path: root/nixos/modules/system/boot/loader/grub/grub.nix

{ config, lib, pkgs, ... }:

with lib;

let

  cfg = config.boot.loader.grub;

  efi = config.boot.loader.efi;

  grubPkgs = 
    # Package set of targeted architecture
    if cfg.forcei686 then pkgs.pkgsi686Linux else pkgs;

  realGrub = if cfg.version == 1 then grubPkgs.grub
    else if cfg.zfsSupport then grubPkgs.grub2.override { zfsSupport = true; }
    else if cfg.trustedBoot.enable
         then if cfg.trustedBoot.isHPLaptop
              then grubPkgs.trustedGrub-for-HP
              else grubPkgs.trustedGrub
         else grubPkgs.grub2;

  grub =
    # Don't include GRUB if we're only generating a GRUB menu (e.g.,
    # in EC2 instances).
    if cfg.devices == ["nodev"]
    then null
    else realGrub;

  grubEfi =
    # EFI version of Grub v2
    if cfg.efiSupport && (cfg.version == 2)
    then realGrub.override { efiSupport = cfg.efiSupport; }
    else null;

  f = x: if x == null then "" else "" + x;

  grubConfig = args:
    let
      efiSysMountPoint = if args.efiSysMountPoint == null then args.path else args.efiSysMountPoint;
      efiSysMountPoint' = replaceChars [ "/" ] [ "-" ] efiSysMountPoint;
    in
    pkgs.writeText "grub-config.xml" (builtins.toXML
    { splashImage = f cfg.splashImage;
      splashMode = f cfg.splashMode;
      backgroundColor = f cfg.backgroundColor;
      grub = f grub;
      grubTarget = f (grub.grubTarget or "");
      shell = "${pkgs.runtimeShell}";
      fullName = (builtins.parseDrvName realGrub.name).name;
      fullVersion = (builtins.parseDrvName realGrub.name).version;
      grubEfi = f grubEfi;
      grubTargetEfi = if cfg.efiSupport && (cfg.version == 2) then f (grubEfi.grubTarget or "") else "";
      bootPath = args.path;
      storePath = config.boot.loader.grub.storePath;
      bootloaderId = if args.efiBootloaderId == null then "NixOS${efiSysMountPoint'}" else args.efiBootloaderId;
      timeout = if config.boot.loader.timeout == null then -1 else config.boot.loader.timeout;
      inherit efiSysMountPoint;
      inherit (args) devices;
      inherit (efi) canTouchEfiVariables;
      inherit (cfg)
        version extraConfig extraPerEntryConfig extraEntries forceInstall useOSProber
        extraEntriesBeforeNixOS extraPrepareConfig extraInitrd configurationLimit copyKernels
        default fsIdentifier efiSupport efiInstallAsRemovable gfxmodeEfi gfxmodeBios gfxpayloadEfi gfxpayloadBios;
      path = with pkgs; makeBinPath (
        [ coreutils gnused gnugrep findutils diffutils btrfs-progs utillinux mdadm ]
        ++ optional (cfg.efiSupport && (cfg.version == 2)) efibootmgr
        ++ optionals cfg.useOSProber [ busybox os-prober ]);
      font = if cfg.font == null then ""
        else (if lib.last (lib.splitString "." cfg.font) == "pf2"
             then cfg.font
             else "${convertedFont}");
    });

  bootDeviceCounters = fold (device: attr: attr // { "${device}" = (attr."${device}" or 0) + 1; }) {}
    (concatMap (args: args.devices) cfg.mirroredBoots);

  convertedFont = (pkgs.runCommand "grub-font-converted.pf2" {}
           (builtins.concatStringsSep " "
             ([ "${realGrub}/bin/grub-mkfont"
               cfg.font
               "--output" "$out"
             ] ++ (optional (cfg.fontSize!=null) "--size ${toString cfg.fontSize}")))
         );

  defaultSplash = "${pkgs.nixos-artwork.wallpapers.simple-dark-gray-bootloader}/share/artwork/gnome/nix-wallpaper-simple-dark-gray_bootloader.png";
in

{

  ###### interface

  options = {

    boot.loader.grub = {

      enable = mkOption {
        default = !config.boot.isContainer;
        type = types.bool;
        description = ''
          Whether to enable the GNU GRUB boot loader.
        '';
      };

      version = mkOption {
        default = 2;
        example = 1;
        type = types.int;
        description = ''
          The version of GRUB to use: <literal>1</literal> for GRUB
          Legacy (versions 0.9x), or <literal>2</literal> (the
          default) for GRUB 2.
        '';
      };

      device = mkOption {
        default = "";
        example = "/dev/disk/by-id/wwn-0x500001234567890a";
        type = types.str;
        description = ''
          The device on which the GRUB boot loader will be installed.
          The special value <literal>nodev</literal> means that a GRUB
          boot menu will be generated, but GRUB itself will not
          actually be installed.  To install GRUB on multiple devices,
          use <literal>boot.loader.grub.devices</literal>.
        '';
      };

      devices = mkOption {
        default = [];
        example = [ "/dev/disk/by-id/wwn-0x500001234567890a" ];
        type = types.listOf types.str;
        description = ''
          The devices on which the boot loader, GRUB, will be
          installed. Can be used instead of <literal>device</literal> to
          install GRUB onto multiple devices.
        '';
      };

      mirroredBoots = mkOption {
        default = [ ];
        example = [
          { path = "/boot1"; devices = [ "/dev/disk/by-id/wwn-0x500001234567890a" ]; }
          { path = "/boot2"; devices = [ "/dev/disk/by-id/wwn-0x500009876543210a" ]; }
        ];
        description = ''
          Mirror the boot configuration to multiple partitions and install grub
          to the respective devices corresponding to those partitions.
        '';

        type = with types; listOf (submodule {
          options = {

            path = mkOption {
              example = "/boot1";
              type = types.str;
              description = ''
                The path to the boot directory where GRUB will be written. Generally
                this boot path should double as an EFI path.
              '';
            };

            efiSysMountPoint = mkOption {
              default = null;
              example = "/boot1/efi";
              type = types.nullOr types.str;
              description = ''
                The path to the efi system mount point. Usually this is the same
                partition as the above path and can be left as null.
              '';
            };

            efiBootloaderId = mkOption {
              default = null;
              example = "NixOS-fsid";
              type = types.nullOr types.str;
              description = ''
                The id of the bootloader to store in efi nvram.
                The default is to name it NixOS and append the path or efiSysMountPoint.
                This is only used if <literal>boot.loader.efi.canTouchEfiVariables</literal> is true.
              '';
            };

            devices = mkOption {
              default = [ ];
              example = [ "/dev/disk/by-id/wwn-0x500001234567890a" "/dev/disk/by-id/wwn-0x500009876543210a" ];
              type = types.listOf types.str;
              description = ''
                The path to the devices which will have the GRUB MBR written.
                Note these are typically device paths and not paths to partitions.
              '';
            };

          };
        });
      };

      configurationName = mkOption {
        default = "";
        example = "Stable 2.6.21";
        type = types.str;
        description = ''
          GRUB entry name instead of default.
        '';
      };

      storePath = mkOption {
        default = "/nix/store";
        type = types.str;
        description = ''
          Path to the Nix store when looking for kernels at boot.
          Only makes sense when copyKernels is false.
        '';
      };

      extraPrepareConfig = mkOption {
        default = "";
        type = types.lines;
        description = ''
          Additional bash commands to be run at the script that
          prepares the GRUB menu entries.
        '';
      };

      extraConfig = mkOption {
        default = "";
        example = "serial; terminal_output.serial";
        type = types.lines;
        description = ''
          Additional GRUB commands inserted in the configuration file
          just before the menu entries.
        '';
      };

      extraPerEntryConfig = mkOption {
        default = "";
        example = "root (hd0)";
        type = types.lines;
        description = ''
          Additional GRUB commands inserted in the configuration file
          at the start of each NixOS menu entry.
        '';
      };

      extraEntries = mkOption {
        default = "";
        type = types.lines;
        example = ''
          # GRUB 1 example (not GRUB 2 compatible)
          title Windows
            chainloader (hd0,1)+1

          # GRUB 2 example
          menuentry "Windows 7" {
            chainloader (hd0,4)+1
          }

          # GRUB 2 with UEFI example, chainloading another distro
          menuentry "Fedora" {
            set root=(hd1,1)
            chainloader /efi/fedora/grubx64.efi
          }
        '';
        description = ''
          Any additional entries you want added to the GRUB boot menu.