1c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved. 2c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// Use of this source code is governed by a BSD-style license that can be 3c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// found in the LICENSE file. 4c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 5c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott#include "base/watchdog.h" 6c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 7c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott#include "base/compiler_specific.h" 8c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott#include "base/platform_thread.h" 9c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 10c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scottusing base::TimeDelta; 11c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scottusing base::TimeTicks; 12c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 13c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott//------------------------------------------------------------------------------ 14c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// Public API methods. 15c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 16c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// Start thread running in a Disarmed state. 17c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick ScottWatchdog::Watchdog(const TimeDelta& duration, 18c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott const std::string& thread_watched_name, 19c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott bool enabled) 20c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott : init_successful_(false), 21c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott lock_(), 22c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott condition_variable_(&lock_), 23c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott state_(DISARMED), 24c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott duration_(duration), 25c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott thread_watched_name_(thread_watched_name), 26c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott ALLOW_THIS_IN_INITIALIZER_LIST(delegate_(this)) { 27c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott if (!enabled) 28c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott return; // Don't start thread, or doing anything really. 29c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott init_successful_ = PlatformThread::Create(0, // Default stack size. 30c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott &delegate_, 31c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott &handle_); 32c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott DCHECK(init_successful_); 33c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott} 34c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 35c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// Notify watchdog thread, and wait for it to finish up. 36c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick ScottWatchdog::~Watchdog() { 37c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott if (!init_successful_) 38c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott return; 39c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott { 40c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott AutoLock lock(lock_); 41c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott state_ = SHUTDOWN; 42c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott } 43c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott condition_variable_.Signal(); 44c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott PlatformThread::Join(handle_); 45c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott} 46c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 47c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scottvoid Watchdog::Arm() { 48c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott ArmAtStartTime(TimeTicks::Now()); 49c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott} 50c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 51c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scottvoid Watchdog::ArmSomeTimeDeltaAgo(const TimeDelta& time_delta) { 52c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott ArmAtStartTime(TimeTicks::Now() - time_delta); 53c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott} 54c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 55c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// Start clock for watchdog. 56c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scottvoid Watchdog::ArmAtStartTime(const TimeTicks start_time) { 57c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott { 58c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott AutoLock lock(lock_); 59c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott start_time_ = start_time; 60c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott state_ = ARMED; 61c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott } 62c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // Force watchdog to wake up, and go to sleep with the timer ticking with the 63c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // proper duration. 64c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott condition_variable_.Signal(); 65c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott} 66c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 67c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// Disable watchdog so that it won't do anything when time expires. 68c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scottvoid Watchdog::Disarm() { 69c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott AutoLock lock(lock_); 70c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott state_ = DISARMED; 71c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // We don't need to signal, as the watchdog will eventually wake up, and it 72c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // will check its state and time, and act accordingly. 73c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott} 74c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 75c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott//------------------------------------------------------------------------------ 76c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// Internal private methods that the watchdog thread uses. 77c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 78c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scottvoid Watchdog::ThreadDelegate::ThreadMain() { 79c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott SetThreadName(); 80c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott TimeDelta remaining_duration; 81c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott while (1) { 82c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott AutoLock lock(watchdog_->lock_); 83c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott while (DISARMED == watchdog_->state_) 84c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott watchdog_->condition_variable_.Wait(); 85c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott if (SHUTDOWN == watchdog_->state_) 86c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott return; 87c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott DCHECK(ARMED == watchdog_->state_); 88c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott remaining_duration = watchdog_->duration_ - 89c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott (TimeTicks::Now() - watchdog_->start_time_); 90c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott if (remaining_duration.InMilliseconds() > 0) { 91c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // Spurios wake? Timer drifts? Go back to sleep for remaining time. 92c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott watchdog_->condition_variable_.TimedWait(remaining_duration); 93c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott continue; 94c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott } 95c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // We overslept, so this seems like a real alarm. 96c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // Watch out for a user that stopped the debugger on a different alarm! 97c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott { 98c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott AutoLock static_lock(static_lock_); 99c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott if (last_debugged_alarm_time_ > watchdog_->start_time_) { 100c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // False alarm: we started our clock before the debugger break (last 101c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // alarm time). 102c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott watchdog_->start_time_ += last_debugged_alarm_delay_; 103c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott if (last_debugged_alarm_time_ > watchdog_->start_time_) 104c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // Too many alarms must have taken place. 105c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott watchdog_->state_ = DISARMED; 106c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott continue; 107c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott } 108c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott } 109c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott watchdog_->state_ = DISARMED; // Only alarm at most once. 110c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott TimeTicks last_alarm_time = TimeTicks::Now(); 111c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott watchdog_->Alarm(); // Set a break point here to debug on alarms. 112c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott TimeDelta last_alarm_delay = TimeTicks::Now() - last_alarm_time; 113c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott if (last_alarm_delay <= TimeDelta::FromMilliseconds(2)) 114c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott continue; 115c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // Ignore race of two alarms/breaks going off at roughly the same time. 116c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott AutoLock static_lock(static_lock_); 117c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // This was a real debugger break. 118c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott last_debugged_alarm_time_ = last_alarm_time; 119c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott last_debugged_alarm_delay_ = last_alarm_delay; 120c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott } 121c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott} 122c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 123c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scottvoid Watchdog::ThreadDelegate::SetThreadName() const { 124c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott std::string name = watchdog_->thread_watched_name_ + " Watchdog"; 125c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott PlatformThread::SetName(name.c_str()); 126c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott DLOG(INFO) << "Watchdog active: " << name; 127c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott} 128c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 129c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// static 130c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scottvoid Watchdog::ResetStaticData() { 131c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott AutoLock lock(static_lock_); 132c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott last_debugged_alarm_time_ = TimeTicks(); 133c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott last_debugged_alarm_delay_ = TimeDelta(); 134c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott} 135c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 136c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// static 137c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick ScottLock Watchdog::static_lock_; // Lock for access of static data... 138c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// static 139c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick ScottTimeTicks Watchdog::last_debugged_alarm_time_ = TimeTicks(); 140c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// static 141c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick ScottTimeDelta Watchdog::last_debugged_alarm_delay_; 142