lightdm-micro-greeter

LightDM µGreeter

A minimalist LightDM greeter written in Go, powered by gotk3 and inspired by lightdm-mini-greeter.

Many thanks to Matt Fischer for his great blog post.

Example screenshot, unknown artist: please open an issue to credit him/her !

Features

• log in
• single-user or multi-user mode
• suited for HiDPI monitor
• triggers
  • poweroff (Ctrl+Shift+P)
  • reboot (Ctrl+Shift+R)
  • suspend (Ctrl+Shift+S)
  • hibernate (Ctrl+Shift+H)
• customization
  • wallpaper
    • autoscaling on your primary monitor
    • random selection from a directory
  • entry
    • width
    • colors (font, background and carret)
  • label
    • choose text for username and password mode

Installation

🚨 Any help to package µGreeter for your favorite distribution is greatly appreciated 🚨

Manual

Requirements

You need the C shared libraries lightdm-gobject-1, gobject-2.0 and glib-2.0. They might be shipped with LightDM, but I can't tell for sure. Depending on your distro, you might have to install some -dev or -devel packages.

Obviously, you also need Go.

Get the binary

go install github.com/nizil/lightdm-micro-greeter@latest

or

git clone github.com/nizil/lightdm-micro-greeter
cd lightdm-micro-greeter
go build

Setup the greeter

Now, you have to tell LightDM to use this greeter, and this is done in two simples steps:

• Create a desktop entry at /usr/share/xgreeters which execute lightdm-micro-greeter.
• Change the LightDM config to use the newly created .desktop, it could be done through the greeter-session parameter of /etc/lightdm/lightdm.conf.

If you have used go install and GOBIN is in your PATH, you could use the desktop file provided.

If you have used go build, you could just run the install.sh script as root, which put the built binary inside /usr/bin/, setup the desktop file and a default configuration, and even modify your LightDM configuration file (while doing a backup).

sudo ./install.sh

Configuration

All the configuration is handled within the /etc/lightdm/lightdm-micro-greeter/config.json file. If the file does not exist, this configuration will be used.

If Wallpaper is a directory, it must only contain images, as the greeter will randomly chose a file from this directory.

Dev notes

I had to rely on C macro G_CALLBACK to bind the LightDM server callbacks, which is unfortunately not accessible through the import "C" statement.
To bind a go function to glib events, I've exported few go functions using //export statement and binded them with G_CALLBACK from C code greeter_signal_connect.c.
With this architecture, it has been pretty difficult to avoid the use of global vars to carry information from the UI to these callbacks. If you have any idea how to make a cleaner code here, open a ticket, I'll be more than happy to discuss about it :)