runWithTimeout

import os, time, select, pty
 
if os.environ.get("TEST_VERBOSE"):
    verbose = True
else:
    verbose = False
 
 
def runWithTimeout(cmd, timeout):
    args = cmd.split()
    pid, fd = pty.fork();
    startTime = time.time()
 
    if pid == 0:
        os.execvp(args[0], args)
    output = ""
    while time.time() - startTime < timeout:
        i, o, e = select.select([fd], [], [], timeout)
        if fd in i:
            try:
                str = os.read(fd, 1)
                output += str 
            except OSError, e:
                exitPid, status = os.waitpid(pid, os.WNOHANG)
 
                if exitPid == pid:
                    if verbose:
                        print "Child exited with %i" % status
                    return status, output
 
    if verbose:
        print "Command timed out: killing pid %i" % pid 
 
    os.kill(pid, signal.SIGINT)
    raise Exception("Command execution time exceeded %i seconds" % timeout,
                       outputSoFar=output)