import os
if os.name == 'nt':

    # The Subprocess module uses CreateProcess with bInheritHandles = TRUE
    # so that it can redirect stdout, stdin, and stderr. Unfortunately this
    # means that the subprocess also inherits all of our sockets. If
    # the process is long living, it will keep those sockets connected.
    #
    # These method patches use the kernel32.dll function SetHandleInformation
    # to make all new sockets uninheritable.
    #
    # TODO: Note that if another thread spawns a process in between the socket
    # creation and the call to SetHandleInformation, we're still out of luck.

    from msvcrt import get_osfhandle
    from ctypes import windll, WinError
    SetHandleInformation = windll.kernel32.SetHandleInformation

    def set_noninheritable(socket):
        if not SetHandleInformation(socket.fileno(), 1, 0):
            raise WinError()

    import socket
    original_socket = socket.socket
    _orig_connect    = original_socket.connect
    _orig_connect_ex = original_socket.connect_ex
    _orig_accept     = original_socket.accept

    def connect(self, address):
        res = _orig_connect(self, address)
        set_noninheritable(self)
        return res

    def connect_ex(self, address):
        res = _orig_connect_ex(self, address)
        set_noninheritable(self)
        return res

    def accept(self):
        conn, addr = _orig_accept(self)
        set_noninheritable(conn)
        return conn, addr

    original_socket.connect    = connect
    original_socket.connect_ex = connect_ex
    original_socket.accept     = accept