* Cleaned up the display manager module a bit.

svn path=/nixos/trunk/; revision=17012

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

@@ -1,74 +1,82 @@
-{pkgs, config, ...}:
+# This module declares the options to define a *display manager*, the
+# program responsible for handling X logins (such as xdm, kdm, 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*
+# (e.g., KDE, Gnome or a plain xterm), and optionally the *window
+# manager* (e.g. kwin or twm).
+
+{ config, pkgs, ... }:
+
+with pkgs.lib;
 
 let
-  inherit (pkgs.lib) mkOption mergeOneOption optionals filter concatMap concatMapStrings;
+
   cfg = config.services.xserver;
   xorg = pkgs.xorg;
 
   # file provided by services.xserver.displayManager.session.script
-  xsession = wm: dm: pkgs.writeScript "xsession" ''
+  xsession = wm: dm: pkgs.writeScript "xsession"
+    ''
       #! /bin/sh
  
+      exec > $HOME/.xsession-errors 2>&1
+
       source /etc/profile
 
-    exec > $HOME/.Xerrors 2>&1
-
-
       ### Load X defaults.
       if test -e ~/.Xdefaults; then
         ${xorg.xrdb}/bin/xrdb -merge ~/.Xdefaults
       fi
 
-    ${if cfg.startSSHAgent then ''
+      ${optionalString cfg.startSSHAgent ''
         ### Start the SSH agent.
         export SSH_ASKPASS=${pkgs.x11_ssh_askpass}/libexec/x11-ssh-askpass
         eval $(${pkgs.openssh}/bin/ssh-agent)
-    '' else ""}
+      ''}
 
       ### Allow user to override system-wide configuration
       if test -f ~/.xsession; then
-        source ~/.xsession;
+          source ~/.xsession
       fi
 
-    # this script expect to have as first argument the following input
+      # The first argument of this script is the session type
-    # "desktop-manager + window-manager".
+      sessionType="$1"
-    arg="$1"
 
-    # extract the window manager.
+      # The session type "<desktop-manager> + <window-manager>", so
+      # extract those.
       windowManager="''${arg##* + }"
       : ''${windowManager:=${cfg.windowManager.default}}
-    # extract the desktop manager.
       desktopManager="''${arg% + *}"
       : ''${desktopManager:=${cfg.desktopManager.default}}
 
-    # used to restart the xserver.
+      # Start the window manager.
-    waitPID=0
-
-    # handle window manager starts.
       case $windowManager in
-      ${concatMapStrings (s: "
+        ${concatMapStrings (s: ''
           (${s.name})
             ${s.start}
             ;;
-      ") wm}
+        '') wm}
         (*) echo "$0: Window manager '$windowManager' not found.";;
       esac
 
-    # handle desktop manager starts.
+      # Start the desktop manager.
       case $desktopManager in
-      ${concatMapStrings (s: "
+        ${concatMapStrings (s: ''
           (${s.name})
             ${s.start}
             ;;
-      ") dm}
+        '') dm}
         (*) echo "$0: Desktop manager '$desktopManager' not found.";;
       esac
 
-    test "$waitPID" != 0 && wait "$waitPID"
+      test -n "$waitPID" && wait "$waitPID"
-    exit
+      exit 0
     '';
 
-  mkDesktops = names: pkgs.runCommand "desktops" {} ''
+  mkDesktops = names: pkgs.runCommand "desktops" {}
+    ''
       ensureDir $out
       ${concatMapStrings (n: ''
         cat - > "$out/${n}.desktop" << EODESKTOP
@@ -86,41 +94,28 @@ let
 in
 
 {
-  # list of display managers.
-  require = [
-    ./kdm.nix
-    ./slim.nix
-  ];
 
-  services = {
+  imports = [ ./kdm.nix ./slim.nix ];
-    xserver = {
+
-      displayManager = {
+
+  options = {
+
+    services.xserver.displayManager = {
 
       xauthBin = mkOption {
         default = "${xorg.xauth}/bin/xauth";
-          description = "
+        description = "Path to the <command>xauth</command> program used by display managers.";
-            Path to the xauth binary used by display managers.
-          ";
       };
 
       xserverBin = mkOption {
         default = "${xorg.xorgserver}/bin/X";
-          description = "
+        description = "Path to the X server used by display managers.";
-            Path to the xserver binary used by display managers.
-          ";
       };
 
       xserverArgs = mkOption {
         default = [];
-          example = [
+        example = [ "-ac" "-logverbose" "-nolisten tcp" ];
-            "-ac"
+        description = "List of arguments for the X server.";
-            "-logverbose"
-            "-nolisten tcp"
-          ];
-          description = "
-            List of arguments which have to be pass to when
-            the display manager start the xserver.
-          ";
         apply = toString;
       };
 
@@ -137,10 +132,10 @@ in
           }
         ];
         description = ''
-            List of session supported with the command used to start each
+          List of sessions supported with the command used to start each
           session.  Each session script can set the
           <varname>waitPID</varname> shell variable to make this script
-            waiting until the end of the user session.  Each script is used
+          wait until the end of the user session.  Each script is used
           to define either a windows manager or a desktop manager.  These
           can be differentiated by setting the attribute
           <varname>manage</varname> either to <literal>"window"</literal>
@@ -161,23 +156,35 @@ in
 
       job = mkOption {
         default = {};
-          example = {
+        type = types.optionSet;
-            preStart = ''
-              rm -f /var/log/slim.log
-            '';
-            environment = { SLIM_CFGFILE = /etc/slim.conf; };
-            execCmd = "${pkgs.slim}/bin/slim";
-          };
-
-          description = "
-            List of arguments which have to be pass to when
-            the display manager start the xserver.
-          ";
-
         merge = mergeOneOption;
+        description = "This option defines how to start the display manager.";
+
+        options = {
+  
+          preStart = mkOption {
+            default = "";
+            example = "rm -f /var/log/my-display-manager.log";
+            description = "Script executed before the display manager is started.";
+          };
+         
+          execCmd = mkOption {
+            example = "${pkgs.slim}/bin/slim";
+            description = "Command to start the display manager.";
+          };
+         
+          environment = mkOption {
+            default = {};
+            example = { SLIM_CFGFILE = /etc/slim.conf; };
+            description = "Additional environment variables needed by the display manager.";
           };
          
         };
+        
       };
+
     };
+    
+  };
+
 }

modules/services/x11/display-managers/kdm.nix

@@ -73,9 +73,7 @@ in
   config = mkIf cfg.enable {
   
     services.xserver.displayManager.job =
-      { beforeScript = "";
+      { execCmd = "${kdebase_workspace}/bin/kdm -config ${kdmrc}";
-        environment = {};
-        execCmd = "${kdebase_workspace}/bin/kdm -config ${kdmrc}";
       };
 
     security.pam.services = [ { name = "kde"; localLogin = true; ckHack = true; } ];

modules/services/x11/xserver.nix

@@ -378,7 +378,7 @@ in
               else ""
              }
 
-            ${cfg.displayManager.job.beforeScript}
+            ${cfg.displayManager.job.preStart}
 
             rm -f /tmp/.X0-lock
           '';