Error: child process close a socket inherited from parent

[narke]

On 2011-05-29, narke <narkewoody at gmail.com> wrote:
> Hi,
>
> As illustrated in the following simple sample:
>
> import sys
> import os
> import socket
>
> class Server:
>     def __init__(self):
>         self._listen_sock = None
>
>     def _talk_to_client(self, conn, addr):
>         text = 'The brown fox jumps over the lazy dog.\n'
>         while True:
>             conn.send(text)
>             data = conn.recv(1024)
>             if not data:
>                 break
>         conn.close()
>
>     def listen(self, port):
>         self._listen_sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
>         self._listen_sock.bind(('', port))
>         self._listen_sock.listen(128)
>         self._wait_conn()
>
>     def _wait_conn(self):
>         while True:
>             conn, addr = self._listen_sock.accept()
>             if os.fork() == 0:
>                 self._listen_sock.close()           # line x
>                 self._talk_to_client(conn, addr)
>             else:
>                 conn.close()
>
> if __name__ == '__main__':
>     Server().listen(int(sys.argv[1]))
>
> Unless I comment out the line x, I will get a 'Bad file descriptor'
> error when my tcp client program (e.g, telnet) closes the connection to
> the server.  But as I understood, a child process can close a unused
> socket (file descriptor).
>
> Do you know what's wrong here?
>
>

I forgot to say, it's Python 2.6.4 running on linux 2.6.33


-- 
Life is the only flaw in an otherwise perfect nonexistence
   -- Schopenhauer

narke