core/pkgs/build-support/kernel/make-initrd-ng.nix
2024-05-13 11:34:52 -04:00

98 lines
4.4 KiB
Nix

let
# Some metadata on various compression programs, relevant to naming
# the initramfs file and, if applicable, generating a u-boot image
# from it.
compressors = import ./initrd-compressor-meta.nix;
# Get the basename of the actual compression program from the whole
# compression command, for the purpose of guessing the u-boot
# compression type and filename extension.
compressorName = fullCommand: builtins.elemAt (builtins.match "([^ ]*/)?([^ ]+).*" fullCommand) 1;
in
{ stdenvNoCC, libarchive, ubootTools, lib, pkgsBuildHost, makeInitrdNGTool, binutils, runCommand
# Name of the derivation (not of the resulting file!)
, name ? "initrd"
, strip ? true
# Program used to compress the cpio archive; use "cat" for no compression.
# This can also be a function which takes a package set and returns the path to the compressor,
# such as `pkgs: "${pkgs.lzop}/bin/lzop"`.
, compressor ? "gzip"
, _compressorFunction ?
if lib.isFunction compressor then compressor
else if ! builtins.hasContext compressor && builtins.hasAttr compressor compressors then compressors.${compressor}.executable
else _: compressor
, _compressorExecutable ? _compressorFunction pkgsBuildHost
, _compressorName ? compressorName _compressorExecutable
, _compressorMeta ? compressors.${_compressorName} or {}
# List of arguments to pass to the compressor program, or null to use its defaults
, compressorArgs ? null
, _compressorArgsReal ? if compressorArgs == null then _compressorMeta.defaultArgs or [] else compressorArgs
# Filename extension to use for the compressed initramfs. This is
# included for clarity, but $out/initrd will always be a symlink to
# the final image.
# If this isn't guessed, you may want to complete the metadata above and send a PR :)
, extension ? _compressorMeta.extension or
(throw "Unrecognised compressor ${_compressorName}, please specify filename extension")
# List of { object = path_or_derivation; symlink = "/path"; }
# The paths are copied into the initramfs in their nix store path
# form, then linked at the root according to `symlink`.
, contents
# List of uncompressed cpio files to prepend to the initramfs. This
# can be used to add files in specified paths without them becoming
# symlinks to store paths.
, prepend ? []
# Whether to wrap the initramfs in a u-boot image.
, makeUInitrd ? stdenvNoCC.hostPlatform.linux-kernel.target == "uImage"
# If generating a u-boot image, the architecture to use. The default
# guess may not align with u-boot's nomenclature correctly, so it can
# be overridden.
# See https://gitlab.denx.de/u-boot/u-boot/-/blob/9bfb567e5f1bfe7de8eb41f8c6d00f49d2b9a426/common/image.c#L81-106 for a list.
, uInitrdArch ? stdenvNoCC.hostPlatform.ubootArch
# The name of the compression, as recognised by u-boot.
# See https://gitlab.denx.de/u-boot/u-boot/-/blob/9bfb567e5f1bfe7de8eb41f8c6d00f49d2b9a426/common/image.c#L195-204 for a list.
# If this isn't guessed, you may want to complete the metadata above and send a PR :)
, uInitrdCompression ? _compressorMeta.ubootName or
(throw "Unrecognised compressor ${_compressorName}, please specify uInitrdCompression")
}: runCommand name ({
compress = "${_compressorExecutable} ${lib.escapeShellArgs _compressorArgsReal}";
passthru = {
compressorExecutableFunction = _compressorFunction;
compressorArgs = _compressorArgsReal;
};
inherit extension makeUInitrd uInitrdArch prepend;
${if makeUInitrd then "uInitrdCompression" else null} = uInitrdCompression;
passAsFile = ["contents"];
contents = lib.concatMapStringsSep "\n" ({ object, symlink, ... }: "${object}\n${lib.optionalString (symlink != null) symlink}") contents + "\n";
nativeBuildInputs = [makeInitrdNGTool libarchive] ++ lib.optional makeUInitrd ubootTools ++ lib.optional strip binutils;
STRIP = if strip then "${pkgsBuildHost.binutils.targetPrefix}strip" else null;
}) ''
mkdir -p ./root/var/empty
make-initrd-ng "$contentsPath" ./root
mkdir "$out"
(cd root && find . -exec touch -h -d '@1' '{}' +)
for PREP in $prepend; do
cat $PREP >> $out/initrd
done
(cd root && find . -print0 | sort -z | bsdtar --uid 0 --gid 0 -cnf - -T - | bsdtar --null -cf - --format=newc @- | eval -- $compress >> "$out/initrd")
if [ -n "$makeUInitrd" ]; then
mkimage -A "$uInitrdArch" -O linux -T ramdisk -C "$uInitrdCompression" -d "$out/initrd" $out/initrd.img
# Compatibility symlink
ln -sf "initrd.img" "$out/initrd"
else
ln -s "initrd" "$out/initrd$extension"
fi
''