#!/usr/bin/python3
#
# Copyright (C) 2017  Lars Wirzenius
#
# Pick a random port that is free to be listened on. For testing.


import errno
import random
import socket
import sys


MAX = 1000
for i in range(MAX):
    port = random.randint(1025, 2**15-1)
    s = socket.socket()
    try:
        s.bind(('0.0.0.0', port))
    except OSError as e:
        if e.errno == errno.EADDRINUSE:
            continue
        raise
    break
else:
    sys.stderr.write("Can't find a free port\n")
    sys.exit(1)
sys.stdout.write('{}\n'.format(port))