[systemd-devel] PATCH: fix logind on xen

[Frederic Crozat]

Le mardi 03 janvier 2012 à 21:52 +0100, Lennart Poettering a écrit :
> On Tue, 03.01.12 21:35, Lennart Poettering (lennart at poettering.net) wrote:
> 
> > > > currently, logind was enforcing the presence of /dev/tty0 to start
> > > > properly. This device is not present on Xen (when using xencons=tty) or
> > > > S/390.
> > > 
> > > Here is a regenerated version against master, since logind was moved to
> > > its own directory.
> > 
> > Thanks for rebasing the patch!
> > 
> > I fear the patch is not complete though. seat_read_active_vt() in
> > login/logind-seat.c needs to guard against the invalid fd in
> > s->manager->console_active_fd.
> > 
> > Also, I assume that if /dev/tty0 doesn't exist /dev/tty1, /dev/tty2 and
> > so on don't exist either. That means calls like seat_preallocate_vts()
> > need to be shortcut in this case, too.
> > 
> > logind currently implicitly and always creates a seat0, that exists
> > unconditionally, and that all hw that isn't assigned to anything else
> > belongs to. That notion is probably nothing we could or should get rid
> > off that easily, but that means that we need to make sure that a couple
> > of its operations become NOPs on the systems in question. Besides
> > seat_preallocate_vts() that's  seat_read_active_vt() and the whole logic
> > that watches VCSA devices (which should be shortcut, as if n_autovts was
> > 0, in manager_connect_udev()).
> 
> I have now commited a patch which reworks a lot of the logic there and
> tries to handle the no-VT case as gracefully as possible. We still
> implicitly create seat0, but we now stop advertising that it was
> multi-session capable. Hence we still end up with a seat, but only with
> the minimal properties that we need. This makes most of the other
> explicit checks unnecessary fortunately.

Hmm, I've tested this patch (I'm extracted the patche you did for it and
applied to our v37 package, thanks to git ;) and from what I see,
"console" login doesn't get any seat attached (but other login, like
over ssh are getting one), unlike my initial patch. So more work is
needed somehow.

-- 
Frederic Crozat <fcrozat at suse.com>
SUSE