Re: [gdm-list] Selecting X server layout from GDM login screen

[Torben Früchtenicht <torben fruechtenicht net>]

Thanks for your quick answer, Brian. See below for the rest of my answer.

Am Dienstag, 6. September 2005 22:53 schrieb Brian Cameron:
> Torben:
>
> You, in other words, want to communicate information from the GUI login
> program to the daemon.  

Sounds like it.

> You will notice a bunch of lines of code in 
> gdmlogin.c that look like this:
>
>       printf ("%c%s\n", STX, language);
>
> STX messages are handled in gdm.c.  You will notice that in
> gdm2/daemon/slave.c that gdm_slave_session_start gets the GDM_SESS and
> GDM_LANG values from the GUI.  The code could be expanded in gdmlogin.c and
> slave.c to support a new option that tells the daemon about the layouts
> made by the user.  It sounds like you already got the menu setup with the
> list of available layouts.  It would be nice to add this to gdmgreeter.c as
> well.  Also, it probably makes sense to add a gdm.conf setting where the
> user can control whether or not this menu choice is visible/available.

Okay, I will have a look at that code. 

>
> How do you build the menu?  I suspect that in order for the menu choices
> to have mnemonics and human understandable descriptions that it might
> be necessary to add some stuff to gdm.conf so that such things can be
> defined for the menu?

I defined a very simple list box for my greeter theme. Nothing fancy, 
everything hardcoded.

What would you add to gdm.conf? The PostLogin script I have written already 
includes a check if the selected server layout is actually defined in 
XF86Config. 

>
> This is a feature that would be useful to have in CVS head, but any changes
> to the gdm.conf file would need to be documented in the docs/C/gdm.xml
> file.

Nice to hear that the maintainer of GDM thinks that this is a useful 
feature. :-) I'll see what I can do. 

Torben

>
> Brian
>
> > I am using my laptop in different places, sometimes connected to an
> > external monitor and sometimes not.
> >
> > As far as the X server is concerned, this can be easily managed by using
> > different server layouts. However, I still have to edit the XF86Config
> > file everytime I want to enable or disable the external screen (and
> > restart GDM and X, respectively).
> >
> > So what I would like to do is use the list widget of GDM to display a
> > list of valid server layouts. Which works fine except for the fact that I
> > have not found an easy way to actually tell the X server which server
> > layout has been selected by the user. What I have tried is running a post
> > login script which reads the selected value from the GreeterInfo file and
> > sets the value as an environment variable. But unfortunately, GDM does
> > not seem to resolve environment variables which are included in the
> > command entry in gdm.conf. (In the gdm.conf command entry, I simply
> > included the layout option via -layout $BLA.)
> >
> > I have looked into the GDM source code (2.6.0.9) and confirmed that no
> > resolving is performed. But it also does not look too difficult to
> > include some code for a call to libc (or whatever library has that
> > function) to resolve an environment variable.
> >
> > However, before I actually try my luck with C coding, I wanted to ask if
> > somebody knows an easier solution...
> >
> > Thanks in advance for any help
> > Torben
> >
> > P.S. I have understood that GDM normally reuses the X server instances.
> > Can a reused X server (i.e. XFree) switch to a different server layout
> > than before? Or do I have to use this special "restart X every time"
> > (forgot the actual name) option?

-- 
Torben Fruechtenicht, Berlin
torben fruechtenicht net
--
Do not paddle down the river of golden dreams.