Double fork / signal handling

import sys
import signal
import time
import os
import logging

class Handler(object):
    def __init__(self, stdin='/dev/null', stdout='/dev/null', stderr='/dev/null'):
        self.stdin = stdin
        self.stdout = stdout
        self.stderr = stderr

    def daemon(self):
        logging.debug('Before first fork')
        try:
            pid = os.fork()
            if pid > 0:
        #exit first parent
                sys.exit(0)
        except OSError, e:
            sys.stderr.write("fork #1 failed: %d (%s)\n" % (e.errno, e.strerror))
            sys.exit(1)
        # decouple from parent environment
        logging.debug('After first fork')
        os.chdir("/")
        os.setsid()
        os.umask(0)
        # do second fork
        try:
            pid = os.fork()
            if pid > 0:
    # exit from second parent
                sys.exit(0)
        except OSError as e:
            sys.stderr.write("fork #2 failed: %d (%s)\n" % (e.errno, e.strerror))
            sys.exit(1)
    # Redirect standard file descriptors
        logging.debug('After second fork')
        sys.stdout.flush()
        sys.stderr.flush()
        si = file(self.stdin, 'r')
        so = file(self.stdout, 'w+')
        se = file(self.stderr, 'w+', 0)
        os.dup2(si.fileno(), sys.stdin.fileno())
        os.dup2(so.fileno(), sys.stdout.fileno())
        os.dup2(se.fileno(), sys.stderr.fileno())
        logging.debug('before setting signal handlers')
        signal.signal(signal.SIGTERM, self.sigint_handler)
        logging.debug('before while')
        while True:
            sys.stdout.write('.')
            sys.stdout.flush()
            time.sleep(1)

    def sigint_handler(self, signum, frame):
        logging.debug('In signal handler')
        os.killpg(0, signal.SIGTERM)

def main():
    logging.basicConfig(filename='log', filemode='w',
        level=logging.DEBUG, format='%(asctime)s %(name)-12s %(levelname)-8s %(message)s')

    han = Handler()
    han.daemon()

##########

if __name__ == "__main__":
    main()