nixos/modules: cosmic-greeter: init

nixos/modules/module-list.nix

@@ -579,6 +579,7 @@
   ./services/development/vsmartcard-vpcd.nix
   ./services/development/zammad.nix
   ./services/display-managers/default.nix
+  ./services/display-managers/cosmic-greeter.nix
   ./services/display-managers/greetd.nix
   ./services/display-managers/sddm.nix
   ./services/display-managers/ly.nix

nixos/modules/services/display-managers/cosmic-greeter.nix

@@ -0,0 +1,70 @@
+# SPDX-License-Identifier: MIT
+# SPDX-FileCopyrightText: Lily Foster <lily@lily.flowers>
+# Portions of this code are adapted from nixos-cosmic
+# https://github.com/lilyinstarlight/nixos-cosmic
+
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
+
+let
+  cfg = config.services.displayManager.cosmic-greeter;
+in
+
+{
+  meta.maintainers = with lib.maintainers; [
+    thefossguy
+    HeitorAugustoLN
+    nyabinary
+    ahoneybun
+  ];
+
+  options.services.displayManager.cosmic-greeter = {
+    enable = lib.mkEnableOption "COSMIC greeter";
+    package = lib.mkPackageOption pkgs "cosmic-greeter" { };
+  };
+
+  config = lib.mkIf cfg.enable {
+    services.greetd = {
+      enable = true;
+      settings = {
+        default_session = {
+          user = "cosmic-greeter";
+          command = ''${lib.getExe' pkgs.coreutils "env"} XCURSOR_THEME="''${XCURSOR_THEME:-Pop}" systemd-cat -t cosmic-greeter ${lib.getExe pkgs.cosmic-comp} ${lib.getExe cfg.package}'';
+        };
+      };
+    };
+
+    # Daemon for querying background state and such
+    systemd.services.cosmic-greeter-daemon = {
+      wantedBy = [ "multi-user.target" ];
+      before = [ "greetd.service" ];
+      serviceConfig = {
+        Type = "dbus";
+        BusName = "com.system76.CosmicGreeter";
+        ExecStart = lib.getExe' cfg.package "cosmic-greeter-daemon";
+        Restart = "on-failure";
+      };
+    };
+
+    # The greeter user is hardcoded in `cosmic-greeter`
+    users.groups.cosmic-greeter = { };
+    users.users.cosmic-greeter = {
+      description = "COSMIC login greeter user";
+      isSystemUser = true;
+      home = "/var/lib/cosmic-greeter";
+      createHome = true;
+      group = "cosmic-greeter";
+    };
+    # Setup PAM authentication for the `cosmic-greeter` user
+    security.pam.services.cosmic-greeter = { };
+
+    hardware.graphics.enable = true;
+    services.accounts-daemon.enable = true;
+    services.dbus.packages = [ cfg.package ];
+    services.libinput.enable = true;
+  };
+}