTION_USER_UNLOCKED广播
在开机将近尾声时WindowManagerService会调用enableScreenIfNeededLocked函数来判断是否将Screen enable。通过Handler发送ENABLE_SCREEN消息到主线程
- void enableScreenIfNeededLocked() {
-
-
- if (mDisplayEnabled) {
-
- return;
-
- }
-
- if (!mSystemBooted && !mShowingBootMessages) {
-
- return;
-
- }
-
-
- mH.sendEmptyMessage(H.ENABLE_SCREEN);
-
- }
在mH的handleMessage中处理消息ENABLE_SCREEN,调用函数performEnableScreen来处理。
- final class H extends Handler {
-
- ........
-
- public static final int ENABLE_SCREEN = 16;
-
- ........
-
- @Override
-
- public void handleMessage(Message msg) {
-
-
- case ENABLE_SCREEN: {
-
- performEnableScreen();
-
- break;
-
- }
-
- ........
-
- }
在performEnableScreen函数中判断是否要enable Screen的两个主要因素有两个:
1.checkWaitingForWindowsLocked所有Windows是否绘制完成
2.checkBootAnimationCompleteLocked开机动画时候完成
如果都完成了会通知AMS开机动画完成了,并且要enable Screen了。
- public void performEnableScreen() {
-
- synchronized(mWindowMap) {
-
- if (mDisplayEnabled) { //如果设备已经enabled,返回
-
- return;
-
- }
-
- if (!mSystemBooted && !mShowingBootMessages) { //如果不是系统启动,并且没有启动信息,返回
-
- return;
-
- }
-
-
- // Don't enable the screen until all existing windows have been drawn.
-
- if (!mForceDisplayEnabled && checkWaitingForWindowsLocked()) { //如果不是强制设备enable,并且Windows还没有绘制完成,返回
-
- return;
-
- }
-
-
- ...........
-
-
- if (!mForceDisplayEnabled && !checkBootAnimationCompleteLocked()) { //如果不是强制设备enable,并且开机动画还没有结束,返回
-
- return;
-
- }
-
-
- EventLog.writeEvent(EventLogTags.WM_BOOT_ANIMATION_DONE, SystemClock.uptimeMillis());
-
- mDisplayEnabled = true;
-
- if (DEBUG_SCREEN_ON || DEBUG_BOOT) Slog.i(TAG_WM, "******************** ENABLING SCREEN!");
-
-
- // Enable input dispatch.
-
- mInputMonitor.setEventDispatchingLw(mEventDispatchingEnabled);
-
- }
-
-
- try {
-
- mActivityManager.bootAnimationComplete(); //通知ActivityManagerService开机动画完成
-
- } catch (RemoteException e) {
-
- }
-
-
- mPolicy.enableScreenAfterBoot(); //通知ActivityManagerService Screen可以enable
-
-
- // Make sure the last requested orientation has been applied.
-
- updateRotationUnchecked(false, false);
-
- }
检查Windows是否绘制完成主要是检查是否有启动message,是否有Wallpaper,Wallpaper是否可用,是否有Keyguard进行判断。
- private boolean checkWaitingForWindowsLocked() {
-
-
- boolean haveBootMsg = false; //是否有启动message
-
- boolean haveApp = false; //是否有APP
-
- // if the wallpaper service is disabled on the device, we're never going to have
- // wallpaper, don't bother waiting for it
-
- boolean haveWallpaper = false; //是否有Wallpaper
-
- boolean wallpaperEnabled = mContext.getResources().getBoolean(
-
- com.android.internal.R.bool.config_enableWallpaperService)
-
- && !mOnlyCore; //Wallpaper是否可用
-
- boolean haveKeyguard = true; //是否有Keyguard
-
- // TODO(multidisplay): Expand to all displays?
-
- final WindowList windows = getDefaultWindowListLocked(); //获取所有的Windows
-
- final int N = windows.size();
-
- for (int i=0; i<N; i++) {
-
- WindowState w = windows.get(i);
-
- if (w.isVisibleLw() && !w.mObscured && !w.isDrawnLw()) {
-
- return true;
-
- }
-
- if (w.isDrawnLw()) { 判断Window的属性
-
- if (w.mAttrs.type == TYPE_BOOT_PROGRESS) {
-
- haveBootMsg = true;
-
- } else if (w.mAttrs.type == TYPE_APPLICATION) {
-
- haveApp = true;
-
- } else if (w.mAttrs.type == TYPE_WALLPAPER) {
-
- haveWallpaper = true;
-
- } else if (w.mAttrs.type == TYPE_STATUS_BAR) {
-
- haveKeyguard = mPolicy.isKeyguardDrawnLw();
-
- }
-
- }
-
- }
-
-
- // If we are turning on the screen to show the boot message,
-
- // don't do it until the boot message is actually displayed.
- if (!mSystemBooted && !haveBootMsg) {
- return true;
- }
- // If we are turning on the screen after the boot is completed
- // normally, don't do so until we have the application and
-
- // wallpaper.
-
- if (mSystemBooted && ((!haveApp && !haveKeyguard) ||
-
- (wallpaperEnabled && !haveWallpaper))) {
-
- return true;
-
- }
-
-
- return false;
-
- }
检查开机动画是否完成,主要就是判断开机动画服务是否在运行,如果仍然在运行,就会发送一个200ms的延迟消息CHECK_IF_BOOT_ANIMATION_FINISHED,每200ms都再检查一次
- private boolean checkBootAnimationCompleteLocked() {
-
- if (SystemService.isRunning(BOOT_ANIMATION_SERVICE)) {
-
- mH.removeMessages(H.CHECK_IF_BOOT_ANIMATION_FINISHED);
-
- mH.sendEmptyMessageDelayed(H.CHECK_IF_BOOT_ANIMATION_FINISHED,
-
- BOOT_ANIMATION_POLL_INTERVAL);
-
- if (DEBUG_BOOT) Slog.i(TAG_WM, "checkBootAnimationComplete: Waiting for anim complete");
-
- return false;
-
- }
-
- if (DEBUG_BOOT) Slog.i(TAG_WM, "checkBootAnimationComplete: Animation complete!");
-
- return true;
-
- }
在处理CHECK_IF_BOOT_ANIMATION_FINISHED消息时,会再次判断开机动画是否完成,如果完成了就会调用performEnableScreen往下面执行,否则的还是每隔200ms发一次消息检查开机动画是否完成。
- case CHECK_IF_BOOT_ANIMATION_FINISHED: {
-
- final boolean bootAnimationComplete;
-
- synchronized (mWindowMap) {
-
- if (DEBUG_BOOT) Slog.i(TAG_WM, "CHECK_IF_BOOT_ANIMATION_FINISHED:");
-
- bootAnimationComplete = checkBootAnimationCompleteLocked();
-
- }
-
- if (bootAnimationComplete) {
-
- performEnableScreen();
-
- }
-
- }
当开机动画完成后就会调用AMS的bootAnimationComplete函数。
- @Override
-
- public void bootAnimationComplete() {
-
- final boolean callFinishBooting;
-
- synchronized (this) {
-
- callFinishBooting = mCallFinishBooting;
-
- mBootAnimationComplete = true; //设置mBootAnimationComplete为true
-
- }
-
- if (callFinishBooting) {
-
- Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "FinishBooting");
-
- finishBooting(); //调用finishBooting
-
- Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
-
- }
-
- }
在finishBooting中通过mUserController调用sendBootCompletedLocked函数
- final void finishBooting() {
-
- synchronized (this) {
-
- if (!mBootAnimationComplete) {
-
- mCallFinishBooting = true;
-
- return;
-
- }
-
- mCallFinishBooting = false;
-
- }
-
- ................
-
- // Let system services know.
-
- mSystemServiceManager.startBootPhase(SystemService.PHASE_BOOT_COMPLETED);
-
- ...............
-
- mUserController.sendBootCompletedLocked(
-
- new IIntentReceiver.Stub() {
-
- @Override
-
- public void performReceive(Intent intent, int resultCode,
- String data, Bundle extras, boolean ordered,
- boolean sticky, int sendingUser) {
-
- synchronized (ActivityManagerService.this) {
-
- requestPssAllProcsLocked(SystemClock.uptimeMillis(),
-
- true, false);
-
- }
-
- }
-
- });
UserController.java代码位置frameworks/base/services/core/java/com/android/server/am/
具体流程图如下:
经过一系列的代码跳转,最终调用UserController的finishUserUnlocked函数来发送ACTION_USER_UNLOCKED广播。
- void finishUserUnlocked(final UserState uss) {
-
- .................
-
- final Intent unlockedIntent = new Intent(Intent.ACTION_USER_UNLOCKED);
-
- unlockedIntent.putExtra(Intent.EXTRA_USER_HANDLE, userId);
-
- unlockedIntent.addFlags(
-
- Intent.FLAG_RECEIVER_REGISTERED_ONLY | Intent.FLAG_RECEIVER_FOREGROUND);
-
- mService.broadcastIntentLocked(null, null, unlockedIntent, null, null, 0, null,
-
- null, null, AppOpsManager.OP_NONE, null, false, false, MY_PID, SYSTEM_UID,
-
- userId);
-
- .................
-
- }
当FallbackHome接收到ACTION_USER_UNLOCKED广播后,并且此时用户已经解锁,就会将将FallbackHome finish掉,启动launcher。
问题分析
就是因为现在启动Launcher时多了一个流程,导致启动launcher比原来6.0要慢。通过查看开机log可以看到从启动FallbackHome到启动google桌面花费了4s
- 18:10:50.653 769 1910 I ActivityManager: START u0 {act=android.intent.action.MAIN cat=[android.intent.category.HOME] flg=0x10000100 cmp=com.android.settings/.FallbackHome} from uid 0 on display 0
-
-
- 18:10:54.586 2029 2029 D FallbackHome: User unlocked and real home found; let's go!
- 18:10:54.615 769 2207 I ActivityManager: START u0 {act=android.intent.action.MAIN cat=[android.intent.category.HOME] flg=0x10000100 cmp=com.google.android.setupwizard/.SetupWizardActivity} from uid 0 on display 0
如果启动FallbackHome到启动launcher之间相隔的时间再长一点就可能发生开机过程中显示launcher时发生几秒的黑屏
小结
Android 7.0新增了DirectBoot功能,AOSP中为实现该功能修改了开机代码流程,并且这部分流程并未根据设备是否支持DirectBoot做区分,只是流程上做了兼容,确保不支持DirectBoot的设备在这套流程下也能正常开机。
在这套流程下,用户解锁后才可进入非directBootAware应用,包括Launcher。com.android.settings/.FallbackHome中判断用户解锁状态,已解锁才会Finish掉去启动Launcher,未解锁就等待ACTION_USER_UNLOCKED广播后再去启动Launcher。非DirectBoot模式下耗时4s就是在等待finishBooting后的系统广播ACTION_USER_UNLOCKED。
目前已从APP和PackageManagerService的角度尝试修改,在开机流程中绕过FallbackHome,但验证失败:
1)去除FallbackHome的android.intent.category.Home属性会导致停留在开机动画之后的界面。因为此时仍旧处于未解锁状态,且Launcher非directBootAware应用,PMS中的限制导致此时无法启动Launcher;
2)修改FallbackHome和Launcher的优先级仍旧先启动FallbackHome;
3)将Launcher标记为directBootAware应用会导致开机后Launcher crash。因为Launcher中的widget仍旧是非directBootAware的,此时仍旧无法启动,除非将widget相关的APP都标记为directBootAware;
4)PMS依赖手机当前的状态,需要user解锁才能正常查询。如果强制修改,不考虑DirectBoot和当前启动状态,即使当前user未解锁,依然可以查询符合条件的component,修改后会有无法开机的现象。因为Launcher不是directBootAware的,当前手机user尚未解锁,涉及存储相关的解锁也未进行。
开机绕过FallbackHome涉及的修改面很多,并非通过修改APP或PMS可以实现,还涉及存储区域解锁以及用户状态和ACTION_USER_UNLOCKED广播的修改,对AOSP开机流程改动较大,暂时尚未有较好的优化方案,欢迎大神指教。
=============================================
1. 现在发现一个问题,关机闹钟的问题,设置闹钟后关机,等快到闹钟的时候自动开机了,就提示闹钟应用停止,然后一直处于Andriod 正在启动“”的状态,看log是因为在maybeFinisth()的时候一直找不到launcher,
只有FallbackHome被匹配到了,目前还在跟踪,比较奇怪,手机根本没有设置任何锁屏密码。
ss:明白了,vender下面的PowerOnAlert没有编译进系统。
2.我现在采取的策略是让开机动画延迟3s结束,可以规避该问题。
具体实现在WindowManagerService.java的performEnableScreen函数中,延迟3s通知surfaceFlinger开机完成。
mH.postDelayed(new Runnable() { @Override public void run() { try { IBinder surfaceFlinger = ServiceManager.getService("SurfaceFlinger"); if (surfaceFlinger != null)
{ ...... surfaceFlinger.transact(IBinder.FIRST_CALL_TRANSACTION, // BOOT_FINISHED data, null, 0); data.recycle(); ......... } }, 3000);
并且在后面将下面代码注销,不让检查开机动画完成,继续向下执行。
/*if (!mForceDisplayEnabled && !checkBootAnimationCompleteLocked())
{ if (DEBUG_BOOT) Slog.i(TAG_WM, "performEnableScreen: Waiting for anim complete"); return }*/ 采用该方案尚未发现有什么副作用。
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