Everyone should be running with safe_mode on in /etc/php.ini (on Centos) as it makes exploiting your system more difficult is PHPcan't execute anything on the system if a script is exploited.
For example with Safe_Mode on the only executable files on the system are ones in the safe_mode_exec_dir = /safephp
This is crucial, if you must execute anything from PHPthen you have to copy the binary and assign to the user that Apache runs your site under.&........