Re: running true multihead...

[Steffen S. <s.s...@ph...>]

Marcus Sundberg wrote:
> 
> Steffen Seeger <s.s...@ph...> writes:
> 
> > However, even if that would have worked, there is another issue I came about
> > when configuring XDM:
> >
> > xterm and some other programs expect /dev/console to be owned by the user
> > sitting on the console. So, even if we map /dev/console to tty's on a
> > per-work-place basis, how do we manage to map ownership and permissions?
> 
> Hmm? xterm doesn't even touch /dev/console on any Linux-system I've
> seen, and I doubt many other regular user application do either.
> Exactly what problems are you experiencing?

The two scripts 

/usr/X11/lib/X11/xdm/TakeConsole
/usr/X11/lib/X11/xdm/GiveConsole

give the following notice:

# Reassign ownership of the console to root, this should disallow
# assignment of console output to any random users's xterm

and change permissions and ownership on /dev/console. It seems as there
is some security issue involved, e.g. xterm and may be xconsole
requiring correct ownership of /dev/console before attaching to the console.

There is a similar mechanism (see /etc/security/console.perms) used to control
access to joysticks, mice, serial lines, etc.).

So, my concern is (as with other device files in /dev/ that virtualize
workplace local devices), that if running two independent sessions from xdm
the session started later will take over devices of the first, unless
the device sets have no common elements. Also, applications that require
user-local preferences (e.g. what is your preferred sound output device)
will fail if you are not logged on to the same head as during configuration.

What I do imagine is something like /proc/self for workplace local devices.
But do not yet know if that is actually enough...

			Steffen

_______________________________________________________________________________
Steffen Seeger                              mailto:se...@ph...
TU-Chemnitz                                      http://www.tu-chemnitz.de/~sse
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