nixpkgs/nixos/modules/installer/cd-dvd/iso-image.nix
Eelco Dolstra 5e364503d5 NixOS ISO: Don't use a unionfs for /
We don't need a unionfs on /, we only need a tmpfs.
2014-05-21 15:55:50 +02:00

322 lines
9.9 KiB
Nix

# This module creates a bootable ISO image containing the given NixOS
# configuration. The derivation for the ISO image will be placed in
# config.system.build.isoImage.
{ config, lib, pkgs, ... }:
with lib;
let
# The Grub image.
grubImage = pkgs.runCommand "grub_eltorito" {}
''
${pkgs.grub2}/bin/grub-mkimage -O i386-pc -o tmp biosdisk iso9660 help linux linux16 chain png jpeg echo gfxmenu reboot
cat ${pkgs.grub2}/lib/grub/*/cdboot.img tmp > $out
''; # */
# The configuration file for Grub.
grubCfg =
''
set default=${builtins.toString config.boot.loader.grub.default}
set timeout=${builtins.toString config.boot.loader.grub.timeout}
if loadfont /boot/grub/unicode.pf2; then
set gfxmode=640x480
insmod gfxterm
insmod vbe
terminal_output gfxterm
insmod png
if background_image /boot/grub/splash.png; then
set color_normal=white/black
set color_highlight=black/white
else
set menu_color_normal=cyan/blue
set menu_color_highlight=white/blue
fi
fi
${config.boot.loader.grub.extraEntries}
'';
# The efi boot image
efiDir = pkgs.runCommand "efi-directory" {} ''
mkdir -p $out/efi/boot
cp -v ${pkgs.gummiboot}/lib/gummiboot/gummiboot${targetArch}.efi $out/efi/boot/boot${targetArch}.efi
mkdir -p $out/loader/entries
echo "title NixOS LiveCD" > $out/loader/entries/nixos-livecd.conf
echo "linux /boot/bzImage" >> $out/loader/entries/nixos-livecd.conf
echo "initrd /boot/initrd" >> $out/loader/entries/nixos-livecd.conf
echo "options init=${config.system.build.toplevel}/init ${toString config.boot.kernelParams}" >> $out/loader/entries/nixos-livecd.conf
echo "default nixos-livecd" > $out/loader/loader.conf
echo "timeout 5" >> $out/loader/loader.conf
'';
efiImg = pkgs.runCommand "efi-image_eltorito" { buildInputs = [ pkgs.mtools ]; }
''
#Let's hope 10M is enough
dd bs=2048 count=5120 if=/dev/zero of="$out"
${pkgs.dosfstools}/sbin/mkfs.vfat "$out"
mcopy -svi "$out" ${efiDir}/* ::
mmd -i "$out" boot
mcopy -v -i "$out" \
${config.boot.kernelPackages.kernel}/bzImage ::boot/bzImage
mcopy -v -i "$out" \
${config.system.build.initialRamdisk}/initrd ::boot/initrd
''; # */
targetArch = if pkgs.stdenv.isi686 then
"ia32"
else if pkgs.stdenv.isx86_64 then
"x64"
else
throw "Unsupported architecture";
in
{
options = {
isoImage.isoName = mkOption {
default = "${config.isoImage.isoName}.iso";
description = ''
Name of the generated ISO image file.
'';
};
isoImage.isoBaseName = mkOption {
default = "nixos";
description = ''
Prefix of the name of the generated ISO image file.
'';
};
isoImage.compressImage = mkOption {
default = false;
description = ''
Whether the ISO image should be compressed using
<command>bzip2</command>.
'';
};
isoImage.volumeID = mkOption {
default = "NIXOS_BOOT_CD";
description = ''
Specifies the label or volume ID of the generated ISO image.
Note that the label is used by stage 1 of the boot process to
mount the CD, so it should be reasonably distinctive.
'';
};
isoImage.contents = mkOption {
example =
[ { source = pkgs.memtest86 + "/memtest.bin";
target = "boot/memtest.bin";
}
];
description = ''
This option lists files to be copied to fixed locations in the
generated ISO image.
'';
};
isoImage.storeContents = mkOption {
example = [pkgs.stdenv];
description = ''
This option lists additional derivations to be included in the
Nix store in the generated ISO image.
'';
};
isoImage.includeSystemBuildDependencies = mkOption {
default = false;
example = true;
description = ''
Set this option to include all the needed sources etc in the
image. It significantly increases image size. Use that when
you want to be able to keep all the sources needed to build your
system or when you are going to install the system on a computer
with slow on non-existent network connection.
'';
};
isoImage.makeEfiBootable = mkOption {
default = false;
description = ''
Whether the ISO image should be an efi-bootable volume.
'';
};
};
config = {
boot.loader.grub.version = 2;
# Don't build the GRUB menu builder script, since we don't need it
# here and it causes a cyclic dependency.
boot.loader.grub.enable = false;
# !!! Hack - attributes expected by other modules.
system.boot.loader.kernelFile = "bzImage";
environment.systemPackages = [ pkgs.grub2 ];
# In stage 1 of the boot, mount the CD as the root FS by label so
# that we don't need to know its device. We pass the label of the
# root filesystem on the kernel command line, rather than in
# `fileSystems' below. This allows CD-to-USB converters such as
# UNetbootin to rewrite the kernel command line to pass the label or
# UUID of the USB stick. It would be nicer to write
# `root=/dev/disk/by-label/...' here, but UNetbootin doesn't
# recognise that.
boot.kernelParams = [ "root=LABEL=${config.isoImage.volumeID}" ];
fileSystems."/" =
{ fsType = "tmpfs";
device = "none";
options = "mode=0755";
};
# Note that /dev/root is a symlink to the actual root device
# specified on the kernel command line, created in the stage 1
# init script.
fileSystems."/iso" =
{ device = "/dev/root";
neededForBoot = true;
noCheck = true;
};
fileSystems."/nix/.ro-store" =
{ fsType = "squashfs";
device = "/iso/nix-store.squashfs";
options = "loop";
neededForBoot = true;
};
fileSystems."/nix/.rw-store" =
{ fsType = "tmpfs";
device = "none";
options = "mode=0755";
neededForBoot = true;
};
boot.initrd.availableKernelModules = [ "squashfs" "iso9660" ];
boot.initrd.kernelModules = [ "loop" ];
# In stage 1, mount a tmpfs on top of /nix/store (the squashfs
# image) to make this a live CD.
boot.initrd.postMountCommands =
''
mkdir -p $targetRoot/nix/store
unionfs -o allow_other,cow,nonempty,chroot=$targetRoot,max_files=32768 /nix/.rw-store=RW:/nix/.ro-store=RO $targetRoot/nix/store
'';
# Closures to be copied to the Nix store on the CD, namely the init
# script and the top-level system configuration directory.
isoImage.storeContents =
[ config.system.build.toplevel ] ++
optional config.isoImage.includeSystemBuildDependencies
config.system.build.toplevel.drvPath;
# Create the squashfs image that contains the Nix store.
system.build.squashfsStore = import ../../../lib/make-squashfs.nix {
inherit (pkgs) stdenv squashfsTools perl pathsFromGraph;
storeContents = config.isoImage.storeContents;
};
# Individual files to be included on the CD, outside of the Nix
# store on the CD.
isoImage.contents =
[ { source = grubImage;
target = "/boot/grub/grub_eltorito";
}
{ source = pkgs.substituteAll {
name = "grub.cfg";
src = pkgs.writeText "grub.cfg-in" grubCfg;
bootRoot = "/boot";
};
target = "/boot/grub/grub.cfg";
}
{ source = config.boot.kernelPackages.kernel + "/bzImage";
target = "/boot/bzImage";
}
{ source = config.system.build.initialRamdisk + "/initrd";
target = "/boot/initrd";
}
{ source = "${pkgs.grub2}/share/grub/unicode.pf2";
target = "/boot/grub/unicode.pf2";
}
{ source = config.boot.loader.grub.splashImage;
target = "/boot/grub/splash.png";
}
{ source = config.system.build.squashfsStore;
target = "/nix-store.squashfs";
}
] ++ optionals config.isoImage.makeEfiBootable [
{ source = efiImg;
target = "/boot/efi.img";
}
{ source = "${efiDir}/efi";
target = "/efi";
}
{ source = "${efiDir}/loader";
target = "/loader";
}
] ++ mapAttrsToList (n: v: { source = v; target = "/boot/${n}"; }) config.boot.loader.grub.extraFiles;
# The Grub menu.
boot.loader.grub.extraEntries =
''
menuentry "NixOS ${config.system.nixosVersion} Installer" {
linux /boot/bzImage init=${config.system.build.toplevel}/init ${toString config.boot.kernelParams}
initrd /boot/initrd
}
menuentry "Boot from hard disk" {
set root=(hd0)
chainloader +1
}
'';
boot.loader.grub.timeout = 10;
# Create the ISO image.
system.build.isoImage = import ../../../lib/make-iso9660-image.nix ({
inherit (pkgs) stdenv perl cdrkit pathsFromGraph;
inherit (config.isoImage) isoName compressImage volumeID contents;
bootable = true;
bootImage = "/boot/grub/grub_eltorito";
} // optionalAttrs config.isoImage.makeEfiBootable {
efiBootable = true;
efiBootImage = "boot/efi.img";
});
boot.postBootCommands =
''
# After booting, register the contents of the Nix store on the
# CD in the Nix database in the tmpfs.
${config.nix.package}/bin/nix-store --load-db < /nix/store/nix-path-registration
# nixos-rebuild also requires a "system" profile and an
# /etc/NIXOS tag.
touch /etc/NIXOS
${config.nix.package}/bin/nix-env -p /nix/var/nix/profiles/system --set /run/current-system
'';
# Add vfat support to the initrd to enable people to copy the
# contents of the CD to a bootable USB stick. Need unionfs-fuse for union mounts
boot.initrd.supportedFilesystems = [ "vfat" "unionfs-fuse" ];
};
}