* Synced with branches/fix-style @ 13861

svn path=/nixos/branches/modular-nixos/; revision=14946

doc/manual/development.xml

@@ -7,6 +7,230 @@
 NixOS.</para>
 
 
+<section>
+
+<title>Extending NixOS</title>
+
+<para>A unique syntax is used to express all system, hardware, computer and
+  service configurations.  This syntax helps for reading and writing new
+  configuration files.  It is coming with some extra strategies defined in
+  NixPkgs which are used to merge and evaluate all configuration files.</para>
+
+  <para>A configuration file is the same as your own computer
+  configuration.</para>
+
+<example xml:id='conf-syntax'><title>Usual configuration file</title>
+<programlisting>
+{pkgs, config, ...}: <co xml:id='conf-syntax-1' />
+
+###### interface
+let
+  inherit (pkgs.lib) mkOption; <co xml:id='conf-syntax-2' />
+
+  options = { <co xml:id='conf-syntax-3' />
+    services = {
+      locate = {
+
+        enable = mkOption {
+          default = false;
+          example = true;
+          description = ''
+            If enabled, NixOS will periodically update the database of
+            files used by the <command>locate</command> command.
+          '';
+        };
+
+        period = mkOption {
+          default = "15 02 * * *";
+          description = ''
+            This option defines (in the format used by cron) when the
+            locate database is updated.
+            The default is to update at 02:15 (at night) every day.
+          '';
+        };
+
+      };
+
+    };
+  };
+in
+
+###### implementation
+let
+  cfg = config.services.locate; <co xml:id='conf-syntax-4' />
+  inherit (pkgs.lib) mkIf mkThenElse;
+
+  locatedb = "/var/cache/locatedb";
+  logfile = "/var/log/updatedb";
+  cmd = "root  updatedb --localuser=nobody --output=${locatedb} > ${logfile}";
+in
+
+mkIf cfg.enable {<co xml:id='conf-syntax-5' />
+  require = [ <co xml:id='conf-syntax-6' />
+    options
+
+    # config.services.cron
+    (import ../../upstart-jobs/cron.nix)
+  ];
+
+  services = {
+    cron = {
+      systemCronJobs = mkThenElse { <co xml:id='conf-syntax-7' />
+        thenPart = "${cfg.period}  root ${cmd}";
+        elsePart = "";
+      };
+    };
+  };
+}</programlisting>
+</example>
+
+<para><xref linkend='conf-syntax' /> shows the <emphasis>configuration
+  file</emphasis> for the locate service which uses cron to update the
+  database at some dates which can be defined by the user.  This nix
+  expression is coming
+  from <filename>upstart-jobs/cron/locate.nix</filename>.  It shows a simple
+  example of a service that can be either distributed on many computer that
+  are using the same configuration or to shared with the community.  This
+  file is divided in two with the interface and the implementation.  Both
+  the interface and the implementation declare a <emphasis>configuration
+  set</emphasis>.
+
+<calloutlist>
+
+  <callout arearefs='conf-syntax-1'>
+
+    <para>This line declares the arguments of the configuration file.  You
+    can omit this line if there is no reference to <varname>pkgs</varname>
+    and <varname>config</varname> inside the configuration file.</para>
+
+    <para>The argument <varname>pkgs</varname> refers to NixPkgs and allow
+    you to access all attributes contained inside it.  In this
+    example <varname>pkgs</varname> is used to retrieve common functions to
+    ease the writing of configuration files
+    like <varname>mkOption</varname>, <varname>mkIf</varname>
+    and <varname>mkThenElse</varname>.</para>
+
+    <para>The argument <varname>config</varname> corresponds to the whole
+    NixOS configuration.  This is a set which is build by merging all
+    configuration files imported to set up the system.  Thus all options
+    declared are contained inside this variable.  In this
+    example <varname>config</varname> is used to retrieve the status of
+    the <varname>enable</varname> flag.  The important point of this
+    argument is that it contains either the result of the merge of different
+    settings or the default value, therefore you cannot assume
+    that <option>config.services.locate.enable</option> is always false
+    because it may have been defined in another configuration file.</para>
+
+  </callout>
+
+  <callout arearefs='conf-syntax-2'>
+
+    <para>This line is used to import a function that is useful for
+    writing this configuration file.</para>
+
+  </callout>
+
+  <callout arearefs='conf-syntax-3'>
+
+    <para>The variable <varname>options</varname> is
+    a <emphasis>configuration set</emphasis> which is only used to declare
+    options with the function <varname>mkOption</varname> imported
+    from <filename>pkgs/lib/default.nix</filename>.  Options may contained
+    any attribute but only the following have a special
+    meaning: <varname>default</varname>, <varname>example</varname>,
+    <varname>description</varname>, <varname>merge</varname>
+    and <varname>apply</varname>.</para>
+
+    <para>The <varname>merge</varname> attribute is used to merge all values
+    defined in all configuration files and this function return a value
+    which has the same type as the default value.  If the merge function is
+    not defined, then a default function
+    (<varname>pkgs.lib.mergeDefaultOption</varname>) is used to merge
+    values.  The <varname>merge</varname> attribute is a function which
+    expect two arguments: the location of the option and the list of values
+    which have to be merged.</para>
+
+    <para>The <varname>apply</varname> attribute is a function used to
+    process the option.  Thus the value return
+    by <option>config.<replaceable>option</replaceable></option> would be
+    the result of the <varname>apply</varname> function called with either
+    the <varname>default</varname> value or the result of
+    the <varname>merge</varname> function.</para>
+
+  </callout>
+
+  <callout arearefs='conf-syntax-4'>
+
+    <para>This line is a common trick used to reduce the amount of
+    writing.  In this case <varname>cfg</varname> is just a sugar over
+    <option>config.services.locate</option></para>
+
+  </callout>
+
+  <callout arearefs='conf-syntax-5'>
+
+    <para>This line is used to declare a special <emphasis>IF</emphasis>
+    statement.  If you had put a usual <emphasis>IF</emphasis> statement
+    here, with the same condition, then you will get an infinite loop.  The
+    reason is that your condition ask for the value of the
+    option <option>config.services.locate.enable</option> but in order to
+    get this value you have to evaluate all configuration sets including the
+    configuration set contained inside your file.</para>
+
+    <para>To remove this extra complexity, <varname>mkIf</varname> has been
+    introduced to get rid of possible infinite loop and to factor your
+    writing.</para>
+
+  </callout>
+
+  <callout arearefs='conf-syntax-6'>
+
+    <para>The attribute <varname>require</varname> is the only special
+    option that exists.  It is used to embed all option declarations that
+    are required by your configuration file and it is also used to provide
+    the options that you are declaring.</para>
+
+    <para>This attribute is processed
+    with <varname>pkgs.lib.uniqFlatten</varname> to collect all
+    configuration files that are used by your system and it avoid the
+    insertion of duplicated elements by comparing the configuration set codes.</para>
+
+    <para>Currently, the file <filename>configuration.nix</filename>
+    implicitly embeds <filename>system/options.nix</filename>.  If you need
+    a special configuration file, then you will have to add similar lines
+    to your computer configuration.</para>
+
+  </callout>
+
+  <callout arearefs='conf-syntax-7'>
+
+    <para>As <varname>mkIf</varname> does not need
+    any <emphasis>then</emphasis> part or <emphasis>else</emphasis> part,
+    then you can specify one on each option definition with the
+    function <varname>mkThenElse</varname>.</para>
+
+    <para>To avoid a lot of <varname>mkThenElse</varname> with empty
+    <emphasis>else</emphasis> part, a sugar has been added to infer the
+    corresponding <emphasis>empty</emphasis>-value of your option when the
+    function <varname>mkThenElse</varname> is not used.</para>
+
+    <para>If your <emphasis>then</emphasis> part
+    and <emphasis>else</emphasis> part are identical, then you should use
+    the function <varname>mkAlways</varname> to ignore the condition.</para>
+
+    <para>If you need to add another condition, then you can add <varname>mkIf</varname> to on
+    the appropriate location.  Thus the <emphasis>then</emphasis> part will
+    only be used if all conditions declared with <varname>mkIf</varname>
+    are satisfied.</para>
+
+  </callout>
+
+</calloutlist>
+
+</para>
+
+</section>
+
 <section>
 
 <title>Building specific parts of NixOS</title>

installer/nixos-hardware-scan.pl

@@ -4,6 +4,7 @@ use File::Spec;
 use File::Basename;
 
 
+my @requireList = ();
 my @kernelModules = ();
 my @initrdKernelModules = ();
 
@@ -56,8 +57,6 @@ push @kernelModules, "kvm-amd" if hasCPUFeature "svm";
 # modules are auto-detected so we don't need to list them here.
 # However, some are needed in the initrd to boot the system.
 
-my $enableIntel2200BGFirmware = "false";
-my $enableIntel3945ABGFirmware = "false";
 my $videoDriver = "vesa";
 
 sub pciCheck {
@@ -97,11 +96,13 @@ sub pciCheck {
     # Can't rely on $module here, since the module may not be loaded
     # due to missing firmware.  Ideally we would check modules.pcimap
     # here.
-    $enableIntel2200BGFirmware = "true" if $vendor eq "0x8086" &&
+    push @requireList, "(import ./configurations/hardware/network/Intel2200BG.nix)" if
+        $vendor eq "0x8086" &&
         ($device eq "0x1043" || $device eq "0x104f" || $device eq "0x4220" ||
          $device eq "0x4221" || $device eq "0x4223" || $device eq "0x4224");
 
-    $enableIntel3945ABGFirmware = "true" if $vendor eq "0x8086" &&
+    push @requireList, "(import ./configurations/hardware/network/Intel3945ABG.nix)" if
+        $vendor eq "0x8086" &&
         ($device eq "0x4229" || $device eq "0x4230" ||
          $device eq "0x4222" || $device eq "0x4227");
 
@@ -197,14 +198,26 @@ sub toNixExpr {
     return $res;
 }
 
+sub multiLineList {
+    my $indent = shift;
+    my $res = "";
+    foreach my $s (@_) {
+        $res .= "\n$indent  $s";
+    }
+    $res .= "\nindent";
+    return $res;
+}
+
 my $initrdKernelModules = toNixExpr(removeDups @initrdKernelModules);
 my $kernelModules = toNixExpr(removeDups @kernelModules);
- 
+my $requireList = multiLineList("  ", removeDups @requireList);
 
 ## This is a generated file.  Do not modify!
 ## Make changes to /etc/nixos/configuration.nix instead.
 print <<EOF ;
 {
+  require = [$requireList];
+
   boot = {
     initrd = {
       extraKernelModules = [ $initrdKernelModules ];
@@ -216,12 +229,15 @@ print <<EOF ;
     maxJobs = $cpus;
   };
 
+  # list of file systems which can be mounted.
+  fileSystems = [
+  ];
+
+  # list of swap devices.
+  swapDevices = [
+  ];
+
   networking = {
-    enableIntel3945ABGFirmware = $enableIntel3945ABGFirmware;
-    
-    # Warning: setting this option to `true' requires acceptance of the
-    # firmware license, see http://ipw2200.sourceforge.net/firmware.php?fid=7.
-    enableIntel2200BGFirmware = $enableIntel2200BGFirmware;
   };
 
   services = {
@@ -229,7 +245,7 @@ print <<EOF ;
     xserver = {
       videoDriver = "$videoDriver";
     };
-      
+
   };
 }
 EOF

system/kernel.nix

@@ -0,0 +1,164 @@
+{pkgs, config, ...}:
+
+###### interface
+let
+  inherit (pkgs.lib) mkOption;
+
+  options = {
+    boot = {
+      kernelPackages = mkOption {
+        default = pkgs.kernelPackages;
+        example = pkgs.kernelPackages_2_6_25;
+        description = "
+          This option allows you to override the Linux kernel used by
+          NixOS.  Since things like external kernel module packages are
+          tied to the kernel you're using, it also overrides those.
+          This option is a function that takes Nixpkgs as an argument
+          (as a convenience), and returns an attribute set containing at
+          the very least an attribute <varname>kernel</varname>.
+          Additional attributes may be needed depending on your
+          configuration.  For instance, if you use the NVIDIA X driver,
+          then it also needs to contain an attribute
+          <varname>nvidiaDrivers</varname>.
+        ";
+      };
+
+      kernelParams = mkOption {
+        default = [
+          "selinux=0"
+          "apm=on"
+          "acpi=on"
+          "vga=0x317"
+          "console=tty1"
+          "splash=verbose"
+        ];
+        description = "
+          The kernel parameters.  If you want to add additional
+          parameters, it's best to set
+          <option>boot.extraKernelParams</option>.
+        ";
+      };
+
+      extraKernelParams = mkOption {
+        default = [
+        ];
+        example = [
+          "debugtrace"
+        ];
+        description = "
+          Additional user-defined kernel parameters.
+        ";
+      };
+
+      extraModulePackages = mkOption {
+        default = [];
+        # !!! example = [pkgs.aufs pkgs.nvidiaDrivers];
+        description = ''
+          A list of additional packages supplying kernel modules.
+        '';
+      };
+
+      kernelModules = mkOption {
+        default = [];
+        description = "
+          The set of kernel modules to be loaded in the second stage of
+          the boot process.  That is, these modules are not included in
+          the initial ramdisk, so they'd better not be required for
+          mounting the root file system.  Add them to
+          <option>boot.initrd.extraKernelModules</option> if they are.
+        ";
+      };
+
+      initrd = {
+
+        kernelModules = mkOption {
+          default = [
+            # Note: most of these (especially the SATA/PATA modules)
+            # shouldn't be included by default since nixos-hardware-scan
+            # detects them, but I'm keeping them for now for backwards
+            # compatibility.
+            
+            # Some SATA/PATA stuff.        
+            "ahci"
+            "sata_nv"
+            "sata_via"
+            "sata_sis"
+            "sata_uli"
+            "ata_piix"
+            "pata_marvell"
+            
+            # Standard SCSI stuff.
+            "sd_mod"
+            "sr_mod"
+            
+            # Standard IDE stuff.
+            "ide_cd"
+            "ide_disk"
+            "ide_generic"
+            
+            # Filesystems.
+            "ext3"
+            
+            # Support USB keyboards, in case the boot fails and we only have
+            # a USB keyboard.
+            "ehci_hcd"
+            "ohci_hcd"
+            "usbhid"
+
+            # LVM.
+            "dm_mod"
+          ];
+          description = "
+            The set of kernel modules in the initial ramdisk used during the
+            boot process.  This set must include all modules necessary for
+            mounting the root device.  That is, it should include modules
+            for the physical device (e.g., SCSI drivers) and for the file
+            system (e.g., ext3).  The set specified here is automatically
+            closed under the module dependency relation, i.e., all
+            dependencies of the modules list here are included
+            automatically.  If you want to add additional
+            modules, it's best to set
+            <option>boot.initrd.extraKernelModules</option>.
+          ";
+        };
+
+        extraKernelModules = mkOption {
+          default = [];
+          description = "
+            Additional kernel modules for the initial ramdisk.  These are
+            loaded before the modules listed in
+            <option>boot.initrd.kernelModules</option>, so they take
+            precedence.
+          ";
+        };
+
+      };
+    };
+  };
+in
+
+###### implementation
+let
+  kernelPackages = config.boot.kernelPackages;
+  kernel = kernelPackages.kernel;
+in
+
+{
+  require = [
+    options
+
+    # udev
+  ];
+
+  system = {
+    # include kernel modules.
+    modulesTree = [ kernel ] ++ config.boot.extraModulePackages;
+  };
+
+  services = {
+    udev = {
+      # The Linux kernel >= 2.6.27 provides firmware
+      addFirmware = [ "${kernel}/lib/firmware" ];
+    };
+  };
+}

system/options.nix

@@ -1,33 +1,7 @@
 {pkgs, config, ...}:
 
 let
-  inherit (pkgs.lib) mkOption;
+  inherit (pkgs.lib) mkOption mergeOneOption;
-  inherit (builtins) head tail;
-
-  obsolete = what: f: name:
-    if builtins ? trace then
-      builtins.trace "${name}: Obsolete ${what}." f name
-    else f name;
-
-  obsoleteMerge =
-    obsolete "option" pkgs.lib.mergeDefaultOption;
-
-  # temporary modifications.
-  # backward here means that expression could either be a value or a
-  # function which expects to have a pkgs argument.
-  optionalPkgs = name: x:
-    if builtins.isFunction x
-    then obsolete "notation" (name: x pkgs) name
-    else x;
-
-  backwardPkgsFunListMerge = name: list:
-    pkgs.lib.concatMap (optionalPkgs name) list;
-
-  backwardPkgsFunMerge = name: list:
-    if list != [] && tail list == []
-    then optionalPkgs name (head list)
-    else abort "${name}: Defined at least twice.";
-
 in
 
 {
@@ -64,51 +38,6 @@ in
       ";
     };
 
-    kernelPackages = mkOption {
-      default = pkgs.kernelPackages;
-      example = pkgs.kernelPackages_2_6_25;
-      merge = backwardPkgsFunMerge;
-      description = "
-        This option allows you to override the Linux kernel used by
-        NixOS.  Since things like external kernel module packages are
-        tied to the kernel you're using, it also overrides those.
-        This option is a function that takes Nixpkgs as an argument
-        (as a convenience), and returns an attribute set containing at
-        the very least an attribute <varname>kernel</varname>.
-        Additional attributes may be needed depending on your
-        configuration.  For instance, if you use the NVIDIA X driver,
-        then it also needs to contain an attribute
-        <varname>nvidiaDrivers</varname>.
-      ";
-    };
-
-    kernelParams = mkOption {
-      default = [
-        "selinux=0"
-        "apm=on"
-        "acpi=on"
-        "vga=0x317"
-        "console=tty1"
-        "splash=verbose"
-      ];
-      description = "
-        The kernel parameters.  If you want to add additional
-        parameters, it's best to set
-        <option>boot.extraKernelParams</option>.
-      ";
-    };
-
-    extraKernelParams = mkOption {
-      default = [
-      ];
-      example = [
-        "debugtrace"
-      ];
-      description = "
-        Additional user-defined kernel parameters.
-      ";
-    };
-
     hardwareScan = mkOption {
       default = true;
       description = "
@@ -121,89 +50,8 @@ in
       ";
     };
 
-    extraModulePackages = mkOption {
-      default = [];
-      # !!! example = [pkgs.aufs pkgs.nvidiaDrivers];
-      description = ''
-        A list of additional packages supplying kernel modules.
-      '';
-      merge = backwardPkgsFunListMerge;
-    };
-
-    kernelModules = mkOption {
-      default = [];
-      description = "
-        The set of kernel modules to be loaded in the second stage of
-        the boot process.  That is, these modules are not included in
-        the initial ramdisk, so they'd better not be required for
-        mounting the root file system.  Add them to
-        <option>boot.initrd.extraKernelModules</option> if they are.
-      ";
-    };
-
     initrd = {
 
-      kernelModules = mkOption {
-        default = [
-          # Note: most of these (especially the SATA/PATA modules)
-          # shouldn't be included by default since nixos-hardware-scan
-          # detects them, but I'm keeping them for now for backwards
-          # compatibility.
-          
-          # Some SATA/PATA stuff.        
-          "ahci"
-          "sata_nv"
-          "sata_via"
-          "sata_sis"
-          "sata_uli"
-          "ata_piix"
-          "pata_marvell"
-          
-          # Standard SCSI stuff.
-          "sd_mod"
-          "sr_mod"
-          
-          # Standard IDE stuff.
-          "ide_cd"
-          "ide_disk"
-          "ide_generic"
-          
-          # Filesystems.
-          "ext3"
-          
-          # Support USB keyboards, in case the boot fails and we only have
-          # a USB keyboard.
-          "ehci_hcd"
-          "ohci_hcd"
-          "usbhid"
-
-          # LVM.
-          "dm_mod"
-        ];
-        description = "
-          The set of kernel modules in the initial ramdisk used during the
-          boot process.  This set must include all modules necessary for
-          mounting the root device.  That is, it should include modules
-          for the physical device (e.g., SCSI drivers) and for the file
-          system (e.g., ext3).  The set specified here is automatically
-          closed under the module dependency relation, i.e., all
-          dependencies of the modules list here are included
-          automatically.  If you want to add additional
-          modules, it's best to set
-          <option>boot.initrd.extraKernelModules</option>.
-        ";
-      };
-
-      extraKernelModules = mkOption {
-        default = [];
-        description = "
-          Additional kernel modules for the initial ramdisk.  These are
-          loaded before the modules listed in
-          <option>boot.initrd.kernelModules</option>, so they take
-          precedence.
-        ";
-      };
-
       allowMissing = mkOption {
         default = false;
         description = ''
@@ -295,17 +143,7 @@ in
       merge = pkgs.lib.mergeListOption;
 
       # Convert the list of path to only one path.
-      apply = list: pkgs.aggregateModules (
+      apply = pkgs.aggregateModules;
-        let
-          kernelPackages = config.boot.kernelPackages;
-          kernel = kernelPackages.kernel;
-        in
-        [ kernel ]
-        ++ pkgs.lib.optional config.hardware.enableGo7007 kernelPackages.wis_go7007
-        ++ config.boot.extraModulePackages
-        # should only keep this one, other have to be set by the option owners.
-        ++ list
-      );
     };
 
     sbin = {
@@ -345,21 +183,6 @@ in
     };
   };
 
-  # Hm, this sounds like a catch-all...
-  hardware = {
-
-    enableGo7007 = mkOption {
-      default = false;
-      merge = obsoleteMerge;
-      description = ''
-        Enable this option to get support for the WIS GO7007SB
-        multi-format video encoder, which is used in a number of
-        devices such as the Plextor ConvertX TV402U USB TV device.
-      '';
-    };
-  
-  };
-
 
   networking = {
 
@@ -411,45 +234,6 @@ in
       ";
     };
 
-    enableIntel2200BGFirmware = mkOption {
-      default = false;
-      merge = obsoleteMerge;
-      description = "
-        Turn on this option if you want firmware for the Intel
-        PRO/Wireless 2200BG to be loaded automatically.  This is
-        required if you want to use this device.  Intel requires you to
-        accept the license for this firmware, see
-        <link xlink:href='http://ipw2200.sourceforge.net/firmware.php?fid=7'/>.
-      ";
-    };
-
-    enableIntel3945ABGFirmware = mkOption {
-      default = false;
-      merge = obsoleteMerge;
-      description = "
-        This option enables automatic loading of the firmware for the Intel
-        PRO/Wireless 3945ABG.
-      ";
-    };
-
-    enableIntel4965AGNFirmware = mkOption {
-      default = false;
-      merge = obsoleteMerge;
-      description = "
-        This option enables automatic loading of the firmware for the Intel
-        PRO/Wireless 4965AGN.
-      ";
-    };
-
-    enableZydasZD1211Firmware = mkOption {
-      default = false;
-      merge = obsoleteMerge;
-      description = "
-        This option enables automatic loading of the firmware for the Zydas
-        ZyDAS ZD1211(b) 802.11a/b/g USB WLAN chip.
-      ";
-    };
-
     localCommands = mkOption {
       default = "";
       example = "text=anything; echo You can put $text here.";
@@ -2346,7 +2130,6 @@ in
     extraPackages = mkOption {
       default = [];
       example = [pkgs.firefox pkgs.thunderbird];
-      merge = backwardPkgsFunListMerge;
       description = "
         This option allows you to add additional packages to the system
         path.  These packages are automatically available to all users,
@@ -2363,7 +2146,7 @@ in
     nix = mkOption {
       default = pkgs.nixUnstable;
       example = pkgs.nixCustomFun /root/nix.tar.gz;
-      merge = backwardPkgsFunMerge;
+      merge = mergeOneOption;
       description = "
         Use non-default Nix easily. Be careful, though, not to break everything.
       ";
@@ -2405,6 +2188,7 @@ in
 
   require = [
     # boot (is it the right place ?)
+    (import ../system/kernel.nix)
     (import ../boot/boot-stage-2.nix)
     (import ../installer/grub.nix)
 
@@ -2435,7 +2219,7 @@ in
     (import ../upstart-jobs/hal.nix)
     (import ../upstart-jobs/gpm.nix)
     (import ../upstart-jobs/nagios/default.nix)
-    (import ../upstart-jobs/xserver.nix)
+    (import ../upstart-jobs/xserver/default.nix)
     (import ../upstart-jobs/zabbix-agent.nix)
     (import ../upstart-jobs/zabbix-server.nix)
     (import ../upstart-jobs/disnix.nix)

system/system-options.nix

@@ -287,7 +287,7 @@ in
         # Set the host name.  Don't clear it if it's not configured in the
         # NixOS configuration, since it may have been set by dhclient in the
         # meantime.
-        ${if config.networking.hostName == "" then
+        ${if config.networking.hostName != "" then
             ''hostname "${config.networking.hostName}"''
         else ''
             # dhclient won't do anything if the hostname isn't empty.

system/system.nix

@@ -11,14 +11,11 @@ rec {
     systemPathList
   ];
 
-  noOption = name: values:
-    abort "${name}: Used without option declaration.";
-
   # Make a configuration object from which we can retrieve option
   # values.
   config =
     pkgs.lib.fixOptionSets
-      (pkgs.lib.mergeOptionSets noOption)
+      pkgs.lib.newMergeOptionSets
       pkgs configComponents;
 
   optionDeclarations =
@@ -158,7 +155,6 @@ rec {
       ++ pkgs.lib.optional config.networking.defaultMailServer.directDelivery pkgs.ssmtp 
       ++ config.environment.extraPackages
       ++ pkgs.lib.optional config.fonts.enableFontDir fontDir
-      ++ pkgs.lib.optional config.hardware.enableGo7007 kernelPackages.wis_go7007
 
       # NSS modules need to be in `systemPath' so that (i) the builder
       # chroot gets to seem them, and (ii) applications can benefit from

upstart-jobs/default.nix

@@ -147,16 +147,8 @@ let
       inherit modprobe config;
       inherit (pkgs) stdenv writeText substituteAll udev procps;
       inherit (pkgs.lib) cleanSource;
-      firmwareDirs =
+      firmwareDirs = config.services.udev.addFirmware;
-           pkgs.lib.optional config.networking.enableIntel2200BGFirmware pkgs.ipw2200fw
+      extraUdevPkgs = config.services.udev.addUdevPkgs;
-        ++ pkgs.lib.optional config.networking.enableIntel3945ABGFirmware pkgs.iwlwifi3945ucode
-        ++ pkgs.lib.optional config.networking.enableIntel4965AGNFirmware kernelPackages.iwlwifi4965ucode
-        ++ pkgs.lib.optional config.networking.enableZydasZD1211Firmware pkgs.zd1211fw
-        ++ pkgs.lib.optional config.hardware.enableGo7007 "${kernelPackages.wis_go7007}/firmware"
-        ++ config.services.udev.addFirmware;
-      extraUdevPkgs =
-           pkgs.lib.optional config.hardware.enableGo7007 kernelPackages.wis_go7007
-        ++ config.services.udev.addUdevPkgs;
     })
       
     # Makes LVM logical volumes available. 

upstart-jobs/disnix.nix

@@ -1,5 +1,5 @@
 # Disnix server
-{config, pkgs}:
+{config, pkgs, ...}:
 
 ###### interface
 let

upstart-jobs/fcron.nix

@@ -1,4 +1,4 @@
-{pkgs, config}:
+{pkgs, config, ...}:
 
 ###### interface
 let

upstart-jobs/xserver/default.nix

@@ -66,6 +66,7 @@ let
           ";
         };
 
+/*
         sessionType = mkOption {
           default = "gnome";
           example = "xterm";
@@ -91,14 +92,6 @@ let
           ";
         };
 
-        renderingFlag = mkOption {
-          default = "";
-          example = "--indirect-rendering";
-          description = "
-            Possibly pass --indierct-rendering to Compiz.
-          ";
-        };
-
         sessionStarter = mkOption {
           example = "${pkgs.xterm}/bin/xterm -ls";
           description = "
@@ -107,6 +100,7 @@ let
             <option>services.xserver.sessionType</option> is empty.
           ";
         };
+*/
 
         startSSHAgent = mkOption {
           default = true;
@@ -118,41 +112,6 @@ let
           ";
         };
 
-        slim = {
-
-          theme = mkOption {
-            default = null;
-            example = pkgs.fetchurl {
-              url = http://download.berlios.de/slim/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.
-            ";
-          };
-
-          defaultUser = mkOption {
-            default = "";
-            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.
-            ";
-          };
-
-          hideCursor = mkOption {
-            default = false;
-            example = true;
-            description = "
-              Hide the mouse cursor on the login screen.
-            ";
-          };
-        };
-
         isClone = mkOption {
           default = true;
           example = false;
@@ -327,7 +286,6 @@ let
   # Abbreviations.
   cfg = config.services.xserver;
   xorg = cfg.package;
-  gnome = pkgs.gnome;
   stdenv = pkgs.stdenv;
 
   knownVideoDrivers = {
@@ -344,25 +302,9 @@ let
   # Get a bunch of user settings.
   videoDriver = cfg.videoDriver;
   resolutions = map (res: ''"${toString res.x}x${toString res.y}"'') (cfg.resolutions);
-  sessionType = cfg.sessionType;
 
   videoDriverModules = getAttr [ videoDriver ] (throw "unkown video driver : \"${videoDriver}\"") knownVideoDrivers;
 
-  sessionCmd =
-    if sessionType == "" then cfg.sessionStarter else
-    if sessionType == "xterm" then "${pkgs.xterm}/bin/xterm -ls" else
-    if sessionType == "gnome" then "${gnome.gnometerminal}/bin/gnome-terminal -ls" else
-    abort ("unknown session type ${sessionType}");
-
-
-  windowManager =
-    let wm = cfg.windowManager; in
-    if wm != "" then wm else
-    if sessionType == "gnome" then "metacity" else
-    if sessionType == "kde" then "none" /* started by startkde */ else
-    "twm";
-
-    
   modules = 
 
     getAttr ["modulesFirst"] [] videoDriverModules
@@ -518,240 +460,7 @@ let
   };
 
 
-  clientScript = pkgs.writeText "xclient" ''
+  nvidiaDrivers = (config.boot.kernelPackages pkgs).nvidiaDrivers;
-
-    source /etc/profile
-
-    exec > $HOME/.Xerrors 2>&1
-
-
-    ### Load X defaults.
-    if test -e ~/.Xdefaults; then
-      ${xorg.xrdb}/bin/xrdb -merge ~/.Xdefaults
-    fi
-
-
-    ${if cfg.startSSHAgent then ''
-      ### Start the SSH agent.
-      export SSH_ASKPASS=${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;
-    fi
-  
-
-    ### Start a window manager.
-  
-    ${if windowManager == "twm" then ''
-      ${xorg.twm}/bin/twm &
-    ''
-
-    else if windowManager == "metacity" then ''
-      env LD_LIBRARY_PATH=${xorg.libX11}/lib:${xorg.libXext}/lib:/usr/lib/
-      # !!! Hack: load the schemas for Metacity.
-      GCONF_CONFIG_SOURCE=xml::~/.gconf ${gnome.GConf}/bin/gconftool-2 \
-        --makefile-install-rule ${gnome.metacity}/etc/gconf/schemas/*.schemas # */
-      ${gnome.metacity}/bin/metacity &
-    ''
-
-    else if windowManager == "kwm" then ''
-      ${pkgs.kdebase}/bin/kwin &
-    ''
-
-    else if windowManager == "compiz" then ''
-      # !!! Hack: load the schemas for Compiz.
-      GCONF_CONFIG_SOURCE=xml::~/.gconf ${gnome.GConf}/bin/gconftool-2 \
-        --makefile-install-rule ${pkgs.compiz}/etc/gconf/schemas/*.schemas # */
-
-      # !!! Hack: turn on most Compiz modules.
-      ${gnome.GConf}/bin/gconftool-2 -t list --list-type=string \
-        --set /apps/compiz/general/allscreens/options/active_plugins \
-        [gconf,png,decoration,wobbly,fade,minimize,move,resize,cube,switcher,rotate,place,scale,water]
-
-      # Start Compiz and the GTK-style window decorator.
-      env LD_LIBRARY_PATH=${xorg.libX11}/lib:${xorg.libXext}/lib:/usr/lib/
-      ${pkgs.compiz}/bin/compiz gconf ${cfg.renderingFlag} &
-      ${pkgs.compiz}/bin/gtk-window-decorator --sync &
-    ''
-
-    else if windowManager == "xmonad" then ''
-      ${pkgs.xmonad}/bin/xmonad &
-    ''
-    
-    else if windowManager == "none" then ''
-      # The session starter will start the window manager.
-    ''
-
-    else abort ("unknown window manager " + windowManager)}
-
-
-    ### Show a background image.
-    # (but not if we're starting a full desktop environment that does it for us)
-    ${if sessionType != "kde" then ''
-    
-      if test -e $HOME/.background-image; then
-        ${pkgs.feh}/bin/feh --bg-scale $HOME/.background-image
-      fi
-      
-    '' else ""}
-    
-
-    ### Start the session.
-    ${if sessionType == "kde" then ''
-
-      # Start KDE.
-      export KDEDIRS=$HOME/.nix-profile:/nix/var/nix/profiles/default:${pkgs.kdebase}:${pkgs.kdelibs}
-      export XDG_CONFIG_DIRS=${pkgs.kdebase}/etc/xdg:${pkgs.kdelibs}/etc/xdg
-      export XDG_DATA_DIRS=${pkgs.kdebase}/share
-      exec ${pkgs.kdebase}/bin/startkde
-
-    '' else ''
-
-      # For all other session types, we currently just start a
-      # terminal of the kind indicated by sessionCmd.
-      # !!! yes, this means that you 'log out' by killing the X server.
-      while ${sessionCmd}; do
-        sleep 1
-      done
-
-    ''}
-    
-  '';
-
-
-  xserverArgs = [
-    "-ac"
-    "-logverbose"
-    "-verbose"
-    "-terminate"
-    "-logfile" "/var/log/X.${toString cfg.display}.log"
-    "-config ${configFile}"
-    ":${toString cfg.display}" "vt${toString cfg.tty}"
-    "-xkbdir" "${pkgs.xkeyboard_config}/etc/X11/xkb"
-  ] ++ optional (!config.services.xserver.tcpEnable) "-nolisten tcp";
-
-  
-  slimConfig = pkgs.writeText "slim.cfg" ''
-    xauth_path ${xorg.xauth}/bin/xauth
-    default_xserver ${xorg.xorgserver}/bin/X
-    xserver_arguments ${toString xserverArgs}
-    login_cmd exec ${stdenv.bash}/bin/sh ${clientScript}
-    halt_cmd ${pkgs.upstart}/sbin/shutdown -h now
-    reboot_cmd ${pkgs.upstart}/sbin/shutdown -r now
-    ${if cfg.slim.defaultUser != "" then "default_user " + cfg.slim.defaultUser else ""}
-    ${if cfg.slim.hideCursor then "hidecursor true" else ""}
-  '';
-
-
-  # Unpack the SLiM theme, or use the default.
-  slimThemesDir =
-    let
-      unpackedTheme = stdenv.mkDerivation {
-        name = "slim-theme";
-        buildCommand = ''
-          ensureDir $out
-          cd $out
-          unpackFile ${cfg.slim.theme}
-          ln -s * default
-        '';
-      };
-    in if cfg.slim.theme == null then "${pkgs.slim}/share/slim/themes" else unpackedTheme;       
-
-    nvidiaDrivers = (config.boot.kernelPackages pkgs).nvidiaDrivers;
-
-  oldJob = rec {
-  # Warning the indentation is wrong since here in order to don't produce noise in diffs.
-
-  name = "xserver";
-
-  
-  extraPath = [
-    xorg.xrandr
-    xorg.xrdb
-    xorg.setxkbmap
-    xorg.iceauth # required for KDE applications (it's called by dcopserver)
-    pkgs.feh
-  ]
-  ++ optional (windowManager == "twm") [
-    xorg.twm
-  ]
-  ++ optional (windowManager == "metacity") [
-    gnome.metacity
-  ]
-  ++ optional (windowManager == "compiz") [
-    pkgs.compiz
-  ]
-  ++ optional (sessionType == "xterm") [
-    pkgs.xterm
-  ]
-  ++ optional (sessionType == "gnome") [
-    gnome.gnometerminal
-    gnome.GConf
-    gnome.gconfeditor
-  ]
-  ++ optional (sessionType == "kde") [
-    pkgs.kdelibs
-    pkgs.kdebase
-    xorg.xset # used by startkde, non-essential
-  ]
-  ++ optional (videoDriver == "nvidia") [
-    kernelPackages.nvidiaDrivers
-  ];
-
-
-  extraEtc =
-    optional (sessionType == "kde")
-      { source = "${pkgs.xkeyboard_config}/etc/X11/xkb";
-        target = "X11/xkb";
-      }
-    ++
-    optional cfg.exportConfiguration
-      { source = "${configFile}";
-        target = "X11/xorg.conf";
-      };
-
-    
-  job = ''
-    start on ${if cfg.autorun then "network-interfaces" else "never"}
-
-    start script
-    
-      rm -f /var/run/opengl-driver
-      ${if videoDriver == "nvidia"        
-        then ''
-          ln -sf ${kernelPackages.nvidiaDrivers} /var/run/opengl-driver
-        ''
-        else if cfg.driSupport
-        then "ln -sf ${pkgs.mesa} /var/run/opengl-driver"
-        else ""
-       }
-
-      rm -f /var/log/slim.log
-       
-    end script
-
-    env SLIM_CFGFILE=${slimConfig}
-    env SLIM_THEMESDIR=${slimThemesDir}
-    env FONTCONFIG_FILE=/etc/fonts/fonts.conf # !!! cleanup
-    env XKB_BINDIR=${xorg.xkbcomp}/bin # Needed for the Xkb extension.
-
-    ${if videoDriver == "nvidia" 
-      then "env LD_LIBRARY_PATH=${xorg.libX11}/lib:${xorg.libXext}/lib:${kernelPackages.nvidiaDrivers}/lib" 
-      else ""
-    }
-
-    ${if videoDriver != "nvidia"
-      then "env XORG_DRI_DRIVER_PATH=${pkgs.mesa}/lib/modules/dri"
-      else ""
-    }
-
-    exec ${pkgs.slim}/bin/slim
-  '';
-  
-};
 
 in
 
@@ -759,14 +468,19 @@ mkIf cfg.enable {
   require = [
     options
 
+    # services.xserver.*Manager
+    (import ./displayManager/default.nix)
+    (import ./windowManager/default.nix)
+    (import ./desktopManager/default.nix)
+
     # services.extraJobs
-    (import ../upstart-jobs/default.nix)
+    (import ../../upstart-jobs/default.nix)
 
     # environment.etc
-    (import ../etc/default.nix)
+    (import ../../etc/default.nix)
 
     # fonts.fonts
-    (import ../system/fonts.nix)
+    (import ../../system/fonts.nix)
 
     # boot.extraModulePackages
     # security.extraSetuidPrograms
@@ -779,29 +493,77 @@ mkIf cfg.enable {
     ];
   };
 
-  security = {
+  environment = {
-    extraSetuidPrograms = mkIf (cfg.sessionType == "kde") [
+    etc = mkIf cfg.exportConfiguration [
-      "kcheckpass"
+      { source = "${configFile}";
+        target = "X11/xorg.conf";
+      }
+    ];
+
+    extraPackages = [
+      xorg.xrandr
+      xorg.xrdb
+      xorg.setxkbmap
+      xorg.iceauth # required for KDE applications (it's called by dcopserver)
+    ]
+    ++ optional (videoDriver == "nvidia") [
+      kernelPackages.nvidiaDrivers
     ];
   };
 
-  environment = {
-    etc = [
-      { source = ../etc/pam.d/kde;
-        target = "pam.d/kde";
-      }
-      { source = ../etc/pam.d/slim;
-        target = "pam.d/slim";
-      }
-    ] ++ oldJob.extraEtc;
-
-    extraPackages =
-      oldJob.extraPath;
-  };
-
   services = {
+    xserver = {
+      displayManager = {
+        xserverArgs = [
+          "-ac"
+          "-logverbose"
+          "-verbose"
+          "-terminate"
+          "-logfile" "/var/log/X.${toString cfg.display}.log"
+          "-config ${configFile}"
+          ":${toString cfg.display}" "vt${toString cfg.tty}"
+          "-xkbdir" "${pkgs.xkeyboard_config}/etc/X11/xkb"
+        ] ++ optional (!cfg.tcpEnable) "-nolisten tcp";
+      };
+    };
+
     extraJobs = [{
-      inherit (oldJob) name job;
+      name = "xserver";
+      job = ''
+        start on ${if cfg.autorun then "network-interfaces" else "never"}
+
+        start script
+        
+          rm -f /var/run/opengl-driver
+          ${if videoDriver == "nvidia"
+            then ''
+              ln -sf ${kernelPackages.nvidiaDrivers} /var/run/opengl-driver
+            ''
+            else if cfg.driSupport
+            then "ln -sf ${pkgs.mesa} /var/run/opengl-driver"
+            else ""
+           }
+
+          ${cfg.displayManager.job.beforeScript}
+          
+        end script
+
+        ${cfg.displayManager.job.env}
+        env FONTCONFIG_FILE=/etc/fonts/fonts.conf # !!! cleanup
+        env XKB_BINDIR=${xorg.xkbcomp}/bin # Needed for the Xkb extension.
+
+        ${if videoDriver == "nvidia" 
+          then "env LD_LIBRARY_PATH=${xorg.libX11}/lib:${xorg.libXext}/lib:${kernelPackages.nvidiaDrivers}/lib"
+          else ""
+        }
+
+        ${if videoDriver != "nvidia"
+          then "env XORG_DRI_DRIVER_PATH=${pkgs.mesa}/lib/modules/dri"
+          else ""
+        }
+
+        exec ${cfg.displayManager.job.execCmd}
+      '';
     }];
   };
 }

upstart-jobs/xserver/desktopManager/default.nix

@@ -0,0 +1,73 @@
+{pkgs, config, ...}:
+
+let
+  inherit (pkgs.lib) mkOption mergeOneOption mkIf filter optionalString any;
+  cfg = config.services.xserver.desktopManager;
+
+  needBGCond = d: ! (d ? bgSupport && d.bgSupport);
+in
+
+{
+  require = [
+    (import ./kde.nix)
+    (import ./gnome.nix)
+    (import ./xterm.nix)
+    (import ./none.nix)
+  ];
+
+  services = {
+    xserver = {
+      displayManager = {
+        session = cfg.session.list;
+      };
+
+      desktopManager = {
+        session = mkOption {
+          default = [];
+          example = [{
+            name = "kde";
+            bgSupport = true;
+            start = "...";
+          }];
+          description = "
+            Internal option used to add some common line to desktop manager
+            scripts before forwarding the value to the
+            <varname>displayManager</varname>.
+          ";
+          apply = list: {
+            list = map (d: d // {
+              manage = "desktop";
+              start = d.start
+              + optionalString (needBGCond d) ''
+                if test -e $HOME/.background-image; then
+                  ${pkgs.feh}/bin/feh --bg-scale $HOME/.background-image
+                fi
+              '';
+            }) list;
+            needBGPackages = [] != filter needBGCond list;
+          };
+        };
+
+
+
+        default = mkOption {
+          default = "xterm";
+          example = "none";
+          description = "
+            Default desktop manager loaded if none have been chosen.
+          ";
+          merge = list:
+            let defaultDM = mergeOneOption list; in
+            if any (w: w.name == defaultDM) cfg.session.list then
+              defaultDM
+            else
+              throw "Default desktop manager not found.";
+        };
+      };
+    };
+  };
+
+  environment = mkIf cfg.session.needBGPackages {
+    extraPackages = [ pkgs.feh ];
+  };
+}

upstart-jobs/xserver/desktopManager/gnome.nix

@@ -0,0 +1,47 @@
+{pkgs, config, ...}:
+
+let
+  inherit (pkgs.lib) mkOption mkIf;
+  cfg = config.services.xserver.desktopManager.gnome;
+  gnome = pkgs.gnome;
+
+  options = { services = { xserver = { desktopManager = {
+
+    gnome = {
+      enable = mkOption {
+        default = false;
+        example = true;
+        description = "Enable a gnome terminal as a desktop manager.";
+      };
+    };
+
+  }; }; }; };
+in
+
+mkIf cfg.enable {
+  require = options;
+
+  services = {
+    xserver = {
+
+      desktopManager = {
+        session = [{
+          name = "gnome";
+          start = ''
+            ${gnome.gnometerminal}/bin/gnome-terminal -ls &
+            waitPID=$!
+          '';
+        }];
+      };
+
+    };
+  };
+
+  environment = {
+    extraPackages = [
+      gnome.gnometerminal
+      gnome.GConf
+      gnome.gconfeditor
+    ];
+  };
+}

upstart-jobs/xserver/desktopManager/kde.nix

@@ -0,0 +1,65 @@
+{pkgs, config, ...}:
+
+let
+  inherit (pkgs.lib) mkOption mkIf;
+  cfg = config.services.xserver.desktopManager.kde;
+  xorg = config.services.xserver.package;
+
+  options = { services = { xserver = { desktopManager = {
+
+    kde = {
+      enable = mkOption {
+        default = false;
+        example = true;
+        description = "Enable the kde desktop manager.";
+      };
+    };
+
+  }; }; }; };
+in
+
+mkIf cfg.enable {
+  require = options;
+
+  services = {
+    xserver = {
+
+      desktopManager = {
+        session = [{
+          name = "kde";
+          start = ''
+            # Start KDE.
+            export KDEDIRS=$HOME/.nix-profile:/nix/var/nix/profiles/default:${pkgs.kdebase}:${pkgs.kdelibs}
+            export XDG_CONFIG_DIRS=${pkgs.kdebase}/etc/xdg:${pkgs.kdelibs}/etc/xdg
+            export XDG_DATA_DIRS=${pkgs.kdebase}/share
+            exec ${pkgs.kdebase}/bin/startkde
+          '';
+        }];
+      };
+
+    };
+  };
+
+  security = {
+    extraSetuidPrograms = [
+      "kcheckpass"
+    ];
+  };
+
+  environment = {
+    extraPackages = [
+      pkgs.kdelibs
+      pkgs.kdebase
+      xorg.xset # used by startkde, non-essential
+    ];
+
+    etc = [
+      { source = ../../../etc/pam.d/kde;
+        target = "pam.d/kde";
+      }
+      { source = "${pkgs.xkeyboard_config}/etc/X11/xkb";
+        target = "X11/xkb";
+      }
+    ];
+  };
+}

upstart-jobs/xserver/desktopManager/none.nix

@@ -0,0 +1,14 @@
+{
+  services = {
+    xserver = {
+
+      desktopManager = {
+        session = [{
+          name = "none";
+          start = "";
+        }];
+      };
+
+    };
+  };
+}

upstart-jobs/xserver/desktopManager/xterm.nix

@@ -0,0 +1,44 @@
+{pkgs, config, ...}:
+
+let
+  inherit (pkgs.lib) mkOption mkIf;
+  cfg = config.services.xserver.desktopManager.xterm;
+
+  options = { services = { xserver = { desktopManager = {
+
+    xterm = {
+      enable = mkOption {
+        default = false;
+        example = true;
+        description = "Enable a xterm terminal as a desktop manager.";
+      };
+    };
+
+  }; }; }; };
+in
+
+mkIf cfg.enable {
+  require = options;
+
+  services = {
+    xserver = {
+
+      desktopManager = {
+        session = [{
+          name = "xterm";
+          start = ''
+            ${pkgs.xterm}/bin/xterm -ls &
+            waitPID=$!
+          '';
+        }];
+      };
+
+    };
+  };
+
+  environment = {
+    extraPackages = [
+      pkgs.xterm
+    ];
+  };
+}

upstart-jobs/xserver/displayManager/default.nix

@@ -0,0 +1,167 @@
+{pkgs, config, ...}:
+
+let
+  inherit (pkgs.lib) mkOption mergeOneOption optionals filter concatMap concatMapStrings;
+  cfg = config.services.xserver;
+  xorg = cfg.package;
+
+  # file provided by services.xserver.displayManager.session.script
+  xsession = wm: dm: pkgs.writeText "xsession" ''
+
+    source /etc/profile
+
+    exec > $HOME/.Xerrors 2>&1
+
+
+    ### Load X defaults.
+    if test -e ~/.Xdefaults; then
+      ${xorg.xrdb}/bin/xrdb -merge ~/.Xdefaults
+    fi
+
+    ${if cfg.startSSHAgent then ''
+      ### Start the SSH agent.
+      export SSH_ASKPASS=${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;
+    fi
+
+    # this script expect to have as first argument the following input
+    # "desktop-manager + window-manager".
+    arg="$1"
+
+    # extract the window manager.
+    windowManager="''${arg##* + }"
+    : ''${windowManager:=${cfg.windowManager.default}}
+    # extract the desktop manager.
+    desktopManager="''${arg% + *}"
+    : ''${desktopManager:=${cfg.desktopManager.default}}
+
+    # used to restart the xserver.
+    waitPID=0
+
+    # handle window manager starts.
+    case $windowManager in
+      ${concatMapStrings (s: "
+        (${s.name})
+          ${s.start}
+          ;;
+      ") wm}
+      (*) echo "$0: Window manager '$windowManager' not found.";;
+    esac
+
+    # handle desktop manager starts.
+    case $desktopManager in
+      ${concatMapStrings (s: "
+        (${s.name})
+          ${s.start}
+          ;;
+      ") dm}
+      (*) echo "$0: Desktop manager '$desktopManager' not found.";;
+    esac
+
+    test "$waitPID" != 0 && wait "$waitPID"
+    exit
+  '';
+
+in
+
+{
+  # list of display managers.
+  require = [
+    (import ./slim.nix)
+  ];
+
+  services = {
+    xserver = {
+      displayManager = {
+
+        xauthBin = mkOption {
+          default = "${xorg.xauth}/bin/xauth";
+          description = "
+            Path to the xauth binary used by display managers.
+          ";
+        };
+
+        xserverBin = mkOption {
+          default = "${xorg.xorgserver}/bin/X";
+          description = "
+            Path to the xserver binary used by display managers.
+          ";
+        };
+
+        xserverArgs = mkOption {
+          default = [];
+          example = [
+            "-ac"
+            "-logverbose"
+            "-nolisten tcp"
+          ];
+          description = "
+            List of arguments which have to be pass to when
+            the display manager start the xserver.
+          ";
+          apply = toString;
+        };
+
+        session = mkOption {
+          default = [];
+          example = [
+            {
+              manage = "desktop";
+              name = "xterm";
+              start = "
+                ${pkgs.xterm}/bin/xterm -ls &
+                waitPID=$!
+              ";
+            }
+          ];
+          description = ''
+            List of session 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
+            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>
+            or <literal>"desktop"</literal>.
+
+            The list of desktop manager and window manager should appear
+            inside the display manager with the desktop manager name
+            followed by the window manager name.
+          '';
+          apply = list: rec {
+            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;
+            script = xsession wm dm;
+          };
+        };
+
+        job = mkOption {
+          default = {};
+          example = {
+            beforeScript = ''
+              rm -f /var/log/slim.log
+            '';
+            env = ''
+              env 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;
+        };
+
+      };
+    };
+  };
+}

upstart-jobs/xserver/displayManager/slim.nix

@@ -0,0 +1,112 @@
+{pkgs, config, ...}:
+
+###### interface
+let
+  inherit (pkgs.lib) mkOption;
+
+  options = { services = { xserver = {
+
+    slim = {
+
+      theme = mkOption {
+        default = null;
+        example = pkgs.fetchurl {
+          url = http://download.berlios.de/slim/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.
+        ";
+      };
+
+      defaultUser = mkOption {
+        default = "";
+        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.
+        ";
+      };
+
+      hideCursor = mkOption {
+        default = false;
+        example = true;
+        description = "
+          Hide the mouse cursor on the login screen.
+        ";
+      };
+    };
+
+  }; /* xserver */ }; /* services */ };
+
+in
+
+###### implementation
+let
+  xcfg = config.services.xserver;
+  dmcfg = xcfg.displayManager;
+  cfg = xcfg.slim;
+
+  slimConfig = pkgs.writeText "slim.cfg" ''
+    xauth_path ${dmcfg.xauthBin}
+    default_xserver ${dmcfg.xserverBin}
+    xserver_arguments ${dmcfg.xserverArgs}
+    sessions ${pkgs.lib.concatStringsSep "," dmcfg.session.names}
+    login_cmd exec ${pkgs.stdenv.bash}/bin/sh ${dmcfg.session.script} "%session"
+    halt_cmd ${pkgs.upstart}/sbin/shutdown -h now
+    reboot_cmd ${pkgs.upstart}/sbin/shutdown -r now
+    ${if cfg.defaultUser != "" then "default_user " + cfg.defaultUser else ""}
+    ${if cfg.hideCursor then "hidecursor true" else ""}
+  '';
+
+
+  # Unpack the SLiM theme, or use the default.
+  slimThemesDir =
+    let
+      unpackedTheme = pkgs.stdenv.mkDerivation {
+        name = "slim-theme";
+        buildCommand = ''
+          ensureDir $out
+          cd $out
+          unpackFile ${cfg.theme}
+          ln -s * default
+        '';
+      };
+    in if cfg.theme == null then "${pkgs.slim}/share/slim/themes" else unpackedTheme;
+
+in
+
+{
+  require = [
+    options
+  ];
+
+  services = {
+    xserver = {
+      displayManager = {
+        job = {
+          beforeScript = ''
+            rm -f /var/log/slim.log
+          '';
+          env = ''
+            env SLIM_CFGFILE=${slimConfig}
+            env SLIM_THEMESDIR=${slimThemesDir}
+          '';
+          execCmd = "${pkgs.slim}/bin/slim";
+        };
+      };
+    };
+  };
+
+  environment = {
+    etc = [
+      { source = ../../../etc/pam.d/slim;
+        target = "pam.d/slim";
+      }
+    ];
+  };
+}

upstart-jobs/xserver/windowManager/compiz.nix

@@ -0,0 +1,64 @@
+{pkgs, config, ...}:
+
+let
+  inherit (pkgs.lib) mkOption mkIf;
+  cfg = config.services.xserver.windowManager.compiz;
+  xorg = config.services.xserver.package;
+  gnome = pkgs.gnome;
+
+  options = { services = { xserver = { windowManager = {
+
+    compiz = {
+      enable = mkOption {
+        default = false;
+        example = true;
+        description = "Enable the compiz window manager.";
+      };
+
+
+      renderingFlag = mkOption {
+        default = "";
+        example = "--indirect-rendering";
+        description = "
+          Possibly pass --indierct-rendering to Compiz.
+        ";
+      };
+    };
+
+  }; }; }; };
+in
+
+mkIf cfg.enable {
+  require = options;
+
+  services = {
+    xserver = {
+
+      windowManager = {
+        session = [{
+          name = "compiz";
+          start = ''
+            # !!! Hack: load the schemas for Compiz.
+            GCONF_CONFIG_SOURCE=xml::~/.gconf ${gnome.GConf}/bin/gconftool-2 \
+              --makefile-install-rule ${pkgs.compiz}/etc/gconf/schemas/*.schemas # */
+
+            # !!! Hack: turn on most Compiz modules.
+            ${gnome.GConf}/bin/gconftool-2 -t list --list-type=string \
+              --set /apps/compiz/general/allscreens/options/active_plugins \
+              [gconf,png,decoration,wobbly,fade,minimize,move,resize,cube,switcher,rotate,place,scale,water]
+
+            # Start Compiz and the GTK-style window decorator.
+            env LD_LIBRARY_PATH=${xorg.libX11}/lib:${xorg.libXext}/lib:/usr/lib/
+            ${pkgs.compiz}/bin/compiz gconf ${cfg.renderingFlag} &
+            ${pkgs.compiz}/bin/gtk-window-decorator --sync &
+          '';
+        }];
+      };
+
+    };
+  };
+
+  environment = {
+    extraPackages = [ pkgs.compiz ];
+  };
+}

upstart-jobs/xserver/windowManager/default.nix

@@ -0,0 +1,58 @@
+{pkgs, config, ...}:
+
+let
+  inherit (pkgs.lib) mkOption mergeOneOption any;
+  cfg = config.services.xserver.windowManager;
+in
+
+{
+  require = [
+    (import ./compiz.nix)
+    (import ./kwm.nix)
+    (import ./metacity.nix)
+    (import ./none.nix)
+    (import ./twm.nix)
+    (import ./wmii.nix)
+    (import ./xmonad.nix)
+  ];
+
+  services = {
+    xserver = {
+      displayManager = {
+        session = cfg.session;
+      };
+
+      windowManager = {
+        session = mkOption {
+          default = [];
+          example = [{
+            name = "wmii";
+            start = "...";
+          }];
+          description = "
+            Internal option used to add some common line to window manager
+            scripts before forwarding the value to the
+            <varname>displayManager</varname>.
+          ";
+          apply = map (d: d // {
+            manage = "window";
+          });
+        };
+
+        default = mkOption {
+          default = "none";
+          example = "wmii";
+          description = "
+            Default window manager loaded if none have been chosen.
+          ";
+          merge = list:
+            let defaultWM = mergeOneOption list; in
+            if any (w: w.name == defaultWM) cfg.session then
+              defaultWM
+            else
+              throw "Default window manager not found.";
+        };
+      };
+    };
+  };
+}

upstart-jobs/xserver/windowManager/kwm.nix

@@ -0,0 +1,46 @@
+{pkgs, config, ...}:
+
+let
+  inherit (pkgs.lib) mkOption mkIf;
+  cfg = config.services.xserver.windowManager.kwm;
+
+  option = { services = { xserver = { windowManager = {
+
+    kwm = {
+      enable = mkOption {
+        default = false;
+        example = true;
+        description = "Enable the kwm window manager.";
+      };
+
+    };
+
+  }; }; }; };
+in
+
+mkIf cfg.enable {
+  require = option;
+
+  services = {
+    xserver = {
+
+      windowManager = {
+        session = [{
+          name = "kwm";
+          start = "
+            ${pkgs.kdebase}/bin/kwin &
+            waitPID=$!
+          ";
+        }];
+      };
+
+    };
+  };
+
+  environment = {
+    extraPackages = [
+      pkgs.kdelibs
+      pkgs.kdebase
+    ];
+  };
+}

upstart-jobs/xserver/windowManager/metacity.nix

@@ -0,0 +1,49 @@
+{pkgs, config, ...}:
+
+let
+  inherit (pkgs.lib) mkOption mkIf;
+  cfg = config.services.xserver.windowManager.metacity;
+  xorg = config.services.xserver.package;
+  gnome = pkgs.gnome;
+
+  option = { services = { xserver = { windowManager = {
+
+    metacity = {
+      enable = mkOption {
+        default = false;
+        example = true;
+        description = "Enable the metacity window manager.";
+      };
+
+    };
+
+  }; }; }; };
+in
+
+mkIf cfg.enable {
+  require = option;
+
+  services = {
+    xserver = {
+
+      windowManager = {
+        session = [{
+          name = "metacity";
+          start = ''
+            env LD_LIBRARY_PATH=${xorg.libX11}/lib:${xorg.libXext}/lib:/usr/lib/
+            # !!! Hack: load the schemas for Metacity.
+            GCONF_CONFIG_SOURCE=xml::~/.gconf ${gnome.GConf}/bin/gconftool-2 \
+              --makefile-install-rule ${gnome.metacity}/etc/gconf/schemas/*.schemas # */
+            ${gnome.metacity}/bin/metacity &
+            waitPID=$!
+          '';
+        }];
+      };
+
+    };
+  };
+
+  environment = {
+    extraPackages = [ gnome.metacity ];
+  };
+}

upstart-jobs/xserver/windowManager/none.nix

@@ -0,0 +1,12 @@
+{
+  services = {
+    xserver = {
+      windowManager = {
+        session = [{
+          name = "none";
+          start = "";
+        }];
+      };
+    };
+  };
+}

upstart-jobs/xserver/windowManager/twm.nix

@@ -0,0 +1,44 @@
+{pkgs, config, ...}:
+
+let
+  inherit (pkgs.lib) mkOption mkIf;
+  cfg = config.services.xserver.windowManager.twm;
+  xorg = config.services.xserver.package;
+
+  option = { services = { xserver = { windowManager = {
+
+    twm = {
+      enable = mkOption {
+        default = false;
+        example = true;
+        description = "Enable the twm window manager.";
+      };
+
+    };
+
+  }; }; }; };
+in
+
+mkIf cfg.enable {
+  require = option;
+
+  services = {
+    xserver = {
+
+      windowManager = {
+        session = [{
+          name = "twm";
+          start = "
+            ${xorg.twm}/bin/twm &
+            waitPID=$!
+          ";
+        }];
+      };
+
+    };
+  };
+
+  environment = {
+    extraPackages = [ xorg.twm ];
+  };
+}

upstart-jobs/xserver/windowManager/wmii.nix

@@ -0,0 +1,32 @@
+{pkgs, config, ...}:
+
+let
+  inherit (pkgs.lib) mkOption mkIf;
+  cfg = config.services.xserver.windowManager.wmii;
+in
+
+{
+  services = {
+    xserver = {
+
+      windowManager = {
+        wmii = {
+          enable = mkOption {
+            default = false;
+            example = true;
+            description = "Enable the wmii window manager.";
+          };
+        };
+
+        session = mkIf cfg.enable [{
+          name = "wmii";
+          start = "
+            ${pkgs.wmiiSnap}/bin/wmii &
+            waitPID=$!
+          ";
+        }];
+      };
+
+    };
+  };
+}

upstart-jobs/xserver/windowManager/xmonad.nix

@@ -0,0 +1,32 @@
+{pkgs, config, ...}:
+
+let
+  inherit (pkgs.lib) mkOption mkIf;
+  cfg = config.services.xserver.windowManager.xmonad;
+in
+
+{
+  services = {
+    xserver = {
+
+      windowManager = {
+        xmonad = {
+          enable = mkOption {
+            default = false;
+            example = true;
+            description = "Enable the xmonad window manager.";
+          };
+        };
+
+        session = mkIf cfg.enable [{
+          name = "xmonad";
+          start = "
+            ${pkgs.xmonad}/bin/xmonad &
+            waitPID=$!
+          ";
+        }];
+      };
+
+    };
+  };
+}

upstart-jobs/zabbix-agent.nix

@@ -1,5 +1,5 @@
 # Zabbix agent daemon.
-{config, pkgs}:
+{config, pkgs, ...}:
 
 ###### interface
 let

upstart-jobs/zabbix-server.nix

@@ -1,5 +1,5 @@
 # Zabbix server daemon.
-{config, pkgs}:
+{config, pkgs, ...}:
 
 ###### interface
 let