Method execute

src/slave/containerizer/mesos/launch.cpp:644–1344

int MesosContainerizerLaunch::execute()
{
  if (flags.help) {
    cerr << flags.usage();
    return EXIT_SUCCESS;
  }

  // The existence of the `runtime_directory` flag implies that we
  // want to checkpoint the container's status upon exit.
  if (flags.runtime_directory.isSome()) {
    containerStatusPath = path::join(
        flags.runtime_directory.get(),
        containerizer::paths::STATUS_FILE);

    Try<int_fd> open = os::open(
        containerStatusPath.get(),
        O_WRONLY | O_CREAT | O_CLOEXEC,
        S_IRUSR | S_IWUSR);

    if (open.isError()) {
      cerr << "Failed to open file for writing the container status"
           << " '" << containerStatusPath.get() << "':"
           << " " << open.error() << endl;
      exitWithStatus(EXIT_FAILURE);
    }

    containerStatusFd = open.get();
  }

#ifndef __WINDOWS__
  // We need a signal fence here to ensure that `containerStatusFd` is
  // actually written to memory and not just to a temporary register.
  // Without this, it's possible that the signal handler we are about
  // to install would never see the correct value since there's no
  // guarantee that it is written to memory until this function
  // completes (which won't happen for a really long time because we
  // do a blocking `waitpid()` below).
  std::atomic_signal_fence(std::memory_order_relaxed);

  // Install signal handlers for all incoming signals.
  Try<Nothing> signals = installSignalHandlers();
  if (signals.isError()) {
    cerr << "Failed to install signal handlers: " << signals.error() << endl;
    exitWithStatus(EXIT_FAILURE);
  }
#else
  // We need a handle to the job object which this container is associated with.
  // Without this handle, the job object would be destroyed by the OS when the
  // agent exits (or crashes), making recovery impossible. By holding a handle,
  // we tie the lifetime of the job object to the container itself. In this way,
  // a recovering agent can reattach to the container by opening a new handle to
  // the job object.
  const pid_t pid = ::GetCurrentProcessId();
  const Try<std::wstring> name = os::name_job(pid);
  if (name.isError()) {
    cerr << "Failed to create job object name from pid: " << name.error()
         << endl;
    exitWithStatus(EXIT_FAILURE);