def give_terminal_to(pgid):
     if pgid is None:
         return False
     oldmask = signal.pthread_sigmask(signal.SIG_BLOCK,
                                      _block_when_giving)
     try:
         os.tcsetpgrp(FD_STDERR, pgid)
         return True
     except ProcessLookupError:
         # when the process finished before giving terminal to it,
         # see issue #2288
         return False
     except OSError as e:
         if e.errno == 22:  # [Errno 22] Invalid argument
             # there are cases that all the processes of pgid have
             # finished, then we don't need to do anything here, see
             # issue #2220
             return False
         elif e.errno == 25:  # [Errno 25] Inappropriate ioctl for device
             # There are also cases where we are not connected to a
             # real TTY, even though we may be run in interactive
             # mode. See issue #2267 for an example with emacs
             return False
         else:
             raise
     finally:
         signal.pthread_sigmask(signal.SIG_SETMASK, oldmask)

    def _run(self):
        if hasattr(signal, 'pthread_sigmask'):
            # this thread should not handle any signal
            mask = range(1, signal.NSIG)
            signal.pthread_sigmask(signal.SIG_BLOCK, mask)

        self.schedule()

        while self.stop_lock.acquire(0):
            self.stop_lock.release()
            delay = self.once()
            if delay is not None:
                assert delay > 0.0
                with self.sleep_lock:
                    interrupted = self.sleep_lock.wait(timeout=delay)
                if interrupted:
                    break
                continue

            task = self._task_ref()
            try:
                task.call()
            except Exception as err:
                # the task is not rescheduled on error
                exc_type, exc_value, exc_tb = sys.exc_info()
                # FIXME: log the traceback
                print(("%s: %s" % (exc_type, exc_value)), file=sys.stderr)
                break
            if self.ncall is not None:
                self.ncall -= 1
                if self.ncall <= 0:
                    break
            self.schedule()

 def _give_terminal_to(pgid):
     st = _shell_tty()
     if st is not None and os.isatty(st):
         oldmask = signal.pthread_sigmask(signal.SIG_BLOCK,
                                          _block_when_giving)
         os.tcsetpgrp(st, pgid)
         signal.pthread_sigmask(signal.SIG_SETMASK, oldmask)

    def _serve(self):
        if hasattr(signal, "pthread_sigmask"):
            signal.pthread_sigmask(signal.SIG_BLOCK, range(1, signal.NSIG))
        while 1:
            try:
                conn = self._listener.accept()
                msg = conn.recv()
                if msg is None:
                    break
                key, destination_pid = msg
                send, close = self._cache.pop(key)
                send(conn, destination_pid)
                close()
                conn.close()
            except:
                if not is_exiting():
                    import traceback

                    sub_warning(
                        "thread for sharing handles raised exception :\n"
                        + "-" * 79
                        + "\n"
                        + traceback.format_exc()
                        + "-" * 79
                    )

    def ensure_running(self):
        '''Make sure that semaphore tracker process is running.

        This can be run from any process.  Usually a child process will use
        the semaphore created by its parent.'''
        with self._lock:
            if self._pid is not None:
                # semaphore tracker was launched before, is it still running?
                try:
                    pid, _ = os.waitpid(self._pid, os.WNOHANG)
                except ChildProcessError:
                    # The process terminated
                    pass
                else:
                    if not pid:
                        # => still alive
                        return

                # => dead, launch it again
                os.close(self._fd)
                self._fd = None
                self._pid = None

                warnings.warn('semaphore_tracker: process died unexpectedly, '
                              'relaunching.  Some semaphores might leak.')

            fds_to_pass = []
            try:
                fds_to_pass.append(sys.stderr.fileno())
            except Exception:
                pass
            cmd = 'from multiprocessing.semaphore_tracker import main;main(%d)'
            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()
                args += ['-c', cmd % 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.
                try:
                    if _HAVE_SIGMASK:
                        signal.pthread_sigmask(signal.SIG_BLOCK, _IGNORED_SIGNALS)
                    pid = util.spawnv_passfds(exe, args, fds_to_pass)
                finally:
                    if _HAVE_SIGMASK:
                        signal.pthread_sigmask(signal.SIG_UNBLOCK, _IGNORED_SIGNALS)
            except:
                os.close(w)
                raise
            else:
                self._fd = w
                self._pid = pid
            finally:
                os.close(r)

    def _do_exit(self, signo):
        if signo == 0 or signo == signal.SIGINT:
            return

        curses.endwin()
        signal.pthread_sigmask(signal.SIG_UNBLOCK, [signo])
        signal.signal(signo, signal.SIG_DFL)
        os.kill(self._pid, signo)

 def _give_terminal_to(pgid):
     # over-simplified version of:
     #    give_terminal_to from bash 4.3 source, jobs.c, line 4030
     # this will give the terminal to the process group pgid
     if _shell_tty is not None and os.isatty(_shell_tty):
         oldmask = signal.pthread_sigmask(signal.SIG_BLOCK, _block_when_giving)
         os.tcsetpgrp(_shell_tty, pgid)
         signal.pthread_sigmask(signal.SIG_SETMASK, oldmask)

 def run(self):
     self.take_snapshot()
     if hasattr(signal, 'pthread_sigmask'):
         # Available on UNIX with Python 3.3+
         signal.pthread_sigmask(signal.SIG_BLOCK, range(1, signal.NSIG))
     time.sleep(init_delay)
     while True:
         self.take_snapshot()
         time.sleep(snapshot_delay)

    def halt(self):
        oldh = signal.signal(signal.SIGINT, lambda i,f: None)
        signal.pthread_sigmask(signal.SIG_BLOCK, {signal.SIGINT})

        for thr in self.threads:
            thr.request.halt_loop()

        signal.pthread_sigmask(signal.SIG_UNBLOCK, {signal.SIGINT})
        signal.signal(signal.SIGINT, oldh)

 def init_signal_handling(self):
     # In Python 3.5 system calls are no longer interrupted by signals.
     # Thus, we can no longer use time.sleep() or otherwise the processing
     # of signals would be delayed until the sleep has finished.
     # So, we now use signal.sigtimedwait() instead. Due to the lack of
     # documentation (and my unwillingness to spend more time on this than
     # necessary) I'm not quite sure, if I'm doing this completely right.
     # In the following, we set all signals that we're interested in as
     # blocked, so that they queue up. In TimeProvider.sleep() they're taken
     # again from the queue by signal.sigtimedwait().
     signal.pthread_sigmask(signal.SIG_BLOCK, SIGNALS)

def run(host, port, Payload):
    """Select loop of scheduler.

    :param host: A string with the host to bind to.
    :param port: An integer with the port to bind to.
    :param Payload: A class that follows the interface of ``types.Payload``.

    """
    scheduler = Scheduler()

    sock = init_socket('127.0.0.1', 8000)
    selector = selectors.DefaultSelector()
    callback = partial(handle_request, klass=Payload)
    selector.register(sock, selectors.EVENT_READ, callback)

    sigint_fd = linuxfd.signalfd(
        signalset={signal.SIGINT, signal.SIGTERM}, nonBlocking=True
    )
    selector.register(sigint_fd, selectors.EVENT_READ, True)
    sighup_fd = linuxfd.signalfd(signalset={signal.SIGHUP}, nonBlocking=True)
    selector.register(sighup_fd, selectors.EVENT_READ, scheduler.report)
    signal.pthread_sigmask(
        signal.SIG_BLOCK, {signal.SIGINT, signal.SIGHUP, signal.SIGTERM}
    )

    timestamp = None
    should_exit = False
    while True:
        if should_exit:
            break
        if timestamp is None:
            timeout = timestamp
        else:
            timeout = timestamp - time.time()
            assert timeout >= 0
        logger.debug('Selecting on timeout {0}'.format(timeout))
        events = selector.select(timeout)
        if not events:
            item = scheduler.pop()
            item.execute()
            timestamp = getattr(scheduler.top(), 'timestamp', None)
        for key, mask in events:
            callback = key.data
            if not callable(callback):
                should_exit = True
            elif key.fileobj == sock:
                item = callback(key.fileobj)
                scheduler.push(item)
                timestamp = scheduler.top().timestamp
            else:
                key.fileobj.read()
                callback()
    close_socket(sock)

def main(fd):
    '''Run semaphore tracker.'''
    # protect the process from ^C and "killall python" etc
    signal.signal(signal.SIGINT, signal.SIG_IGN)
    signal.signal(signal.SIGTERM, signal.SIG_IGN)
    if _HAVE_SIGMASK:
        signal.pthread_sigmask(signal.SIG_UNBLOCK, _IGNORED_SIGNALS)

    for f in (sys.stdin, sys.stdout):
        try:
            f.close()
        except Exception:
            pass

    cache = set()
    try:
        # keep track of registered/unregistered semaphores
        with open(fd, 'rb') as f:
            for line in f:
                try:
                    cmd, name = line.strip().split(b':')
                    if cmd == b'REGISTER':
                        cache.add(name)
                    elif cmd == b'UNREGISTER':
                        cache.remove(name)
                    else:
                        raise RuntimeError('unrecognized command %r' % cmd)
                except Exception:
                    try:
                        sys.excepthook(*sys.exc_info())
                    except:
                        pass
    finally:
        # all processes have terminated; cleanup any remaining semaphores
        if cache:
            try:
                warnings.warn('semaphore_tracker: There appear to be %d '
                              'leaked semaphores to clean up at shutdown' %
                              len(cache))
            except Exception:
                pass
        for name in cache:
            # For some reason the process which created and registered this
            # semaphore has failed to unregister it. Presumably it has died.
            # We therefore unlink it.
            try:
                name = name.decode('ascii')
                try:
                    _multiprocessing.sem_unlink(name)
                except Exception as e:
                    warnings.warn('semaphore_tracker: %r: %s' % (name, e))
            finally:
                pass

 def run(self):
     if hasattr(signal, 'pthread_sigmask'):
         # Available on UNIX with Python 3.3+
         signal.pthread_sigmask(signal.SIG_BLOCK, range(1, signal.NSIG))
     while True:
         if self.interval and self.snapshot_q.empty():
             time.sleep(self.interval)
         item = self.snapshot_q.get()
         logger.info('Sending {0} snapshot file'.format(item))
         logger.info('{0} items pending to send.'.format(
             self.snapshot_q.qsize())
         )
         snapshot = tracemalloc.Snapshot.load(item)
         self.client.send(snapshot)

    def check_sigwait(self, wait_func):
        signum = signal.SIGUSR1
        pid = os.getpid()

        old_handler = signal.signal(signum, lambda *args: None)
        self.addCleanup(signal.signal, signum, old_handler)

        code = '\n'.join((
            'import os, time',
            'pid = %s' % os.getpid(),
            'signum = %s' % int(signum),
            'sleep_time = %r' % self.sleep_time,
            'time.sleep(sleep_time)',
            'os.kill(pid, signum)',
        ))

        old_mask = signal.pthread_sigmask(signal.SIG_BLOCK, [signum])
        self.addCleanup(signal.pthread_sigmask, signal.SIG_UNBLOCK, [signum])

        t0 = time.monotonic()
        proc = self.subprocess(code)
        with kill_on_error(proc):
            wait_func(signum)
            dt = time.monotonic() - t0

        self.assertEqual(proc.wait(), 0)

 def _serve(self):
     if hasattr(signal, 'pthread_sigmask'):
         signal.pthread_sigmask(signal.SIG_BLOCK, range(1, signal.NSIG))
     while 1:
         try:
             with self._listener.accept() as conn:
                 msg = conn.recv()
                 if msg is None:
                     break
                 key, destination_pid = msg
                 send, close = self._cache.pop(key)
                 try:
                     send(conn, destination_pid)
                 finally:
                     close()
         except:
             if not util.is_exiting():
                 sys.excepthook(*sys.exc_info())

 def run(self):
     if hasattr(signal, 'pthread_sigmask'):
         # Available on UNIX with Python 3.3+
         signal.pthread_sigmask(signal.SIG_BLOCK, range(1, signal.NSIG))
     while True:
         logger.debug('Sleeping {0} secongs...'.format(self.interval))
         time.sleep(self.interval)
         filename = ("/tmp/tracemalloc-%d-%04d.dump"
                     % (os.getpid(), self.counter))
         logger.info("Write snapshot into %s..." % filename)
         gc.collect()
         snapshot = tracemalloc.take_snapshot()
         snapshot.dump(filename )
         self.snapshot_q.put(filename)
         logger.debug('Queue size: {0}'.format(self.snapshot_q.qsize()))
         snapshot = None
         logger.info("Snapshot written into %s" % filename)
         self.counter += 1

    def run(self):
        with no_daemon_context(self.working_dir, self.lock_file, self.signals):
            signal_map = {
                signal.SIGHUP: self._handle_reconfigure,
                signal.SIGINT: self._handle_shutdown,
                signal.SIGTERM: self._handle_shutdown,
                signal.SIGQUIT: self._handle_shutdown,
                signal.SIGUSR1: self._handle_debug,
            }
            signal.pthread_sigmask(signal.SIG_BLOCK, signal_map.keys())

            self._run_mcp()
            self._run_www_api()
            self._run_manhole()
            self._run_reactor()

            while True:
                signum = signal.sigwait(list(signal_map.keys()))
                if signum in signal_map:
                    logging.info(f"Got signal {str(signum)}")
                    signal_map[signum](signum, None)

 def action_toggle(self, from_, chan, msg, parts):
     t = time.time()
     if t - self.last_toggle >= 5:
         self.last_toggle = t
         try:
             signal.pthread_sigmask(signal.SIG_BLOCK, {signal.SIGUSR1})
             subprocess.call(
                 ["/home/simark/avr/serieViaUSB/serieViaUSB", "-e", "-f", "/home/simark/avr/serieViaUSB/fichier"])
             self.irc.privmsg(chan, "Your wish is my command")
             # time.sleep(1)
             if get_plafond_status():
                 self.irc.privmsg(chan, "Light is now on")
             else:
                 self.irc.privmsg(chan, "Light is now off")
         except:
             raise
         finally:
             signal.pthread_sigmask(signal.SIG_UNBLOCK, {signal.SIGUSR1})
     else:
         self.irc.privmsg(
             chan, "You have to wait 5 seconds between two toggles.")

 def test_pthread_sigmask_arguments(self):
     self.assertRaises(TypeError, signal.pthread_sigmask)
     self.assertRaises(TypeError, signal.pthread_sigmask, 1)
     self.assertRaises(TypeError, signal.pthread_sigmask, 1, 2, 3)
     self.assertRaises(OSError, signal.pthread_sigmask, 1700, [])
     with self.assertRaises(ValueError):
         signal.pthread_sigmask(signal.SIG_BLOCK, [signal.NSIG])
     with self.assertRaises(ValueError):
         signal.pthread_sigmask(signal.SIG_BLOCK, [0])
     with self.assertRaises(ValueError):
         signal.pthread_sigmask(signal.SIG_BLOCK, [1<<1000])

 def test_pthread_sigmask_valid_signals(self):
     s = signal.pthread_sigmask(signal.SIG_BLOCK, signal.valid_signals())
     self.addCleanup(signal.pthread_sigmask, signal.SIG_SETMASK, s)
     # Get current blocked set
     s = signal.pthread_sigmask(signal.SIG_UNBLOCK, signal.valid_signals())
     self.assertLessEqual(s, signal.valid_signals())