# Create an initramfs containing the closure of the specified # file system objects. An initramfs is used during the initial # stages of booting a Linux system. It is loaded by the boot loader # along with the kernel image. It's supposed to contain everything # (such as kernel modules) necessary to allow us to mount the root # file system. Once the root file system is mounted, the `real' boot # script can be called. # # An initramfs is a cpio archive, and may be compressed with a number # of algorithms. 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, perl, cpio, ubootTools, lib, pkgsBuildHost # Name of the derivation (not of the resulting file!) , name ? "initrd" # 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.linuxArch # 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") }: let # !!! Move this into a public lib function, it is probably useful for others toValidStoreName = x: with builtins; lib.concatStringsSep "-" (filter (x: !(isList x)) (split "[^a-zA-Z0-9_=.?-]+" x)); in stdenvNoCC.mkDerivation rec { inherit name makeUInitrd extension uInitrdArch prepend; ${if makeUInitrd then "uInitrdCompression" else null} = uInitrdCompression; builder = ./make-initrd.sh; nativeBuildInputs = [ perl cpio ] ++ lib.optional makeUInitrd ubootTools; compress = "${_compressorExecutable} ${lib.escapeShellArgs _compressorArgsReal}"; # Pass the function through, for reuse in append-initrd-secrets. The # function is used instead of the string, in order to support # cross-compilation (append-initrd-secrets running on a different # architecture than what the main initramfs is built on). passthru = { compressorExecutableFunction = _compressorFunction; compressorArgs = _compressorArgsReal; }; # !!! should use XML. objects = map (x: x.object) contents; symlinks = map (x: x.symlink) contents; suffices = map (x: if x ? suffix then x.suffix else "none") contents; # For obtaining the closure of `contents'. # Note: we don't use closureInfo yet, as that won't build with nix-1.x. # See #36268. exportReferencesGraph = lib.zipListsWith (x: i: [("closure-${toValidStoreName (baseNameOf x.symlink)}-${toString i}") x.object]) contents (lib.range 0 (lib.length contents - 1)); pathsFromGraph = ./paths-from-graph.pl; }