Implement Relaunch on Linux

atom/browser/relauncher_linux.cc

@@ -0,0 +1,74 @@
+// 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 <signal.h>
+#include <sys/prctl.h>
+#include <sys/signalfd.h>
+
+#include "atom/common/atom_command_line.h"
+#include "base/files/file_util.h"
+#include "base/logging.h"
+#include "base/posix/eintr_wrapper.h"
+#include "base/process/launch.h"
+
+namespace relauncher {
+
+namespace internal {
+
+void RelauncherSynchronizeWithParent() {
+  base::ScopedFD relauncher_sync_fd(kRelauncherSyncFD);
+
+  // Don't execute signal handlers of SIGUSR2.
+  sigset_t mask;
+  sigemptyset(&mask);
+  sigaddset(&mask, SIGUSR2);
+  if (sigprocmask(SIG_BLOCK, &mask, NULL) < 0) {
+    PLOG(ERROR) << "sigprocmask";
+    return;
+  }
+
+  // Create a signalfd that watches for SIGUSR2.
+  int usr2_fd = signalfd(-1, &mask, 0);
+  if (usr2_fd < 0) {
+    PLOG(ERROR) << "signalfd";
+    return;
+  }
+
+  // Send SIGUSR2 to current process when parent process ends.
+  if (HANDLE_EINTR(prctl(PR_SET_PDEATHSIG, SIGUSR2)) != 0) {
+    PLOG(ERROR) << "prctl";
+    return;
+  }
+
+  // Write a '\0' character to the pipe.
+  if (HANDLE_EINTR(write(relauncher_sync_fd.get(), "", 1)) != 1) {
+    PLOG(ERROR) << "write";
+    return;
+  }
+
+  // Wait the SIGUSR2 signal to happen.
+  struct signalfd_siginfo si;
+  HANDLE_EINTR(read(usr2_fd, &si, sizeof(si)));
+}
+
+int LaunchProgram(const std::vector<std::string>& relauncher_args,
+                  const std::string& program,
+                  const std::vector<std::string>& args) {
+  std::vector<std::string> argv;
+  argv.reserve(1 + args.size());
+  argv.push_back(program);
+  argv.insert(argv.end(), args.begin(), args.end());
+
+  base::LaunchOptions options;
+  options.allow_new_privs = true;
+  options.new_process_group = true;  // detach
+  base::Process process = base::LaunchProcess(argv, options);
+  return process.IsValid() ? 0 : 1;
+}
+
+}  // namespace internal
+
+}  // namespace relauncher