LXDM

From LXDM - LXDE Display Manager:

LXDM is the lightweight display manager aimed to replace gdm in LXDE distros. The UI is implemented with GTK+. It is stil in early stages of development.

Installation

Install the lxdm package which is available in the official repositories.

To make the graphical login the default method of logging into the system, edit your /etc/inittab file (recommended) by adding or uncommenting this line:

x:5:respawn:/usr/sbin/lxdm >& /dev/null

Alternatively you can add lxdm to your list of daemons in /etc/rc.conf. These procedures are detailed on the Display Manager page.

Configuration

The configuration files for LXDM are all located in /etc/lxdm. The main configuration file is lxdm.conf, and is well documented in it's comments. Another file, Xsession, is the systemwide x session configuration file and should generally not be edited. The other files in this folder are all bash scripts, which are run when certain events happen in LXDM.

These are:

1. LoginReady: Is executed with root priviledges when LXDM is ready to show the login window.
2. PreLogin: Is run as root before logging a user in.
3. PostLogin: Is run as the logged-in user right after they have logged in.
4. PostLogout: Is run as the logged-in user right after they have logged out.
5. PreReboot: Is run as root before rebooting with LXDM.
6. PreShutdown: Is run as root before poweroff with LXDM.

Autologin

If you want to log in to one account automatically, without providing a password, find the line in /etc/lxdm/lxdm.conf that looks like this:

#autologin=username

Uncomment it, then substitute your own username instead of "username".

This will cause LXDM to automatically log you in to the specified account when it first starts up. However, if you were to log out of that account, you would have to enter its password to log back into it; and if the password was empty, you would find yourself unable to log into the account. To make it so that you can manually log into the account without entering a password, first delete the password:

$ passwd -d USERNAME

Then, edit the PAM file for LXDM, which is /etc/pam.d/lxdm. The files in this directory describe how users are authenticated by the various installed programs that need to do some sort of authentication. Change the line that says

auth    required    pam_unix.so

to this:

auth    required    pam_unix.so nullok

This will tell the pam_unix authentication module that blank passwords are to be accepted. After making this change, LXDM will let you log into accounts with blank passwords.

Default background color

Useful if you have a theme such as archlinux-lxdm-theme from the AUR. All you have to do to set a background is add the following to the configuration file.

bg=#deadbeaf

Default session

If you want to change the default session or DE for LXDM to run instead of the default LXDE. Edit /etc/lxdm/lxdm.conf and change the line:

session=/usr/bin/startlxde

to whatever session or DE you want as default. Example to use Xfce as your default:

session=/usr/bin/startxfce4

This is useful if your theme has no visible session selection box or you have trouble using autologin.

Expected Logout Behavior

What might be slightly surprising with LXDM is that, by default, it does not clear the last user's desktop background or kill the user's processes when that user logs out. If you desire this behaviour, you can edit /etc/lxdm/PostLogout like this:

#!/bin/sh

# Kills all your processes when you log out.
killall --user $USER -TERM

# Set's the desktop background to solid black. Useful if you have multiple monitors.
xsetroot -solid black

Note: This will kill daemons such as tmux, urxvtd, etc.

Unlocking Keyrings upon Login

When using a key manager such as gnome-keyring to manage passwords for ssh keys, /etc/pam.d/lxde should be adjusted to allow users to unlock keyrings upon login if desired. The following is an functional configuration:

#%PAM-1.0
auth            requisite       pam_nologin.so
auth            required        pam_env.so
auth            required        pam_unix.so
auth            optional        pam_gnome_keyring.so
account         required        pam_unix.so
session         required        pam_limits.so
session         required        pam_unix.so
session         optional        pam_gnome_keyring.so auto_start
password        required        pam_unix.so