PIDLockFile.acquire() may loop indefinitely

[Valentine Sinitsyn]

Steps to reproduce:
1. Create PIDLockFile() instance for some random pid file and aquire() it with no timeout value (e.g. PIDLockFile('/tmp/sample.pid').acquire())
2. Repeat it again for the same file.

Expected result: AlreadyLocked exception is raised.

Actual result: The code loops indefinitely.

The problem is likely around line 84 in pidlockfile.py: if timeout is None, you never branch into the code raising exceptions. And timeout can be None if it wasn't specified both in acquire() and during object construction.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/221123

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/221123
Committed: https://git.openstack.org/cgit/openstack/pylockfile/commit/?id=6e9888d592f92319c63ccbd86ea61db32076ae1c
Submitter: Jenkins
Branch: master

commit 6e9888d592f92319c63ccbd86ea61db32076ae1c
Author: Davanum Srinivas <email address hidden>
Date: Mon Sep 7 19:35:30 2015 -0400

    Fix PIDLockFile.acquire() may loop indefinitely

    end_time takes timeout into account, so when time.time()
    does hit the end_time, we should check if timeout was
    set or not and throw either LockTimeout or AlreadyLocked.

    Closes-Bug: #1472101
    Change-Id: I1f369628e765a173ff0cafd01c31eca725b41cae