nixos/gdm: fix greeter

[enzuru]

This fixes GDM permissions so that users can login and logout appropriately. GNOME 50 is broken without these permission changes.

Things done

• Built on platform:
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• Tested, as applicable:
  • NixOS tests in nixos/tests.
  • Package tests at passthru.tests.
  • Tests in lib/tests or pkgs/test for functions and "core" functionality.
• Ran nixpkgs-review on this PR. See nixpkgs-review usage.
• Tested basic functionality of all binary files, usually in ./result/bin/.
• Nixpkgs Release Notes
  • Package update: when the change is major or breaking.
• NixOS Release Notes
  • Module addition: when adding a new NixOS module.
  • Module update: when the change is significant.
• Fits CONTRIBUTING.md, pkgs/README.md, maintainers/README.md and other READMEs.

[enzuru]

thanks @qweered I committed your change, fixed a syntax issue, and linted it.

I realized BTW my local build of GNOME 50 was cached from a previous PR, and was not rebased on staging. I am doing that right now. I may need to re-test everything tomorrow as I need to go to sleep soon.

[enzuru]

Okay, so after rebuilding this patch on GNOME I am running into an unrelated failure about a gnome-tecla patch that may be outdated. GNOME used to do this:

Util.spawn(['tecla']);

which we patched to

Util.spawn(['@tecla@']);

https://github.com/NixOS/nixpkgs/pull/517777/changes#diff-7599d9270d69fe3616b5323e252158c9e9f3168a52942e98cd2cdfba1796cb25L34

50.1 now does this:

Shell.AppSystem.get_default().lookup_app('org.gnome.Tecla.desktop');

https://gitlab.gnome.org/GNOME/gnome-shell/-/blob/50.1/js/ui/status/keyboard.js?ref_type=tags#L1178

I think the old patch is no longer needed.

Added as a separate commit.

[nekowinston]

Okay, so after rebuilding this patch on GNOME I am running into an unrelated failure about a gnome-tecla patch that may be outdated.

#518038

[enzuru]

ah okay @nekowinston , let me undo my commit then, thanks

[nekowinston]

Can confirm this works (building from staging-next @ d6a0b47), but it still feels like a workaround to keep #440720 (comment) working rather than preparing for the blog post linked in #458058.

I'm looking into getting userdbd to work.

[enzuru]

I can confirm that after rebasing on staging-next that this patch works still.

[nekowinston]

@enzuru does the much smaller patch

diff --git a/nixos/modules/services/display-managers/gdm.nix b/nixos/modules/services/display-managers/gdm.nix
index 38b9f919bab2..79eb5b4537cc 100644
--- a/nixos/modules/services/display-managers/gdm.nix
+++ b/nixos/modules/services/display-managers/gdm.nix
@@ -44,6 +44,10 @@ let
   defaultSessionName = config.services.displayManager.defaultSession;
 
   setSessionScript = pkgs.callPackage ../x11/display-managers/account-service-util.nix { };
+
+  greeterEnvFile = pkgs.writeText "gdm-greeter-env" ''
+    DCONF_PROFILE=gdm
+  '';
 in
 
 {
@@ -452,6 +456,12 @@ in
               settings.conffile = "/etc/pam/environment";
               settings.readenv = 0;
             }
+            {
+              name = "env-greeter";
+              control = "required";
+              modulePath = "${config.security.pam.package}/lib/security/pam_env.so";
+              settings.envfile = greeterEnvFile;
+            }
             {
               name = "systemd";
               control = "optional";

also still work for you?

[enzuru]

Will try your smaller patch tonight PST, thanks for all the support @nekowinston

[enzuru]

thanks @nekowinston the much smaller patch worked, I've updated this PR accordingly

[nekowinston]

I'm looking into getting userdbd to work.

I opened #519148 :)

[emilazy]

The patch looks benign to me, so I’m going to merge this to unblock GNOME 50 for the cycle. Sorry to the GNOME team if this is overstepping; please feel free to revert if necessary.

[emilazy]

Oh, staging-next already branched off. So I guess this needs a backport.

[emilazy]

Oh, sorry, no; staging branched off but staging-next didn’t. So this is fine.