#!/usr/bin/env python2.6

import os, signal, sys, time
from resource import setrlimit, RLIMIT_AS
configs = {}
quitnow = False
judgehome = os.path.abspath(os.path.dirname(sys.argv[0]))

def main():
    os.chdir(judgehome)

    # redirect stdout and stderr to file
    os.close(1)
    fd = os.open('log/daemon.log', os.O_WRONLY | os.O_APPEND | os.O_CREAT)
    os.close(2)
    fd = os.dup(fd)

    # setup resource usage
    setrlimit(RLIMIT_AS, (1024 * 1024 * 256, 1024 * 1024 * 256))

    # setup signal handler
    signal.signal(signal.SIGINT, quit)
    signal.signal(signal.SIGQUIT, quit)

    # find config files
    files = os.listdir(os.path.join(judgehome, 'conf'))
    for filename in files:
        if filename[:5] == 'conf-' and filename[-3:] == '.py':
            configs[filename] = 0

    # start all the judge process
    for conf in configs.keys():
        configs[conf] = run(conf)

    # check for the dead of judge process
    while not quitnow:
        for conf in configs.keys():
            pid = configs[conf]
            ret = os.waitpid(pid, os.WNOHANG)
            if ret[0]:
                print >>sys.stderr, 'judge process %d dead, restarting...' % pid
                configs[conf] = run(conf)
        time.sleep(1)

def run(conf):
    pid = os.fork()
    if pid:
        return pid
    else:
        cmd = '/usr/bin/python'
        conf = os.path.join('conf', conf)
        os.execvp(cmd, (cmd, 'judge', conf))

def quit(sig, frame):
    quitnow = True
    for conf in configs.keys():
        pid = configs[conf]
        os.kill(pid, sig)

    for conf in configs.keys():
        pid = configs[conf]
        os.waitpid(pid, 0)
    exit()

if __name__ == '__main__':
    main()