[systemd-devel] PATCH: fix logind on xen

[Lennart Poettering]

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.

I haven't tested this since I don't have S390 nor Xen. Would be cool if
you could test this. (though right now is not the ideal point in time,
because systemd git is a bit borked. please wait a few days in order not
to burn your fingers on it.)

Lennart

-- 
Lennart Poettering - Red Hat, Inc.