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