nixpkgs/instances/rescue-cd.nix

let

  # The label used to identify the installation CD.
  cdromLabel = "NIXOS";

in

  # Build boot scripts for the CD that find the CD-ROM automatically.
  with import ../configuration/boot-environment.nix {
    autoDetectRootDevice = true;
    rootLabel = cdromLabel;
    stage2Init = "/init";
    readOnlyRoot = true;
  };

  
rec {

  inherit nixosInstaller bootStage1 upstartJobs; # !!! debug


  # Since the CD is read-only, the mount points must be on disk.
  cdMountPoints = pkgs.runCommand "mount-points" {} "
    ensureDir $out
    cd $out
    mkdir proc sys tmp etc dev var mnt nix nix/var
    touch $out/${cdromLabel}
  ";


  # We need a copy of the Nix expressions for Nixpkgs and NixOS on the
  # CD.  We put them in a tarball because accessing that many small
  # files from a slow device like a CD-ROM takes too long.
  makeTarball = tarName: input: pkgs.runCommand "tarball" "
    ensureDir $out
    (cd ${input} && tar cvfj $out/${tarName} . \\
      --exclude '*~' --exclude '.svn' \\
      --exclude 'pkgs' --exclude 'result')
  ";

  
  # Put the current directory in the tarball.  !!! This gives us a lot
  # of crap (like .svn if this is a working copy).  An "svn export"
  # would be better, but that's impure.
  nixosTarball = makeTarball "nixos.tar.bz2" ./.;

  
  nixpkgsTarball = pkgs.fetchurl {
    url = http://nix.cs.uu.nl/dist/nix/nixpkgs-0.11pre7087/nixpkgs-0.11pre7087.tar.bz2;
    md5 = "c5840fcd049d75e00ad856ecbbef6857";
  };


  # Create an ISO image containing the isolinux boot loader, the
  # kernel, the initrd produced above, and the closure of the stage 2
  # init.
  rescueCD = import ../helpers/make-iso9660-image.nix {
    inherit (pkgs) stdenv cdrtools;
    isoName = "nixos.iso";
    
    contents = [
      { source = pkgs.syslinux + "/lib/syslinux/isolinux.bin";
        target = "isolinux/isolinux.bin";
      }
      { source = ../helpers/isolinux.cfg;
        target = "isolinux/isolinux.cfg";
      }
      { source = pkgs.kernel + "/vmlinuz";
        target = "isolinux/vmlinuz";
      }
      { source = initialRamdisk + "/initrd";
        target = "isolinux/initrd";
      }
      { source = cdMountPoints;
        target = "/";
      }
      { source = nixosTarball + "/" + nixosTarball.tarName;
        target = "/" + nixosTarball.tarName;
      }
      { source = nixpkgsTarball;
        target = "/nixpkgs.tar.bz2";
      }
    ];

    init = bootStage2;
    
    bootable = true;
    bootImage = "isolinux/isolinux.bin";
  };


}