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/*
* Copyright (C) 2020 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <signal.h>
#include <sys/time.h>
#include <unistd.h>
#include <algorithm>
#include <mutex>
#include <thread>
#include <android-base/logging.h>
#include <android-base/parsebool.h>
#include <android-base/parseint.h>
#include <android-base/properties.h>
#include <android-base/thread_annotations.h>
#include "property_monitor.h"
static constexpr char kAdbWatchdogProperty[] = "persist.adb.watchdog";
static constexpr char kTestHarnessProperty[] = "persist.sys.test_harness";
static constexpr unsigned int kDefaultAdbWatchdogTimeoutSeconds = 600;
static unsigned int g_watchdog_timeout_seconds;
static std::mutex g_watchdog_mutex [[clang::no_destroy]];
// The watchdog is "running" when it's enabled via property and there are no connected clients.
static bool g_watchdog_running GUARDED_BY(g_watchdog_mutex) = false;
static PropertyMonitor g_property_monitor [[clang::no_destroy]];
static void UpdateWatchdog() REQUIRES(g_watchdog_mutex) {
static std::once_flag once;
std::call_once(once, []() {
signal(SIGALRM, [](int) {
execl("/system/bin/reboot", "/system/bin/reboot", "bootloader", nullptr);
});
});
static bool alarm_set = false;
static auto Arm = []() {
LOG(INFO) << "adb watchdog armed, triggering in " << g_watchdog_timeout_seconds
<< " seconds";
alarm(g_watchdog_timeout_seconds);
alarm_set = true;
};
static auto Disarm = []() {
unsigned int previous = alarm(0);
if (previous != 0) {
LOG(INFO) << "adb watchdog disarmed with " << previous << " seconds left";
}
alarm_set = false;
};
bool watchdog_enabled = android::base::GetBoolProperty(
kAdbWatchdogProperty, android::base::GetBoolProperty(kTestHarnessProperty, false));
if (!watchdog_enabled) {
if (alarm_set) {
Disarm();
}
return;
}
if (g_watchdog_running) {
if (!alarm_set) {
Arm();
}
} else {
Disarm();
}
}
namespace watchdog {
void Start() {
std::lock_guard<std::mutex> lock(g_watchdog_mutex);
g_watchdog_running = true;
UpdateWatchdog();
}
void Stop() {
std::lock_guard<std::mutex> lock(g_watchdog_mutex);
g_watchdog_running = false;
UpdateWatchdog();
}
void Initialize() {
for (auto& property : {kAdbWatchdogProperty, kTestHarnessProperty}) {
g_property_monitor.Add(property, [property](std::string value) {
LOG(INFO) << property << " set to '" << value << "'";
std::lock_guard<std::mutex> lock(g_watchdog_mutex);
UpdateWatchdog();
return true;
});
}
g_property_monitor.Add("persist.adb.watchdog.timeout_secs", [](std::string value) {
// This presumably isn't going to change while the watchdog is armed,
// so we don't need to recalculate a timer.
{
std::lock_guard<std::mutex> lock(g_watchdog_mutex);
if (!android::base::ParseUint(value, &g_watchdog_timeout_seconds)) {
g_watchdog_timeout_seconds = kDefaultAdbWatchdogTimeoutSeconds;
}
}
LOG(INFO) << "adb watchdog timeout set to " << g_watchdog_timeout_seconds << " seconds";
return true;
});
Start();
std::thread([]() { g_property_monitor.Run(); }).detach();
}
} // namespace watchdog