* Refactoring: moved some options out of system/options.nix (almost

empty now), do more of bashrc.sh declaratively, and moved nsswitch
  generation to modules/config/nsswitch.nix.

svn path=/nixos/branches/modular-nixos/; revision=15754

default.nix

@@ -23,11 +23,9 @@ in
     config.environment.checkConfigurationOptions
     optionDeclarations config;
 
-  nix = config.environment.nix;
-  
+  # The following are used by nixos-rebuild.
   nixFallback = pkgs.nixUnstable;
-
-  manifests = config.installer.manifests; # exported here because nixos-rebuild uses it
+  manifests = config.installer.manifests;
 
   tests = config.tests;
 }

etc/bashrc.sh

@@ -1,15 +1,10 @@
 # Initialise a bunch of environment variables.
 export PATH=/var/run/current-system/sw/bin:/var/run/current-system/sw/sbin
 export LD_LIBRARY_PATH=/var/run/opengl-driver/lib
-if test -n "@nssModulesPath@"; then
-    LD_LIBRARY_PATH=@nssModulesPath@:$LD_LIBRARY_PATH
-fi
 export MODULE_DIR=@modulesTree@/lib/modules
 export NIXPKGS_CONFIG=/nix/etc/config.nix
 export NIXPKGS_ALL=/etc/nixos/nixpkgs
 export PAGER="less -R"
-export TZ=@timeZone@
-export TZDIR=@glibc@/share/zoneinfo
 export FONTCONFIG_FILE=/etc/fonts/fonts.conf
 export LANG=@defaultLocale@
 export EDITOR=nano
@@ -18,6 +13,7 @@ export LOCATE_PATH=/var/cache/locatedb
 @shellInit@
 export LOCALE_ARCHIVE=/var/run/current-system/sw/lib/locale/locale-archive
 
+
 # Set up secure multi-user builds: non-root users build through the
 # Nix daemon.
 if test "$USER" != root; then

etc/default.nix

@@ -38,7 +38,6 @@ let
   shellInit = config.environment.shellInit;
   nixEnvVars = config.nix.envVars;
   modulesTree = config.system.modulesTree;
-  nssModulesPath = config.system.nssModules.path;
   wrapperDir = config.security.wrapperDir;
   systemPath = config.system.path;
   binsh = config.system.build.binsh;
@@ -121,9 +120,7 @@ let
     { # Script executed when the shell starts as a non-login shell (system-wide version).
       source = pkgs.substituteAll {
         src = ./bashrc.sh;
-        inherit systemPath wrapperDir modulesTree nssModulesPath;
-        inherit (pkgs) glibc;
-        timeZone = config.time.timeZone;
+        inherit systemPath wrapperDir modulesTree;
         defaultLocale = config.i18n.defaultLocale;
         inherit nixEnvVars shellInit;
       };

maintainers/scripts/gen-module-list.sh

@@ -34,7 +34,7 @@ generate_index(){
   local path="$1"
   cd "$path"
   echo -n "$path: " 1>&2
-  { echo "[ # This file have been generated by $(basename $prog)";
+  { echo "[ # This file has been generated by $(basename $prog)";
     for file in : $(find ./ -wholename '*.impl[./]*' -or -wholename './module-list.nix' -or -type f -name '*.nix' -print | sort); do
        [ "$file" = ':' ] && continue;
        echo -n . 1>&2

modules/config/nsswitch.nix

@@ -0,0 +1,56 @@
+# Configuration for the Name Service Switch (/etc/nsswitch.conf).
+
+{config, pkgs, ...}:
+
+let
+
+  options = {
+
+    # NSS modules.  Hacky!
+    system.nssModules = pkgs.lib.mkOption {
+      internal = true;
+      default = [];
+      description = "
+        Search path for NSS (Name Service Switch) modules.  This allows
+        several DNS resolution methods to be specified via
+        <filename>/etc/nsswitch.conf</filename>.
+      ";
+      merge = pkgs.lib.mergeListOption;
+      apply = list:
+        let
+          list2 =
+            list
+            # !!! this should be in the LDAP module
+            ++ pkgs.lib.optional config.users.ldap.enable pkgs.nss_ldap;
+        in {
+          list = list2;
+          path = pkgs.lib.makeLibraryPath list2;
+        };
+    };
+
+  };
+
+in
+
+{
+  require = [options];
+
+  environment.etc =
+    [ # Name Service Switch configuration file.  Required by the C library.
+      # !!! Factor out the mdns stuff.  The avahi module should define
+      # an option used by this module.
+      { source =
+          if config.services.avahi.nssmdns
+          then ./nsswitch-mdns.conf
+          else ./nsswitch.conf;
+        target = "nsswitch.conf";
+      }
+    ];
+
+  environment.shellInit =
+    if config.system.nssModules.path != "" then
+      ''
+        LD_LIBRARY_PATH=${config.system.nssModules.path}:$LD_LIBRARY_PATH
+      ''
+    else "";
+}

modules/config/timezone.nix

@@ -0,0 +1,25 @@
+{pkgs, config, ...}:
+
+let
+
+  options = {
+
+    time.timeZone = pkgs.lib.mkOption {
+      default = "CET";
+      example = "America/New_York";
+      description = "The time zone used when displaying times and dates.";
+    };
+
+  };
+
+in
+
+{
+  require = [options];
+
+  environment.shellInit =
+    ''
+      export TZ=${config.time.timeZone}
+      export TZDIR=${pkgs.glibc}/share/zoneinfo
+    '';
+}

modules/installer/grub/grub.nix

@@ -77,6 +77,15 @@ let
         ";
       };
 
+      copyKernels = mkOption {
+        default = false;
+        description = "
+          Whether the Grub menu builder should copy kernels and initial
+          ramdisks to /boot.  This is necessary when /nix is on a
+          different file system than /boot.
+        ";
+      };
+
     };
   };
 in

modules/module-list.nix

@@ -1,10 +1,13 @@
 [ # This file have been generated by gen-module-list.sh
   ./config/fonts.nix
   ./config/i18n.nix
+  ./config/nsswitch.nix
+  ./config/system-path.nix
+  ./config/timezone.nix
   ./config/unix-odbc-drivers.nix
   ./config/users-groups.nix
-  ./config/system-path.nix
   ./installer/grub/grub.nix
+  ./legacy.nix
   ./security/setuid-wrappers.nix
   ./security/sudo.nix
   ./services/audio/alsa.nix
@@ -59,27 +62,27 @@
 ##### ./services/web-servers/apache-httpd/per-server-options.nix
 # error: while evaluating the attribute `<let-body>' at `(string):2:8':
 # while evaluating the function at `(string):3:22':
-# while evaluating the function at `/trace/nixos/modules/services/web-servers/apache-httpd/per-server-options.nix:6:2':
+# while evaluating the function at `/home/eelco/Dev/modular-nixos/modules/services/web-servers/apache-httpd/per-server-options.nix:6:2':
 # the argument named `forMainServer' required by the function is missing
 ##### ./services/web-servers/apache-httpd/subversion.nix
 # error: while evaluating the attribute `<let-body>' at `(string):2:8':
 # while evaluating the function at `(string):3:22':
-# while evaluating the function at `/trace/nixos/modules/services/web-servers/apache-httpd/subversion.nix:1:2':
+# while evaluating the function at `/home/eelco/Dev/modular-nixos/modules/services/web-servers/apache-httpd/subversion.nix:1:2':
 # the argument named `serverInfo' required by the function is missing
 ##### ./services/web-servers/apache-httpd/tomcat-connector.nix
 # error: while evaluating the attribute `<let-body>' at `(string):2:8':
 # while evaluating the function at `(string):3:22':
-# while evaluating the function at `/trace/nixos/modules/services/web-servers/apache-httpd/tomcat-connector.nix:1:2':
+# while evaluating the function at `/home/eelco/Dev/modular-nixos/modules/services/web-servers/apache-httpd/tomcat-connector.nix:1:2':
 # the argument named `serverInfo' required by the function is missing
 ##### ./services/web-servers/apache-httpd/twiki.nix
 # error: while evaluating the attribute `<let-body>' at `(string):2:8':
 # while evaluating the function at `(string):3:22':
-# while evaluating the function at `/trace/nixos/modules/services/web-servers/apache-httpd/twiki.nix:1:2':
+# while evaluating the function at `/home/eelco/Dev/modular-nixos/modules/services/web-servers/apache-httpd/twiki.nix:1:2':
 # the argument named `serverInfo' required by the function is missing
 ##### ./services/web-servers/apache-httpd/zabbix.nix
 # error: while evaluating the attribute `<let-body>' at `(string):2:8':
 # while evaluating the function at `(string):3:22':
-# while evaluating the function at `/trace/nixos/modules/services/web-servers/apache-httpd/zabbix.nix:1:2':
+# while evaluating the function at `/home/eelco/Dev/modular-nixos/modules/services/web-servers/apache-httpd/zabbix.nix:1:2':
 # the argument named `serverInfo' required by the function is missing
   ./services/web-servers/jboss.nix
   ./services/web-servers/tomcat.nix
@@ -87,9 +90,9 @@
   ./services/x11/xserver/default.nix
   ./services/x11/xserver/desktop-managers/default.nix
   ./services/x11/xserver/desktop-managers/gnome.nix
+  ./services/x11/xserver/desktop-managers/kde4.nix
   ./services/x11/xserver/desktop-managers/kde-environment.nix
   ./services/x11/xserver/desktop-managers/kde.nix
-  ./services/x11/xserver/desktop-managers/kde4.nix
   ./services/x11/xserver/desktop-managers/none.nix
   ./services/x11/xserver/desktop-managers/xterm.nix
   ./services/x11/xserver/display-managers/default.nix
@@ -114,9 +117,8 @@
 ##### ./system/upstart/make-job.nix
 # error: while evaluating the attribute `<let-body>' at `(string):2:8':
 # while evaluating the function at `(string):3:22':
-# while evaluating the function at `/trace/nixos/modules/system/upstart/make-job.nix:1:2':
+# while evaluating the function at `/home/eelco/Dev/modular-nixos/modules/system/upstart/make-job.nix:1:2':
 # the argument named `runCommand' required by the function is missing
   ./system/upstart/tools.nix
   ./system/upstart/upstart.nix
-  ./legacy.nix
 ]

modules/services/hardware/udev.nix

@@ -5,6 +5,19 @@ let
   inherit (pkgs.lib) mkOption mkIf;
 
   options = {
+
+    boot.hardwareScan = mkOption {
+      default = true;
+      description = "
+        Whether to try to load kernel modules for all detected hardware.
+        Usually this does a good job of providing you with the modules
+        you need, but sometimes it can crash the system or cause other
+        nasty effects.  If the hardware scan is turned on, it can be
+        disabled at boot time by adding the <literal>safemode</literal>
+        parameter to the kernel command line.
+      ";
+    };
+  
     services = {
       udev = {
 

modules/services/networking/avahi-daemon.nix

@@ -136,22 +136,6 @@ mkIf cfg.enable {
 
   environment = {
     extraPackages = [avahi];
-
-    # Name Service Switch configuration file.  Required by the C library.
-    # !!! This should be done in some other way, e.g., this module
-    # should define an option used by the hypothetical module that
-    # generates nsswitch.conf.
-    etc = mkIf cfg.nssmdns (mkThenElse {
-      thenPart = [{
-        source = ../../../etc/nsswitch-mdns.conf;
-        target = "nsswitch.conf";
-      }];
-
-      elsePart = [{
-        source = ../../../etc/nsswitch.conf;
-        target = "nsswitch.conf";
-      }];
-    });
   };
 
   users = {

modules/system/boot/stage-1.nix

@@ -11,6 +11,16 @@ let
 
   options = {
 
+    boot.isLiveCD = mkOption {
+      default = false;
+      description = "
+        If set to true, the root device will be mounted read-only and
+        a ramdisk will be mounted on top of it using unionfs to
+        provide a writable root.  This is used for the NixOS
+        Live-CD/DVD.
+      ";
+    };
+
     boot.resumeDevice = mkOption {
       default = "";
       example = "0:0";

modules/system/boot/stage-2.nix

@@ -1,10 +1,22 @@
 {pkgs, config, ...}:
 
 let
+
+  options = {
+
+    boot.localCommands = pkgs.lib.mkOption {
+      default = "";
+      example = "text=anything; echo You can put $text here.";
+      description = "
+        Shell commands to be executed just before Upstart is started.
+      ";
+    };
+
+  };
+
   inherit (pkgs) substituteAll writeText coreutils utillinux udev upstart;
   kernel = config.boot.kernelPackages.kernel;
   activateConfiguration = config.system.activationScripts.script;
-  inherit (config.boot) isLiveCD;
 
   # Path for Upstart jobs.  Should be quite minimal.
   upstartPath = [
@@ -20,7 +32,7 @@ let
   bootStage2 = substituteAll {
     src = ./stage-2-init.sh;
     isExecutable = true;
-    inherit kernel upstart isLiveCD activateConfiguration upstartPath;
+    inherit kernel upstart activateConfiguration upstartPath;
     path = [
       coreutils
       utillinux
@@ -32,16 +44,7 @@ let
 in
 
 {
-  require = [
-    # config.boot.localCommands
-    # config.boot.kernelPackages
-
-    # config.system.activationScripts
-    # ../system/activate-configuration.nix
-
-    # config.system.build
-    # ../system/system-options.nix
-  ];
+  require = [options];
 
   system = {
     build = {

modules/system/upstart/upstart.nix

@@ -52,14 +52,6 @@ in
 
 ###### implementation
 let
-  # should be moved to the corresponding jobs.
-  nix = config.environment.nix;
-  nixEnvVars = config.nix.envVars;
-  kernelPackages = config.boot.kernelPackages;
-  nssModulesPath = config.system.nssModules.path;
-  modprobe = config.system.sbin.modprobe;
-  mount = config.system.sbin.mount;
-
   makeJob = import ./make-job.nix {
     inherit (pkgs) runCommand;
   };

system/options.nix

@@ -6,58 +6,8 @@ in
 
 {
 
-  time = {
-
-    timeZone = mkOption {
-      default = "CET";
-      example = "America/New_York";
-      description = "The time zone used when displaying times and dates.";
-    };
-
-  };
-
-  
   boot = {
 
-    isLiveCD = mkOption {
-      default = false;
-      description = "
-        If set to true, the root device will be mounted read-only and
-        a ramdisk will be mounted on top of it using unionfs to
-        provide a writable root.  This is used for the NixOS
-        Live-CD/DVD.
-      ";
-    };
-
-    hardwareScan = mkOption {
-      default = true;
-      description = "
-        Whether to try to load kernel modules for all detected hardware.
-        Usually this does a good job of providing you with the modules
-        you need, but sometimes it can crash the system or cause other
-        nasty effects.  If the hardware scan is turned on, it can be
-        disabled at boot time by adding the <literal>safemode</literal>
-        parameter to the kernel command line.
-      ";
-    };
-
-    copyKernels = mkOption {
-      default = false;
-      description = "
-        Whether the Grub menu builder should copy kernels and initial
-        ramdisks to /boot.  This is necessary when /nix is on a
-        different file system than /boot.
-      ";
-    };
-
-    localCommands = mkOption {
-      default = "";
-      example = "text=anything; echo You can put $text here.";
-      description = "
-        Shell commands to be executed just before Upstart is started.
-      ";
-    };
-
     extraTTYs = mkOption {
       default = [];
       example = [8 9];
@@ -73,53 +23,6 @@ in
 
   };
 
-  system = {
-    # NSS modules.  Hacky!
-    nssModules = mkOption {
-      internal = true;
-      default = [];
-      description = "
-        Search path for NSS (Name Service Switch) modules.  This allows
-        several DNS resolution methods to be specified via
-        <filename>/etc/nsswitch.conf</filename>.
-      ";
-      merge = pkgs.lib.mergeListOption;
-      apply = list:
-        let
-          list2 =
-             list
-          ++ pkgs.lib.optional config.users.ldap.enable pkgs.nss_ldap;
-        in {
-          list = list2;
-          path = pkgs.lib.makeLibraryPath list2;
-        };
-    };
-
-    sbin = {
-      # !!! The mount option should not stay in /system/option.nix
-      mount = mkOption {
-        internal = true;
-        default = pkgs.utillinuxng.override {
-          buildMountOnly = true;
-          mountHelpers = pkgs.buildEnv {
-            name = "mount-helpers";
-            paths = [
-              pkgs.ntfs3g
-              pkgs.mount_cifs
-              pkgs.nfsUtils
-            ];
-            pathsToLink = "/sbin";
-          } + "/sbin";
-        };
-        description = "
-          A patched `mount' command that looks in a directory in the Nix
-          store instead of in /sbin for mount helpers (like mount.ntfs-3g or
-          mount.cifs).
-        ";
-      };
-    };
-  };
-
 
   networking = {
 
@@ -239,61 +142,6 @@ in
   };
 
 
-  fileSystems = mkOption {
-    default = null;
-    example = [
-      { mountPoint = "/";
-        device = "/dev/hda1";
-      }
-      { mountPoint = "/data";
-        device = "/dev/hda2";
-        fsType = "ext3";
-        options = "data=journal";
-      }
-      { mountPoint = "/bigdisk";
-        label = "bigdisk";
-      }
-    ];
-    description = "
-      The file systems to be mounted.  It must include an entry for
-      the root directory (<literal>mountPoint = \"/\"</literal>).  Each
-      entry in the list is an attribute set with the following fields:
-      <literal>mountPoint</literal>, <literal>device</literal>,
-      <literal>fsType</literal> (a file system type recognised by
-      <command>mount</command>; defaults to
-      <literal>\"auto\"</literal>), and <literal>options</literal>
-      (the mount options passed to <command>mount</command> using the
-      <option>-o</option> flag; defaults to <literal>\"defaults\"</literal>).
-
-      Instead of specifying <literal>device</literal>, you can also
-      specify a volume label (<literal>label</literal>) for file
-      systems that support it, such as ext2/ext3 (see <command>mke2fs
-      -L</command>).
-
-      <literal>autocreate</literal> forces <literal>mountPoint</literal> to be created with 
-      <command>mkdir -p</command> .
-    ";
-  };
-
-
-  swapDevices = mkOption {
-    default = [];
-    example = [
-      { device = "/dev/hda7"; }
-      { device = "/var/swapfile"; }
-      { label = "bigswap"; }
-    ];
-    description = "
-      The swap devices and swap files.  These must have been
-      initialised using <command>mkswap</command>.  Each element
-      should be an attribute set specifying either the path of the
-      swap device or file (<literal>device</literal>) or the label
-      of the swap device (<literal>label</literal>, see
-      <command>mkswap -L</command>).  Using a label is
-      recommended.
-    ";
-  };
-
   nesting = {
     children = mkOption {
       default = [];
@@ -304,14 +152,5 @@ in
   };
 
   
-  passthru = mkOption {
-    default = {};
-    description = "
-      Additional parameters. Ignored. When you want to be sure that 
-      /etc/nixos/nixos -A config.passthru.* is that same thing the 
-      system rebuild will use.
-    ";
-  };
-
   require = import ../modules/module-list.nix;
 }

upstart-jobs/filesystems.nix

@@ -1,11 +1,75 @@
 {pkgs, config, ...}:
 
+let
+
+###### interface
+
+  options = {
+
+    fileSystems = pkgs.lib.mkOption {
+      default = null;
+      example = [
+        { mountPoint = "/";
+          device = "/dev/hda1";
+        }
+        { mountPoint = "/data";
+          device = "/dev/hda2";
+          fsType = "ext3";
+          options = "data=journal";
+        }
+        { mountPoint = "/bigdisk";
+          label = "bigdisk";
+        }
+      ];
+      description = "
+        The file systems to be mounted.  It must include an entry for
+        the root directory (<literal>mountPoint = \"/\"</literal>).  Each
+        entry in the list is an attribute set with the following fields:
+        <literal>mountPoint</literal>, <literal>device</literal>,
+        <literal>fsType</literal> (a file system type recognised by
+        <command>mount</command>; defaults to
+        <literal>\"auto\"</literal>), and <literal>options</literal>
+        (the mount options passed to <command>mount</command> using the
+        <option>-o</option> flag; defaults to <literal>\"defaults\"</literal>).
+
+        Instead of specifying <literal>device</literal>, you can also
+        specify a volume label (<literal>label</literal>) for file
+        systems that support it, such as ext2/ext3 (see <command>mke2fs
+        -L</command>).
+
+        <literal>autocreate</literal> forces <literal>mountPoint</literal> to be created with 
+        <command>mkdir -p</command> .
+      ";
+    };
+  
+    system.sbin.mount = pkgs.lib.mkOption {
+      internal = true;
+      default = pkgs.utillinuxng.override {
+        buildMountOnly = true;
+        mountHelpers = pkgs.buildEnv {
+          name = "mount-helpers";
+          paths = [
+            pkgs.ntfs3g
+            pkgs.mount_cifs
+            pkgs.nfsUtils
+          ];
+          pathsToLink = "/sbin";
+        } + "/sbin";
+      };
+      description = "
+        A patched `mount' command that looks in a directory in the Nix
+        store instead of in /sbin for mount helpers (like mount.ntfs-3g or
+        mount.cifs).
+      ";
+    };
+    
+  };
+
 ###### implementation
 
-let
   inherit (pkgs) e2fsprogs;
-  mountPoints = map (fs: fs.mountPoint) fileSystems;
   fileSystems = config.fileSystems;
+  mountPoints = map (fs: fs.mountPoint) fileSystems;
   devices = map (fs: if fs ? device then fs.device else "LABEL=" + fs.label) fileSystems;
   fsTypes = map (fs: if fs ? fsType then fs.fsType else "auto") fileSystems;
   optionss = map (fs: if fs ? options then fs.options else "defaults") fileSystems;
@@ -13,110 +77,111 @@ let
   mount = config.system.sbin.mount;
 
   job = ''
-  start on startup
-  start on new-devices
-  start on ip-up
-  
-  script
-    PATH=${e2fsprogs}/sbin:$PATH
-  
-    mountPoints=(${toString mountPoints})  
-    devices=(${toString devices})
-    fsTypes=(${toString fsTypes})
-    optionss=(${toString optionss})
-    autocreates=(${toString autocreates})
-  
-    newDevices=1
-  
-    # If we mount any file system, we repeat this loop, because new
-    # mount opportunities may have become available (such as images
-    # for loopback mounts).
-  
-    while test -n "$newDevices"; do
-  
-      newDevices=
-  
-      for ((n = 0; n < ''${#mountPoints[*]}; n++)); do
-        mountPoint=''${mountPoints[$n]}
-        device=''${devices[$n]}
-        fsType=''${fsTypes[$n]}
-        options=''${optionss[$n]}
-        autocreate=''${autocreates[$n]}
-  
-        isLabel=
-        if echo "$device" | grep -q '^LABEL='; then isLabel=1; fi
-  
-        isPseudo=
-        if test "$fsType" = "nfs" || test "$fsType" = "tmpfs" ||
-          test "$fsType" = "ext3cow"; then isPseudo=1; fi
-  
-        if ! test -n "$isLabel" -o -n "$isPseudo" -o -e "$device"; then
-            echo "skipping $device, doesn't exist (yet)"
-            continue
-        fi
-  
-        # !!! quick hack: if mount point already exists, try a
-        # remount to change the options but nothing else.
-        if cat /proc/mounts | grep -F -q " $mountPoint "; then
-            echo "remounting $device on $mountPoint"
-            ${mount}/bin/mount -t "$fsType" \
-                -o remount,"$options" \
-                "$device" "$mountPoint" || true
-            continue
-        fi
-  
-        # If $device is already mounted somewhere else, unmount it first.
-        # !!! Note: we use /etc/mtab, not /proc/mounts, because mtab
-        # contains more accurate info when using loop devices.
-  
-        # !!! not very smart about labels yet; should resolve the label somehow.
-        if test -z "$isLabel" -a -z "$isPseudo"; then
-  
-          device=$(readlink -f "$device")
-  
-          prevMountPoint=$(
-              cat /etc/mtab \
-              | grep "^$device " \
-              | sed 's|^[^ ]\+ \+\([^ ]\+\).*|\1|' \
-          )
-  
-          if test "$prevMountPoint" = "$mountPoint"; then
+    start on startup
+    start on new-devices
+    start on ip-up
+
+    script
+      PATH=${e2fsprogs}/sbin:$PATH
+
+      mountPoints=(${toString mountPoints})  
+      devices=(${toString devices})
+      fsTypes=(${toString fsTypes})
+      optionss=(${toString optionss})
+      autocreates=(${toString autocreates})
+
+      newDevices=1
+
+      # If we mount any file system, we repeat this loop, because new
+      # mount opportunities may have become available (such as images
+      # for loopback mounts).
+
+      while test -n "$newDevices"; do
+
+        newDevices=
+
+        for ((n = 0; n < ''${#mountPoints[*]}; n++)); do
+          mountPoint=''${mountPoints[$n]}
+          device=''${devices[$n]}
+          fsType=''${fsTypes[$n]}
+          options=''${optionss[$n]}
+          autocreate=''${autocreates[$n]}
+
+          isLabel=
+          if echo "$device" | grep -q '^LABEL='; then isLabel=1; fi
+
+          isPseudo=
+          if test "$fsType" = "nfs" || test "$fsType" = "tmpfs" ||
+            test "$fsType" = "ext3cow"; then isPseudo=1; fi
+
+          if ! test -n "$isLabel" -o -n "$isPseudo" -o -e "$device"; then
+              echo "skipping $device, doesn't exist (yet)"
+              continue
+          fi
+
+          # !!! quick hack: if mount point already exists, try a
+          # remount to change the options but nothing else.
+          if cat /proc/mounts | grep -F -q " $mountPoint "; then
               echo "remounting $device on $mountPoint"
               ${mount}/bin/mount -t "$fsType" \
                   -o remount,"$options" \
                   "$device" "$mountPoint" || true
               continue
           fi
-  
-          if test -n "$prevMountPoint"; then
-              echo "unmount $device from $prevMountPoint"
-              ${mount}/bin/umount "$prevMountPoint" || true
+
+          # If $device is already mounted somewhere else, unmount it first.
+          # !!! Note: we use /etc/mtab, not /proc/mounts, because mtab
+          # contains more accurate info when using loop devices.
+
+          # !!! not very smart about labels yet; should resolve the label somehow.
+          if test -z "$isLabel" -a -z "$isPseudo"; then
+
+            device=$(readlink -f "$device")
+
+            prevMountPoint=$(
+                cat /etc/mtab \
+                | grep "^$device " \
+                | sed 's|^[^ ]\+ \+\([^ ]\+\).*|\1|' \
+            )
+
+            if test "$prevMountPoint" = "$mountPoint"; then
+                echo "remounting $device on $mountPoint"
+                ${mount}/bin/mount -t "$fsType" \
+                    -o remount,"$options" \
+                    "$device" "$mountPoint" || true
+                continue
+            fi
+
+            if test -n "$prevMountPoint"; then
+                echo "unmount $device from $prevMountPoint"
+                ${mount}/bin/umount "$prevMountPoint" || true
+            fi
+
           fi
-  
-        fi
-  
-        echo "mounting $device on $mountPoint"
-  
-        # !!! should do something with the result; also prevent repeated fscks.
-        if test -z "$isPseudo"; then
-            fsck -a "$device" || true
-        fi
-  
-        if test "$autocreate" = 1; then mkdir -p "$mountPoint"; fi
-  
-        if ${mount}/bin/mount -t "$fsType" -o "$options" "$device" "$mountPoint"; then
-            newDevices=1
-        fi
-  
+
+          echo "mounting $device on $mountPoint"
+
+          # !!! should do something with the result; also prevent repeated fscks.
+          if test -z "$isPseudo"; then
+              fsck -a "$device" || true
+          fi
+
+          if test "$autocreate" = 1; then mkdir -p "$mountPoint"; fi
+
+          if ${mount}/bin/mount -t "$fsType" -o "$options" "$device" "$mountPoint"; then
+              newDevices=1
+          fi
+
+        done
+
       done
-  
-    done
-  
-  end script
+
+    end script
   '';
 in
 
 {
+  require = [options];
   services = {
     extraJobs = [{
       name = "filesystems";

upstart-jobs/swap.nix

@@ -1,9 +1,34 @@
 {pkgs, config, ...}:
 
-###### implementation
-
 let
 
+###### interface
+
+  options = {
+
+    swapDevices = pkgs.lib.mkOption {
+      default = [];
+      example = [
+        { device = "/dev/hda7"; }
+        { device = "/var/swapfile"; }
+        { label = "bigswap"; }
+      ];
+      description = "
+        The swap devices and swap files.  These must have been
+        initialised using <command>mkswap</command>.  Each element
+        should be an attribute set specifying either the path of the
+        swap device or file (<literal>device</literal>) or the label
+        of the swap device (<literal>label</literal>, see
+        <command>mkswap -L</command>).  Using a label is
+        recommended.
+      ";
+    };
+
+  };
+
+
+###### implementation
+
   inherit (pkgs) utillinux lib;
 
   swapDevices = config.swapDevices;
@@ -18,37 +43,37 @@ in
 
 
 {
-  services = {
-    extraJobs = [{
-      name = "swap";
-      
-      job = "
-        start on startup
-        start on new-devices
-        
-        script
-            for device in ${toString devicesByPath}; do
-                ${utillinux}/sbin/swapon \"$device\" || true
-            done
-            
-            for label in ${toString devicesByLabel}; do
-                ${utillinux}/sbin/swapon -L \"$label\" || true
-            done
-            
-            # Remove swap devices not listed in swapDevices.
-            # !!! disabled because it doesn't work with labels
-            #for used in $(cat /proc/swaps | grep '^/' | sed 's/ .*//'); do
-            #    found=
-            #    for device in $ {toString swapDevices}; do
-            #        if test \"$used\" = \"$device\"; then found=1; fi
-            #    done
-            #    if test -z \"$found\"; then
-            #        ${utillinux}/sbin/swapoff \"$used\" || true
-            #    fi
-            #done
-            
-        end script
-      ";
-    }];
-  };
+  require = [options];
+
+  services.extraJobs = [{
+    name = "swap";
+
+    job = ''
+      start on startup
+      start on new-devices
+
+      script
+          for device in ${toString devicesByPath}; do
+              ${utillinux}/sbin/swapon "$device" || true
+          done
+
+          for label in ${toString devicesByLabel}; do
+              ${utillinux}/sbin/swapon -L "$label" || true
+          done
+
+          # Remove swap devices not listed in swapDevices.
+          # !!! disabled because it doesn't work with labels
+          #for used in $(cat /proc/swaps | grep '^/' | sed 's/ .*//'); do
+          #    found=
+          #    for device in $ {toString swapDevices}; do
+          #        if test "$used" = "$device"; then found=1; fi
+          #    done
+          #    if test -z "$found"; then
+          #        ${utillinux}/sbin/swapoff "$used" || true
+          #    fi
+          #done
+
+      end script
+    '';
+  }];
 }