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|
{ pkgs
, lib
, # The NixOS configuration to be installed onto the disk image.
config
, # The size of the disk, in megabytes.
diskSize
# The files and directories to be placed in the target file system.
# This is a list of attribute sets {source, target} where `source'
# is the file system object (regular file or directory) to be
# grafted in the file system at path `target'.
, contents ? []
, # Type of partition table to use; either "legacy", "efi", or "none".
# For "efi" images, the GPT partition table is used and a mandatory ESP
# partition of reasonable size is created in addition to the root partition.
# If `installBootLoader` is true, GRUB will be installed in EFI mode.
# For "legacy", the msdos partition table is used and a single large root
# partition is created. If `installBootLoader` is true, GRUB will be
# installed in legacy mode.
# For "none", no partition table is created. Enabling `installBootLoader`
# most likely fails as GRUB will probably refuse to install.
partitionTableType ? "legacy"
, # The root file system type.
fsType ? "ext4"
, # Filesystem label
label ? "nixos"
, # The initial NixOS configuration file to be copied to
# /etc/nixos/configuration.nix.
configFile ? null
, # Shell code executed after the VM has finished.
postVM ? ""
, name ? "nixos-disk-image"
, # Disk image format, one of qcow2, qcow2-compressed, vpc, raw.
format ? "raw"
}:
assert partitionTableType == "legacy" || partitionTableType == "efi" || partitionTableType == "none";
# We use -E offset=X below, which is only supported by e2fsprogs
assert partitionTableType != "none" -> fsType == "ext4";
with lib;
let format' = format; in let
format = if format' == "qcow2-compressed" then "qcow2" else format';
compress = optionalString (format' == "qcow2-compressed") "-c";
filename = "nixos." + {
qcow2 = "qcow2";
vpc = "vhd";
raw = "img";
}.${format};
rootPartition = { # switch-case
legacy = "1";
efi = "2";
}.${partitionTableType};
partitionDiskScript = { # switch-case
legacy = ''
parted --script $diskImage -- \
mklabel msdos \
mkpart primary ext4 1MiB -1
'';
efi = ''
parted --script $diskImage -- \
mklabel gpt \
mkpart ESP fat32 8MiB 256MiB \
set 1 boot on \
mkpart primary ext4 256MiB -1
'';
none = "";
}.${partitionTableType};
nixpkgs = cleanSource pkgs.path;
# FIXME: merge with channel.nix / make-channel.nix.
channelSources = pkgs.runCommand "nixos-${config.system.nixos.version}" {} ''
mkdir -p $out
cp -prd ${nixpkgs.outPath} $out/nixos
chmod -R u+w $out/nixos
if [ ! -e $out/nixos/nixpkgs ]; then
ln -s . $out/nixos/nixpkgs
fi
rm -rf $out/nixos/.git
echo -n ${config.system.nixos.versionSuffix} > $out/nixos/.version-suffix
'';
binPath = with pkgs; makeBinPath (
[ rsync
utillinux
parted
e2fsprogs
lkl
config.system.build.nixos-install
config.system.build.nixos-enter
nix
] ++ stdenv.initialPath);
# I'm preserving the line below because I'm going to search for it across nixpkgs to consolidate
# image building logic. The comment right below this now appears in 4 different places in nixpkgs :)
# !!! should use XML.
sources = map (x: x.source) contents;
targets = map (x: x.target) contents;
closureInfo = pkgs.closureInfo { rootPaths = [ config.system.build.toplevel channelSources ]; };
prepareImage = ''
export PATH=${binPath}
# Yes, mkfs.ext4 takes different units in different contexts. Fun.
sectorsToKilobytes() {
echo $(( ( "$1" * 512 ) / 1024 ))
}
sectorsToBytes() {
echo $(( "$1" * 512 ))
}
mkdir $out
diskImage=nixos.raw
truncate -s ${toString diskSize}M $diskImage
${partitionDiskScript}
${if partitionTableType != "none" then ''
# Get start & length of the root partition in sectors to $START and $SECTORS.
eval $(partx $diskImage -o START,SECTORS --nr ${rootPartition} --pairs)
mkfs.${fsType} -F -L ${label} $diskImage -E offset=$(sectorsToBytes $START) $(sectorsToKilobytes $SECTORS)K
'' else ''
mkfs.${fsType} -F -L ${label} $diskImage
''}
root="$PWD/root"
mkdir -p $root
# Copy arbitrary other files into the image
# Semi-shamelessly copied from make-etc.sh. I (@copumpkin) shall factor this stuff out as part of
# https://github.com/NixOS/nixpkgs/issues/23052.
set -f
sources_=(${concatStringsSep " " sources})
targets_=(${concatStringsSep " " targets})
set +f
for ((i = 0; i < ''${#targets_[@]}; i++)); do
source="''${sources_[$i]}"
target="''${targets_[$i]}"
if [[ "$source" =~ '*' ]]; then
# If the source name contains '*', perform globbing.
mkdir -p $root/$target
for fn in $source; do
rsync -a --no-o --no-g "$fn" $root/$target/
done
else
mkdir -p $root/$(dirname $target)
if ! [ -e $root/$target ]; then
rsync -a --no-o --no-g $source $root/$target
else
echo "duplicate entry $target -> $source"
exit 1
fi
fi
done
export HOME=$TMPDIR
# Provide a Nix database so that nixos-install can copy closures.
export NIX_STATE_DIR=$TMPDIR/state
nix-store --load-db < ${closureInfo}/registration
echo "running nixos-install..."
nixos-install --root $root --no-bootloader --no-root-passwd \
--system ${config.system.build.toplevel} --channel ${channelSources} --substituters ""
echo "copying staging root to image..."
cptofs -p ${optionalString (partitionTableType != "none") "-P ${rootPartition}"} -t ${fsType} -i $diskImage $root/* /
'';
in pkgs.vmTools.runInLinuxVM (
pkgs.runCommand name
{ preVM = prepareImage;
buildInputs = with pkgs; [ utillinux e2fsprogs dosfstools ];
postVM = ''
${if format == "raw" then ''
mv $diskImage $out/${filename}
'' else ''
${pkgs.qemu}/bin/qemu-img convert -f raw -O ${format} ${compress} $diskImage $out/${filename}
''}
diskImage=$out/${filename}
${postVM}
'';
memSize = 1024;
}
''
export PATH=${binPath}:$PATH
rootDisk=${if partitionTableType != "none" then "/dev/vda${rootPartition}" else "/dev/vda"}
# Some tools assume these exist
ln -s vda /dev/xvda
ln -s vda /dev/sda
mountPoint=/mnt
mkdir $mountPoint
mount $rootDisk $mountPoint
# Create the ESP and mount it. Unlike e2fsprogs, mkfs.vfat doesn't support an
# '-E offset=X' option, so we can't do this outside the VM.
${optionalString (partitionTableType == "efi") ''
mkdir -p /mnt/boot
mkfs.vfat -n ESP /dev/vda1
mount /dev/vda1 /mnt/boot
''}
# Install a configuration.nix
mkdir -p /mnt/etc/nixos
${optionalString (configFile != null) ''
cp ${configFile} /mnt/etc/nixos/configuration.nix
''}
# Set up core system link, GRUB, etc.
NIXOS_INSTALL_BOOTLOADER=1 nixos-enter --root $mountPoint -- /nix/var/nix/profiles/system/bin/switch-to-configuration boot
# The above scripts will generate a random machine-id and we don't want to bake a single ID into all our images
rm -f $mountPoint/etc/machine-id
umount -R /mnt
# Make sure resize2fs works. Note that resize2fs has stricter criteria for resizing than a normal
# mount, so the `-c 0` and `-i 0` don't affect it. Setting it to `now` doesn't produce deterministic
# output, of course, but we can fix that when/if we start making images deterministic.
${optionalString (fsType == "ext4") ''
tune2fs -T now -c 0 -i 0 $rootDisk
''}
''
)
|