Starting single app from Xvnc -inetd

[Brian Candler]

I want to used Xvnc -inetd to launch a single application (firefox, or
firefox plus twm) for each incoming client connect. This is for a
cybercafe-like application.

My question is: it is really necessary to go through XDMCP to start the
application? Or is there a way to get Xvnc to start the application
directly?

The latter for would be more lightweight, and also not interfere with my gdm
settings which I use for console access (for instance, if I configure gdm to
autologin as user 'cybercaf' then I lose my ability to login directly on the
console) 

I can happily run Xvnc directly from xinetd, but without a -query option all
I get is a blank window when each client connects.

Running Xvnc via xinit doesn't seem to work:

$ Xvnc -inetd
RFB 003.008
$ xinit /usr/bin/xterm -- /usr/bin/Xvnc -inetd

<< no response, times out after a few seconds >>

which seems to suggest that xinit doesn't pass stdin/stdout onto Xvnc.

Any other suggestions as to how I can make this work?

Thanks,

Brian.