Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sdd.hp.com!think.com!snorkelwacker.mit.edu!bloom-beacon!dont-send-mail-to-path-lines
From: mouse@lightning.mcrcim.mcgill.EDU
Newsgroups: comp.windows.x
Subject: Re:  Sun console problem
Message-ID: <9102221205.AA01177@lightning.McRCIM.McGill.EDU>
Date: 22 Feb 91 12:05:23 GMT
Sender: daemon@athena.mit.edu (Mr Background)
Organization: The Internet
Lines: 38

> I am having a problem with people running X clients off SparcStations
> onto X-terminals (Sun 3/50s).  The problem is that sometimes the
> console locks up and it cannot be used to log in or whatever.  From a
> remote terminal I can start X on the console, or blank it using
> clear_colormap, but I can't get the getty running on it again.  There
> IS a getty process, but it won't talk to the physical console.  I
> think it is something to do with xterm -C which redirects console
> output to the pty of the xterm, but how can I switch it back again?

Convince xterm to close the pty.  The easiest way to do this is to kill
xterm.  (Any xterm -C running on *our* servers gets blown away as soon
as I notice it.  We don't take kindly to users stealing the consoles
away.)

> I need some utility that will redirect console output back to the
> physical console,

You can do this by writing a program which grabs a pty, does TIOCCONS
on it, and immediately closes it.  This works because the kernel
doesn't remember that you grabbed the console away from another pty
instead of from the real console, so when you close the pty it reverts
back to the real console.

I don't have such a program; I've never needed it.

> or else some way of stopping people redirecting it in the first
> place!

IMO there should be a kernel variable (ie, patchable with adb) to
control whether TIOCCONS works or not.  If 4.1.1 (which we will be
installing soon, I hope) doesn't have something of the sort, I'll
probably take a dive into the kernel myself and try to create a patch
which will just disable TIOCCONS altogether....

					der Mouse

			old: mcgill-vision!mouse
			new: mouse@larry.mcrcim.mcgill.edu