refactor: rename the atom directory to shell

shell/browser/relauncher_linux.cc

@@ -0,0 +1,73 @@
+// 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 "atom/browser/relauncher.h"
+
+#include <fcntl.h>
+#include <signal.h>
+#include <sys/prctl.h>
+#include <sys/signalfd.h>
+
+#include "base/files/file_util.h"
+#include "base/files/scoped_file.h"
+#include "base/logging.h"
+#include "base/process/launch.h"
+#include "base/synchronization/waitable_event.h"
+
+namespace relauncher {
+
+namespace internal {
+
+// this is global to be visible to the sa_handler
+base::WaitableEvent parentWaiter;
+
+void RelauncherSynchronizeWithParent() {
+  base::ScopedFD relauncher_sync_fd(kRelauncherSyncFD);
+  static const auto signum = SIGUSR2;
+
+  // send signum to current process when parent process ends.
+  if (HANDLE_EINTR(prctl(PR_SET_PDEATHSIG, signum)) != 0) {
+    PLOG(ERROR) << "prctl";
+    return;
+  }
+
+  // set up a signum handler
+  struct sigaction action;
+  memset(&action, 0, sizeof(action));
+  action.sa_handler = [](int /*signum*/) { parentWaiter.Signal(); };
+  if (sigaction(signum, &action, nullptr) != 0) {
+    PLOG(ERROR) << "sigaction";
+    return;
+  }
+
+  // write a '\0' character to the pipe to the parent process.
+  // this is how the parent knows that we're ready for it to exit.
+  if (HANDLE_EINTR(write(relauncher_sync_fd.get(), "", 1)) != 1) {
+    PLOG(ERROR) << "write";
+    return;
+  }
+
+  // Wait for the parent to exit
+  parentWaiter.Wait();
+}
+
+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.allow_new_privs = true;
+  options.new_process_group = true;  // detach
+  options.fds_to_remap.push_back(std::make_pair(devnull.get(), STDERR_FILENO));
+  options.fds_to_remap.push_back(std::make_pair(devnull.get(), STDOUT_FILENO));
+
+  base::Process process = base::LaunchProcess(argv, options);
+  return process.IsValid() ? 0 : 1;
+}
+
+}  // namespace internal
+
+}  // namespace relauncher