linux-kernel - Re: Running an application on a new VT

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Message-ID: <e7ed4b28070ef828902ebb6bd610da9a@cs.uni-dortmund.de>
Date:   Wed, 18 Sep 2019 17:32:55 +0200
From:   Christoph Pleger <christoph.pleger@...uni-dortmund.de>
To:     linux-kernel@...r.kernel.org
Subject: Re: Running an application on a new VT

Hello,

On 2019-09-16 13:53, Christoph Pleger wrote:

> I am using the program openvt to run another program. openvt is used
> to open a new virtual terminal and then run the given program on the
> new VT. In my case, I want to start a KDE Plasma session on the new
> VT.
> 
> Unfortunately, this did not work as expected: After entering the
> command 'openvt -s -w -- dbus-run-session startplasmacompositor', the
> KDE session did not start on the new VT, but on tty1, from where I had
> entered the openvt command. Then, I tried with 'openvt -s -w --
> /bin/bash', but though this ran bash on a new virtual terminal,
> entering 'dbus-run-session startplasmacompositor' on the new VT caused
> a switch back to tty1 and again, the desktop session started there.
> 
> Does anybody know why not the new VT is used for the desktop session
> and how that behaviour can be changed?

This is totally crazy: Even when I omit the -w option to openvt, so that 
I can log out from tty1, then switch to the new VT and enter 
'dbus-run-session startplasmacompositor' there, the KDE session starts 
on tty1, though of course logging out from /dev/tty1 changed its owner 
to root. So, how can a process with real UID, effective UID and saved 
UID (I checked that) change the ownership of a device that was owned by 
root?

Still nobody who has an idea what is going on here with the virtual 
terminals?

Regards
   Christoph