Re: [gdm-list] GDM - gdmdynamic and Sun Ray support

["William Jon McCann" <mccann jhu edu>]

On 10/11/07, Bob Doolittle <Robert Doolittle sun com> wrote:
> (Jerry answered some of this already but my writeup
> is focused more on the gdm/X interfaces so sending
> it anyway).
>
> William Jon McCann wrote:
> > Hi Jerry,
> >
> > On 10/11/07, Jerry Wall <Jerry Wall sun com> wrote:
> >
> >> The issue with Sun Ray and other thin clients is that there
> >> is no local hardware and no kernel drivers involved in
> >> plumbing one into the system. They are strictly network
> >> connected client so there is nothing to tell something
> >> like ConsoleKit about.
> >>
> >
> > Interesting.  The SRSS 4.0 Administrators guide (Chapter 4) seems to
> > indicate otherwise.  What would be really useful then is a description
> > of exactly how Sun Ray client and server software works and a link to
> > the code.  Would you mind providing them?
> >
>
> The code is proprietary at this time, I'm afraid.

That is really unfortunate.  Do you expect this to change?

> In a small nutshell (and focusing on the DM/X
> interactions), there is a "DDX" driver in the X
> server that simply generates the necessary
> rendering protocol and handles keyboard/mouse
> event protocol directly over the network to a thin
> client (and miscellaneous things like monitor
> power management and LEDs).
>
> SRSS handles rendezvous with a new thin client
> when it connects to the server, and if no X
> session yet exists and one is required it will use
> gdmdynamic to tell the Display Manager to create a
> new X session.  It will also put necessary state
> information on the system for the DDX to use to
> connect to the thin client when the X server
> starts up.

What is the necessary state?

> If an appropriate X session already exists, SRSS
> simply tells the DDX directly to connect the thin
> client to it and gdm is not involved.  It simply begins
> rendering to the new thin client.

How do you determine if an appropriate session exists?  How do you
disconnect the user session?  How do you indicate to the user session
that it has been disconnected?

> Finally, a session may be torn down either due to
> administrative action or when a session is sitting
> at a greeter and has been disconnected for some
> time (we instrument the gdm.conf file to create
> entries for PreSessionScriptDir,
> PostSessionScriptDir, and DisplayInitDir so that
> we can know when a session is sitting at a
> greeter).  Again, gdmdynamic is used for this
> purpose (tearing down sessions).


> Our thin client also handles audio and USB devices
> but none of that involves gdm in any way so it's
> not relevant.  Happy to discuss it if interested, however.
> Suffice it to say that this is handled directly from user
> space to the thin client over the network when possible,
> aided by some trivial loopback drivers and some mass
> storage glue (quite a bit less trivial).

So do you not have any kind of HAL support for / awareness of client
side devices?

How do you handle policy for, permissions of, and sharing of devices
on the server side?

Jon