Re: [gdm-list] how to use authentication feature of GDM in a screen saver

[Jeff Cai <Jeff Cai Sun COM>]

On Tue, 2010-04-20 at 09:55 -0400, Ray Strode wrote:
> Hi Jeff,
> 
> > Currently there are two cases we need to consider, one is the
> > environment with display switching support and the other is that of
> > without display switching, i.e remote display.
> right.
> 
> > For the environment with display switching offered by VT, we can use the
> > GDM framework which contains the 'factory mode'. But the greeter session
> > is always running in a VT. For screen lock, it looks like there should
> > be more unlock greeter sessions running at the same time for different
> > user sessions. For example, if two user sessions are locked in one
> > machine, two unlock greeter sessions with two VTs need running.
> Why?  Doesn't it make more sense to just have the one factory greeter session?
GdmGreeterSlave may be one, but the unlock greeter UI should be more for
multiple user sessions that have been locked.
> 
> > For the environment without display switching, it seems hard to use
> > GdmSessionRelay interface since GdmSessionRelay does not provide DBus
> > interfaces that can be used by the Unlock dialog. The DBus interfaces
> > GdmSessionRelay exposed are used by GdmProductSlave, while not GUI
> > applications like greeter.
> Well you guys are talking about writing new code.  The fact that the
> dbus interface isn't exposed in the way you need it doesn't matter.
> It's just a little more new code.
> 
> Nothing is a perfect fit for what you want yet, because what you want
> isn't implemented yet.

The interfaces that can be used were not defined yet, I think. Maybe
some DBus interfaces that can be used directly by the unlock
application?

Jeff
> 
> > If we can not use the GreeterServer interface, since the implementation
> > of PAM backend is in gdm-session-worker, how about interacting directly
> > with gdm-session-worker? Although gdm-session-worker does not provide
> > DBus services, we can imitate what GdmSessionDirect has done in the
> > screen unlock program.
> Well I think the right way to interface with the gdm-session-worker,
> is via the GdmSession GInterface.  Note GdmSessionDirect implements
> that interface.  GdmSessionRelay does as well.  You could potentially
> add new code that implements that interface, and that might be the
> right answer.  I think that code would look a lot like GdmSessionRelay
> though, so using GdmSessionRelay might be the right answer, too.  I
> don't have all the answers here, because I haven't implemented it,
> yet.  I might be wrong about certain things. I'm just telling you my
> general intuition on things.
> 
> --Ray