#!/usr/bin/python
#
# Script to stress test flock on an ocfs2 filesystem
# The script will print a '.' whenever it tries to get an exclusive lock
#
# Brad Plant
# bplant@iinet.net.au
# 3rd July 2009
#

import sys
import os
import fcntl
import random
import time

if len(sys.argv) != 3:
	print "Takes 2 args, the number of processes to create and the number of iterations per process"
	sys.exit()

if sys.argv[1] <= 0:
	print "You must specify at least 1 process to create"
	sys.exit()

x = int(sys.argv[1])
while x > 0:
	x -= 1
	pid = os.fork()
	if pid == 0:
		i = int(sys.argv[2])

		while i > 0:
			i -= 1
			f = open("flock.test", "r")
			fcntl.flock(f.fileno(), fcntl.LOCK_SH)
			f.readlines()
			fcntl.flock(f.fileno(), fcntl.LOCK_UN)
			f.close()

			if random.randint(1, 1000) == 1:
				sys.stdout.write(".")
				f = open("flock.test", "a+")
				fcntl.flock(f.fileno(), fcntl.LOCK_EX)
				os.ftruncate(f.fileno(), 0)
				f.write(str(time.time()))
				fcntl.flock(f.fileno(), fcntl.LOCK_UN)
				f.close()
		sys.exit()