/*
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* Copyright (C) 2018 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.android.server;
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import android.util.Log;
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import android.util.LogWriter;
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import android.util.Slog;
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import com.android.internal.annotations.VisibleForTesting;
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import com.android.server.Watchdog.HandlerChecker;
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import dalvik.system.AnnotatedStackTraceElement;
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import dalvik.system.VMStack;
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import java.io.PrintWriter;
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import java.util.List;
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/**
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* Class to give diagnostic messages for Watchdogs.
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*/
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class WatchdogDiagnostics {
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private static String getBlockedOnString(Object blockedOn) {
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return String.format("- waiting to lock <0x%08x> (a %s)",
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System.identityHashCode(blockedOn), blockedOn.getClass().getName());
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}
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private static String getLockedString(Object heldLock) {
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return String.format("- locked <0x%08x> (a %s)", System.identityHashCode(heldLock),
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heldLock.getClass().getName());
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}
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/**
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* Print the annotated stack for the given thread. If the annotated stack cannot be retrieved,
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* returns false.
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*/
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@VisibleForTesting
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public static boolean printAnnotatedStack(Thread thread, PrintWriter out) {
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AnnotatedStackTraceElement stack[] = VMStack.getAnnotatedThreadStackTrace(thread);
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if (stack == null) {
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return false;
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}
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out.println(thread.getName() + " annotated stack trace:");
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for (AnnotatedStackTraceElement element : stack) {
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out.println(" at " + element.getStackTraceElement());
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if (element.getBlockedOn() != null) {
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out.println(" " + getBlockedOnString(element.getBlockedOn()));
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}
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if (element.getHeldLocks() != null) {
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for (Object held : element.getHeldLocks()) {
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out.println(" " + getLockedString(held));
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}
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}
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}
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return true;
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}
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public static void diagnoseCheckers(final List<HandlerChecker> blockedCheckers) {
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PrintWriter out = new PrintWriter(new LogWriter(Log.WARN, Watchdog.TAG, Log.LOG_ID_SYSTEM),
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true);
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for (int i=0; i<blockedCheckers.size(); i++) {
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Thread blockedThread = blockedCheckers.get(i).getThread();
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if (printAnnotatedStack(blockedThread, out)) {
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continue;
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}
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// Fall back to "regular" stack trace, if necessary.
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Slog.w(Watchdog.TAG, blockedThread.getName() + " stack trace:");
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StackTraceElement[] stackTrace = blockedThread.getStackTrace();
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for (StackTraceElement element : stackTrace) {
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Slog.w(Watchdog.TAG, " at " + element);
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}
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}
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}
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}
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