Introduction to Lightdm

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



Development versions of BLFS may not build or run some packages properly if dependencies have been updated since the most recent stable versions of the book.

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-1.10.2, itstool-2.0.7, Linux-PAM-1.5.3, and Xorg-Server-21.1.8 (Runtime)



AccountsService-23.13.9 (run time), at-spi2-core-2.48.3, GTK-Doc-1.33.2, Qt-5.15.9, libido, and libindicator

User Notes:

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-2.0.8.tar.gz &&
cd lightdm-gtk-greeter-2.0.8 &&

./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-2.0.8 &&

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


Systemd Unit

Install the lightdm.service unit included in the blfs-systemd-units-20220720 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-2.0.8, /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