Ludwig:
Could you explain in more detail how the messages pass back and forth to support the Face Browser?Well, you are the maintainer of GDM. Don't ask me how or why it works the way it works :-)This section of the code was written by the previous maintainer, so I'm probably not that much more familiar with it than you. I do know that GDM supports a few different mechanisms for communicating between the client and server (e.g. FIFO, SUP, and SOP protocols as mentioned in the daemon/gdm.h file). Perhaps GDM already has another protocol mechanism that would be more appropriate for passing the face browser data?No idea.
Well the code has been working reasonably well for users who want to use the Face Browser. If someone wants to make the code smarter, I'd happily accept a patch.
That's overkill for little gain. IMHO custom images are just a gimmick for home users which means low number of users and local home directories. So the most simple way to read the images is to just access the file in the home directory directly as user gdm. If gdm is not allowed to access the file then so it be.The problem with making this sort of change is that GDM may seem to break for users if we change this behavior. You will have to talk me into making a change that will generate a log of bug reports asking why things stopped working. Can't we think of a way to fix this that would be less likely to break current behavior? Also there may be reasons we're not thinking about why it makes sense for the daemon to poke for these image files rather than the GDM user. I've reviewed the GDM ChangeLog and docs, but don't see any real explination why it works this way. Thoughts?Well, it allows gdm to display files the gdm user is not permitted to read. That's the only reason I can think of why you need to be root for that job. Maybe some distro has rather restrictive permissons on ~ by default?
If you wanted to write a patch that removed the code where the daemon accesses these files and require that the gdm user has read access to the user's $HOME directory to show the image files, then we could float the patch for testing and see what people think of it. I wouldn't accept such a patch for GNOME 2.18, but I'd be willing to put it into 2.19 and see how many people freak out by the change. Brian