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# SPDX-FileCopyrightText: 2021-2022 Alyssa Ross <hi@alyssa.is>
# SPDX-License-Identifier: MIT

{ pkgs ? import <nixpkgs> {}
, rootfs ? import ../rootfs { inherit pkgs; }
}:

pkgs.callPackage (
{ lib, stdenv, runCommand, writeReferencesToFile, pkgsStatic
, busybox, cpio, cryptsetup, lvm2
}:

let
  inherit (lib) cleanSource cleanSourceWith concatMapStringsSep;

  linux = rootfs.kernel;

  packages = [
    pkgsStatic.execline pkgsStatic.kmod pkgsStatic.mdevd

    (pkgsStatic.cryptsetup.override {
      programs = {
        cryptsetup = false;
        cryptsetup-reencrypt = false;
        integritysetup = false;
      };
    })

    (busybox.override {
      enableStatic = true;
      extraConfig = ''
        CONFIG_DEPMOD n
        CONFIG_FINDFS n
        CONFIG_INSMOD n
        CONFIG_LSMOD n
        CONFIG_MODINFO n
        CONFIG_MODPROBE n
        CONFIG_RMMOD n
      '';
    })
  ];

  packagesSysroot = runCommand "packages-sysroot" {} ''
    mkdir -p $out/bin
    ln -s ${concatMapStringsSep " " (p: "${p}/bin/*") packages} $out/bin
    cp -R ${linux}/lib $out
    ln -s /bin $out/sbin

    # TODO: this is a hack and we should just build the util-linux
    # programs we want.
    # https://lore.kernel.org/util-linux/87zgrl6ufb.fsf@alyssa.is/
    cp ${pkgsStatic.util-linuxMinimal}/bin/{findfs,lsblk} $out/bin
  '';

  packagesCpio = runCommand "packages.cpio" {
    nativeBuildInputs = [ cpio ];
    storePaths = writeReferencesToFile packagesSysroot;
  } ''
    cd ${packagesSysroot}
    (printf "/nix\n/nix/store\n" && find . $(< $storePaths)) |
        cpio -o -H newc -R +0:+0 --reproducible > $out
  '';
in

stdenv.mkDerivation {
  name = "initramfs";

  src = cleanSourceWith {
    filter = name: _type: name != "${toString ./.}/build";
    src = cleanSource ./.;
  };

  PACKAGES_CPIO = packagesCpio;

  nativeBuildInputs = [ cpio ];

  installPhase = ''
    runHook preInstall
    cp build/initramfs $out
    runHook postInstall
  '';

  enableParallelBuilding = true;
}
) {}