starting my own tool , before the login screen to intercept the xmessages

["Rajegowda, Vikas Aralaguppe \(UMKC-Student\)" <varx32 umkc edu>]

Hi,
  i am currently working on X security. Our Approach requires us to intercept Xmesseges and this means i have 
to intercept the Xmessages for the login screen as well.

Our tool basically works as follows:
 Tool establishes a connection with xserver on unix:0.0 , and changes the DISPALY variable to unix:3.0 ( 3 is just an example) where it will be listening. Thus it forwards the Xmessages form xclients to the xserver. 

This brought me to the gdm code. So my objective is to start my tool after the Xserver is started and before
the the greeter establishes a connection to the Xserver. After going throught the gdm code, i decided to start the tool after the control connection is established by the slave process. But the server is rejecting the
connection:
 
Xlib: connection to "unix:0.0" refused by server
Xlib: No protocol specified

I feel that, it is a problem with authorization. Can anyone point me to more information on this?? How can
i get around this ???


thanking you,
Vikas Rajegowda