Xauth running in an interactive CUPS shell

[Cups Seg]

Hello,

I have written a cups backend that uses a tool to send a printing job to an X Client. The way it works is simple, the tool checks for which display that client is connected to and then executes the tool with two switches, display names and filename.

In order to achieve this, with xauth in use, I have had to inject the MIT-COOKIE into the lp users .Xauthoirty file. I'm doing this with an ugly method of sudo, not very secure, but working. I dont mind to much as it's an segregated environemtn.

However, when I execute the util, after doing su - lp (Yes, I changed the shell to a working one), I am able to run the utility and it uses the MIT-COOKIE. However, when I try to run "lp filename" as another user, and execute the backend script, I get the following error message :

D [02/Mar/2011:13:19:24 +0000] [Job 6] elpr - Exceed Remote Print Utility, Version 13.7
D [02/Mar/2011:13:19:24 +0000] [Job 6]
D [02/Mar/2011:13:19:24 +0000] [Job 6] Successful socket connection to app01.wa.vs.jepphost.com:11
D [02/Mar/2011:13:19:24 +0000] [Job 6] XOpenDisplay Failed reason: "No protocol specified
D [02/Mar/2011:13:19:24 +0000] [Job 6] "
D [02/Mar/2011:13:19:24 +0000] [Job 6] Could not open display: "hostname.domain.tld:11"

This per say doesn't mean that the tool doesn't work, but that the lp user doesn't pick up it's .Xauthority file before sending of the job.

Does anyone know how I can get the lp user to use the .Xauthority file?