KDE GUI Login Configuration HOWTO
John P. Meshkoff,II johnm@sivakalpa.org
<mailto:johnm@sivakalpa.org>
v1.03 2003/04/13 update icon notes and kde 3.1 handbook
notes
This is the KDE GUI Login Configuration HOWTO, a tutorial on customiz
ing the GUI login screen. Topics include: How to add other window
managers to the drop-down selection list; how to enable user selection
icons in the login window; and requiring root permission for system
shutdown.
______________________________________________________________________
Table of Contents
1. Copyright
2. Introduction
3. Adding new window manager selections to the drop-down list
4. Enabling user selection icons in the login dialog box
5. Requiring root permission for shutdown
6. Bibliography
______________________________________________________________________
1. Copyright
Copyright (c) 2002 by John Meshkoff
Please freely copy and distribute (sell or give away) this document in
any format. It's requested that corrections and/or comments be
forwarded to the document maintainer. You may create a derivative
work and distribute it provided that you:
1. Send your derivative work (in the most suitable format such as
sgml) to the LDP (Linux Documentation Project) or the like for posting
on the Internet. If not the LDP, then let the LDP know where it is
available.
2. License the derivative work with this same license or use GPL.
Include a copyright notice and at least a pointer to the license used.
3. Give due credit to previous authors and major contributors.
If you're considering making a derived work other than a translation,
it's requested that you discuss your plans with the current
maintainer.
2. Introduction
This info is based on my RedHat 6.1 default KDE Workstation
installation. If you are using another distribution, or even another
version of RedHat, or a different Workstation install, then you may
have to do some detective work. Hopefully, this info will give you
what you need to start detecting! This HOWTO began as the result of
wondering how to add another window manager or desktop environment to
the drop-down list on the GUI login screen; further investigation
revealed other configuration options.
I began my own "detective work" when I found a reference on a RedHat
List which mentioned /etc/inittab, and its role in system startup. In
/etc/inittab I found the following entries, which define how the X
Window System is started in my distribution and version:
______________________________________________________________________
# Run xdm in runlevel 5
# xdm is now a separate service
x:5:respawn:/etc/X11/prefdm -nodaemon
______________________________________________________________________
Here is what prefdm looks like:
______________________________________________________________________
#!/bin/sh
PATH=/sbin:/usr/sbin:/bin:/usr/bin:/usr/X11R6/bin
# Run preferred X display manager
preferred=
if [ -f /etc/sysconfig/desktop ]; then
if grep -q GNOME /etc/sysconfig/desktop 2>/dev/null; then
preferred=gdm
elif grep -q KDE /etc/sysconfig/desktop 2> /dev/null; then
preferred=kdm
elif grep -q AnotherLevel /etc/sysconfig/desktop 2> /dev/null; then
preferred=xdm
fi
fi
if [ -z ":$preferred" ]; then
if which gdm >/dev/null 2>&1; then
preferred=gdm
elif which kdm >/dev/null 2>&1; then
preferred=kdm
elif which xdm >/dev/null 2>&1; then
preferred=xdm
fi
fi
if [ -n "$preferred" ] && which $preferred >/dev/null 2>&1; then
exec `which $preferred` $*
fi
exit 1
______________________________________________________________________
No changes to prefdm are necessary; it determines which display
manager is the system default, and which runs the GUI login. During
boot-up, prefdm parses /etc/sysconfig/desktop and selects the display
manager listed there; in the case of my KDE Workstation install, this
is kdm (KDE Display Manager). Note that gdm (Gnome Display Manager)
is not installed on my system; xdm (X Display Manager) is installed by
default as part of the X Window System, and was apparently used by
older versions of Red Hat.
3. Adding new window manager selections to the drop-down list
WARNING: The procedures explained in this HOWTO involve making
changes to system configuration files; if you are not experienced in
making such changes, some caution is required. Introducing errors
into such files may make your system unstable, or cause it to crash.
The procedures explained in this HOWTO have been tested and should not
cause problems if used correctly.
If you have KDE 2.2 or higher, and you are not comfortable with manual
editing of system files, you may open a terminal window (xterm or
konsole) from your user desktop (NOT the root desktop), then type and
enter:
______________________________________________________________________
su -c 'kcontrol'
______________________________________________________________________
Enter your root password at the prompt, and make the changes from
within the KDE Control Center that appears: go to Applications ==>
Login Manager. Choose the appropriate configuration tab; you can
easily configure every aspect of the login screen from there. In
Earlier versions of KDE, kcontrol can modify kdmrc, but cannot modify
Xsession which is used in those versions; see the note below about
changes from KDE 2.2 and higher.
To see how to manually configure some of these, and see what these
configuration files do, proceed as follows:
(Caution: Some configuration files have changed since the version of
kdm I'm using, particularly since KDE > 2.0:
The following is quoted from the FreeBSD Handbook-X11:
<http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/x11-wm.html>
"Note: In KDE 2.2 this has changed: kdm now uses its own configuration
files. Please see the KDE 2.2 documentation for details.")
Note: KDE 3.1 has added kdm documentation, see The kdm Handbook
<http://docs.kde.org/en/3.1/kdebase/kdm/>
Much of the material in this new handbook applies to the older
versions; new features are also described therein.
Check the documentation for your version to identify the current
configuration files if you want to manually edit these, or just want
to see how they work.
Do not use a word-processor program for editing system configuration
files; such programs introduce special formatting characters which
will corrupt the files. Use a text-editor, particularly one which can
handle long lines without introducing extra carriage-return or line
feed characters into existing code. Suitable editors include vim (vi
improved), vi, and emacs. There are others, but these are usually
installed by default in Linux workstation installations; they each
have features which make them especially suitable for writing and
editing computer code. See the bibliography section at the end of
this HOWTO for more information.
IMPORTANT: Before making changes to any system configuration files,
you should make back-up copies of the originals, so you can restore
them in case of serious errors!
The files which we will be changing here are /usr/share/config/kdmrc,
which is where we add selection labels to the drop-down list on the
login screen, and /etc/X11/xdm/Xsession, which is where we add the
path to the executables for our labels (if you are using a different
distribution, the path to these files may be different; just do
"locate kdmrc" and "locate Xsession" in the shell [i.e., in a terminal
emulation, such as xterm, or KDE's konsole] to find them).
The default line to change in kdmrc looks like this:
______________________________________________________________________
SessionTypes=kde;gnome;anotherlevel;default;failsafe;
______________________________________________________________________
After adding selection labels for two new window managers, windowmaker
and blackbox, the line looks like this:
______________________________________________________________________
SessionTypes=kde;gnome;windowmaker;blackbox;anotherlevel;default;failsafe;
______________________________________________________________________
Notice the positions where I have added the labels for the new window
managers; all entries will appear on the drop-down list in the same
order as they appear in the SessionTypes list. Next, the actual choos
ing takes place in /etc/X11/xdm/Xsession. Here is what the appropriate
section of Xsession looks like before adding the new entries:
______________________________________________________________________
# now, we see if xdm/gdm/kdm has asked for a specific environment
#
case $# in
1)
case $1 in
failsafe)
exec xterm -geometry 80x24-0-0
;;
gnome)
exec gnome-session
;;
kde)
exec startkde
;;
anotherlevel)
# we assume that switchdesk is installed.
exec /usr/share/apps/switchdesk/Xclients.anotherlevel
;;
esac
esac
______________________________________________________________________
Here is what this section of the Xsession file looks like after adding
the new entries (NOTE that the selection labels must be exactly the
same in Xsession and prefdm, i.e., spelling and case must be
identical):
______________________________________________________________________
# now, we see if xdm/gdm/kdm has asked for a specific environment
#
case $# in
1)
case $1 in
failsafe)
exec xterm -geometry 80x24-0-0
;;
gnome)
exec gnome-session
;;
kde)
exec startkde
;;
windowmaker)
exec wmaker
;;
blackbox)
exec blackbox
;;
anotherlevel)
# we assume that switchdesk is installed.
exec /usr/share/apps/switchdesk/Xclients.anotherlevel
;;
esac
esac
______________________________________________________________________
Note that when the executables are installed in one of the paths shown
below, only the executable name is required after "exec"; otherwise
the full path must be included, as shown for "Xclients.anotherlevel"
(above):
/usr/bin/
/usr/local/bin/
/usr/X11R6/bin/
/usr/bin/X11/
These examples should be enough for you to add your favorite window
manager(s) to the KDE graphical login, or to give you a starting point
to find out how it's done in your particular installation.
4. Enabling user selection icons in the login dialog box
In RedHat 6.1, the default KDE login window shows a dialog box with a
space to type in the user name, one in which to type the user
password, and a drop down list to select the window manager/desktop
environment of choice. By making the following changes to
/usr/share/config/kdmrc, user icons will appear in the top of the
login box. Here is what the default lines that control user icon view
in kdmrc look like (other lines between these two are not shown, and
are represented by "..."):
______________________________________________________________________
#Users=root;johndoe
...
UserView=false
______________________________________________________________________
Here are the same lines after editing; delete the comment character
("#") in front of "Users=..." and change "johndoe" to your username
(if there are more user accounts on your system, you may add their
usernames here, separated by semi-colons as shown). Change
"UserView=false" to "UserView=true" as shown here:
______________________________________________________________________
Users=root;johnpipe
...
UserView=true
______________________________________________________________________
Now, when you login, you may click on an icon with the mouse to enter
the user name; you must still type in your password.
You can add your own icons in place of the default icons; place you
own icons in /usr/share/apps/kdm/pics/users/. They should be of size
64 x 64, according to the kdm handbook; in KDE 1.x, the default icons
are 62 x 63, and my new user icon is 60 x 60, so if icons are
reasonably close to the specified 64 x 64 size, they will work OK.
The handbook says "kdm is able to handle icons of different sizes, but
the result looks messy.", so there is evidently some leeway here.
Your icons should be named 'username.xpm', for example my username is
"johnpipe" and my new icon is named 'johnpipe.xpm'
NOTE: at some time since kde 1.x, the icon format has been changed
from '.xpm' (XPixMap) to '.png' (portable network graphic).
5. Requiring root permission for shutdown
The default for the shutdown button on the login box allows anyone to
use it to shutdown the system. The section in /usr/share/config/kdmrc
controlling who may use this button looks like this:
______________________________________________________________________
#ShutdownButton=RootOnly
ShutdownButton=ConsoleOnly
______________________________________________________________________
To enable only the root user to shutdown the system, change the lines
as shown below:
______________________________________________________________________
ShutdownButton=RootOnly
#ShutdownButton=ConsoleOnly
______________________________________________________________________
Clicking the shutdown button will now prompt for the root password
before shutting down the system.
6. Bibliography
For more HOWTO's, see The Linux Documentation Project
<http://www.tldp.org/>
Recommended reading:
· XWindow-User-HOWTO <http://www.tldp.org/HOWTO/XWindow-User-HOWTO/>
· Emacs Beginner's HOWTO <http://www.tldp.org/HOWTO/Emacs-Beginner-
HOWTO.html>
· Vim Color Editor HOW-TO (Vi Improved with syntax color
highlighting) <http://www.tldp.org/HOWTO/Vim-HOWTO.html>
Depending on your Linux distribution and version, you may already have
the above HOWTO's installed on your system. If not installed, you may
have them on your installation CD.
