import os
import sys
import threading
import subprocess

master_popen = None
lock = threading.Lock()

def dummy_daemon():
    global master_popen
    args=['sleep', '600']
    lock.acquire()
    master_popen = subprocess.Popen(args)
    lock.release()
    master_popen.wait()

while True:
    threading.Thread(target=dummy_daemon).start()
    
    args=['sleep', '0.1']
    slave_popen = subprocess.Popen(args, 
            stdin=open(os.devnull), stdout=open(os.devnull),
            stderr=open(os.devnull), bufsize=-1)
    slave_popen.wait()
    
    lock.acquire()
    if master_popen:
        master_popen.kill()
    lock.release()

    sys.stdout.write('.')
    sys.stdout.flush()