Beyond Linux® From Scratch (systemd edition) - Version 8.4

Chapter 26. Display Managers

lightdm-1.28.0

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-8.4 platform.

Lightdm Package Information

[Note]

Note

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 https://en.wikipedia.org/wiki/LightDM.

Lightdm-gtk-greeter Package Information

Lightdm Dependencies

Required

GTK+-3.24.5, libgcrypt-1.8.4, Linux-PAM-1.3.0, and PCRE-8.42

Recommended

gobject-introspection-1.58.3, libxklavier-5.4, and Vala-0.42.5

Optional

at-spi2-core-2.30.0, Exo-0.12.4, GTK-Doc-1.29, itstool-2.0.5, Qt-5.12.1, libido, and libindicator

User Notes: http://wiki.linuxfromscratch.org/blfs/wiki/lightdm

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-1.28.0 &&
make

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-2.0.5.tar.gz &&
cd lightdm-gtk-greeter-2.0.5 &&

./configure                      \
   --prefix=/usr                 \
   --libexecdir=/usr/lib/lightdm \
   --sbindir=/usr/bin            \
   --sysconfdir=/etc             \
   --with-libxklavier            \
   --enable-kill-on-sigterm      \
   --disable-libido              \
   --disable-libindicator        \
   --disable-static              \
   --docdir=/usr/share/doc/lightdm-gtk-greeter-2.0.5 &&

make

Now, as the root user: 

make install

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

/etc/lightdm/{lightdm,users,keys}.conf

Systemd Unit

Install and enable the systemd unit. From the blfs-systemd-units-20180105 package: 

make install-lightdm &&
systemctl enable 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.

Contents

Installed Programs: dm-tool, lightdm, and lightdm-gtk-greeter
Installed Libraries: liblightdm-gobject-1.so
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-2.0.5, /var/lib/lightdm, /var/lib/lightdm-data, /var/cache/lightdm, and /var/log/lightdm

Short Descriptions

lightdm

is a display and login manager.

lightdm-gtk-greeter

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.

Last updated on 2019-02-20 15:33:51 -0800