chromium/chrome/browser/shutdown_signal_handlers_posix.cc

// Copyright 2017 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifdef UNSAFE_BUFFERS_BUILD
// TODO(crbug.com/40285824): Remove this and convert code to safer constructs.
#pragma allow_unsafe_buffers
#endif

#include "chrome/browser/shutdown_signal_handlers_posix.h"

#include <limits.h>
#include <signal.h>
#include <string.h>
#include <unistd.h>

#include <utility>

#include "base/debug/leak_annotations.h"
#include "base/functional/callback.h"
#include "base/logging.h"
#include "base/posix/eintr_wrapper.h"
#include "base/task/single_thread_task_runner.h"
#include "base/threading/platform_thread.h"

namespace {

// The OSX fork() implementation can crash in the child process before
// fork() returns.  In that case, the shutdown pipe will still be
// shared with the parent process.  To prevent child crashes from
// causing parent shutdowns, |g_pipe_pid| is the pid for the process
// which registered |g_shutdown_pipe_write_fd|.
// See <http://crbug.com/175341>.
pid_t g_pipe_pid = …;
int g_shutdown_pipe_write_fd = …;
int g_shutdown_pipe_read_fd = …;

// Common code between SIG{HUP, INT, TERM}Handler.
void GracefulShutdownHandler(int signal) { … }

void SIGHUPHandler(int signal) { … }

void SIGINTHandler(int signal) { … }

void SIGTERMHandler(int signal) { … }

// Runs a thread that invokes a callback when a termination signal handler
// is invoked. Uses a pipe to wait for the signal handler to run.
class ShutdownDetector : public base::PlatformThread::Delegate { … };

ShutdownDetector::ShutdownDetector(
    int shutdown_fd,
    base::OnceCallback<void(int)> shutdown_callback,
    const scoped_refptr<base::SingleThreadTaskRunner>& task_runner)
    : … { … }

ShutdownDetector::~ShutdownDetector() { … }

// These functions are used to help us diagnose crash dumps that happen
// during the shutdown process.
NOINLINE void ShutdownFDReadError() { … }

NOINLINE void ShutdownFDClosedError() { … }

NOINLINE void ExitPosted() { … }

void ShutdownDetector::ThreadMain() { … }

}  // namespace

void InstallShutdownSignalHandlers(
    base::OnceCallback<void(int)> shutdown_callback,
    const scoped_refptr<base::SingleThreadTaskRunner>& task_runner) { … }