Re: Different config options for different X servers?

[Brian Cameron <Brian Cameron Sun COM>]

Seb:

> Thanks for the response.
>
> Perhaps I am missing the point, but I don't see how your message relates 
> to my query.

I misunderstood your problem.  It seems reasonable to enhance the gdm.conf
file to support configuration options that only affect specific
configurations.  I believe the SunRay team here at Sun is adding
features that might do what you want.  I've cc:ed Bob Terek so he can
respond.  I believe he will be submitting a patch to support having
configuration options per configuration to bugzilla soon and you might
be able to test it and see if it helps.

> My problem was wanting different *gdm2* configurations for different 
> xservers. To make it concrete, let's say I want some of my displays to 
> have one value for HaltCommand and others to have another value, 
> although in fact there are many other configuration options, 
> particularly in [greeter] and [gui], which I might want to be different 
> on different displays.
>
> Your message seemed to talk about different *xserver* configurations. I 
> am already doing this: in my [servers] section I have things like:
>
>  0=Standard
>  10=VNC
>  11=VNC
>  12=VNC
>
> and I define a [server-VNC] section later in the file. This all works 
> fine. But as far as I can see it only allows me to specify xserver 
> configuration separately, not general options such as HaltCommand, 
> GtkTheme etc. Have I misunderstood you?
>
> The solution I initially suggested, which is a bit of a hack, is to 
> allow some xservers to be defined as 'remote' even if they are not via 
> XDMCP, and then make use of the gdm2's existing capability to set 
> different values for some setttings for "remote" servers (e.g. Welcome 
> and RemoteWelcome). Basically this would mean not passing the 
> GDM_IS_LOCAL environment variable to the greeter for some servers even 
> though the gdm daemon does think of that server as local (rather than 
> XMCP). This is a bit of hack, although perhaps a useful one given the 
> existance of X servers like VNC which do to all intents and purposes 
> provide "remote" access but which gdm considers local.
>
> A better solution to the problem would be to allow gdm.conf to contain 
> server-specific versions of each of its configuration sections. So as 
> well as a global [security] section, there could optionally be a 
> [security-foo]
> section which can override default settings in [security] but which only 
> applies to the particular server "foo" (i.e. the server defined in a 
> [server-foo] section.
>
> Having had a quick look through the source just now, I begin to get an 
> idea how this could be implemented. A few options which the gdm daemon 
> processes (and which it makes sense to have defined per server) would 
> have be to read later than they are now, once the server definitions 
> have been parsed. But most of the per-server options are in the parts of 
> the config file which are used by the greeter. gdm (the daemon) could 
> pass an environment variable to the greeter specifying the name of the 
> server on which it is appearing (e.g. "Standard", "foo",...), and 
> gdmlogin could check for <section>-<servername>/<key> for each key it 
> reads from the config file before checking <section>/<key>. Does this 
> sound reasonable? It would allow any configuration option which 
> gdmgreeter reads to be configurable either globally (applying to all 
> servers) or per server type.
>
> In your message you talked about people wanting a menu to select the 
> xserver config. This seems to me to be a different feature entirely.
>
> Although it's unlikely I would get around to working on this any time 
> soon, I'd be interested to what you would think, in priciple, about 
> allowing per-server versions of each of the config file sections (e.g. 
> [gui-Standard], [gui-foo], [gui-VNC], etc).
>
> Cheers
>
> Seb
>
> Brian wrote:
>
> > Seb wrote:
> >
> > > I use gdm to start several local, 'static' X servers. One is an 
> > > ordinary X.Org server. The others are Xvnc servers. In reality these 
> > > provide remote access (since a remote VNC client of some kind 
> > > connects to them), although gdm thinks of them as local X servers 
> > > because they are not via XDMCP.
> > >
> > > I'd like to be able to specify different settings for some gdm 
> > > options for these two classes of server. For example, I want Reboot 
> > > and Shutdown buttons enabled on the local X.Org display, but not on 
> > > the VNC displays.
> > >
> > > Is there any way I can do this?
> >
> >
> > The gdm.conf file does let you specify multiple server configurations,
> > but each one is assigned a different DISPLAY value.  So, if you can set
> > up your machine to use different displays (via virtual tty's), then this
> > might work for you.
> >
> > > Since gdm already has sensible and/or separately configurable 
> > > behaviour for what it thinks of as "remote" logins (i.e. XDMCP), the 
> > > neatest solution would be to be able to specify in an X server 
> > > definition that gdm should consider it to be a "remote" login even if 
> > > it is not via XDMCP.
> >
> >
> > There have been a number of users who have requested that gdm2 support a
> > new feature that allows the user to pick the xserver configuration via a
> > menu in the login program.  This way if you set up an alternative xserver
> > config, it would simply appear in a new menu where you could select it.
> > Aside from adding the code to add the menu, this would also require a 
> > minor
> > change to make use of the selection when starting up the Xserver.
> >
> > If you wanted to work on patching the code to support this sort of 
> > feature,
> > I'd be happy to help you understand the code.
> >
> > > Another option I pondered was running two instances of gdm. I'm 
> > > guessing that would get a bit problematic though since gdm integrates 
> > > so closely with the system.
> >
> >
> > Never tried this.  Does sound hacky.  You might be able to get it to work
> > if you install gdm2 to different locations.  Though you would probably
> > have difficulty getting them to share the same DISPLAY's.
> >
> > > Any thoughts? I think the ability to define a seemingly-local server 
> > > as remote would be a useful feature, and perfect for VNC servers.
> >
> >
> > I think the best option would be to allow user's to pick the Xserver
> > config in the menu.  This would need to be a non-default feature, but
> > a flag could be added to the gdm.conf to turn on the menu for this.
> >
> > --
> >
> > Brian


--

Brian