The Fast User Switch Applet

I can only assume if you’re at this page, you’ve been directed here by an old link in either some source code I wrote, or a web page describing the source code I wrote. Just to give you a feel for how old I’m talking about, I worked on FUSA for two years, from 2004 to 2006. If you’re reading this, you’re looking for information about a bit of code I stopped paying attention to 7 years ago as of this writing.

So, what is FUSA? Well, it was the drop-down menu that shipped as part of GNOME 2.14 (and later 2.x series)—a panel applet that shows your name in the top-right corner, and lets you click a menu and flip to a different user. Of course, it never quite worked properly, because it was written before GNOME had the infrastructure to do things like that properly:

  1. GDM did not have a mechanism to cause a new PAM session to start (i.e. when you clicked on someone who wasn’t already logged in, it would just open a new login screen, not fill in their username/password).
  2. Flipping to an existing user would present you with a blank screen/their screensaver, because there was no mechanism to communicate with the second-user’s screensaver and say “try to unlock now”. You had to manually fiddle around to get the password prompt.
  3. There was no method to handle multi-seat permissioning or anything else—if Billy left his audio playing on his account, you were screwed in yours. There was no way to associate mount points, hadrware, etc. with particular sessions, so it was also wildly insecure.

Eventually, brand-new hotness like systemd and GNOME Shell replaced FUSA with something that has a better chance of working seamlessly, now that the infrastructure to allow it is in place.

In other words, the author of the bit of GNOME 2 that you’re looking for is telling you to totally upgrade to GNOME 3. Unless, of course, you hate blind people. 😉

P.S. Ubuntu forked my code into their user menu, and I assume some of it is still there, at least as of this writing (i.e. 2013).

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