On Sat, 22 Dec 2007, Steven M. Bellovin wrote:
> Figuring out who's running X is certainly a necessary step.

I think the right question is not "who's running X", but "who's
responsible for the currently-active virtual console".  I often have
different users logged in on different virtual consoles in text mode.
It's been some time since last I did so, but I have also had different
users simultaneously running X on different virtual consoles, with or
without xdm (or kdm or equivalent).

--apb (Alan Barrett)