02.Android崩溃Crash库之App崩溃分析 02.Android崩溃Crash库之App崩溃分

目录总结

01.抛出异常导致崩溃分析
02.RuntimeInit类分析
03.Looper停止App就退出吗
04.handleApplicationCrash
05.native_crash如何监控
06.ANR是如何监控的
07.回过头看addErrorToDropBox

前沿

上一篇整体介绍了crash崩溃库崩溃重启，崩溃记录记录，查看以及分享日志等功能。
项目地址：https://github.com/yangchong211/YCAndroidTool
欢迎star，哈哈哈

01.抛出异常导致崩溃分析

线程中抛出异常以后的处理逻辑。
- 一旦线程出现抛出异常，并且我们没有捕捉的情况下，JVM将调用Thread中的dispatchUncaughtException方法把异常传递给线程的未捕获异常处理器。
- 如果没有设置uncaughtExceptionHandler，将使用线程所在的线程组来处理这个未捕获异常。线程组ThreadGroup实现了UncaughtExceptionHandler，所以可以用来处理未捕获异常。
public final void dispatchUncaughtException(Throwable e) { Thread.UncaughtExceptionHandler initialUeh = Thread.getUncaughtExceptionPreHandler(); if (initialUeh != null) { try { initialUeh.uncaughtException(this, e); } catch (RuntimeException | Error ignored) { // Throwables thrown by the initial handler are ignored } } getUncaughtExceptionHandler().uncaughtException(this, e); }public static UncaughtExceptionHandler getUncaughtExceptionPreHandler() { return uncaughtExceptionPreHandler; }public UncaughtExceptionHandler getUncaughtExceptionHandler() { return uncaughtExceptionHandler != null ? uncaughtExceptionHandler : group; }private ThreadGroup group;
然后看一下ThreadGroup中实现uncaughtException(Thread t, Throwable e)方法，代码如下
- 默认情况下，线程组处理未捕获异常的逻辑是，首先将异常消息通知给父线程组，
- 然后尝试利用一个默认的defaultUncaughtExceptionHandler来处理异常，
- 如果没有默认的异常处理器则将错误信息输出到System.err。
- 也就是JVM提供给我们设置每个线程的具体的未捕获异常处理器，也提供了设置默认异常处理器的方法。
public void uncaughtException(Thread t, Throwable e) { if (parent != null) { parent.uncaughtException(t, e); } else { Thread.UncaughtExceptionHandler ueh = Thread.getDefaultUncaughtExceptionHandler(); if (ueh != null) { ueh.uncaughtException(t, e); } else if (!(e instanceof ThreadDeath)) { System.err.print("Exception in thread \"" + t.getName() + "\" "); e.printStackTrace(System.err); } } }
既然Android遇到异常会发生崩溃，然后找一些哪里用到设置setDefaultUncaughtExceptionHandler，即可定位到RuntimeInit类。

02.RuntimeInit类分析

然后看一下RuntimeInit类，由于是java代码，所以首先找main方法入口。代码如下所示
public static final void main(String[] argv) { enableDdms(); if (argv.length == 2 && argv[1].equals("application")) { if (DEBUG) Slog.d(TAG, "RuntimeInit: Starting application"); redirectLogStreams(); } else { if (DEBUG) Slog.d(TAG, "RuntimeInit: Starting tool"); }commonInit(); /* * Now that we're running in interpreted code, call back into native code * to run the system. */ nativeFinishInit(); if (DEBUG) Slog.d(TAG, "Leaving RuntimeInit!"); }
然后再来看一下commonInit()方法，看看里面做了什么操作？
- 可以发现这里调用了setDefaultUncaughtExceptionHandler方法，设置了自定义的Handler类
protected static final void commonInit() { if (DEBUG) Slog.d(TAG, "Entered RuntimeInit!"); /* * set handlers; these apply to all threads in the VM. Apps can replace * the default handler, but not the pre handler. */ LoggingHandler loggingHandler = new LoggingHandler(); Thread.setUncaughtExceptionPreHandler(loggingHandler); Thread.setDefaultUncaughtExceptionHandler(new KillApplicationHandler(loggingHandler)); initialized = true; }
接着看一下KillApplicationHandler类，可以发现该类实现了Thread.UncaughtExceptionHandler 接口
private static class KillApplicationHandler implements Thread.UncaughtExceptionHandler { private final LoggingHandler mLoggingHandler; @Override public void uncaughtException(Thread t, Throwable e) { try { ensureLogging(t, e); // Don't re-enter -- avoid infinite loops if crash-reporting crashes. if (mCrashing) return; mCrashing = true; // Try to end profiling. If a profiler is running at this point, and we kill the // process (below), the in-memory buffer will be lost. So try to stop, which will // flush the buffer. (This makes method trace profiling useful to debug crashes.) if (ActivityThread.currentActivityThread() != null) { ActivityThread.currentActivityThread().stopProfiling(); }// Bring up crash dialog, wait for it to be dismissed ActivityManager.getService().handleApplicationCrash( mApplicationObject, new ApplicationErrorReport.ParcelableCrashInfo(e)); } catch (Throwable t2) { if (t2 instanceof DeadObjectException) { // System process is dead; ignore } else { try { Clog_e(TAG, "Error reporting crash", t2); } catch (Throwable t3) { // Even Clog_e() fails!Oh well. } } } finally { // Try everything to make sure this process goes away. Process.killProcess(Process.myPid()); System.exit(10); } } }
得出结论
- 其实在fork出app进程的时候，系统已经为app设置了一个异常处理，并且最终崩溃后会直接导致执行该handler的finallly方法最后杀死app直接退出app。如果你要自己处理，你可以自己实现Thread.UncaughtExceptionHandler。

03.Looper停止App就退出吗

looper如果停止了，那么app会退出吗，先做个实验看一下。代码如下所示
- 可以发现调用这句话，是会让app退出的。会报错崩溃日志是：java.lang.IllegalStateException: Main thread not allowed to quit.
Looper.getMainLooper().quit(); //下面这种是安全退出 if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR2) { Looper.getMainLooper().quitSafely(); }
然后看一下Looper中quit方法源码
- Looper的quit方法源码如下：
public void quit() { mQueue.quit(false); }
- Looper的quitSafely方法源码如下：
public void quitSafely() { mQueue.quit(true); }
以上两个方法中mQueue是MessageQueue类型的对象，二者都调用了MessageQueue中的quit方法，MessageQueue的quit方法源码如下:
- 可以发现上面调用了quit方法，即会出现出现崩溃，主要原因是因为调用prepare()-->new Looper(true)--->new MessageQueue(true)--->mQuitAllowed设置为true
void quit(boolean safe) { if (!mQuitAllowed) { throw new IllegalStateException("Main thread not allowed to quit."); }synchronized (this) { if (mQuitting) { return; } mQuitting = true; if (safe) { removeAllFutureMessagesLocked(); } else { removeAllMessagesLocked(); }// We can assume mPtr != 0 because mQuitting was previously false. nativeWake(mPtr); } }
通过观察以上源码我们可以发现:
- 当我们调用Looper的quit方法时，实际上执行了MessageQueue中的removeAllMessagesLocked方法，该方法的作用是把MessageQueue消息池中所有的消息全部清空，无论是延迟消息（延迟消息是指通过sendMessageDelayed或通过postDelayed等方法发送的需要延迟执行的消息）还是非延迟消息。
- 当我们调用Looper的quitSafely方法时，实际上执行了MessageQueue中的removeAllFutureMessagesLocked方法，通过名字就可以看出，该方法只会清空MessageQueue消息池中所有的延迟消息，并将消息池中所有的非延迟消息派发出去让Handler去处理，quitSafely相比于quit方法安全之处在于清空消息之前会派发所有的非延迟消息。
- 无论是调用了quit方法还是quitSafely方法只会，Looper就不再接收新的消息。即在调用了Looper的quit或quitSafely方法之后，消息循环就终结了，这时候再通过Handler调用sendMessage或post等方法发送消息时均返回false，表示消息没有成功放入消息队列MessageQueue中，因为消息队列已经退出了。
- 需要注意的是Looper的quit方法从API Level 1就存在了，但是Looper的quitSafely方法从API Level 18才添加进来。

04.handleApplicationCrash

在KillApplicationHandler类中的uncaughtException方法，可以看到ActivityManager.getService().handleApplicationCrash被调用，那么这个是用来做什么的呢？
- ActivityManager.getService().handleApplicationCrash-->ActivityManagerService.handleApplicationCrash-->handleApplicationCrashInner方法
- 从下面可以看出,若传入app为null时,processName就设置为system_server
public void handleApplicationCrash(IBinder app, ApplicationErrorReport.ParcelableCrashInfo crashInfo) { ProcessRecord r = findAppProcess(app, "Crash"); final String processName = app == null ? "system_server" : (r == null ? "unknown" : r.processName); handleApplicationCrashInner("crash", r, processName, crashInfo); }
然后接着看一下handleApplicationCrashInner方法做了什么
- 调用addErrorToDropBox将应用crash,进行封装输出。
void handleApplicationCrashInner(String eventType, ProcessRecord r, String processName, ApplicationErrorReport.CrashInfo crashInfo) {addErrorToDropBox(eventType, r, processName, null, null, null, null, null, crashInfo); mAppErrors.crashApplication(r, crashInfo); }

05.native_crash如何监控

native_crash，顾名思义，就是native层发生的crash。其实他是通过一个NativeCrashListener线程去监控的。
final class NativeCrashListener extends Thread { ...@Override public void run() { final byte[] ackSignal = new byte[1]; ...// The file system entity for this socket is created with 0777 perms, owned // by system:system. selinux restricts things so that only crash_dump can // access it. { File socketFile = new File(DEBUGGERD_SOCKET_PATH); if (socketFile.exists()) { socketFile.delete(); } }try { FileDescriptor serverFd = Os.socket(AF_UNIX, SOCK_STREAM, 0); final UnixSocketAddress sockAddr = UnixSocketAddress.createFileSystem( DEBUGGERD_SOCKET_PATH); Os.bind(serverFd, sockAddr); Os.listen(serverFd, 1); Os.chmod(DEBUGGERD_SOCKET_PATH, 0777); //1.一直循环地读peerFd文件,若发生存在,则进入consumeNativeCrashData while (true) { FileDescriptor peerFd = null; try { if (MORE_DEBUG) Slog.v(TAG, "Waiting for debuggerd connection"); peerFd = Os.accept(serverFd, null /* peerAddress */); if (MORE_DEBUG) Slog.v(TAG, "Got debuggerd socket " + peerFd); if (peerFd != null) { // the reporting thread may take responsibility for // acking the debugger; make sure we play along. //2.进入native crash数据处理流程 consumeNativeCrashData(peerFd); } } catch (Exception e) { Slog.w(TAG, "Error handling connection", e); } finally { ... } } } catch (Exception e) { Slog.e(TAG, "Unable to init native debug socket!", e); } }// Read a crash report from the connection void consumeNativeCrashData(FileDescriptor fd) { try { ... //3.启动NativeCrashReporter作为上报错误的新线程 final String reportString = new String(os.toByteArray(), "UTF-8"); (new NativeCrashReporter(pr, signal, reportString)).start(); } catch (Exception e) { ... } } }
上报native_crash的线程-->NativeCrashReporter:
class NativeCrashReporter extends Thread { ProcessRecord mApp; int mSignal; String mCrashReport; NativeCrashReporter(ProcessRecord app, int signal, String report) { super("NativeCrashReport"); mApp = app; mSignal = signal; mCrashReport = report; }@Override public void run() { try { //1.包装崩溃信息 CrashInfo ci = new CrashInfo(); ci.exceptionClassName = "Native crash"; ci.exceptionMessage = Os.strsignal(mSignal); ci.throwFileName = "unknown"; ci.throwClassName = "unknown"; ci.throwMethodName = "unknown"; ci.stackTrace = mCrashReport; if (DEBUG) Slog.v(TAG, "Calling handleApplicationCrash()"); //2.转到ams中处理,跟普通crash一致,只是类型不一样 mAm.handleApplicationCrashInner("native_crash", mApp, mApp.processName, ci); if (DEBUG) Slog.v(TAG, "<-- handleApplicationCrash() returned"); } catch (Exception e) { Slog.e(TAG, "Unable to report native crash", e); } } }
native crash跟到这里就结束了，后面的流程就是跟application crash一样，都会走到addErrorToDropBox中，这个最后在说。

06.ANR是如何监控的

这里就不讨论每种anr发生后的原因和具体的流程了，直接跳到已经触发ANR的位置。AppErrors.appNotResponding:
final void appNotResponding(ProcessRecord app, ActivityRecord activity, ActivityRecord parent, boolean aboveSystem, final String annotation) { ArrayList firstPids = new ArrayList(5); SparseArray lastPids = new SparseArray(20); if (mService.mController != null) { try { //1.判断是否继续后面的流程,还是直接kill掉当前进程 // 0 == continue, -1 = kill process immediately int res = mService.mController.appEarlyNotResponding( app.processName, app.pid, annotation); if (res < 0 && app.pid != MY_PID) { app.kill("anr", true); } } catch (RemoteException e) { mService.mController = null; Watchdog.getInstance().setActivityController(null); } }//2.记录发生anr的时间 long anrTime = SystemClock.uptimeMillis(); //3.更新cpu使用情况 if (ActivityManagerService.MONITOR_CPU_USAGE) { mService.updateCpuStatsNow(); }//可以在设置中设置发生anr后,是弹框显示还是后台处理,默认是后台 // Unless configured otherwise, swallow ANRs in background processes & kill the process. boolean showBackground = Settings.Secure.getInt(mContext.getContentResolver(), Settings.Secure.ANR_SHOW_BACKGROUND, 0) != 0; boolean isSilentANR; synchronized (mService) { ...// In case we come through here for the same app before completing // this one, mark as anring now so we will bail out. app.notResponding = true; //3.将anr写入event log中 EventLog.writeEvent(EventLogTags.AM_ANR, app.userId, app.pid, app.processName, app.info.flags, annotation); // Dump thread traces as quickly as we can, starting with "interesting" processes. firstPids.add(app.pid); // Don't dump other PIDs if it's a background ANR isSilentANR = !showBackground && !isInterestingForBackgroundTraces(app); if (!isSilentANR) { int parentPid = app.pid; if (parent != null && parent.app != null && parent.app.pid > 0) { parentPid = parent.app.pid; } if (parentPid != app.pid) firstPids.add(parentPid); if (MY_PID != app.pid && MY_PID != parentPid) firstPids.add(MY_PID); for (int i = mService.mLruProcesses.size() - 1; i >= 0; i--) { ProcessRecord r = mService.mLruProcesses.get(i); if (r != null && r.thread != null) { int pid = r.pid; if (pid > 0 && pid != app.pid && pid != parentPid && pid != MY_PID) { if (r.persistent) { firstPids.add(pid); if (DEBUG_ANR) Slog.i(TAG, "Adding persistent proc: " + r); } else if (r.treatLikeActivity) { firstPids.add(pid); if (DEBUG_ANR) Slog.i(TAG, "Adding likely IME: " + r); } else { lastPids.put(pid, Boolean.TRUE); if (DEBUG_ANR) Slog.i(TAG, "Adding ANR proc: " + r); } } } } }}// 4.将主要的anr信息写到main.log中 StringBuilder info = new StringBuilder(); info.setLength(0); info.append("ANR in ").append(app.processName); if (activity != null && activity.shortComponentName != null) { info.append(" (").append(activity.shortComponentName).append(")"); } info.append("\n"); info.append("PID: ").append(app.pid).append("\n"); if (annotation != null) { info.append("Reason: ").append(annotation).append("\n"); } if (parent != null && parent != activity) { info.append("Parent: ").append(parent.shortComponentName).append("\n"); }ProcessCpuTracker processCpuTracker = new ProcessCpuTracker(true); ArrayList nativePids = null; // don't dump native PIDs for background ANRs unless it is the process of interest String[] nativeProc = null; if (isSilentANR) { for (int i = 0; i < NATIVE_STACKS_OF_INTEREST.length; i++) { if (NATIVE_STACKS_OF_INTEREST[i].equals(app.processName)) { nativeProc = new String[] { app.processName }; break; } } int[] pid = nativeProc == null ? null : Process.getPidsForCommands(nativeProc); if(pid != null){ nativePids = new ArrayList(pid.length); for (int i : pid) { nativePids.add(i); } } } else { nativePids = Watchdog.getInstance().getInterestingNativePids(); }//5.dump出stacktraces文件 // For background ANRs, don't pass the ProcessCpuTracker to // avoid spending 1/2 second collecting stats to rank lastPids. File tracesFile = ActivityManagerService.dumpStackTraces( true, firstPids, (isSilentANR) ? null : processCpuTracker, (isSilentANR) ? null : lastPids, nativePids); String cpuInfo = null; if (ActivityManagerService.MONITOR_CPU_USAGE) { //6.再次更新cpu使用情况 mService.updateCpuStatsNow(); synchronized (mService.mProcessCpuTracker) { //7.打印anr时cpu使用状态 cpuInfo = mService.mProcessCpuTracker.printCurrentState(anrTime); } info.append(processCpuTracker.printCurrentLoad()); info.append(cpuInfo); }info.append(processCpuTracker.printCurrentState(anrTime)); //8.当traces文件不存在时,只能打印线程日志了 if (tracesFile == null) { // There is no trace file, so dump (only) the alleged culprit's threads to the log Process.sendSignal(app.pid, Process.SIGNAL_QUIT); }... //9.关键,回到了我们熟悉的addErrorToDropBox,进行错误信息包装跟上传了 mService.addErrorToDropBox("anr", app, app.processName, activity, parent, annotation, cpuInfo, tracesFile, null); if (mService.mController != null) { try { //10.根据appNotResponding返回结果,看是否继续等待,还是结束当前进程 // 0 == show dialog, 1 = keep waiting, -1 = kill process immediately int res = mService.mController.appNotResponding( app.processName, app.pid, info.toString()); if (res != 0) { if (res < 0 && app.pid != MY_PID) { app.kill("anr", true); } else { synchronized (mService) { mService.mServices.scheduleServiceTimeoutLocked(app); } } return; } } catch (RemoteException e) { mService.mController = null; Watchdog.getInstance().setActivityController(null); } }... }
我们来看一下traces文件是怎么dump出来的：
public static File dumpStackTraces(boolean clearTraces, ArrayList firstPids, ProcessCpuTracker processCpuTracker, SparseArray lastPids, ArrayList nativePids) { ArrayList extraPids = null; //1.测量CPU的使用情况，以便在请求时对顶级用户进行实际的采样。 if (processCpuTracker != null) { processCpuTracker.init(); try { Thread.sleep(200); } catch (InterruptedException ignored) { }processCpuTracker.update(); // 2.爬取顶级应用到的cpu使用情况 final int N = processCpuTracker.countWorkingStats(); extraPids = new ArrayList<>(); for (int i = 0; i < N && extraPids.size() < 5; i++) { ProcessCpuTracker.Stats stats = processCpuTracker.getWorkingStats(i); if (lastPids.indexOfKey(stats.pid) >= 0) { if (DEBUG_ANR) Slog.d(TAG, "Collecting stacks for extra pid " + stats.pid); extraPids.add(stats.pid); } else if (DEBUG_ANR) { Slog.d(TAG, "Skipping next CPU consuming process, not a java proc: " + stats.pid); } } }//3.读取trace文件的保存目录 File tracesFile; final String tracesDirProp = SystemProperties.get("dalvik.vm.stack-trace-dir", ""); if (tracesDirProp.isEmpty()) { ... String globalTracesPath = SystemProperties.get("dalvik.vm.stack-trace-file", null); ... } else { ... }//4.传入指定目录,进入实际dump逻辑 dumpStackTraces(tracesFile.getAbsolutePath(), firstPids, nativePids, extraPids, useTombstonedForJavaTraces); return tracesFile; }
dumpStackTraces
private static void dumpStackTraces(String tracesFile, ArrayList firstPids, ArrayList nativePids, ArrayList extraPids, boolean useTombstonedForJavaTraces) {... final DumpStackFileObserver observer; if (useTombstonedForJavaTraces) { observer = null; } else { // Use a FileObserver to detect when traces finish writing. // The order of traces is considered important to maintain for legibility. observer = new DumpStackFileObserver(tracesFile); }//我们必须在20秒内完成所有堆栈转储。 long remainingTime = 20 * 1000; try { if (observer != null) { observer.startWatching(); }// 首先收集所有最重要的pid堆栈。 if (firstPids != null) { int num = firstPids.size(); for (int i = 0; i < num; i++) { if (DEBUG_ANR) Slog.d(TAG, "Collecting stacks for pid " + firstPids.get(i)); final long timeTaken; if (useTombstonedForJavaTraces) { timeTaken = dumpJavaTracesTombstoned(firstPids.get(i), tracesFile, remainingTime); } else { timeTaken = observer.dumpWithTimeout(firstPids.get(i), remainingTime); }remainingTime -= timeTaken; if (remainingTime <= 0) { Slog.e(TAG, "Aborting stack trace dump (current firstPid=" + firstPids.get(i) + "); deadline exceeded."); return; }if (DEBUG_ANR) { Slog.d(TAG, "Done with pid " + firstPids.get(i) + " in " + timeTaken + "ms"); } } }//接下来收集native pid的堆栈 if (nativePids != null) { for (int pid : nativePids) { if (DEBUG_ANR) Slog.d(TAG, "Collecting stacks for native pid " + pid); final long nativeDumpTimeoutMs = Math.min(NATIVE_DUMP_TIMEOUT_MS, remainingTime); final long start = SystemClock.elapsedRealtime(); Debug.dumpNativeBacktraceToFileTimeout( pid, tracesFile, (int) (nativeDumpTimeoutMs / 1000)); final long timeTaken = SystemClock.elapsedRealtime() - start; remainingTime -= timeTaken; if (remainingTime <= 0) { Slog.e(TAG, "Aborting stack trace dump (current native pid=" + pid + "); deadline exceeded."); return; }if (DEBUG_ANR) { Slog.d(TAG, "Done with native pid " + pid + " in " + timeTaken + "ms"); } } }// 最后，从CPU跟踪器转储所有额外PID的堆栈。 if (extraPids != null) { for (int pid : extraPids) { if (DEBUG_ANR) Slog.d(TAG, "Collecting stacks for extra pid " + pid); final long timeTaken; if (useTombstonedForJavaTraces) { timeTaken = dumpJavaTracesTombstoned(pid, tracesFile, remainingTime); } else { timeTaken = observer.dumpWithTimeout(pid, remainingTime); }remainingTime -= timeTaken; if (remainingTime <= 0) { Slog.e(TAG, "Aborting stack trace dump (current extra pid=" + pid + "); deadline exceeded."); return; }if (DEBUG_ANR) { Slog.d(TAG, "Done with extra pid " + pid + " in " + timeTaken + "ms"); } } } } finally { if (observer != null) { observer.stopWatching(); } } }
看完之后，应该可以很清楚地的明白。ANR的流程就是打印一些 ANR reason、cpu stats、线程日志，然后分别写入main.log、event.log，然后调用到addErrorToDropBox中，最后kill该进程。

07.回过头看addErrorToDropBox

为什么说addErrorToDropBox是殊途同归呢，因为无论是crash、native_crash、ANR或是wtf，最终都是来到这里，交由它去处理。那下面我们就来揭开它的神秘面纱吧。
public void addErrorToDropBox(String eventType, ProcessRecord process, String processName, ActivityRecord activity, ActivityRecord parent, String subject, final String report, final File dataFile, final ApplicationErrorReport.CrashInfo crashInfo) { // NOTE -- this must never acquire the ActivityManagerService lock, // otherwise the watchdog may be prevented from resetting the system.// Bail early if not published yet if (ServiceManager.getService(Context.DROPBOX_SERVICE) == null) return; final DropBoxManager dbox = mContext.getSystemService(DropBoxManager.class); //只有这几种类型的错误,才会进行上传 final boolean shouldReport = ("anr".equals(eventType) || "crash".equals(eventType) || "native_crash".equals(eventType) || "watchdog".equals(eventType)); // Exit early if the dropbox isn't configured to accept this report type. final String dropboxTag = processClass(process) + "_" + eventType; //1.如果DropBoxManager没有初始化,或不是要上传的类型,则直接返回 if (dbox == null || !dbox.isTagEnabled(dropboxTag)&& !shouldReport) return; ...final StringBuilder sb = new StringBuilder(1024); //2.添加一些头部log信息 appendDropBoxProcessHeaders(process, processName, sb); //3.添加崩溃进程和界面的信息 try { if (process != null) { //添加是否前台前程log sb.append("Foreground: ") .append(process.isInterestingToUserLocked() ? "Yes" : "No") .append("\n"); } //触发该崩溃的界面,可以为null if (activity != null) { sb.append("Activity: ").append(activity.shortComponentName).append("\n"); } if (parent != null && parent.app != null && parent.app.pid != process.pid) { sb.append("Parent-Process: ").append(parent.app.processName).append("\n"); } if (parent != null && parent != activity) { sb.append("Parent-Activity: ").append(parent.shortComponentName).append("\n"); } //定入简要信息 if (subject != null) { sb.append("Subject: ").append(subject).append("\n"); } sb.append("Build: ").append(Build.FINGERPRINT).append("\n"); //是否连接了调试 if (Debug.isDebuggerConnected()) { sb.append("Debugger: Connected\n"); } } catch (NullPointerException e) { e.printStackTrace(); } finally { sb.append("\n"); }final String fProcessName = processName; final String fEventType = eventType; final String packageName = getErrorReportPackageName(process, crashInfo, eventType); Slog.i(TAG,"addErrorToDropbox, real report package is "+packageName); // Do the rest in a worker thread to avoid blocking the caller on I/O // (After this point, we shouldn't access AMS internal data structures.) Thread worker = new Thread("Error dump: " + dropboxTag) { @Override public void run() { //4.添加进程的状态到dropbox中 BufferedReader bufferedReader = null; String line; try { bufferedReader = new BufferedReader(new FileReader("/proc/" + pid + "/status")); for (int i = 0; i < 5; i++) { if ((line = bufferedReader.readLine()) != null && line.contains("State")) { sb.append(line + "\n"); break; } } } catch (IOException e) { e.printStackTrace(); } finally { if (bufferedReader != null) { try { bufferedReader.close(); } catch (IOException e) { e.printStackTrace(); } } }if (report != null) { sb.append(report); }String setting = Settings.Global.ERROR_LOGCAT_PREFIX + dropboxTag; int lines = Settings.Global.getInt(mContext.getContentResolver(), setting, 0); int maxDataFileSize = DROPBOX_MAX_SIZE - sb.length() - lines * RESERVED_BYTES_PER_LOGCAT_LINE; //5.将dataFile文件定入dropbox中,一般只有anr时,会将traces文件通过该参数传递进来者,其他类型都不传. if (dataFile != null && maxDataFileSize > 0) { try { sb.append(FileUtils.readTextFile(dataFile, maxDataFileSize, "\n\n[[TRUNCATED]]")); } catch (IOException e) { Slog.e(TAG, "Error reading " + dataFile, e); } }//6.如果是crash类型,会传入crashInfo,此时将其写入dropbox中 if (crashInfo != null && crashInfo.stackTrace != null) { sb.append(crashInfo.stackTrace); }if (lines > 0) { sb.append("\n"); // 7.合并几个logcat流,取最新部分log InputStreamReader input = null; try { java.lang.Process logcat = new ProcessBuilder( "/system/bin/timeout", "-k", "15s", "10s", "/system/bin/logcat", "-v", "threadtime", "-b", "events", "-b", "system", "-b", "main", "-b", "crash", "-t", String.valueOf(lines)) .redirectErrorStream(true).start(); try { logcat.getOutputStream().close(); } catch (IOException e) {} try { logcat.getErrorStream().close(); } catch (IOException e) {} input = new InputStreamReader(logcat.getInputStream()); int num; char[] buf = new char[8192]; while ((num = input.read(buf)) > 0) sb.append(buf, 0, num); } catch (IOException e) { Slog.e(TAG, "Error running logcat", e); } finally { if (input != null) try { input.close(); } catch (IOException e) {} } }...if (shouldReport) { synchronized (mErrorListenerLock) { try { if (mIApplicationErrorListener == null) { return; } //8.关键,在这里可以添加一个application error的接口，用来实现应用层接收崩溃信息 mIApplicationErrorListener.onError(fEventType, packageName, fProcessName, subject, dropboxTag + "-" + uuid, crashInfo); } catch (DeadObjectException e) { Slog.i(TAG, "ApplicationErrorListener.onError() E :" + e, e); mIApplicationErrorListener = null; } catch (Exception e) { Slog.i(TAG, "ApplicationErrorListener.onError() E :" + e, e); } } } } }; ... }
调用appendDropBoxProcessHeaders添加头部log信息:
private void appendDropBoxProcessHeaders(ProcessRecord process, String processName, StringBuilder sb) { // Watchdog thread ends up invoking this function (with // a null ProcessRecord) to add the stack file to dropbox. // Do not acquire a lock on this (am) in such cases, as it // could cause a potential deadlock, if and when watchdog // is invoked due to unavailability of lock on am and it // would prevent watchdog from killing system_server. if (process == null) { sb.append("Process: ").append(processName).append("\n"); return; } // Note: ProcessRecord 'process' is guarded by the service // instance.(notably process.pkgList, which could otherwise change // concurrently during execution of this method) synchronized (this) { sb.append("Process: ").append(processName).append("\n"); sb.append("PID: ").append(process.pid).append("\n"); int flags = process.info.flags; IPackageManager pm = AppGlobals.getPackageManager(); //添加该进程的flag sb.append("Flags: 0x").append(Integer.toHexString(flags)).append("\n"); for (int ip=0; ip【02.Android崩溃Crash库之App崩溃分析】

 
 项目地址：https://github.com/yangchong211/YCAndroidTool 



		  	

    
    




    
    
    


推荐阅读

           
                  
              
                  汽车积碳是什么意思 
                
                   
                
              
            

                  
              
                  redis多节点同步 
                
                   
                
              
            

                  
              
                  27岁有稳定工作,想用20万存款当做第二职业来投资,投资什么好呢？ 
                
                   
                
              
            

                  
              
                  上海戏剧学院分数线 2019年上海戏剧学院分数线 
                
                   
                
              
            

                  
              
                  去加拿大必买清单 去加拿大买什么最划算 
                
                   
                
              
            

                  
              
                  室内阳台养什么花最好 室内阳台适合养什么花好 
                
                   
                
              
            

                  
              
                  火理财什么时间可以申请债权转让？债权转让收费吗 
                
                   
                
              
            

                  
              
                  塑料菜板发黑怎么办 
                
                   
                
              
            

                  
              
                  癌细胞|癌细胞已经转移，为什么人的精神依旧很好，而且很能吃？是好事？ 
                
                   
                
              
            

                  
              
                  详细步骤及注意事项 g2810加墨水后如何操作 
                
                   
                
              
            

                  
              
                  佳能相机7100 佳能7100单反 
                
                   
                
              
            

                  
              
                  有什么好看的书推荐？ 
                
                   
                
              
            

                  
              
                  你喜欢看军事小说吗？ 
                
                   
                
              
            

                  
              
                  空气阻尼器时间继电器 空气阻尼器结构图 
                
                   
                
              
            

                  
              
                  2023春节坐高铁需要全程戴口罩吗 2021春节能坐高铁吗 
                
                   
                
              
            

                  
              
                  台高官被问“你有接受过性招待吗 
                
                   
                
              
            

                  
              
                  农村籍独生子女补贴如何领取？四类人无法领取有你吗？ 
                
                   
                
              
            

                  
              
                  甲氰菊酯有效是多久 甲氰菊酯药效是几天，水里多久失效 
                
                   
                
              
            

                  
              
                  c语言连接数据库函数 c语言数据库连接池 
                
                   
                
              
            

                  
              
                  有宠app怎么关闭资讯推送通知？有宠app关闭资讯推送通知的方法 
                
                   
                
              
            

          

深入理解|深入理解 Android 9.0 Crash 机制（二） 
 retrofit2-kotlin-coroutines-adapter|retrofit2-kotlin-coroutines-adapter 超时引起的崩溃 
 4月15号 
 当我崩溃时，思想是如此的自虐 
 单核处理器的崩溃 
 59管仲为什么要改革，姜子牙创立的齐国在齐桓公时已濒临崩溃（） 
 大鹏录制《奇遇人生》潸然落泪！网友（现代人崩溃就在一瞬间） 
 符号化二进制崩溃问题 
 Android|莫名Crash---目睹Baidu地图API之怪现象一 
 成年人，被藏起来的崩溃要如何调整（你的崩溃瞬间要这样做……）