XDM, XSM and not getting the proper environment

Glynn Clements glynn at gclements.plus.com
Wed Jan 17 10:58:21 PST 2007

Ryan Daly wrote:

> I've been using XDM for quite a while.  After installing Fedora Core 6,
> XDM seems to be behaving differently.  When I first logged in, it didn't
> seem to use my ~/.Xclients.  I read a little and discovered that it was
> looking for xsm.  I installed it and created a ~/.xsession file which
> had the same lines as my .Xclients had.
> Things somewhat work, however when I log in my fonts are not what they
> should be, and some environment settings are not getting set.
> Using GDM things work as they should.
> What changed,

You would do better asking that particular question on a Fedora list.

> and how do I modify my config so that XDM works as it did?

First, check how XDM is being started. Unless you're starting it
manually, there will typically either be a dedicated entry in
/etc/inittab, or an rc file in /etc/init.d (or /etc/rc.d etc) which
starts a display manager. Any environment settings which are made
prior to starting XDM will be inherited by XDM and may affect its

Then, examine the xdm-config file (e.g. /etc/X11/xdm/xdm-config). The
scripts which are run by XDM are determined by the setup, startup,
session and reset resources, e.g.:

	DisplayManager*startup:		/usr/lib/X11/xdm/Xstartup
	DisplayManager*session:		/usr/lib/X11/xdm/Xsession
	DisplayManager*reset:		/usr/lib/X11/xdm/Xreset
	! The following three resources set up display :0 as the console.
	DisplayManager._0.setup:	/usr/lib/X11/xdm/Xsetup_0
	DisplayManager._0.startup:	/usr/lib/X11/xdm/GiveConsole
	DisplayManager._0.reset:	/usr/lib/X11/xdm/TakeConsole

The first three lines specify the default scripts, while the last
three specify scripts which are used for the display ":0".

The setup script is run as root before the login dialog is displayed. 
After login, the startup script is run as root then the session script
is run as the user who logged in. When the session script terminates,
the reset script is run as root, the server is reset, then the process

Most of the details are normally in the session script. The scripts
are invariably customised by the distribution vendor/maintainer, so if
you want to know the specifics, you need to either ask in a forum
which is specific to your distribution (i.e. a Fedora list) or read
the scripts.

Glynn Clements <glynn at gclements.plus.com>

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