XDM

From xdm(8) § DESCRIPTION:

Xdm manages a collection of X displays, which may be on the local host or remote servers. The design of xdm was guided by the needs of X terminals as well as The Open Group standard XDMCP, the X Display Manager Control Protocol. Xdm provides services similar to those provided by init, getty and login on character terminals: prompting for login name and password, authenticating the user, and running a "session."

XDM provides a simple and straightforward graphical login prompt.

Installation

Install the xorg-xdm package. Optionally, install the xdm-archlinux package for Arch Linux themes.

Follow Display manager#Loading the display manager to start XDM at boot.

Note If xdm-archlinux is installed, the corresponding service to be used is xdm-archlinux.service instead of the standard xdm.service.

Configuration

Defining the session

Unlike many more modern display managers such as GDM or LightDM, XDM does not source available sessions from .desktop files located in the /usr/share/xsessions directory. As such, XDM does not have a 'session menu.' Instead, XDM will execute the .xsession file in the home directory.

For example, to start Xfce upon login, the ~/.xsession file should look like this:

startxfce4

Ensure that the .xsession file in your home directory is executable.

Theming

For the exact meanings of the options discussed below, see xdm(8). The configuration file is located in /etc/X11/xdm/Xresources, notice that if you installed xdm-archlinux the configuration file will instead be located in /etc/X11/xdm/archlinux/Xresources.

Background wallpaper

Install qiv^AUR.

Create a directory to put wallpapers in, e.g /usr/local/share/backgrounds and then place them inside it.

Edit /etc/X11/xdm/Xsetup_0. Change the xconsole command to /usr/bin/qiv -zr /usr/local/share/backgrounds/*

Font

Edit /etc/X11/xdm/Xresources. Add/replace the following defines:

xlogin*greetFont:  -adobe-helvetica-bold-o-normal--20------iso8859-1
xlogin*font:       -adobe-helvetica-medium-r-normal--14------iso8859-1
xlogin*promptFont: -adobe-helvetica-bold-r-normal--14------iso8859-1
xlogin*failFont:   -adobe-helvetica-bold-r-normal--14------iso8859-1

Login dialog positioning

This configuration will move the login dialog to the bottom right of the screen.

xlogin*frameWidth: 1
xlogin*innerFramesWidth: 1
xlogin*logoPadding: 0
xlogin*geometry:    300x175-0-0

Removing the logo

Comment out the logo defines:

#xlogin*logoFileName: /usr/share/xdm/pixmaps/xorg.xpm
#xlogin*logoFileName: /usr/share/xdm/pixmaps/xorg-bw.xpm

Multiple X sessions & Login in the window

With the XDMCP enabled, you can easily connect to local or remote XDM instance and run multiple X sessions simultaneously on the same machine:

# X -query xdmcp-server-ip :2

This command will launch the second session in window using Xephyr:

$ Xephyr -query xdmcp-server-ip :2

Passwordless login

In order to enable passwordless login for XDM, add the line below to /etc/X11/xdm/Xresources:

xlogin*allowNullPasswd: true