[gdm-list] How can I run a GUI application before gdmgreeter?

[Yi Yu <alexdoer yu gmail com>]

Hi,
 
I am alex from China, I need your help on some questions about gdm. Below is detail:
 
[background]:
I want to run a GUI application to do initial configuration before login at first boot, my app is implemented by gtk+/glade on ubuntu8.04, the gdm version is 2.20.7. Moreover, there is a vedio played in my app.

 
[my questions]:
1> How can I run a GUI application before gdm in script, or add some code in gdm to launch it before gdm launching gdmgreeter/gdmlogin?
2> How does gdmgreeter finish the login process? for I can not find any code to do it in greeter, maybe I lost some important detail. the reason of this question is that I can run my app after gdmgreeter by add some lines in xsession script, so I want to ignore the login process or remove greeter, then launch my app directly.
 
additionally, May you provide more document about gdm work process? for there is less comment in code, and i can not find enough doc on web to help us to understand the mechanism of gdm. Thanks in advance!!!
 
BRs
Alex