[FreeNX-kNX] race conditions around xauth calls

[Ed Warnicke]

In the process of trying to test some of the changes to NX to deal with
*other* race conditions, I have recently been launching 10 or so
nxclients at a time, which are logging into one server as 
one user.  This led to all kinds of new issues, that turn out to be related
to the braindead way xauth handles locking the $HOME/.Xauthority file.

It seems that when you execute the xauth command it locks the 
.Xauthority file.  In general this is good.  But when you run an 
xauth command and the .Xauthority file is already locked,
it simply outputs and error to that effect and returns.  The 
result is that opening multiple session in rapid succession to one
server as one user causes frequent cryptic failures because
the xauthority isn't set up correctly.

I solved that problem by dropping a lock file in temp and
syncing any nxnode needs to call xauth over it using the ln
trick.

What is now vexing me is that kde during startup seems to
be having the same sorts of issues around ICE.  It looks like
near as I can tell, ICE needs to read from the .Xauthority
file and can't because it's locked (I forgot to mention 
earlier, even xauth list fails if the file is locked).

Does anyone have any pointers to deep ICE mysteries?
I'm not even sure how to figure out where what package
is responsible for it... so I don't even know who to contact
to complain to them, or how to try to confirm my hunch...

Ed