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process_singleton_win.cc

 1 year ago
source link: https://source.chromium.org/chromium/chromium/src/+/main:chrome/browser/process_singleton_win.cc;l=386;drc=7f3bd3d40fffacda522b97ddfa94085a35d0a0c9
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process_singleton_win.cc - Chromium Code Search

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// 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.
#include <windows.h>
#include <shellapi.h>
#include <stddef.h>
#include "base/bind.h"
const char kLockfile[] = "lockfile";
// A helper class that acquires the given |mutex| while the AutoLockMutex is in
// scope.
class AutoLockMutex {
public:
TRACE_EVENT0("startup",
"ProcessSingleton:AutoLockMutex:WaitForSingleObject");
DWORD result = ::WaitForSingleObject(mutex_, INFINITE);
DPCHECK(result == WAIT_OBJECT_0) << "Result = " << result;
BOOL released = ::ReleaseMutex(mutex_);
private:
// Checks the visibility of the enumerated window and signals once a visible
// window has been found.
bool* result = reinterpret_cast<bool*>(param);
*result = ::IsWindowVisible(window) != 0;
// Stops enumeration if a visible window has been found.
return !*result;
bool ParseCommandLine(const COPYDATASTRUCT* cds,
// We should have enough room for the shortest command (min_message_size)
// and also be a multiple of wchar_t bytes. The shortest command
// possible is L"START\0\0" (empty current directory and command line).
static const int min_message_size = 7;
if (cds->cbData < min_message_size * sizeof(wchar_t) ||
cds->cbData % sizeof(wchar_t) != 0) {
LOG(WARNING) << "Invalid WM_COPYDATA, length = " << cds->cbData;
return false;
// We split the string into 4 parts on NULLs.
DCHECK(cds->lpData);
const std::wstring msg(static_cast<wchar_t*>(cds->lpData),
cds->cbData / sizeof(wchar_t));
const std::wstring::size_type first_null = msg.find_first_of(L'\0');
if (first_null == 0 || first_null == std::wstring::npos) {
// no NULL byte, don't know what to do
LOG(WARNING) << "Invalid WM_COPYDATA, length = " << msg.length() <<
", first null = " << first_null;
return false;
// Decode the command, which is everything until the first NULL.
if (msg.substr(0, first_null) == L"START") {
// Another instance is starting parse the command line & do what it would
// have done.
VLOG(1) << "Handling STARTUP request from another process";
const std::wstring::size_type second_null =
msg.find_first_of(L'\0', first_null + 1);
if (second_null == std::wstring::npos ||
first_null == msg.length() - 1 || second_null == msg.length()) {
LOG(WARNING) << "Invalid format for start command, we need a string in 4 "
"parts separated by NULLs";
return false;
// Get current directory.
*current_directory = base::FilePath(msg.substr(first_null + 1,
second_null - first_null));
const std::wstring::size_type third_null =
msg.find_first_of(L'\0', second_null + 1);
if (third_null == std::wstring::npos ||
third_null == msg.length()) {
LOG(WARNING) << "Invalid format for start command, we need a string in 4 "
"parts separated by NULLs";
// Get command line.
msg.substr(second_null + 1, third_null - second_null);
*parsed_command_line = base::CommandLine::FromString(cmd_line);
return true;
return false;
if (message != WM_COPYDATA)
return false;
TRACE_EVENT0("startup", "ProcessSingleton:ProcessLaunchNotification");
// Handle the WM_COPYDATA message from another process.
const COPYDATASTRUCT* cds = reinterpret_cast<COPYDATASTRUCT*>(lparam);
if (!ParseCommandLine(cds, &parsed_command_line, &current_directory)) {
*result = TRUE;
return true;
*result = notification_callback.Run(parsed_command_line, current_directory) ?
TRUE : FALSE;
return true;
TRACE_EVENT0("startup", "ProcessSingleton:DisplayShouldKillMessageBox");
return chrome::ShowQuestionMessageBoxSync(
// Function was copied from Process::Terminate.
int exit_code) {
TRACE_EVENT0("startup", "ProcessSingleton:TerminateProcessWithHistograms");
bool result = (::TerminateProcess(process.Handle(), exit_code) != FALSE);
if (result) {
// The process may not end immediately due to pending I/O
TRACE_EVENT0("startup",
"ProcessSingleton:TerminateProcessWithHistograms:"
"WaitForSingleObject");
wait_result = ::WaitForSingleObject(process.Handle(), 60 * 1000);
if (wait_result != WAIT_OBJECT_0) {
if (wait_result == WAIT_FAILED)
DPLOG(ERROR) << "Error waiting for process exit";
} else {
UMA_HISTOGRAM_TIMES("Chrome.ProcessSingleton.TerminateProcessTime",
"Chrome.ProcessSingleton.TerminationWaitErrorCode.Windows", wait_error);
} else {
DPLOG(ERROR) << "Unable to terminate process";
"Chrome.ProcessSingleton.TerminateProcessErrorCode.Windows",
} // namespace
// Microsoft's Softricity virtualization breaks the sandbox processes.
// So, if we detect the Softricity DLL we use WMI Win32_Process.Create to
// break out of the virtualization environment.
TRACE_EVENT0("startup", "ProcessSingleton:EscapeVirtualization");
if (::GetModuleHandle(L"sftldr_wow64.dll") ||
::GetModuleHandle(L"sftldr.dll")) {
int process_id;
if (!base::win::WmiLaunchProcess(::GetCommandLineW(), &process_id))
return false;
is_virtualized_ = true;
// The new window was spawned from WMI, and won't be in the foreground.
// So, first we sleep while the new chrome.exe instance starts (because
// WaitForInputIdle doesn't work here). Then we poll for up to two more
// seconds and make the window foreground if we find it (or we give up).
::Sleep(90);
for (int tries = 200; tries; --tries) {
if (hwnd) {
::SetForegroundWindow(hwnd);
break;
::Sleep(10);
return true;
return false;
: notification_callback_(notification_callback),
is_virtualized_(false),
user_data_dir_(user_data_dir),
should_kill_remote_process_callback_(
base::BindRepeating(&DisplayShouldKillMessageBox)) {}
DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
::CloseHandle(lock_file_);
// Code roughly based on Mozilla.
TRACE_EVENT0("startup", "ProcessSingleton::NotifyOtherProcess");
return PROCESS_NOTIFIED; // We already spawned the process in this case.
return LOCK_ERROR;
} else if (!remote_window_) {
return PROCESS_NONE;
case chrome::NOTIFY_SUCCESS:
case chrome::NOTIFY_FAILED:
return PROCESS_NONE;
case chrome::NOTIFY_WINDOW_HUNG:
// Fall through and potentially terminate the hung browser.
break;
// The window is hung.
DWORD thread_id = ::GetWindowThreadProcessId(remote_window_, &process_id);
"startup",
"ProcessSingleton::NotifyOtherProcess:GetWindowThreadProcessId failed");
return PROCESS_NONE;
// Get a handle to the process that created the window.
// Scan for every window to find a visible one.
bool visible_window = false;
TRACE_EVENT0("startup",
"ProcessSingleton::NotifyOtherProcess:EnumThreadWindows");
::EnumThreadWindows(thread_id, &BrowserWindowEnumeration,
reinterpret_cast<LPARAM>(&visible_window));
// If there is a visible browser window, ask the user before killing it.
if (visible_window && !should_kill_remote_process_callback_.Run()) {
// The user denied. Quit silently.
// Time to take action. Kill the browser process.
return PROCESS_NONE;
TRACE_EVENT0("startup", "ProcessSingleton::NotifyOtherProcessOrCreate");
for (int i = 0; i < 2; ++i) {
if (Create()) {
UMA_HISTOGRAM_MEDIUM_TIMES("Chrome.ProcessSingleton.TimeToCreate",
return PROCESS_NONE; // This is the single browser process.
UMA_HISTOGRAM_MEDIUM_TIMES("Chrome.ProcessSingleton.TimeToNotify",
} else {
UMA_HISTOGRAM_MEDIUM_TIMES("Chrome.ProcessSingleton.TimeToFailure",
// The single browser process was notified, the user chose not to
// terminate a hung browser, or the lock file could not be created.
// Nothing more to do.
return result;
// The process could not be notified for some reason, or it was hung and
// terminated. Retry once if this is the first time; otherwise, fall through
// to report that the process must exit because the profile is in use.
UMA_HISTOGRAM_MEDIUM_TIMES("Chrome.ProcessSingleton.TimeToFailure",
return PROFILE_IN_USE;
// Look for a Chrome instance that uses the same profile directory. If there
// isn't one, create a message window with its title set to the profile
// directory path.
TRACE_EVENT0("startup", "ProcessSingleton::Create");
static const wchar_t kMutexName[] = L"Local\\ChromeProcessSingletonStartup!";
remote_window_ = chrome::FindRunningChromeWindow(user_data_dir_);
if (!remote_window_ && !EscapeVirtualization(user_data_dir_)) {
// Make sure we will be the one and only process creating the window.
// We use a named Mutex since we are protecting against multi-process
// access. As documented, it's clearer to NOT request ownership on creation
// since it isn't guaranteed we will get it. It is better to create it
// without ownership and explicitly get the ownership afterward.
base::win::ScopedHandle only_me(::CreateMutex(NULL, FALSE, kMutexName));
if (!only_me.IsValid()) {
DPLOG(FATAL) << "CreateMutex failed";
return false;
// We now own the mutex so we are the only process that can create the
// window at this time, but we must still check if someone created it
// between the time where we looked for it above and the time the mutex
// was given to us.
remote_window_ = chrome::FindRunningChromeWindow(user_data_dir_);
if (!remote_window_) {
// We have to make sure there is no Chrome instance running on another
// machine that uses the same profile.
TRACE_EVENT0("startup", "ProcessSingleton::Create:CreateLockFile");
base::FilePath lock_file_path = user_data_dir_.AppendASCII(kLockfile);
lock_file_ = ::CreateFile(
lock_file_path.value().c_str(), GENERIC_WRITE, FILE_SHARE_READ,
NULL, CREATE_ALWAYS,
FILE_ATTRIBUTE_NORMAL | FILE_FLAG_DELETE_ON_CLOSE, NULL);
error == ERROR_ALREADY_EXISTS) << "Lock file exists but is writable.";
<< "Lock file can not be created! Error code: " << error;
// Set the window's title to the path of our user data directory so
// other Chrome instances can decide if they should forward to us.
TRACE_EVENT0("startup", "ProcessSingleton::Create:CreateWindow");
bool result =
window_.CreateNamed(base::BindRepeating(&ProcessLaunchNotification,
notification_callback_),
user_data_dir_.value());
CHECK(result && window_.hwnd());
return window_.hwnd() != NULL;
should_kill_remote_process_callback_ = display_dialog_callback;

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