Revert "Merge pull request NixOS#73251 which removes SLiM DM"

This reverts commit 4583e29,
reversing changes made to d6fa540.

The fact that SLiM is not officially actively maintained is not a good
reason to remove it. It works, and, in some instances, like automatic
logins, it is the only thing that actually works. See
NixOS#46396 and
NixOS#30890 (comment).

Author: oxij

nixos/doc/manual/configuration/x-windows.xml

@@ -39,7 +39,7 @@
   can select an alternative one by picking one of the following lines:
 <programlisting>
 <xref linkend="opt-services.xserver.displayManager.sddm.enable"/> = true;
-<xref linkend="opt-services.xserver.displayManager.gdm.enable"/> = true;
+<xref linkend="opt-services.xserver.displayManager.slim.enable"/> = true;
 </programlisting>
  </para>
  <para>

nixos/doc/manual/development/option-declarations.xml

@@ -99,7 +99,7 @@ xlink:href="https://nixos.org/nixpkgs/manual/#sec-package-naming">
   <para>
    As an example, we will take the case of display managers. There is a central
    display manager module for generic display manager options and a module file
-   per display manager backend (sddm, gdm ...).
+   per display manager backend (slim, sddm, gdm ...).
   </para>
 
   <para>
@@ -146,7 +146,7 @@ xlink:href="https://nixos.org/nixpkgs/manual/#sec-package-naming">
       />), and to extend
    it in each backend module
    (<xref
-      linkend='ex-option-declaration-eot-backend-gdm' />,
+      linkend='ex-option-declaration-eot-backend-slim' />,
    <xref
       linkend='ex-option-declaration-eot-backend-sddm' />).
   </para>
@@ -167,11 +167,11 @@ services.xserver.displayManager.enable = mkOption {
 };</screen>
   </example>
 
-  <example xml:id='ex-option-declaration-eot-backend-gdm'>
-   <title>Extending <literal>services.xserver.displayManager.enable</literal> in the <literal>gdm</literal> module</title>
+  <example xml:id='ex-option-declaration-eot-backend-slim'>
+   <title>Extending <literal>services.xserver.displayManager.enable</literal> in the <literal>slim</literal> module</title>
 <screen>
 services.xserver.displayManager.enable = mkOption {
-  type = with types; nullOr (enum [ "gdm" ]);
+  type = with types; nullOr (enum [ "slim" ]);
 };</screen>
   </example>
 

nixos/doc/manual/release-notes/rl-2003.xml

@@ -175,13 +175,6 @@ services.xserver.displayManager.defaultSession = "xfce+icewm";
       Now, all bash code is held to the same high standard, and the rather complex stateful manipulation of the options can be discarded.
     </para>
    </listitem>
-   <listitem>
-    <para>
-     The SLIM Display Manager has been removed, as it has been unmaintained since 2013.
-     Consider migrating to a different display manager such as LightDM (current default in NixOS),
-     SDDM, GDM, or using the startx module which uses Xinitrc.
-    </para>
-   </listitem>
    <listitem>
     <para>
      The Way Cooler wayland compositor has been removed, as the project has been officially canceled.

nixos/lib/testing-python.nix

@@ -265,6 +265,7 @@ in rec {
           inherit require;
           virtualisation.memorySize = 1024;
           services.xserver.enable = true;
+          services.xserver.displayManager.slim.enable = false;
           services.xserver.displayManager.auto.enable = true;
           services.xserver.displayManager.defaultSession = "none+icewm";
           services.xserver.windowManager.icewm.enable = true;

nixos/lib/testing.nix

@@ -248,6 +248,7 @@ in rec {
           inherit require;
           virtualisation.memorySize = 1024;
           services.xserver.enable = true;
+          services.xserver.displayManager.slim.enable = false;
           services.xserver.displayManager.auto.enable = true;
           services.xserver.displayManager.defaultSession = "none+icewm";
           services.xserver.windowManager.icewm.enable = true;

nixos/modules/hardware/video/nvidia.nix

@@ -75,7 +75,7 @@ in
 
         Note that this configuration will only be successful when a display manager
         for which the <option>services.xserver.displayManager.setupCommands</option>
-        option is supported is used.
+        option is supported is used; notably, SLiM is not supported.
       '';
     };
 

nixos/modules/services/x11/desktop-managers/plasma5.nix

@@ -222,6 +222,7 @@ in
       security.pam.services.kdm.enableKwallet = true;
       security.pam.services.lightdm.enableKwallet = true;
       security.pam.services.sddm.enableKwallet = true;
+      security.pam.services.slim.enableKwallet = true;
 
       xdg.portal.enable = true;
       xdg.portal.extraPortals = [ pkgs.xdg-desktop-portal-kde ];

nixos/modules/services/x11/display-managers/default.nix

@@ -1,9 +1,9 @@
 # This module declares the options to define a *display manager*, the
-# program responsible for handling X logins (such as LightDM, GDM, or SDDM).
-# The display manager allows the user to select a *session
-# type*. When the user logs in, the display manager starts the
+# program responsible for handling X logins (such as xdm, gdb, or
+# SLiM).  The display manager allows the user to select a *session
+# type*.  When the user logs in, the display manager starts the
 # *session script* ("xsession" below) to launch the selected session
-# type. The session type defines two things: the *desktop manager*
+# type.  The session type defines two things: the *desktop manager*
 # (e.g., KDE, Gnome or a plain xterm), and optionally the *window
 # manager* (e.g. kwin or twm).
 
@@ -308,14 +308,15 @@ in
         execCmd = mkOption {
           type = types.str;
           example = literalExample ''
-            "''${pkgs.lightdm}/bin/lightdm"
+            "''${pkgs.slim}/bin/slim"
           '';
           description = "Command to start the display manager.";
         };
 
         environment = mkOption {
           type = types.attrsOf types.unspecified;
           default = {};
+          example = { SLIM_CFGFILE = "/etc/slim.conf"; };
           description = "Additional environment variables needed by the display manager.";
         };
 

nixos/modules/services/x11/display-managers/slim.nix

@@ -2,15 +2,155 @@
 
 with lib;
 
+let
+
+  dmcfg = config.services.xserver.displayManager;
+
+  cfg = dmcfg.slim;
+
+  slimConfig = pkgs.writeText "slim.cfg"
+    ''
+      xauth_path ${dmcfg.xauthBin}
+      default_xserver ${dmcfg.xserverBin}
+      xserver_arguments ${toString dmcfg.xserverArgs}
+      sessiondir ${dmcfg.session.desktops}/share/xsessions
+      login_cmd exec ${pkgs.runtimeShell} ${dmcfg.session.wrapper} "%session"
+      halt_cmd ${config.systemd.package}/sbin/shutdown -h now
+      reboot_cmd ${config.systemd.package}/sbin/shutdown -r now
+      logfile /dev/stderr
+      ${optionalString (cfg.defaultUser != null) ("default_user " + cfg.defaultUser)}
+      ${optionalString (cfg.defaultUser != null) ("focus_password yes")}
+      ${optionalString cfg.autoLogin "auto_login yes"}
+      ${optionalString (cfg.consoleCmd != null) "console_cmd ${cfg.consoleCmd}"}
+      ${cfg.extraConfig}
+    '';
+
+  # Unpack the SLiM theme, or use the default.
+  slimThemesDir =
+    let
+      unpackedTheme = pkgs.runCommand "slim-theme" { preferLocalBuild = true; }
+        ''
+          mkdir -p $out
+          cd $out
+          unpackFile ${cfg.theme}
+          ln -s * default
+        '';
+    in if cfg.theme == null then "${pkgs.slim}/share/slim/themes" else unpackedTheme;
+
+in
+
 {
-  # added 2019-11-11
-  imports = [
-    (mkRemovedOptionModule [ "services" "xserver" "displayManager" "slim" ] ''
-      The SLIM project is abandoned and their last release was in 2013.
-      Because of this it poses a security risk to your system.
-      Other issues include it not fully supporting systemd and logind sessions.
-      Please use a different display manager such as LightDM, SDDM, or GDM.
-      You can also use the startx module which uses Xinitrc.
-    '')
-  ];
+
+  ###### interface
+
+  options = {
+
+    services.xserver.displayManager.slim = {
+
+      enable = mkOption {
+        type = types.bool;
+        default = false;
+        description = ''
+          Whether to enable SLiM as the display manager.
+        '';
+      };
+
+      theme = mkOption {
+        type = types.nullOr types.path;
+        default = pkgs.fetchurl {
+          url = "https://github.com/jagajaga/nixos-slim-theme/archive/2.0.tar.gz";
+          sha256 = "0lldizhigx7bjhxkipii87y432hlf5wdvamnfxrryf9z7zkfypc8";
+        };
+        defaultText = ''pkgs.fetchurl {
+          url = "https://github.com/jagajaga/nixos-slim-theme/archive/2.0.tar.gz";
+          sha256 = "0lldizhigx7bjhxkipii87y432hlf5wdvamnfxrryf9z7zkfypc8";
+        }'';
+        example = literalExample ''
+          pkgs.fetchurl {
+            url = "mirror://sourceforge/slim.berlios/slim-wave.tar.gz";
+            sha256 = "0ndr419i5myzcylvxb89m9grl2xyq6fbnyc3lkd711mzlmnnfxdy";
+          }
+        '';
+        description = ''
+          The theme for the SLiM login manager.  If not specified, SLiM's
+          default theme is used.  See <link
+          xlink:href='http://slim.berlios.de/themes01.php'/> for a
+          collection of themes. TODO: berlios shut down.
+        '';
+      };
+
+      defaultUser = mkOption {
+        type = types.nullOr types.str;
+        default = null;
+        example = "login";
+        description = ''
+          The default user to load. If you put a username here you
+          get it automatically loaded into the username field, and
+          the focus is placed on the password.
+        '';
+      };
+
+      autoLogin = mkOption {
+        type = types.bool;
+        default = false;
+        description = ''
+          Automatically log in as the default user.
+        '';
+      };
+
+      extraConfig = mkOption {
+        type = types.lines;
+        default = "";
+        description = ''
+          Extra configuration options for SLiM login manager. Do not
+          add options that can be configured directly.
+        '';
+      };
+
+      consoleCmd = mkOption {
+        type = types.nullOr types.str;
+        default = ''
+          ${pkgs.xterm}/bin/xterm -C -fg white -bg black +sb -T "Console login" -e ${pkgs.shadow}/bin/login
+        '';
+        defaultText = ''
+          ''${pkgs.xterm}/bin/xterm -C -fg white -bg black +sb -T "Console login" -e ''${pkgs.shadow}/bin/login
+        '';
+        description = ''
+          The command to run when "console" is given as the username.
+        '';
+      };
+    };
+
+  };
+
+
+  ###### implementation
+
+  config = mkIf cfg.enable {
+
+    services.xserver.displayManager.job =
+      { environment =
+          { SLIM_CFGFILE = slimConfig;
+            SLIM_THEMESDIR = slimThemesDir;
+          };
+        execCmd = "exec ${pkgs.slim}/bin/slim";
+      };
+
+    services.xserver.displayManager.sessionCommands =
+      ''
+        # Export the config/themes for slimlock.
+        export SLIM_THEMESDIR=${slimThemesDir}
+      '';
+
+    # Allow null passwords so that the user can login as root on the
+    # installation CD.
+    security.pam.services.slim = { allowNullPassword = true; startSession = true; };
+
+    # Allow slimlock to work.
+    security.pam.services.slimlock = {};
+
+    environment.systemPackages = [ pkgs.slim ];
+
+  };
+
 }

nixos/modules/services/x11/xserver.nix

@@ -558,6 +558,7 @@ in
       let dmconf = cfg.displayManager;
           default = !(dmconf.gdm.enable
                     || dmconf.sddm.enable
+                    || dmconf.slim.enable
                     || dmconf.xpra.enable );
       in mkIf (default) true;
 

nixos/release-combined.nix

@@ -132,6 +132,7 @@ in rec {
         (all nixos.tests.proxy)
         (all nixos.tests.sddm.default)
         (all nixos.tests.simple)
+        (all nixos.tests.slim)
         (all nixos.tests.switchTest)
         (all nixos.tests.udisks2)
         (all nixos.tests.xfce)

nixos/tests/all-tests.nix

@@ -261,6 +261,7 @@ in
   shiori = handleTest ./shiori.nix {};
   signal-desktop = handleTest ./signal-desktop.nix {};
   simple = handleTest ./simple.nix {};
+  slim = handleTest ./slim.nix {};
   slurm = handleTest ./slurm.nix {};
   smokeping = handleTest ./smokeping.nix {};
   snapper = handleTest ./snapper.nix {};

nixos/tests/slim.nix

@@ -0,0 +1,66 @@
+import ./make-test.nix ({ pkgs, ...} : {
+  name = "slim";
+
+  meta = with pkgs.stdenv.lib.maintainers; {
+    maintainers = [ aszlig ];
+  };
+
+  machine = { pkgs, ... }: {
+    imports = [ ./common/user-account.nix ];
+    services.xserver.enable = true;
+    services.xserver.windowManager.default = "icewm";
+    services.xserver.windowManager.icewm.enable = true;
+    services.xserver.desktopManager.default = "none";
+    services.xserver.displayManager.slim = {
+      enable = true;
+
+      # Use a custom theme in order to get best OCR results
+      theme = pkgs.runCommand "slim-theme-ocr" {
+        nativeBuildInputs = [ pkgs.imagemagick ];
+      } ''
+        mkdir "$out"
+        convert -size 1x1 xc:white "$out/background.jpg"
+        convert -size 200x100 xc:white "$out/panel.jpg"
+        cat > "$out/slim.theme" <<EOF
+        background_color #ffffff
+        background_style tile
+
+        input_fgcolor #000000
+        msg_color #000000
+
+        session_color #000000
+        session_font Verdana:size=16:bold
+
+        username_msg Username:
+        username_font Verdana:size=16:bold
+        username_color #000000
+        username_x 50%
+        username_y 40%
+
+        password_msg Password:
+        password_x 50%
+        password_y 40%
+        EOF
+      '';
+    };
+  };
+
+  enableOCR = true;
+
+  testScript = { nodes, ... }: let
+    user = nodes.machine.config.users.users.alice;
+  in ''
+    startAll;
+    $machine->waitForText(qr/Username:/);
+    $machine->sendChars("${user.name}\n");
+    $machine->waitForText(qr/Password:/);
+    $machine->sendChars("${user.password}\n");
+
+    $machine->waitForFile('${user.home}/.Xauthority');
+    $machine->succeed('xauth merge ${user.home}/.Xauthority');
+    $machine->waitForWindow('^IceWM ');
+
+    # Make sure SLiM doesn't create a log file
+    $machine->fail('test -e /var/log/slim.log');
+  '';
+})