Taming LightDM
Living with Ubuntu
Ubuntu 12.04 LTS (the Precise Pangolin) uses LightDM as its display manager. While attractive out-of-the-box, it continues the recent trend in display managers of offering far less functionality than we had 5 years ago. Simple settings, like “please don’t let strangers use my computer,” are lacking from its interface. Fortunately, there are some low-level controls that help make LightDM a little more bearable.
Guest users
There’s no doubt that guest sessions can be convenient in many circumstances, but there are plenty of others in which unauthorized users should not be allowed to access a given piece of hardware. To disable LightDM’s guest session, edit the file /etc/lightdm/lightdm.conf and add the line allow-guest=false.
Boot sound
By default, when LightDM starts (including at first boot), it plays a drum sound at whatever volume the last user had their audio set to. In a working environment, it’d be nice to be able to turn on our computer without bringing so much attention to ourselves. Unlike guest sessions, however, the “ready sound” is not controlled by a configuration file. Rather, the setting is stored in dconf for the “lightdm” user. To disable the ready sound, execute the following commands:
sudo xhost +SI:localuser:lightdm sudo -u lightdm gsettings set com.canonical.unity-greeter play-ready-sound false
The first command is necessary because the gsettings “set” command needs to talk to the X server. No, I don’t know why either…
Closing remarks
Even with these tweaks, LightDM is still not appropriate for an enterprise environment (does anyone else see a privacy problem with showing every user’s wallpaper to any passer-by?), but hopefully the login experience is now a bit less unpleasant with these two issues under control.