Add a ‘wantedBy’ attribute to unit definitions

This attribute allows a unit to make itself a dependency of another unit.

Also, add an option to set the default target unit.

modules/services/networking/ssh/sshd.nix

@@ -317,13 +317,15 @@ in
       }
     ];
 
-    boot.systemd.units."sshd.service" =
+    boot.systemd.units."sshd.service".text =
       ''
         [Unit]
         Description=SSH daemon
 
         [Service]
         Environment=PATH=${pkgs.coreutils}/bin:${pkgs.openssh}/bin
+        Environment=LD_LIBRARY_PATH=${nssModulesPath}
+        Environment=LOCALE_ARCHIVE=/var/run/current-system/sw/lib/locale/locale-archive
         ExecStartPre=${preStart}
         ExecStart=\
           ${pkgs.openssh}/sbin/sshd -h ${cfg.hostKeyPath} \
@@ -334,39 +336,8 @@ in
         PIDFile=/run/sshd.pid
       '';
 
-    jobs.sshd =
-      { description = "OpenSSH server";
-
-        startOn = "started network-interfaces";
-
-        environment = {
-          LD_LIBRARY_PATH = nssModulesPath;
-          # Duplicated from bashrc. OpenSSH needs a patch for this.
-          LOCALE_ARCHIVE = "/var/run/current-system/sw/lib/locale/locale-archive";
-        };
-
-        path = [ pkgs.openssh pkgs.gnused ];
-
-        preStart =
-          ''
-            ${mkAuthkeyScript}
-
-            mkdir -m 0755 -p /etc/ssh
-
-            if ! test -f ${cfg.hostKeyPath}; then
-                ssh-keygen -t ${hktn} -b ${toString hktb} -f ${cfg.hostKeyPath} -N ""
-            fi
-          '';
-
-        daemonType = "fork";
-
-        exec =
-          ''
-            ${pkgs.openssh}/sbin/sshd -h ${cfg.hostKeyPath} \
-              -f ${pkgs.writeText "sshd_config" cfg.extraConfig}
-          '';
-      };
-
+    boot.systemd.units."sshd.service".wantedBy = [ "multi-user.target" ];
+    
     networking.firewall.allowedTCPPorts = cfg.ports;
 
     services.openssh.extraConfig =

modules/services/system/dbus.nix

@@ -118,7 +118,7 @@ in
 
     # FIXME: these are copied verbatim from the dbus source tree.  We
     # should install and use the originals.
-    boot.systemd.units."dbus.socket" =
+    boot.systemd.units."dbus.socket".text =
       ''
         [Unit]
         Description=D-Bus System Message Bus Socket
@@ -127,7 +127,7 @@ in
         ListenStream=/var/run/dbus/system_bus_socket
       '';
       
-    boot.systemd.units."dbus.service" =
+    boot.systemd.units."dbus.service".text =
       ''
         [Unit]
         Description=D-Bus System Message Bus
@@ -142,6 +142,7 @@ in
         OOMScoreAdjust=-900
       '';
 
+    /*
     jobs.dbus =
       { startOn = "started udev and started syslogd";
       
@@ -164,15 +165,6 @@ in
 
         exec = "dbus-daemon --system";
 
-        /*
-        postStart =
-          ''
-            # Signal Upstart to connect to the system bus.  This
-            # allows ‘initctl’ to work for non-root users.
-            kill -USR1 1
-          '';
-        */
-
         postStop =
           ''
             # !!! Hack: doesn't belong here.
@@ -183,6 +175,7 @@ in
             fi
           '';
       };
+    */    
 
     security.setuidOwners = singleton
       { program = "dbus-daemon-launch-helper";

modules/system/boot/systemd.nix

@@ -4,10 +4,12 @@ with pkgs.lib;
 
 let
 
+  cfg = config.boot.systemd;
+
   systemd = pkgs.systemd;
 
-  makeUnit = name: text:
-    pkgs.writeTextFile { name = "unit"; inherit text; destination = "/${name}"; };
+  makeUnit = name: unit:
+    pkgs.writeTextFile { name = "unit"; inherit (unit) text; destination = "/${name}"; };
 
   upstreamUnits =
     [ # Targets.
@@ -109,7 +111,7 @@ let
       "shutdown.target.wants"
     ];
 
-  nixosUnits = mapAttrsToList makeUnit config.boot.systemd.units;
+  nixosUnits = mapAttrsToList makeUnit cfg.units;
     
   units = pkgs.runCommand "units" { preferLocalBuild = true; }
     ''
@@ -123,6 +125,7 @@ let
           ln -s $fn $out/system
         fi
       done
+      
       for i in ${toString upstreamWants}; do
         fn=${systemd}/example/systemd/system/$i
         [ -e $fn ]
@@ -134,9 +137,18 @@ let
           if ! [ -e $y ]; then rm -v $y; fi
         done
       done
+      
       for i in ${toString nixosUnits}; do
         cp $i/* $out/system
       done
+
+      ${concatStrings (mapAttrsToList (name: unit:
+          concatMapStrings (name2: ''
+            mkdir -p $out/system/${name2}.wants
+            ln -sfn ../${name} $out/system/${name2}.wants/
+          '') unit.wantedBy) cfg.units)}
+
+      ln -s ${cfg.defaultUnit} $out/system/default.target
     ''; # */
     
 in
@@ -148,10 +160,28 @@ in
   options = {
 
     boot.systemd.units = mkOption {
-      default = {} ;
-      description = "Systemd units.";
+      default = {};
+      type = types.attrsOf types.optionSet;
+      options = {
+        text = mkOption {
+          types = types.uniq types.string;
+          description = "Text of this systemd unit.";
+        };
+        wantedBy = mkOption {
+          default = [];
+          types = types.listOf types.string;
+          description = "Units that want (i.e. depend on) this unit.";
+        };
+      };
+      description = "Definition of systemd units.";
     };
 
+    boot.systemd.defaultUnit = mkOption {
+      default = "multi-user.target";
+      type = types.uniq types.string;
+      description = "Default unit started when the system boots.";
+    };
+    
   };
 
   
@@ -171,18 +201,7 @@ in
         }
       ];
 
-    boot.systemd.units."default.target" =
-      ''
-        [Unit]
-        Description=Default System
-        Requires=multi-user.target
-        After=multi-user.target
-        Conflicts=rescue.target
-        AllowIsolate=yes
-        Wants=sshd.service
-      '';
-    
-    boot.systemd.units."getty@.service" =
+    boot.systemd.units."getty@.service".text =
       ''
         [Unit]
         Description=Getty on %I
@@ -218,7 +237,7 @@ in
         KillSignal=SIGHUP
       '';
 
-    boot.systemd.units."rescue.service" =
+    boot.systemd.units."rescue.service".text =
       ''
         [Unit]
         Description=Rescue Shell

modules/system/upstart/upstart.nix

@@ -51,6 +51,7 @@ let
           #! ${pkgs.stdenv.shell} -e
           ${job.postStop}
         '';
+    in {
 
       text =
         ''
@@ -93,6 +94,13 @@ let
           ${optionalString (!job.task && job.respawn) "Restart=always"}
         '';
 
+      wantedBy =
+        if job.startOn == "" then [ ]
+        else if job.startOn == "startup" then [ "basic.target" ]
+        else [ "multi-user.target" ];
+
+    };
+
       /*
       text =
         ''
@@ -189,8 +197,6 @@ let
         '';
       */
 
-    in text;
-
 
   # Shell functions for use in Upstart jobs.
   jobHelpers = pkgs.writeText "job-helpers.sh"
@@ -440,10 +446,9 @@ let
 
     options = {
     
-      unitText = mkOption {
+      unit = mkOption {
         default = makeUnit config;
-        type = types.uniq types.string;
-        description = "Generated text of the systemd unit corresponding to this job.";
+        description = "Generated definition of the systemd unit corresponding to this job.";
       };
       
     };
@@ -504,7 +509,7 @@ in
 
     boot.systemd.units =
       flip mapAttrs' config.jobs (name: job:
-        nameValuePair "${job.name}.service" job.unitText);
+        nameValuePair "${job.name}.service" job.unit);
         
   };
 

modules/tasks/lvm.nix

@@ -14,8 +14,6 @@
             # Make all logical volumes on all volume groups available, i.e.,
             # make them appear in /dev.
             ${pkgs.lvm2}/sbin/vgchange --available y
-
-            initctl emit -n new-devices
           '';
 
         task = true;