blob: 8913fd7c73235bb9c9e0fe89806822a4d378762c [file] [log] [blame]
// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// This test validates that the ProcessSingleton class properly makes sure
// that there is only one main browser process.
// It is currently compiled and run on Windows and Posix(non-Mac) platforms.
// Mac uses system services and ProcessSingletonMac is a noop. (Maybe it still
// makes sense to test that the system services are giving the behavior we
// want?)
#include <stddef.h>
#include <memory>
#include "base/bind.h"
#include "base/command_line.h"
#include "base/files/file_path.h"
#include "base/files/scoped_temp_dir.h"
#include "base/location.h"
#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "base/path_service.h"
#include "base/process/launch.h"
#include "base/process/process.h"
#include "base/process/process_iterator.h"
#include "base/single_thread_task_runner.h"
#include "base/synchronization/waitable_event.h"
#include "base/test/test_timeouts.h"
#include "base/threading/thread.h"
#include "build/build_config.h"
#include "chrome/common/chrome_constants.h"
#include "chrome/common/chrome_paths.h"
#include "chrome/common/chrome_result_codes.h"
#include "chrome/common/chrome_switches.h"
#include "chrome/test/base/in_process_browser_test.h"
#include "chrome/test/base/test_launcher_utils.h"
#include "testing/gmock/include/gmock/gmock.h"
using ::testing::AnyOf;
using ::testing::Eq;
namespace {
// This is for the code that is to be ran in multiple threads at once,
// to stress a race condition on first process start.
// We use the thread safe ref counted base class so that we can use the
// base::Bind to run the StartChrome methods in many threads.
class ChromeStarter : public base::RefCountedThreadSafe<ChromeStarter> {
ChromeStarter(base::TimeDelta timeout,
const base::FilePath& user_data_dir,
const base::CommandLine& initial_command_line_for_relaunch)
: ready_event_(base::WaitableEvent::ResetPolicy::AUTOMATIC,
initial_command_line_for_relaunch_(initial_command_line_for_relaunch) {}
// We must reset some data members since we reuse the same ChromeStarter
// object and start/stop it a few times. We must start fresh! :-)
void Reset() {
if (process_.IsValid())
process_terminated_ = false;
void StartChrome(base::WaitableEvent* start_event, bool first_run) {
base::CommandLine command_line_for_relaunch(
initial_command_line_for_relaunch_, switches::kUserDataDir,
if (first_run) {
base::CommandLine tmp_command_line = command_line_for_relaunch;
tmp_command_line, switches::kNoFirstRun, &command_line_for_relaunch);
// Try to get all threads to launch the app at the same time.
// So let the test know we are ready.
// And then wait for the test to tell us to GO!
ASSERT_NE(nullptr, start_event);
// Here we don't wait for the app to be terminated because one of the
// process will stay alive while the others will be restarted. If we would
// wait here, we would never get a handle to the main process...
process_ =
base::LaunchProcess(command_line_for_relaunch, base::LaunchOptions());
// We can wait on the handle here, we should get stuck on one and only
// one process. The test below will take care of killing that process
// to unstuck us once it confirms there is only one.
process_terminated_ =
process_.WaitForExitWithTimeout(timeout_, &exit_code_);
// Let the test know we are done.
// Public access to simplify the test code using them.
base::WaitableEvent ready_event_;
base::WaitableEvent done_event_;
base::Process process_;
bool process_terminated_;
// Process exit code. Only meaningful if |process_terminated_| is true.
int exit_code_;
friend class base::RefCountedThreadSafe<ChromeStarter>;
~ChromeStarter() {}
base::TimeDelta timeout_;
base::FilePath user_data_dir_;
base::CommandLine initial_command_line_for_relaunch_;
} // namespace
// Our test fixture that initializes and holds onto a few global vars.
class ProcessSingletonTest : public InProcessBrowserTest {
// We use a manual reset so that all threads wake up at once when signaled
// and thus we must manually reset it for each attempt.
: threads_waker_(base::WaitableEvent::ResetPolicy::MANUAL,
base::WaitableEvent::InitialState::NOT_SIGNALED) {
void TearDown() override {
// Stop the threads.
for (size_t i = 0; i < kNbThreads; ++i)
// This method is used to make sure we kill the main browser process after
// all of its child processes have successfully attached to it. This was added
// when we realized that if we just kill the parent process right away, we
// sometimes end up with dangling child processes. If we Sleep for a certain
// amount of time, we are OK... So we introduced this method to avoid a
// flaky wait. Instead, we kill all descendants of the main process after we
// killed it, relying on the fact that we can still get the parent id of a
// child process, even when the parent dies.
void KillProcessTree(const base::Process& process) {
class ProcessTreeFilter : public base::ProcessFilter {
explicit ProcessTreeFilter(base::ProcessId parent_pid) {
bool Includes(const base::ProcessEntry& entry) const override {
if (ancestor_pids_.find(entry.parent_pid()) != ancestor_pids_.end()) {
return true;
} else {
return false;
mutable std::set<base::ProcessId> ancestor_pids_;
} process_tree_filter(process.Pid());
// Start by explicitly killing the main process we know about...
static const int kExitCode = 42;
EXPECT_TRUE(process.Terminate(kExitCode, true /* wait */));
// Then loop until we can't find any of its descendant.
// But don't try more than kNbTries times...
static const int kNbTries = 10;
int num_tries = 0;
base::FilePath program;
ASSERT_TRUE(base::PathService::Get(base::FILE_EXE, &program));
base::FilePath::StringType exe_name = program.BaseName().value();
while (base::GetProcessCount(exe_name, &process_tree_filter) > 0 &&
num_tries++ < kNbTries) {
base::KillProcesses(exe_name, kExitCode, &process_tree_filter);
DLOG_IF(ERROR, num_tries >= kNbTries) << "Failed to kill all processes!";
// Since this is a hard to reproduce problem, we make a few attempts.
// We stop the attempts at the first error, and when there are no errors,
// we don't time-out of any wait, so it executes quite fast anyway.
static const size_t kNbAttempts = 5;
// The idea is to start chrome from multiple threads all at once.
static const size_t kNbThreads = 5;
scoped_refptr<ChromeStarter> chrome_starters_[kNbThreads];
std::unique_ptr<base::Thread> chrome_starter_threads_[kNbThreads];
// The event that will get all threads to wake up simultaneously and try
// to start a chrome process at the same time.
base::WaitableEvent threads_waker_;
// We don't want to use the default profile, but can't use UITest's since we
// don't use UITest::LaunchBrowser.
base::ScopedTempDir temp_profile_dir_;
// ChromeOS hits DCHECKS on ProcessSingleton rendezvous:
#if defined(OS_CHROMEOS) || defined(OS_LINUX) || defined(OS_WIN)
#define MAYBE_StartupRaceCondition DISABLED_StartupRaceCondition
#define MAYBE_StartupRaceCondition StartupRaceCondition
IN_PROC_BROWSER_TEST_F(ProcessSingletonTest, MAYBE_StartupRaceCondition) {
// Start the threads and create the starters.
for (size_t i = 0; i < kNbThreads; ++i) {
chrome_starter_threads_[i] =
chrome_starters_[i] = base::MakeRefCounted<ChromeStarter>(
TestTimeouts::action_max_timeout(), temp_profile_dir_.GetPath(),
for (size_t attempt = 0; attempt < kNbAttempts && !HasFailure(); ++attempt) {
SCOPED_TRACE(testing::Message() << "Attempt: " << attempt << ".");
// We use a single event to get all threads to do the AppLaunch at the
// same time...
// Test both with and without the first-run dialog, since they exercise
// different paths.
#if defined(OS_POSIX)
// TODO(mattm): test first run dialog singleton handling on linux too.
// On posix if we test the first run dialog, GracefulShutdownHandler gets
// the TERM signal, but since the message loop isn't running during the gtk
// first run dialog, the ShutdownDetector never handles it, and KillProcess
// has to time out (60 sec!) and SIGKILL.
bool first_run = false;
// Test for races in both regular start up and first run start up cases.
bool first_run = attempt % 2;
// Here we prime all the threads with a ChromeStarter that will wait for
// our signal to launch its chrome process.
for (size_t i = 0; i < kNbThreads; ++i) {
ASSERT_NE(static_cast<ChromeStarter*>(NULL), chrome_starters_[i].get());
base::BindOnce(&ChromeStarter::StartChrome, chrome_starters_[i],
&threads_waker_, first_run));
// Wait for all the starters to be ready.
// We could replace this loop if we ever implement a WaitAll().
for (size_t i = 0; i < kNbThreads; ++i) {
SCOPED_TRACE(testing::Message() << "Waiting on thread: " << i << ".");
// GO!
// As we wait for all threads to signal that they are done, we remove their
// index from this vector so that we get left with only the index of
// the thread that started the main process.
std::vector<size_t> pending_starters(kNbThreads);
for (size_t i = 0; i < kNbThreads; ++i)
pending_starters[i] = i;
// We use a local array of starter's done events we must wait on...
// These are collected from the starters that we have not yet been removed
// from the pending_starters vector.
base::WaitableEvent* starters_done_events[kNbThreads];
// At the end, "There can be only one" main browser process alive.
while (pending_starters.size() > 1) {
SCOPED_TRACE(testing::Message() << pending_starters.size() <<
" starters left.");
for (size_t i = 0; i < pending_starters.size(); ++i) {
starters_done_events[i] =
size_t done_index = base::WaitableEvent::WaitMany(
starters_done_events, pending_starters.size());
size_t starter_index = pending_starters[done_index];
// If the starter is done but has not marked itself as terminated,
// it is because it timed out of its WaitForExitCodeWithTimeout(). Only
// the last one standing should be left waiting... So we failed...
<< "There is more than one main process.";
if (chrome_starters_[starter_index]->process_terminated_) {
// Generally PROCESS_NOTIFIED would be the expected exit code. In some
// rare cases the ProcessSingleton race can result in PROFILE_IN_USE
// exit code, which we also allow, though it would be ideal if that
// never happened.
// TODO(mattm): investigate why PROFILE_IN_USE occurs sometimes.
} else {
// But we let the last loop turn finish so that we can properly
// kill all remaining processes. Starting with this one...
if (chrome_starters_[starter_index]->process_.IsValid()) {
pending_starters.erase(pending_starters.begin() + done_index);
// "There can be only one!" :-)
ASSERT_EQ(static_cast<size_t>(1), pending_starters.size());
size_t last_index = pending_starters.front();
if (chrome_starters_[last_index]->process_.IsValid()) {