Python fcntl.FD_CLOEXEC Examples

def _set_cloexec(self):
        """Set the CLOEXEC flag on all open files (except stdin/out/err).

        If self.max_cloexec_files is an integer (the default), then on
        platforms which support it, it represents the max open files setting
        for the operating system. This function will be called just before
        the process is restarted via os.execv() to prevent open files
        from persisting into the new process.

        Set self.max_cloexec_files to 0 to disable this behavior.
        """
        for fd in range(3, self.max_cloexec_files):  # skip stdin/out/err
            try:
                flags = fcntl.fcntl(fd, fcntl.F_GETFD)
            except IOError:
                continue
            fcntl.fcntl(fd, fcntl.F_SETFD, flags | fcntl.FD_CLOEXEC) 

def get_vm_logger(vmname):
    '''Initialise logging for particular VM name

    :param str vmname: VM's name
    :rtype: :py:class:`logging.Logger`
    '''

    logger = logging.getLogger('vm.' + vmname)
    if logger.handlers:
        return logger
    old_umask = os.umask(0o007)
    try:
        handler = logging.FileHandler(
            os.path.join(LOGPATH, 'vm-{}.log'.format(vmname)))
        fcntl.fcntl(handler.stream.fileno(),
            fcntl.F_SETFD, fcntl.FD_CLOEXEC)
    finally:
        os.umask(old_umask)
    handler.setFormatter(formatter_log)
    logger.addHandler(handler)

    return logger 

def write_pid_or_exit(self):

        self.pf = open(self.pidfile, 'w+r')
        pf = self.pf

        fd = pf.fileno()
        fcntl.fcntl(fd, fcntl.F_SETFD,
                    fcntl.fcntl(fd, fcntl.F_GETFD, 0)
                    | fcntl.FD_CLOEXEC)

        try:
            pid = os.getpid()
            logger.debug('write pid:' + str(pid))

            pf.truncate(0)
            pf.write(str(pid))
            pf.flush()
        except Exception as e:
            logger.exception('write pid failed.' + repr(e))
            sys.exit(0) 

def set_inheritable(fd, inheritable):
    # On py34+ we can use os.set_inheritable but < py34 we must polyfill
    # with fcntl and SetHandleInformation
    if hasattr(os, 'get_inheritable'):
        if os.get_inheritable(fd) != inheritable:
            os.set_inheritable(fd, inheritable)

    elif WIN:
        h = get_handle(fd)
        flags = winapi.HANDLE_FLAG_INHERIT if inheritable else 0
        winapi.SetHandleInformation(h, winapi.HANDLE_FLAG_INHERIT, flags)

    else:
        flags = fcntl.fcntl(fd, fcntl.F_GETFD)
        if inheritable:
            new_flags = flags & ~fcntl.FD_CLOEXEC
        else:
            new_flags = flags | fcntl.FD_CLOEXEC
        if new_flags != flags:
            fcntl.fcntl(fd, fcntl.F_SETFD, new_flags) 

def bind(self, port, address=""):
        """Binds this server to the given port on the given IP address.

        To start the server, call start(). If you want to run this server
        in a single process, you can call listen() as a shortcut to the
        sequence of bind() and start() calls.
        """
        assert not self._socket
        self._socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM, 0)
        flags = fcntl.fcntl(self._socket.fileno(), fcntl.F_GETFD)
        flags |= fcntl.FD_CLOEXEC
        fcntl.fcntl(self._socket.fileno(), fcntl.F_SETFD, flags)
        self._socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
        self._socket.setblocking(0)
        self._socket.bind((address, port))
        self._socket.listen(128) 

def _set_close_exec(self, fd):
        flags = fcntl.fcntl(fd, fcntl.F_GETFD)
        fcntl.fcntl(fd, fcntl.F_SETFD, flags | fcntl.FD_CLOEXEC) 

def test_get_inheritable_cloexec(self):
        sock = socket.socket()
        with sock:
            fd = sock.fileno()
            self.assertEqual(sock.get_inheritable(), False)

            # clear FD_CLOEXEC flag
            flags = fcntl.fcntl(fd, fcntl.F_GETFD)
            flags &= ~fcntl.FD_CLOEXEC
            fcntl.fcntl(fd, fcntl.F_SETFD, flags)

            self.assertEqual(sock.get_inheritable(), True) 

def set_close_exec(fd):
    flags = fcntl.fcntl(fd, fcntl.F_GETFD)
    fcntl.fcntl(fd, fcntl.F_SETFD, flags | fcntl.FD_CLOEXEC) 

def _setCloseOnExec(fd):
        """
        Make a file descriptor close-on-exec.
        """
        flags = fcntl.fcntl(fd, fcntl.F_GETFD)
        flags = flags | fcntl.FD_CLOEXEC
        fcntl.fcntl(fd, fcntl.F_SETFD, flags) 

def _set_non_inheritable_non_atomic(fd):
        """Set the close-on-exec flag on the given file descriptor."""
        flags = fcntl(fd, F_GETFD)
        fcntl(fd, F_SETFD, flags | FD_CLOEXEC) 

def set_close_exec(fd):
    flags = fcntl.fcntl(fd, fcntl.F_GETFD)
    fcntl.fcntl(fd, fcntl.F_SETFD, flags | fcntl.FD_CLOEXEC) 

def __init__(self, addr, requestHandler=SimpleXMLRPCRequestHandler,
                 logRequests=True, allow_none=False, encoding=None,
                 bind_and_activate=True, use_builtin_types=False):
        self.logRequests = logRequests

        SimpleXMLRPCDispatcher.__init__(self, allow_none, encoding, use_builtin_types)
        socketserver.TCPServer.__init__(self, addr, requestHandler, bind_and_activate)

        # [Bug #1222790] If possible, set close-on-exec flag; if a
        # method spawns a subprocess, the subprocess shouldn't have
        # the listening socket open.
        if fcntl is not None and hasattr(fcntl, 'FD_CLOEXEC'):
            flags = fcntl.fcntl(self.fileno(), fcntl.F_GETFD)
            flags |= fcntl.FD_CLOEXEC
            fcntl.fcntl(self.fileno(), fcntl.F_SETFD, flags) 

def write_pid_file(pid_file, pid):
    import fcntl
    import stat

    try:
        fd = os.open(pid_file, os.O_RDWR | os.O_CREAT,
                     stat.S_IRUSR | stat.S_IWUSR)
    except OSError as e:
        shell.print_exception(e)
        return -1
    flags = fcntl.fcntl(fd, fcntl.F_GETFD)
    assert flags != -1
    flags |= fcntl.FD_CLOEXEC
    r = fcntl.fcntl(fd, fcntl.F_SETFD, flags)
    assert r != -1
    # There is no platform independent way to implement fcntl(fd, F_SETLK, &fl)
    # via fcntl.fcntl. So use lockf instead
    try:
        fcntl.lockf(fd, fcntl.LOCK_EX | fcntl.LOCK_NB, 0, 0, os.SEEK_SET)
    except IOError:
        r = os.read(fd, 32)
        if r:
            logging.error('already started at pid %s' % common.to_str(r))
        else:
            logging.error('already started')
        os.close(fd)
        return -1
    os.ftruncate(fd, 0)
    os.write(fd, common.to_bytes(str(pid)))
    return 0 

def close_on_exec(fd):
    flags = fcntl.fcntl(fd, fcntl.F_GETFD)
    flags |= fcntl.FD_CLOEXEC
    fcntl.fcntl(fd, fcntl.F_SETFD, flags) 

def _unsetCloseOnExec(fd):
        """
        Make a file descriptor close-on-exec.
        """
        flags = fcntl.fcntl(fd, fcntl.F_GETFD)
        flags = flags & ~fcntl.FD_CLOEXEC
        fcntl.fcntl(fd, fcntl.F_SETFD, flags) 

def __init__(self):
        self.rtc_fd = os.open("/dev/rtc", os.O_RDONLY)
        flags = fcntl.fcntl(self.rtc_fd, fcntl.F_GETFD)
        fcntl.fcntl(self.rtc_fd, fcntl.F_SETFD, flags | fcntl.FD_CLOEXEC) 

def close_on_exec(fd):
    flags = fcntl.fcntl(fd, fcntl.F_GETFD)
    flags |= fcntl.FD_CLOEXEC
    fcntl.fcntl(fd, fcntl.F_SETFD, flags) 

def prevent_socket_inheritance(sock):
        """Mark the given socket fd as non-inheritable (POSIX)."""
        fd = sock.fileno()
        old_flags = fcntl.fcntl(fd, fcntl.F_GETFD)
        fcntl.fcntl(fd, fcntl.F_SETFD, old_flags | fcntl.FD_CLOEXEC) 

def prevent_socket_inheritance(sock):
        """Mark the given socket fd as non-inheritable (POSIX)."""
        fd = sock.fileno()
        old_flags = fcntl.fcntl(fd, fcntl.F_GETFD)
        fcntl.fcntl(fd, fcntl.F_SETFD, old_flags | fcntl.FD_CLOEXEC) 

def _set_cloexec_flag(self, fd, cloexec=True):
            try:
                cloexec_flag = fcntl.FD_CLOEXEC
            except AttributeError:
                cloexec_flag = 1

            old = fcntl.fcntl(fd, fcntl.F_GETFD)
            if cloexec:
                fcntl.fcntl(fd, fcntl.F_SETFD, old | cloexec_flag)
            else:
                fcntl.fcntl(fd, fcntl.F_SETFD, old & ~cloexec_flag) 

def __init__(self, addr, requestHandler=SimpleXMLRPCRequestHandler,
                 logRequests=True, allow_none=False, encoding=None, bind_and_activate=True):
        self.logRequests = logRequests

        SimpleXMLRPCDispatcher.__init__(self, allow_none, encoding)
        SocketServer.TCPServer.__init__(self, addr, requestHandler, bind_and_activate)

        # [Bug #1222790] If possible, set close-on-exec flag; if a
        # method spawns a subprocess, the subprocess shouldn't have
        # the listening socket open.
        if fcntl is not None and hasattr(fcntl, 'FD_CLOEXEC'):
            flags = fcntl.fcntl(self.fileno(), fcntl.F_GETFD)
            flags |= fcntl.FD_CLOEXEC
            fcntl.fcntl(self.fileno(), fcntl.F_SETFD, flags) 

def _set_cloexec(fd):
        try:
            flags = _fcntl.fcntl(fd, _fcntl.F_GETFD, 0)
        except IOError:
            pass
        else:
            # flags read successfully, modify
            flags |= _fcntl.FD_CLOEXEC
            _fcntl.fcntl(fd, _fcntl.F_SETFD, flags) 

def trylock_or_exit(self, timeout=10):

        interval = 0.1
        n = int(timeout / interval) + 1
        flag = fcntl.LOCK_EX | fcntl.LOCK_NB

        for ii in range(n):

            fd = os.open(self.lockfile, os.O_RDWR | os.O_CREAT)

            fcntl.fcntl(fd, fcntl.F_SETFD,
                        fcntl.fcntl(fd, fcntl.F_GETFD, 0)
                        | fcntl.FD_CLOEXEC)

            try:
                fcntl.lockf(fd, flag)

                self.lockfp = os.fdopen(fd, 'w+r')
                break

            except IOError as e:
                os.close(fd)
                if e[0] == errno.EAGAIN:
                    time.sleep(interval)
                else:
                    raise

        else:
            logger.info("Failure acquiring lock %s" % (self.lockfile, ))
            sys.exit(1)

        logger.info("OK acquired lock %s" % (self.lockfile)) 

def request_memory(self, amount):
        self.sock = socket.socket(socket.AF_UNIX)

        flags = fcntl.fcntl(self.sock.fileno(), fcntl.F_GETFD)
        flags |= fcntl.FD_CLOEXEC
        fcntl.fcntl(self.sock.fileno(), fcntl.F_SETFD, flags)

        self.sock.connect("/var/run/qubes/qmemman.sock")
        self.sock.send(str(int(amount)).encode('ascii')+b"\n")
        received = self.sock.recv(1024).strip()
        if received == b'OK':
            return True
        else:
            return False 

def enable():
    '''Enable global logging

    Use :py:mod:`logging` module from standard library to log messages.

    >>> import qubes.log
    >>> qubes.log.enable()          # doctest: +SKIP
    >>> import logging
    >>> logging.warning('Foobar')   # doctest: +SKIP
    '''

    if logging.root.handlers:
        return

    handler_console = logging.StreamHandler(sys.stderr)
    handler_console.setFormatter(formatter_console)
    logging.root.addHandler(handler_console)

    if os.path.exists('/var/log/qubes'):
        log_path = '/var/log/qubes/qubes.log'
    else:
        # for tests, travis etc
        log_path = '/tmp/qubes.log'
    old_umask = os.umask(0o007)
    try:
        handler_log = logging.FileHandler(log_path, 'a', encoding='utf-8')
        fcntl.fcntl(handler_log.stream.fileno(),
            fcntl.F_SETFD, fcntl.FD_CLOEXEC)
    finally:
        os.umask(old_umask)
    handler_log.setFormatter(formatter_log)
    logging.root.addHandler(handler_log)

    logging.root.setLevel(logging.INFO) 

def __init__(self, addr, requestHandler=SimpleXMLRPCRequestHandler,
                 logRequests=True, allow_none=False, encoding=None,
                 bind_and_activate=True, use_builtin_types=False):
        self.logRequests = logRequests

        SimpleXMLRPCDispatcher.__init__(self, allow_none, encoding, use_builtin_types)
        socketserver.TCPServer.__init__(self, addr, requestHandler, bind_and_activate)

        # [Bug #1222790] If possible, set close-on-exec flag; if a
        # method spawns a subprocess, the subprocess shouldn't have
        # the listening socket open.
        if fcntl is not None and hasattr(fcntl, 'FD_CLOEXEC'):
            flags = fcntl.fcntl(self.fileno(), fcntl.F_GETFD)
            flags |= fcntl.FD_CLOEXEC
            fcntl.fcntl(self.fileno(), fcntl.F_SETFD, flags) 

def set_close_exec(fd: int) -> None:
    flags = fcntl.fcntl(fd, fcntl.F_GETFD)
    fcntl.fcntl(fd, fcntl.F_SETFD, flags | fcntl.FD_CLOEXEC) 

def set_close_exec(fd: int) -> None:
    flags = fcntl.fcntl(fd, fcntl.F_GETFD)
    fcntl.fcntl(fd, fcntl.F_SETFD, flags | fcntl.FD_CLOEXEC) 

def set_close_exec(fd):
    flags = fcntl.fcntl(fd, fcntl.F_GETFD)
    fcntl.fcntl(fd, fcntl.F_SETFD, flags | fcntl.FD_CLOEXEC) 

def _set_cloexec_flag(self, fd, cloexec=True):
            try:
                cloexec_flag = fcntl.FD_CLOEXEC
            except AttributeError:
                cloexec_flag = 1

            old = fcntl.fcntl(fd, fcntl.F_GETFD)
            if cloexec:
                fcntl.fcntl(fd, fcntl.F_SETFD, old | cloexec_flag)
            else:
                fcntl.fcntl(fd, fcntl.F_SETFD, old & ~cloexec_flag)