This is a dorky question and the merits of it are pointless. I have a system for guests and I want a BSOD screensaver for the login. I've been fiddling around for a while with various attempts at making it happen.
The system runs Debian Jessie.
What I tried at least got the xscreensaver-demo window running when lightdm starts. The daemon will not start. If someone can help me get the daemon to start it will be a step in the right direction. In fact, all my problems should be solved.
At this point I've not cared about security implications. I found I can have a script for the greeter by adding this line to /etc/lightdm.conf:
The script simply was this, so I could get xscreensaver-demo to run and bootstrap what I want. It says this greeter setup script runs as root, and just having the script run xscreensaver-demo did create a window. However, it could not start the xscreensaver daemon.
I then tried running xscreensaver-demo as lightdm with this with my script:
su -l "lightdm" -c "/usr/bin/xscreensaver-demo" &
At that point nothing happened, and I am running out of ideas and bad hacks to attempt this. I honestly don't understand lightdm very well, but I still think this can be done.
Note: I am trying to get xscreensaver-demo running so I can select a screensaver, after that the greeter can just run with xscreensaver.
I've considered adding a window manager to the greeter, but twm is all that came to mind and manually placing all the windows lightdm makes it pretty silly.