#!/usr/bin/python
#
# Run the program given on the command line, binding its stdin to a socket
# that is readable but which will never have anything to read.  We accomplish
# this by spinning off a copy of "cat" that will read from the other end
# of the socket, but never write anything.  When our program dies, cat
# will see EOF and also terminate cleanly.
#
# This can be used to keep alive a program that exits when its stdout gets
# EOF.

import os
import socket
import sys

s1, s2 = socket.socketpair()
pid = os.fork()
if pid == 0:
  # first child
  try:
    s1.close()
    os.dup2(s2.fileno(), 0)
    os.execvp('cat', ['cat'])
  finally:
    os._exit(99)

s2.close()
os.dup2(s1.fileno(), 0)
os.execvp(sys.argv[1], sys.argv[1:])