nixpkgs/nixos/modules/image/repart-image.nix
WilliButz 3f1f20b2a7
nixos/repart-image: pass partition attrs to builder instead of JSON file
Having access to the original Nix partition definitions in the builder
should make it a bit easier to manipulate them and still provide access
to the manipulated results.
2024-09-30 20:10:51 +02:00

184 lines
4.5 KiB
Nix

# This is an expression meant to be called from `./repart.nix`, it is NOT a
# NixOS module that can be imported.
{ lib
, stdenvNoCC
, runCommand
, python3
, black
, ruff
, mypy
, systemd
, fakeroot
# filesystem tools
, dosfstools
, mtools
, e2fsprogs
, squashfsTools
, erofs-utils
, btrfs-progs
, xfsprogs
# compression tools
, zstd
, xz
# arguments
, name
, version
, imageFileBasename
, compression
, fileSystems
, finalPartitions
, split
, seed
, definitionsDirectory
, sectorSize
, mkfsEnv ? {}
, createEmpty ? true
}:
let
systemdArch = let
inherit (stdenvNoCC) hostPlatform;
in
if hostPlatform.isAarch32 then "arm"
else if hostPlatform.isAarch64 then "arm64"
else if hostPlatform.isx86_32 then "x86"
else if hostPlatform.isx86_64 then "x86-64"
else if hostPlatform.isMips32 then "mips-le"
else if hostPlatform.isMips64 then "mips64-le"
else if hostPlatform.isPower then "ppc"
else if hostPlatform.isPower64 then "ppc64"
else if hostPlatform.isRiscV32 then "riscv32"
else if hostPlatform.isRiscV64 then "riscv64"
else if hostPlatform.isS390 then "s390"
else if hostPlatform.isS390x then "s390x"
else if hostPlatform.isLoongArch64 then "loongarch64"
else if hostPlatform.isAlpha then "alpha"
else hostPlatform.parsed.cpu.name;
amendRepartDefinitions = runCommand "amend-repart-definitions.py"
{
# TODO: ruff does not splice properly in nativeBuildInputs
depsBuildBuild = [ ruff ];
nativeBuildInputs = [ python3 black mypy ];
} ''
install ${./amend-repart-definitions.py} $out
patchShebangs --build $out
black --check --diff $out
ruff check --line-length 88 $out
mypy --strict $out
'';
fileSystemToolMapping = {
"vfat" = [ dosfstools mtools ];
"ext4" = [ e2fsprogs.bin ];
"squashfs" = [ squashfsTools ];
"erofs" = [ erofs-utils ];
"btrfs" = [ btrfs-progs ];
"xfs" = [ xfsprogs ];
};
fileSystemTools = builtins.concatMap (f: fileSystemToolMapping."${f}") fileSystems;
compressionPkg = {
"zstd" = zstd;
"xz" = xz;
}."${compression.algorithm}";
compressionCommand = {
"zstd" = "zstd --no-progress --threads=$NIX_BUILD_CORES -${toString compression.level}";
"xz" = "xz --keep --verbose --threads=$NIX_BUILD_CORES -${toString compression.level}";
}."${compression.algorithm}";
in
stdenvNoCC.mkDerivation (finalAttrs:
(if (version != null)
then { pname = name; inherit version; }
else { inherit name; }
) // {
__structuredAttrs = true;
nativeBuildInputs = [
systemd
fakeroot
] ++ lib.optionals (compression.enable) [
compressionPkg
] ++ fileSystemTools;
env = mkfsEnv;
inherit finalPartitions definitionsDirectory;
partitionsJSON = builtins.toJSON finalAttrs.finalPartitions;
# relative path to the repart definitions that are read by systemd-repart
finalRepartDefinitions = "repart.d";
systemdRepartFlags = [
"--architecture=${systemdArch}"
"--dry-run=no"
"--size=auto"
"--seed=${seed}"
"--definitions=${finalAttrs.finalRepartDefinitions}"
"--split=${lib.boolToString split}"
"--json=pretty"
] ++ lib.optionals createEmpty [
"--empty=create"
] ++ lib.optionals (sectorSize != null) [
"--sector-size=${toString sectorSize}"
];
dontUnpack = true;
dontConfigure = true;
doCheck = false;
patchPhase = ''
runHook prePatch
amendedRepartDefinitionsDir=$(${amendRepartDefinitions} <(echo "$partitionsJSON") $definitionsDirectory)
ln -vs $amendedRepartDefinitionsDir $finalRepartDefinitions
runHook postPatch
'';
buildPhase = ''
runHook preBuild
echo "Building image with systemd-repart..."
fakeroot systemd-repart \
''${systemdRepartFlags[@]} \
${imageFileBasename}.raw \
| tee repart-output.json
runHook postBuild
'';
installPhase = ''
runHook preInstall
mkdir -p $out
''
# Compression is implemented in the same derivation as opposed to in a
# separate derivation to allow users to save disk space. Disk images are
# already very space intensive so we want to allow users to mitigate this.
+ lib.optionalString compression.enable
''
for f in ${imageFileBasename}*; do
echo "Compressing $f with ${compression.algorithm}..."
# Keep the original file when compressing and only delete it afterwards
${compressionCommand} $f && rm $f
done
'' + ''
mv -v repart-output.json ${imageFileBasename}* $out
runHook postInstall
'';
passthru = {
inherit amendRepartDefinitions;
};
})