Method _launch

Lib/multiprocessing/resource_tracker.py:169–207

(self)

                      'relaunching.  Some resources might leak.')

    def _launch(self):
        fds_to_pass = []
        try:
            fds_to_pass.append(sys.stderr.fileno())
        except Exception:
            pass
        r, w = os.pipe()
        try:
            fds_to_pass.append(r)
            # process will out live us, so no need to wait on pid
            exe = spawn.get_executable()
            args = [
                exe,
                *util._args_from_interpreter_flags(),
                '-c',
                f'from multiprocessing.resource_tracker import main;main({r})',
            ]
            # bpo-33613: Register a signal mask that will block the signals.
            # This signal mask will be inherited by the child that is going
            # to be spawned and will protect the child from a race condition
            # that can make the child die before it registers signal handlers
            # for SIGINT and SIGTERM. The mask is unregistered after spawning
            # the child.
            prev_sigmask = None
            try:
                if _HAVE_SIGMASK:
                    prev_sigmask = signal.pthread_sigmask(signal.SIG_BLOCK, _IGNORED_SIGNALS)
                pid = util.spawnv_passfds(exe, args, fds_to_pass)
            finally:
                if prev_sigmask is not None:
                    signal.pthread_sigmask(signal.SIG_SETMASK, prev_sigmask)
        except:
            os.close(w)
            raise
        else:
            self._fd = w
            self._pid = pid
        finally:
            os.close(r)

    def _make_probe_message(self):
        """Return a probe message."""