electron/shell/browser/relauncher_mac.cc

93 lines
2.9 KiB
C++

// Copyright (c) 2016 GitHub, Inc.
// Use of this source code is governed by the MIT license that can be
// found in the LICENSE file.
#include "shell/browser/relauncher.h"
#include <sys/event.h>
#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>
#include "base/apple/osstatus_logging.h"
#include "base/files/file_util.h"
#include "base/files/scoped_file.h"
#include "base/logging.h"
#include "base/posix/eintr_wrapper.h"
#include "base/process/launch.h"
namespace relauncher::internal {
void RelauncherSynchronizeWithParent() {
base::ScopedFD relauncher_sync_fd(kRelauncherSyncFD);
int parent_pid = getppid();
// PID 1 identifies init. launchd, that is. launchd never starts the
// relauncher process directly, having this parent_pid means that the parent
// already exited and launchd "inherited" the relauncher as its child.
// There's no reason to synchronize with launchd.
if (parent_pid == 1) {
LOG(ERROR) << "unexpected parent_pid";
return;
}
// Set up a kqueue to monitor the parent process for exit.
base::ScopedFD kq(kqueue());
if (!kq.is_valid()) {
PLOG(ERROR) << "kqueue";
return;
}
struct kevent change = {0};
EV_SET(&change, parent_pid, EVFILT_PROC, EV_ADD, NOTE_EXIT, 0, nullptr);
if (kevent(kq.get(), &change, 1, nullptr, 0, nullptr) == -1) {
PLOG(ERROR) << "kevent (add)";
return;
}
// Write a '\0' character to the pipe.
if (HANDLE_EINTR(write(relauncher_sync_fd.get(), "", 1)) != 1) {
PLOG(ERROR) << "write";
return;
}
// Up until now, the parent process was blocked in a read waiting for the
// write above to complete. The parent process is now free to exit. Wait for
// that to happen.
struct kevent event;
int events = kevent(kq.get(), nullptr, 0, &event, 1, nullptr);
if (events != 1) {
if (events < 0) {
PLOG(ERROR) << "kevent (monitor)";
} else {
LOG(ERROR) << "kevent (monitor): unexpected result " << events;
}
return;
}
if (event.filter != EVFILT_PROC || event.fflags != NOTE_EXIT ||
event.ident != static_cast<uintptr_t>(parent_pid)) {
LOG(ERROR) << "kevent (monitor): unexpected event, filter " << event.filter
<< ", fflags " << event.fflags << ", ident " << event.ident;
return;
}
}
int LaunchProgram(const StringVector& relauncher_args,
const StringVector& argv) {
// Redirect the stdout of child process to /dev/null, otherwise after
// relaunch the child process will raise exception when writing to stdout.
base::ScopedFD devnull(HANDLE_EINTR(open("/dev/null", O_WRONLY)));
base::LaunchOptions options;
options.new_process_group = true; // detach
options.fds_to_remap.emplace_back(devnull.get(), STDERR_FILENO);
options.fds_to_remap.emplace_back(devnull.get(), STDOUT_FILENO);
base::Process process = base::LaunchProcess(argv, options);
return process.IsValid() ? 0 : 1;
}
} // namespace relauncher::internal