Re: [gdm-list] Testing gdm

[Bob Doolittle <Robert Doolittle Sun COM>]

To me, this sounds like a job for VirtualBox. If that's not a sandbox, I 
don't know what is.
You can create a snapshot before experimenting, and if it "goes south" 
you can restore the snapshot and try again in a couple of minutes.

Obviously qemu, VMware, etc are alternative approaches.

-Bob

Brian Cameron wrote:
> Yan:
>
> > I'm tryong to make some modifications to gdm. I've got my shiny new 
> > binary, but how do I go about testing it?
> >
> > gdm seems to be greedy, and running it in Xephyr still results in gdm 
> > trying to grab all displays. I just want it to manage the local 
> > Xephyr|Xnest|Xgl window, and also want to make sure it's cleanly 
> > running only the new binary.
>
> Unfortunately it is not very easy to "test" GDM in any sort of sandbox.
> You need to install it and try it out. You can run gdm-restart as root
> to restart GDM with the latest installed code to test any changes you
> have built and installed.
>
> This can be a pain if you hack GDM in a way that breaks it, in which
> case you may need to fix it without X to get it running again. So it is
> often useful to have a known working copy you can reinstall if you get
> into this situation. Typically I use gdm_debug calls when doing
> development and turn on GDM debug so I can see what is going on by
> reviewing the syslog. Not the nicest way to debug problems, but it can
> be a bit of work to set up a system so you can attach a debugger to the
> running GDM processes (e.g. you could use run a debugger after telneting
> into the machine from a remote machine). Since GDM is the program which
> starts up the user sessions, you often cannot debug GDM issues from user
> sessions.
>
> Though, if your changes are only to the GUI login programs, you can test
> these by simply logging out and logging back in after installing the new
> GUI code (or logging in via Xephyr, etc.).
>
> You can also set "DOING_GDM_DEVELOPMENT=1" and run the GDM GUI programs
> to test them from your normal user session. However running the GUI
> programs in this way disables a lot of functionality and may not
> be helpful depending on what you are testing. I do not think the new
> GDM rewrite GUI programs has this environment variable debugging
> feature, though.
>
> Unfortunately messing around with the gdmdynamic command (at least how
> the daemon responds to the gdmdynamic command) and automatic login
> does not fit into this "GUI development" category.