From 985bafa5fc9e3ad846a54a68a71c06235c4aaaae Mon Sep 17 00:00:00 2001
From: nikstur <nikstur@outlook.com>
Date: Sat, 30 Dec 2023 03:36:36 +0100
Subject: [PATCH] nixos/uki: init

---
 nixos/modules/module-list.nix     |  1 +
 nixos/modules/system/boot/uki.nix | 85 +++++++++++++++++++++++++++++++
 2 files changed, 86 insertions(+)
 create mode 100644 nixos/modules/system/boot/uki.nix

diff --git a/nixos/modules/module-list.nix b/nixos/modules/module-list.nix
index e6fffd4716de..356569644e63 100644
--- a/nixos/modules/module-list.nix
+++ b/nixos/modules/module-list.nix
@@ -1466,6 +1466,7 @@
   ./system/boot/stratisroot.nix
   ./system/boot/modprobe.nix
   ./system/boot/networkd.nix
+  ./system/boot/uki.nix
   ./system/boot/unl0kr.nix
   ./system/boot/plymouth.nix
   ./system/boot/resolved.nix
diff --git a/nixos/modules/system/boot/uki.nix b/nixos/modules/system/boot/uki.nix
new file mode 100644
index 000000000000..63c4e0c0e391
--- /dev/null
+++ b/nixos/modules/system/boot/uki.nix
@@ -0,0 +1,85 @@
+{ config, lib, pkgs, ... }:
+
+let
+
+  cfg = config.boot.uki;
+
+  inherit (pkgs.stdenv.hostPlatform) efiArch;
+
+  format = pkgs.formats.ini { };
+  ukifyConfig = format.generate "ukify.conf" cfg.settings;
+
+in
+
+{
+  options = {
+
+    boot.uki = {
+      name = lib.mkOption {
+        type = lib.types.str;
+        description = lib.mdDoc "Name of the UKI";
+      };
+
+      version = lib.mkOption {
+        type = lib.types.nullOr lib.types.str;
+        default = config.system.image.version;
+        defaultText = lib.literalExpression "config.system.image.version";
+        description = lib.mdDoc "Version of the image or generation the UKI belongs to";
+      };
+
+      settings = lib.mkOption {
+        type = format.type;
+        description = lib.mdDoc ''
+          The configuration settings for ukify. These control what the UKI
+          contains and how it is built.
+        '';
+      };
+    };
+
+    system.boot.loader.ukiFile = lib.mkOption {
+      type = lib.types.str;
+      internal = true;
+      description = lib.mdDoc "Name of the UKI file";
+    };
+
+  };
+
+  config = {
+
+    boot.uki.name = lib.mkOptionDefault (if config.system.image.id != null then
+      config.system.image.id
+    else
+      "nixos");
+
+    boot.uki.settings = lib.mkOptionDefault {
+      UKI = {
+        Linux = "${config.boot.kernelPackages.kernel}/${config.system.boot.loader.kernelFile}";
+        Initrd = "${config.system.build.initialRamdisk}/${config.system.boot.loader.initrdFile}";
+        Cmdline = "init=${config.system.build.toplevel}/init ${toString config.boot.kernelParams}";
+        Stub = "${pkgs.systemd}/lib/systemd/boot/efi/linux${efiArch}.efi.stub";
+        Uname = "${config.boot.kernelPackages.kernel.modDirVersion}";
+        OSRelease = "@${config.system.build.etc}/etc/os-release";
+        # This is needed for cross compiling.
+        EFIArch = efiArch;
+      };
+    };
+
+    system.boot.loader.ukiFile =
+      let
+        name = config.boot.uki.name;
+        version = config.boot.uki.version;
+        versionInfix = if version != null then "_${version}" else "";
+      in
+      name + versionInfix + ".efi";
+
+    system.build.uki = pkgs.runCommand config.system.boot.loader.ukiFile { } ''
+      mkdir -p $out
+      ${pkgs.buildPackages.systemdUkify}/lib/systemd/ukify build \
+        --config=${ukifyConfig} \
+        --output="$out/${config.system.boot.loader.ukiFile}"
+    '';
+
+    meta.maintainers = with lib.maintainers; [ nikstur ];
+
+  };
+}