* Allow Upstart's init to be upgraded in a running system.

svn path=/nixos/trunk/; revision=9375

boot/boot-stage-2-init.sh

@@ -115,7 +115,10 @@ export MODULE_DIR=@kernel@/lib/modules/
 @shell@ @bootLocal@
 
 
-# Start Upstart's init.
+# Start Upstart's init.  We start it through the
+# /var/run/current-system symlink indirection so that we can upgrade
+# init in a running system by changing the symlink and sending init a
+# HUP signal.
 export UPSTART_CFG_DIR=/etc/event.d
 setPath "@upstartPath@"
-exec @upstart@/sbin/init -v
+exec /var/run/current-system/upstart/sbin/init -v

system/system.nix

@@ -313,7 +313,7 @@ rec {
     name = "system";
     builder = ./system.sh;
     switchToConfiguration = ./switch-to-configuration.sh;
-    inherit (pkgs) grub coreutils gnused gnugrep diffutils findutils;
+    inherit (pkgs) grub coreutils gnused gnugrep diffutils findutils upstart;
     grubDevice = config.get ["boot" "grubDevice"];
     kernelParams =
       (config.get ["boot" "kernelParams"]) ++

system/system.sh

@@ -9,6 +9,7 @@ ln -s $initrd $out/initrd
 ln -s $activateConfiguration $out/activate
 ln -s $etc/etc $out/etc
 ln -s $systemPath $out/sw
+ln -s $upstart $out/upstart
 
 echo "$kernelParams" > $out/kernel-params
 echo "$configurationName" > $out/configuration-name