This is just a very quick and dirty how-to for getting Synergy 1 Pro to run on LightDM before logging in. All the other instructions I have found haven’t really worked out for me, so let this be my best try…
Step 1: Setting up
Before we can set up LightDM’s configuration we first need to create a PEM cert and configuration with the root user, as that is what is my LightDM process is running as.
Log into a normal interactive X session. Start the graphical Synergy 1 Pro client via “sudo synergy”, generate a certificate and set the client up in a way that it actually can connect and is approved by the server.
Step 2: Adjust LightDM’s configuration
I am on Arch, so my configuration sits in /etc/lightdm/lightdm.conf. Open the configuration and add the following block:
greeter-setup-script=/usr/bin/synergyc --daemon --name <CLIENT_NAME> --enable-crypto --tls-cert /root/.synergy/SSL/Synergy.pem <SERVER_IP/HOST>:24800
There is no step 3.
Whenever a session gets terminated, the synergy client will also briefly be killed and respawned for the lightdm greeter. I have found no reason to setup anything other than the greeter-setup-script.