Introduction to Lightdm

The lightdm package contains a lightweight display manager based upon GTK.

This package is known to build and work properly using an LFS 12.1 platform.

Lightdm Package Information

Additional download



The greeter is a program to present a graphical login screen. There are several alternative greeters, but the gtk+ package is the reference implementation. For a list of other greeters, see

Lightdm Dependencies


Exo-4.18.0 (for the greeter), libgcrypt-1.10.3, itstool-2.0.7, Linux-PAM-1.6.0, and Xorg-Server-21.1.11 (Runtime)



AccountsService-23.13.9 (run time), at-spi2-core-2.50.1, GTK-Doc-1.33.2, (Qt-5.15.12 or qt-alternate-5.15.12), libido, and libindicator

Installation of Lightdm

First, create a dedicated user and group to take control of the lightdm daemon after it is started. Issue the following commands as the root user:

groupadd -g 65 lightdm       &&
useradd  -c "Lightdm Daemon" \
         -d /var/lib/lightdm \
         -u 65 -g lightdm    \
         -s /bin/false lightdm

Install lightdm by running the following commands:

./configure --prefix=/usr                 \
            --libexecdir=/usr/lib/lightdm \
            --localstatedir=/var          \
            --sbindir=/usr/bin            \
            --sysconfdir=/etc             \
            --disable-static              \
            --disable-tests               \
            --with-greeter-user=lightdm   \
            --with-greeter-session=lightdm-gtk-greeter \
            --docdir=/usr/share/doc/lightdm-1.32.0 &&

This package does not come with a test suite.

Now, as the root user:

make install                                                  &&
cp tests/src/lightdm-session /usr/bin                         &&
sed -i '1 s/sh/bash --login/' /usr/bin/lightdm-session        &&
rm -rf /etc/init                                              &&
install -v -dm755 -o lightdm -g lightdm /var/lib/lightdm      &&
install -v -dm755 -o lightdm -g lightdm /var/lib/lightdm-data &&
install -v -dm755 -o lightdm -g lightdm /var/cache/lightdm    &&
install -v -dm770 -o lightdm -g lightdm /var/log/lightdm

Now build the greeter:

tar -xf ../lightdm-gtk-greeter-2.0.9.tar.gz &&
cd lightdm-gtk-greeter-2.0.9 &&

./configure --prefix=/usr                 \
            --libexecdir=/usr/lib/lightdm \
            --sbindir=/usr/bin            \
            --sysconfdir=/etc             \
            --with-libxklavier            \
            --enable-kill-on-sigterm      \
            --disable-libido              \
            --disable-libindicator        \
            --disable-static              \
            --disable-maintainer-mode     \
            --docdir=/usr/share/doc/lightdm-gtk-greeter-2.0.9 &&

Now, as the root user:

make install


If you installed Xorg in /opt, you will need to create a symbolic link so lightdm can find the Xorg server. As the root user:

ln -sf /opt/xorg/bin/Xorg /usr/bin/X

Command Explanations

sed ... /usr/bin/lightdm-session: This command ensures that the initial login via the greeter sources /etc/profile and ~/.bash_profile. Without this, commands that depend on different environment variables may not work as expected.

Configuring lightdm

Config Files


The configuration files offer many options. If, for instance, you have a multiple monitor setup but prefer the login window to be displayed on only one monitor, set 'active-monitor=<monitor-name>' in lightdm-gtk-greeter.conf. For example you could use active-monitor=HDMI-1. You can determine the monitor-names with xrandr --listmonitors. Note that the monitor names may change if you change the graphics driver and you may have to adjust the configuration accordingly.

Systemd Unit

Install the lightdm.service unit included in the blfs-systemd-units-20240205 package:

make install-lightdm

Available Sessions

The greeter offers a list of available sessions, depending on the Window Managers and Desktop Environments installed. The list includes sessions which have a corresponding .desktop file installed under /usr/share/xsessions. Most of the Window Managers and Desktop Environments automatically provide those files, but if necessary, you may include a custom one.


Installed Programs: dm-tool, lightdm, and lightdm-gtk-greeter
Installed Libraries:
Installed Directories: /etc/lightdm, /etc/apparmor.d, /usr/lib/lightdm, /usr/include/lightdm-gobject-1, /usr/share/help/C/lightdm /usr/share/gtk-doc/html/lightdm-gobject-1, /usr/share/doc/lightdm-gtk-greeter-2.0.9, /var/lib/lightdm, /var/lib/lightdm-data, /var/cache/lightdm, and /var/log/lightdm

Short Descriptions


is a display and login manager


is an auxiliary process that displays the greeter, a graphical user interface that performs user authentication and initiates the selected window manager or display environment