KDM: Add support for extra window & desktop manager.

svn path=/nixos/branches/modular-nixos/; revision=15011

upstart-jobs/xserver/displayManager/default.nix

@@ -6,7 +6,7 @@ let
   xorg = cfg.package;
 
   # file provided by services.xserver.displayManager.session.script
-  xsession = wm: dm: pkgs.writeText "xsession" ''
+  xsession = wm: dm: pkgs.writeScript "xsession" ''#!/bin/sh
 
     source /etc/profile
 
@@ -67,6 +67,21 @@ let
     exit
   '';
 
+  mkDesktops = names: pkgs.runCommand "desktops" {} ''
+    ensureDir $out
+    ${concatMapStrings (n: ''
+      cat - > "$out/${n}.desktop" << EODESKTOP
+      [Desktop Entry]
+      Version=1.0
+      Type=XSession
+      TryExec=${cfg.displayManager.session.script}
+      Exec=${cfg.displayManager.session.script} '${n}'
+      Name=${n}
+      Comment=
+      EODESKTOP
+    '') names}
+  '';
+
 in
 
 {
@@ -138,6 +153,7 @@ in
             wm = filter (s: s.manage == "window") list;
             dm = filter (s: s.manage == "desktop") list;
             names = concatMap (d: map (w: d.name + " + " + w.name) wm) dm;
+            desktops = mkDesktops names;
             script = xsession wm dm;
           };
         };

upstart-jobs/xserver/displayManager/kdm.nix

@@ -31,6 +31,7 @@ let
 
   kdmrc = stdenv.mkDerivation {
     name = "kdmrc";
+# 	     -e "s|Session=${kdebase_workspace}/share/config/kdm/Xsession|Session=${dmcfg.session.script}|" \
     buildCommand = ''
       cp ${kdebase_workspace}/share/config/kdm/kdmrc .
       sed -i -e "s|#HaltCmd=|HaltCmd=${pkgs.upstart}/sbin/halt|" \
@@ -38,7 +39,7 @@ let
 	     -e "s|#Xrdb=|Xrdb=${pkgs.xlibs.xrdb}/bin/xrdb|" \
 	     -e "s|#HiddenUsers=root|HiddenUsers=root,nixbld1,nixbld2,nixbld3,nixbld4,nixbld5,nixbld6,nixbld7,nixbld8,nixbld9,nixbld10|" \
 	     -e "s|ServerCmd=/FOO/bin/X|ServerCmd=${dmcfg.xserverBin} ${dmcfg.xserverArgs}|" \
-	     -e "s|Session=${kdebase_workspace}/share/config/kdm/Xsession|Session=${dmcfg.session.script}|" \
+ 	     -e "s|^SessionsDirs=.*$|SessionsDirs=${dmcfg.session.desktops}|" \
 	     -e "s|#FailsafeClient=|FailsafeClient=${pkgs.xterm}/bin/xterm|" \
 	     -e "s|#PluginsLogin=sign|PluginsLogin=${kdebase_workspace}/lib/kde4/kgreet_classic.so|" \
       kdmrc