QUOTE (michaelk @ Oct 28 2012, 10:09 AM)

What linux distribution/version/desktop are you running?
As an example Gnome uses gdm and so you would need to modify its source code.
projects.gnome.org/gdm/
I am running ubuntu 12.10 I am not sure if that is gnome i started using linux 5 days ago it is 64 bit