[ConsoleKit] Future of GDM & ConsoleKit

[Brian Cameron]

I notice on the FreeDesktop ConsoleKit mailing list that Lennart
Poettering recently suggested that ConsoleKit is going away and
being replaced with systemd on some Linux distros.[1]

I am interested to discuss how GDM can continue to support systems
without systemd.  As Lennart mentions, part of the reason for migrating
to systemd is to better support multi-seat features with device
management.  I worked on a project to also add multi-seat support to
ConsoleKit.[2]  As mentioned in comment #27 of bug #536355[3], it seems
the main reason this work has not yet been accepted upstream was
because this design lacks device management features.  Unfortunately,
the developers at Oracle have not yet been able to implement Linux
device management features into this work.

When Simon Zheng, Halton Huo, and myself designed these interfaces, the
intent was that they could be extended to support device management.  I
am sure that the "Devices" line in the design for
/etc/ConsoleKit/seat.d is too primitive and needs work.  But it seems a
starting point to discuss.

For the sake of discussion, can we explore the idea of continuing to
support ConsoleKit interfaces?  If this is not possible, then it would
be interesting to know why.  Could ConsoleKit and a systemd-based
solution share a common (or extended) D-Bus API?  Or is there something
very fundamental about the two designs that is just incompatible?

If Linux moves away from using ConsoleKit in favor of systemd in GDM,
then would it be reasonable for GDM on systems that do not have systemd
to just continue to use ConsoleKit?

It seems that GDM could support two backends for supporting multi-seat.
One based on systemd and another based on this ConsoleKit work.  I
realize this ConsoleKit-based approach does not yet support device
management as well as the systemd proposal, but it is better than GDM
not working on systems that do not have systemd at all, I should think.

Brian

[1] http://lists.freedesktop.org/archives/consolekit/2011-May/000136.html
[2] 
http://wiki.genunix.org/wiki/index.php/design_for_newgdm_consolekit_multiseat_multidisplay
or
https://bugzilla.gnome.org/show_bug.cgi?id=536355#c27