7fd6cea253
cpio includes the number of directory hard links in archives it creates. Some filesystems, like btrfs, do not count directory hard links the same way as more common filesystems like ext4 or tmpfs, so archives built when /tmp is on such a filesystem do not reproduce. This patch replaces cpio with bsdtar, which does not have this issue. The specific invocation is from this page: https://reproducible-builds.org/docs/archives/
114 lines
5.0 KiB
Nix
114 lines
5.0 KiB
Nix
# Create an initramfs containing the closure of the specified
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# file system objects. An initramfs is used during the initial
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# stages of booting a Linux system. It is loaded by the boot loader
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# along with the kernel image. It's supposed to contain everything
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# (such as kernel modules) necessary to allow us to mount the root
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# file system. Once the root file system is mounted, the `real' boot
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# script can be called.
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#
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# An initramfs is a cpio archive, and may be compressed with a number
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# of algorithms.
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let
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# Some metadata on various compression programs, relevant to naming
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# the initramfs file and, if applicable, generating a u-boot image
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# from it.
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compressors = import ./initrd-compressor-meta.nix;
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# Get the basename of the actual compression program from the whole
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# compression command, for the purpose of guessing the u-boot
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# compression type and filename extension.
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compressorName = fullCommand: builtins.elemAt (builtins.match "([^ ]*/)?([^ ]+).*" fullCommand) 1;
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in
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{ stdenvNoCC, perl, libarchive, ubootTools, lib, pkgsBuildHost
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# Name of the derivation (not of the resulting file!)
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, name ? "initrd"
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# Program used to compress the cpio archive; use "cat" for no compression.
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# This can also be a function which takes a package set and returns the path to the compressor,
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# such as `pkgs: "${pkgs.lzop}/bin/lzop"`.
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, compressor ? "gzip"
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, _compressorFunction ?
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if lib.isFunction compressor then compressor
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else if ! builtins.hasContext compressor && builtins.hasAttr compressor compressors then compressors.${compressor}.executable
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else _: compressor
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, _compressorExecutable ? _compressorFunction pkgsBuildHost
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, _compressorName ? compressorName _compressorExecutable
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, _compressorMeta ? compressors.${_compressorName} or {}
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# List of arguments to pass to the compressor program, or null to use its defaults
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, compressorArgs ? null
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, _compressorArgsReal ? if compressorArgs == null then _compressorMeta.defaultArgs or [] else compressorArgs
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# Filename extension to use for the compressed initramfs. This is
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# included for clarity, but $out/initrd will always be a symlink to
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# the final image.
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# If this isn't guessed, you may want to complete the metadata above and send a PR :)
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, extension ? _compressorMeta.extension or
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(throw "Unrecognised compressor ${_compressorName}, please specify filename extension")
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# List of { object = path_or_derivation; symlink = "/path"; }
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# The paths are copied into the initramfs in their nix store path
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# form, then linked at the root according to `symlink`.
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, contents
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# List of uncompressed cpio files to prepend to the initramfs. This
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# can be used to add files in specified paths without them becoming
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# symlinks to store paths.
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, prepend ? []
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# Whether to wrap the initramfs in a u-boot image.
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, makeUInitrd ? stdenvNoCC.hostPlatform.linux-kernel.target == "uImage"
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# If generating a u-boot image, the architecture to use. The default
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# guess may not align with u-boot's nomenclature correctly, so it can
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# be overridden.
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# See https://gitlab.denx.de/u-boot/u-boot/-/blob/9bfb567e5f1bfe7de8eb41f8c6d00f49d2b9a426/common/image.c#L81-106 for a list.
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, uInitrdArch ? stdenvNoCC.hostPlatform.linuxArch
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# The name of the compression, as recognised by u-boot.
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# See https://gitlab.denx.de/u-boot/u-boot/-/blob/9bfb567e5f1bfe7de8eb41f8c6d00f49d2b9a426/common/image.c#L195-204 for a list.
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# If this isn't guessed, you may want to complete the metadata above and send a PR :)
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, uInitrdCompression ? _compressorMeta.ubootName or
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(throw "Unrecognised compressor ${_compressorName}, please specify uInitrdCompression")
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}:
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let
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# !!! Move this into a public lib function, it is probably useful for others
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toValidStoreName = x: with builtins;
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lib.concatStringsSep "-" (filter (x: !(isList x)) (split "[^a-zA-Z0-9_=.?-]+" x));
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in stdenvNoCC.mkDerivation rec {
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inherit name makeUInitrd extension uInitrdArch prepend;
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${if makeUInitrd then "uInitrdCompression" else null} = uInitrdCompression;
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builder = ./make-initrd.sh;
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nativeBuildInputs = [ perl libarchive ]
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++ lib.optional makeUInitrd ubootTools;
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compress = "${_compressorExecutable} ${lib.escapeShellArgs _compressorArgsReal}";
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# Pass the function through, for reuse in append-initrd-secrets. The
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# function is used instead of the string, in order to support
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# cross-compilation (append-initrd-secrets running on a different
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# architecture than what the main initramfs is built on).
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passthru = {
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compressorExecutableFunction = _compressorFunction;
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compressorArgs = _compressorArgsReal;
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};
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# !!! should use XML.
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objects = map (x: x.object) contents;
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symlinks = map (x: x.symlink) contents;
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suffices = map (x: if x ? suffix then x.suffix else "none") contents;
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# For obtaining the closure of `contents'.
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# Note: we don't use closureInfo yet, as that won't build with nix-1.x.
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# See #36268.
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exportReferencesGraph =
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lib.zipListsWith
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(x: i: [("closure-${toValidStoreName (baseNameOf x.symlink)}-${toString i}") x.object])
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contents
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(lib.range 0 (lib.length contents - 1));
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pathsFromGraph = ./paths-from-graph.pl;
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}
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