#!/usr/bin/env python
# Copyright: 2006 Gentoo Foundation
# License: GPL2
# $Id:$
#
#  Zac Medico <zmedico@gentoo.org>
#

import portage_locks
import atexit, errno, os, random, signal, sys

def locker_process(data_file):
	try:
		while True:
			mylock = portage_locks.lockfile(data_file, wantnewlockfile=1)
			rand = random.random()
			rand_str = repr(rand)
			f = open(data_file, "w")
			f.write(rand_str)
			f.close()
			f = open(data_file)
			s = f.read()
			f.close()
			portage_locks.unlockfile(mylock)
			if rand_str != s:
				print "%s!=%s" % (rand_str,s)
				break
	except KeyboardInterrupt:
		pass
	
	# clean up the lock file and data file
	mylock = portage_locks.lockfile(data_file, wantnewlockfile=1)
	try:
		os.unlink(data_file)
	except OSError, oe:
		if oe.errno == errno.ENOENT:
			pass
		else:
			raise oe
	portage_locks.unlockfile(mylock)
	os._exit(0)

if __name__ == "__main__":
	fork_count = 2
	data_file = "/dev/shm/aux_db_key_temp"
	if len(sys.argv) > 1:
		data_file = sys.argv[1]
	
	spawned_pids = []
	def cleanup():
		print "cleaning up..."
		while spawned_pids:
			pid = spawned_pids.pop()
			try:
				if os.waitpid(pid, os.WNOHANG) == (0, 0):
					os.kill(pid, signal.SIGTERM)
					os.waitpid(pid, 0)
			except OSError, oe:
				if oe.errno == errno.ESRCH:
					pass
				else:
					raise oe

	atexit.register(cleanup)
	
	def child_signal_handler(signum, frame):
		signal.signal(signal.SIGCHLD, signal.SIG_IGN)
		sys.exit(1)
	
	signal.signal(signal.SIGCHLD, child_signal_handler)
	
	for i in xrange(fork_count):
		pid = os.fork()
		if pid == 0:
			locker_process(data_file)
		else:
			spawned_pids.append(pid)
	try:
		os.wait()
	except KeyboardInterrupt:
		pass