[systemd-devel] Systemd not correctly handle audio device acls for the active session?

[Colin Guthrie]

'Twas brillig, and Kawing Chiu at 29/03/14 02:13 did gyre and gimble:
> So, is that simply not achievable in systemd? I mean, since logind "has
> no way to know about my session on vt7", then what about I *tell* it
> explicitly? Maybe through some cmdline tools, for example, something
> like: `loginctl add-vt vt7 session03`, or through proper configuration
> of logind? Or can I just spawn startx in a new session that is
> associative with vt7, i.e. something like `systemd-setsid startx -- vt7`?

As far as I understand it, this is more of a PAM problem than a systemd
one. The problem would be starting a second session from within an
initial one.

All in all, it would be possible to hack something up that still
switched VTs and did all the necessary stuff but it would be a bit of a
pain to do.

e.g. you could have "startx" do soemthing like:

1. Write a one-time config for gdm/kdm/whatever to trigger an autologin
by a given user.
2. Start a new display server (gdm/kdm/whatever) and let it pick the
next available vt (or favour vt7 onwards although the whole "vt7 is
graphics" thing is not really true these days - most folks start on vt1
these days). Perhaps this is done simply by starting "x at 7.service" or
some similar templated unit)
3. Let the display server pick up the autologin config and log you in,
registering a new session (which will be active).
4. Cleanup the autologin config after it's been used.
5. Wait for the X server to exit.
6. Switch back to the original VT.

All in all, this is a pretty messy and not easy to configure and also
needs privileges to run so isn't nice from a security perspective.

All in all it's just easier to do the whole "reuse the current vt" thing
instead.

Col

-- 

Colin Guthrie
gmane(at)colin.guthr.ie
http://colin.guthr.ie/

Day Job:
  Tribalogic Limited http://www.tribalogic.net/
Open Source:
  Mageia Contributor http://www.mageia.org/
  PulseAudio Hacker http://www.pulseaudio.org/
  Trac Hacker http://trac.edgewall.org/