gdm xdmcp access

[Alexander Chuzhoy]

Hi all,
does anyone know a way to set the vaules in gdm.conf file without restarting the gdm?
What I'm trying to achieve is the following:
I see all available via chooser hosts using the following command:
X -indirect
As soon as I change the default 177 port in gdm.conf file to any other port - the host becomes invisible in the list. In order for this change to take place - I have to restart the gdm.
Another way is to run the gdmsetup (graphical tool) and to change values there. Upon closure this utility changes the seetings without restarting the gdm. But I need to be able to change the settings via script- that's why I'm looking some CLI tool or responsible file in /proc for example.
The system is RHEL 4.
Thanks.

[Ivan Ferreira]

It looks like the "safe" way to reload the configuration is to run gdm-safe-restart, this script sends a USR1 signal to the daemon.

According to the man page:

gdm-safe-restart restarts the current daemon after everyone has logged out.

[Alexander Chuzhoy]

I wish.
gdm-safe-restart waits for all users to logout and then restarts - tried it already.
anything else?

[Alexander Chuzhoy]

Restarting GDM means that all logged via GDM users are kicked out.
gdmsetup handles it in such way that sessions aren't closed and the settings take affect.
I tried to use strace utility to see what files it looks in- but at some point the process detaches....

[Steven E. Protter]

Shalom Alexander,

Possible problem:

xdmcp access won't work outside the vlan the machine is in.

Modern vlans that limit network collision domains prevent xdmcp servers from broadcasting outside the vlan.

SEP

[Alexander Chuzhoy]

Thanks Steven,
I have no such problem.
All my X servers are in the same VLAN and I'm able to see them all via chooser.
My problem is:
how to change the settings in gdm.conf without restarting the whole GDM.
What I want to achieve finally:
At some point (when there're to many users on the same station for example) a script runs and changes the gdm.conf respectively (opens/closes the xdmcp and makes the changes affective).
So other users won;t be able to connect to this station via X.
When a user logs out-the gdm.conf will be changed again and so on...
Is there any other suggestion for that?

[Alexander Chuzhoy]

In addition to above:
It's possible to limit the xdmcp to a certain number of users. But we're looking for a better way than to try every server.
X -indirect allows us to see all available servers.
So changing the gdm.conf will basically cause the server to appear/disappear in the list.
Hope it's clear.

Thanks for the help-it's appreciated.