Re: [PATCHES] Update elogind to 219.13

[ludo@gnu.org (Ludovic Courtès)]

Andy Wingo <wingo@igalia.com> skribis:

> On Mon 07 Mar 2016 11:01, ludo@gnu.org (Ludovic Courtès) writes:
>
>> BTW, a few days ago we were discussing on IRC the fact that elogind
>> would start before dbus-daemon, and thus get respawned a couple of times
>> at system startup, etc.  Yesterday, with commit 956ad60, I changed it to
>> be started through D-Bus activation, so we should be safe now.
>
> FWIW I am not sure that this is the right solution.  Logind has some
> other interfaces (notably the /run/systemd file system and the cgroups)
> and it really wants to be running from beginning to end.  If it's
> bus-activated, could it be killed at some point if it's inactive?  If so
> that would be bad I think.

I think it wouldn’t miss any log-in, because as soon as you log in
pam_elogind calls out to elogind, at which point it is started if it’s
not running yet.

Also it seems to me that dbus-daemon never kills inactive daemons, does
it?

On systemd-based systems, does logind get started on demand?

It seems safe, but perhaps I overlooked something.

> Maybe it's OK.  It certainly solves the race, in some way.  I think
> before a "guix system reconfigure" would restart logind, also; is that
> still the case?  Which is better?  Very murky to me.

‘guix system reconfigure’ starts new services, and restarts services
that are currently stopped.

If the ‘elogind’ Shepherd service was already started at the time ‘guix
system reconfigure’ runs, it would conservatively leave it as is instead
of trying to upgrade and restart it.

Thanks,
Ludo’.