title: Issues with PHP 5.3 and sessions folder
body: <p>I recently upgraded to PHP 5.3 and since then I get (sporadic) error messages which indicate Apache (or may be the cleaner of the session files) has no permissions to the folder where the sessions are stored.<br>
  This happens randomly and can't be reproduced with exact steps, which led me to guess it is the session cleaner.<br>
  Any one has any experience with such errors?</p>
  
  <p>The error message (which is fired on the <code>session_start()</code> line) is:</p>
  
  <blockquote>
    <p>ps_files_cleanup_dir:
    opendir(/var/lib/php5) failed:
    Permission denied.</p>
  </blockquote>
  
  <p>ls -ltr on the session directory gives:</p>
  
  <pre><code>drwx-wx-wt  2 root          root          4096 2010-05-25 12:39 php5
  </code></pre>
  
  <p>Inside this directory I do see session files owned by www-data which is my Apache, and the app does work fine. 
  Which makes me wonder, under which user does the session GC runs?</p>