bug#37380: gdm doesn't load pam-limits

[Jesse Gibbons <jgibbons2357@gmail.com>]

On Sat, 2019-09-14 at 17:13 -0600, Jesse Gibbons wrote:
> On Wed, 2019-09-11 at 21:48 +0200, Ricardo Wurmus wrote:
> > Hi Jesse,
> > 
> > > I have been trying to set up ardour, but jackd doesn't start in
> > > real-
> > > time mode. I made an os definition that replicates this issue when
> > > I
> > > use a VM[0].
> > > [0] https://lists.gnu.org/archive/html/help-guix/2019-09/msg00065.h
> > > tml
> > > I asked the gnome and gdm IRC and found out gdm loads the gdm-
> > > password
> > > pam config, which seems untouched by pam-limits-service. My
> > > /etc/pam.d/gdm-password (which should be the default) is attached.
> > 
> > I can reproduce this.
> > 
> > (I’m sorry for accidentally misleading you earlier.  Turns out I used
> > JACK a little longer ago than I initially realized.)
> > 
> > I think it should be pretty easy to fix this:
> > 
> > 1) we should generate a single file that is used for generic session
> > settings.
> > 
> > 2) all login programs (including gdm) should include that file in
> > their
> > PAM settings.
> > 
> > 3) the pam-limits-service should extend that single file instead of
> > attempting to update a bunch of PAM files for a selected list of
> > programs.
> > 
> > --
> > Ricardo
> > 
> 
> Is all this best practice?
> 
> This solution would have patches for three files:
> - gnu/system/pam.scm (adding the generic session settings file and
> patching the "su" and "login" configurations)
> - gnu/services/base.scm (patching pam-limits-service)
> - gnu/services/desktop.scm (patching the graphical login
> configurations).
> 
> All new login services would require a patch to just one file with
> these steps implemented(to add the service), whereas they would each
> need a patch to two files if they are not implemented (one to add the
> service, another to have pam-limits-service modify the service's pam
> config.
> 
> If you think this solution is better design than what we currently
> have, and others in this mailing list agree, I will work to provide
> these patches.
> 
> I previously said adding gdm-password to the list of pam configs
> amended by pam-limits-service did not work. I then discovered the
> changes in the environment will not work unless I run "make". I don't
> know if this is a bug in guix or guile, or if it is intentionally this
> way; the manual should be updated to clarify that guix needs to be
> built in the environment for the changes to work.
> 
> I sent a patch (bug#37405) that fixes this issue for gdm-password. A
> simple change can probably fix it for gdm-autologin (not added because
> I haven't tested it) and whatever gdm loads when the user logs in with
> biometric fingerprints (I don't know the name). When we add ldm and
> kdm, I think we can do something similar.
> 
ping