First attempt at using systemd

Basic booting works.  Systemd starts agetty instances on tty1 and
tty2.  Shutdown and journald also work.

modules/config/system-path.nix

@@ -17,7 +17,6 @@ let
 
   requiredPackages =
     [ config.system.sbin.modprobe # must take precedence over module_init_tools
-      config.system.build.upstart
       config.environment.nix
       pkgs.acl
       pkgs.attr

modules/module-list.nix

@@ -198,6 +198,7 @@
   ./system/boot/stage-1.nix
   ./system/boot/stage-1-extratools.nix
   ./system/boot/stage-2.nix
+  ./system/boot/systemd.nix
   ./system/etc/etc.nix
   ./system/upstart-events/control-alt-delete.nix
   ./system/upstart-events/runlevel.nix

modules/system/activation/top-level.nix

@@ -117,12 +117,12 @@ let
 
       ln -s ${config.system.build.etc}/etc $out/etc
       ln -s ${config.system.path} $out/sw
-      ln -s ${config.system.build.upstart} $out/upstart
+      ln -s ${pkgs.systemd} $out/systemd
       ln -s ${config.hardware.firmware} $out/firmware
 
       echo -n "$kernelParams" > $out/kernel-params
       echo -n "$configurationName" > $out/configuration-name
-      echo -n "${toString config.system.build.upstart.interfaceVersion}" > $out/upstart-interface-version
+      #echo -n "${toString config.system.build.upstart.interfaceVersion}" > $out/upstart-interface-version
       echo -n "$nixosVersion" > $out/nixos-version
 
       mkdir $out/fine-tune
@@ -173,7 +173,7 @@ let
         pkgs.gnugrep
         pkgs.findutils
         pkgs.diffutils
-        config.system.build.upstart # for initctl
+        pkgs.systemd
       ];
 
     # Boot loaders

modules/system/boot/stage-2-init.sh

@@ -56,7 +56,7 @@ fi
 mkdir -m 0755 -p /etc
 test -e /etc/fstab || touch /etc/fstab # to shut up mount
 rm -f /etc/mtab* # not that we care about stale locks
-cat /proc/mounts > /etc/mtab
+ln -s /proc/mounts /etc/mtab
 
 
 # Process the kernel command line.
@@ -184,6 +184,12 @@ if [ -n "$debug2" ]; then
 fi
 
 
-# Start Upstart's init.
-echo "starting Upstart..."
-PATH=/var/run/current-system/upstart/sbin exec init --no-sessions ${debug2:+--verbose}
+# FIXME: auto-loading of kernel modules in systemd doesn't work yet
+# because it uses libkmod.
+"$(cat /proc/sys/kernel/modprobe)" autofs4
+"$(cat /proc/sys/kernel/modprobe)" ipv6
+
+
+# Start systemd.
+echo "starting systemd..."
+PATH=/var/run/current-system/systemd/lib/systemd exec systemd --log-level debug --log-target=console --crash-shell

modules/system/boot/systemd.nix

@@ -0,0 +1,158 @@
+{ config, pkgs, ... }:
+
+with pkgs.lib;
+
+let
+
+  systemd = pkgs.systemd;
+
+  makeUnit = name: text:
+    pkgs.writeTextFile { name = "unit"; inherit text; destination = "/${name}"; };
+
+  defaultTarget = makeUnit "default.target"
+    ''
+      [Unit]
+      Description=Default System
+      Requires=getty.target
+      After=getty.target
+      Conflicts=rescue.target
+      AllowIsolate=yes
+    '';
+
+  gettyTarget = makeUnit "getty.target"
+    ''
+      [Unit]
+      Description=Login Prompts
+      Requires=getty@tty1.service getty@tty2.service
+      After=getty@tty1.service getty@tty2.service
+    '';
+
+  gettyService = makeUnit "getty@.service"
+    ''
+      [Unit]
+      Description=Getty on %I
+      #BindTo=dev-%i.device
+      #After=dev-%i.device systemd-user-sessions.service plymouth-quit-wait.service
+      Before=getty.target
+
+      [Service]
+      Environment=TERM=linux
+      ExecStart=-${pkgs.utillinux}/sbin/agetty --noclear --login-program ${pkgs.shadow}/bin/login %I 38400
+      Restart=always
+      RestartSec=0
+      UtmpIdentifier=%I
+      TTYPath=/dev/%I
+      TTYReset=yes
+      TTYVHangup=yes
+      TTYVTDisallocate=yes
+      KillMode=process
+      IgnoreSIGPIPE=no
+
+      # Unset locale for the console getty since the console has problems
+      # displaying some internationalized messages.
+      Environment=LANG= LANGUAGE= LC_CTYPE= LC_NUMERIC= LC_TIME= LC_COLLATE= LC_MONETARY= LC_MESSAGES= LC_PAPER= LC_NAME= LC_ADDRESS= LC_TELEPHONE= LC_MEASUREMENT= LC_IDENTIFICATION=
+
+      # Some login implementations ignore SIGTERM, so we send SIGHUP
+      # instead, to ensure that login terminates cleanly.
+      KillSignal=SIGHUP
+    '';
+
+  rescueTarget = makeUnit "rescue.target"
+    ''
+      [Unit]
+      Description=Rescue Mode
+      Requires=rescue.service
+      After=rescue.service
+      AllowIsolate=yes
+    '';
+
+  rescueService = makeUnit "rescue.service"
+    ''
+      [Unit]
+      Description=Rescue Shell
+      DefaultDependencies=no
+      #After=basic.target
+      #Before=shutdown.target
+
+      [Service]
+      Environment=HOME=/root
+      WorkingDirectory=/root
+      ExecStartPre=-${pkgs.coreutils}/bin/echo 'Welcome to rescue mode. Use "systemctl default" or ^D to enter default mode.'
+      #ExecStart=-/sbin/sulogin
+      ExecStart=-${pkgs.bashInteractive}/bin/bash --login
+      ExecStopPost=-${systemd}/bin/systemctl --fail --no-block default
+      StandardInput=tty-force
+      StandardOutput=inherit
+      StandardError=inherit
+      KillMode=process
+
+      # Bash ignores SIGTERM, so we send SIGHUP instead, to ensure that bash
+      # terminates cleanly.
+      KillSignal=SIGHUP
+    '';
+
+  upstreamUnits =
+    [ "systemd-journald.socket"
+      "systemd-journald.service"
+      "basic.target"
+      "sysinit.target"
+      "sysinit.target.wants"
+      "sockets.target"
+      "sockets.target.wants"
+
+      # Filesystems.
+      "local-fs.target"
+      "local-fs.target.wants"
+      "local-fs-pre.target"
+      "remote-fs.target"
+      "remote-fs-pre.target"
+      "swap.target"
+      "media.mount"
+      "dev-mqueue.mount"
+
+      # Reboot stuff.
+      "reboot.target"
+      "reboot.service"
+      "poweroff.target"
+      "poweroff.service"
+      "halt.target"
+      "halt.service"
+      "ctrl-alt-del.target"
+      "shutdown.target"
+      "umount.target"
+      "final.target"
+    ];
+
+  systemUnits = pkgs.runCommand "system-units" { }
+    ''
+      mkdir -p $out/system
+      for i in ${toString upstreamUnits}; do
+        fn=${systemd}/example/systemd/system/$i
+        echo $fn
+        [ -e $fn ]
+        ln -s $fn $out/system
+      done
+      for i in ${toString [ defaultTarget gettyTarget gettyService rescueTarget rescueService ]}; do
+        cp $i/* $out/system
+      done
+    ''; # */
+    
+in
+
+{
+
+  ###### implementation
+
+  config = {
+
+    environment.systemPackages = [ systemd ];
+  
+    environment.etc =
+      [ { source = systemUnits;
+          target = "systemd";
+        }
+      ];
+    
+  };
+
+}