I don't want to say this again, freaking backup your files before you edit a single letter of your files first, then proceed with the work.

Below are the exact steps to enable a particular PHP function:

1. Remove all functions from disable_functions in php.ini
2. Add functions in php.ini suhosin.executor.func.blacklist = “” those you want to disable globally.

After that in the virtual host section of a domain you can add below code to enable a function only for one domain:

<VirtualHost 127.0.0.1>
………..
<IfModule mod_php5.c>
php_admin_value suhosin.executor.func.blacklist = “shell_exec”
</IfModule>
……
</VirtualHost>

In this example shell_exec has been enabled for the VirtualHost.