sigil/flake.nix

{
  description = "Nix flavored Genode distribution";

  inputs = {
    eris = {
      url = "git+https://codeberg.org/eris/nix-eris";
      inputs.nixpkgs.follows = "nixpkgs";
    };
    nimble.follows = "eris/nimble";
    nixpkgs.url = "github:ehmry/nixpkgs/sigil-21.11";
  };

  outputs = { self, eris, nixpkgs, nimble }:
    let
      systems = {
        localSystem = [ "x86_64-linux" ]; # build platforms
        crossSystem = [ "aarch64-genode" "x86_64-genode" ]; # target platforms
      };

      systemSpace =
        # All combinations of build and target systems
        nixpkgs.lib.cartesianProductOfSets systems;

      forAllLocalSystems =
        # Apply a function over all self-hosting (Linux) systems.
        f:
        nixpkgs.lib.genAttrs systems.localSystem (system: f system);

      forAllCrossSystems =
        # Apply a function over all cross-compiled systems (Genode).
        f:
        with builtins;
        let
          f' = { localSystem, crossSystem }:
            let system = localSystem + "-" + crossSystem;
            in {
              name = system;
              value = f { inherit system localSystem crossSystem; };
            };
          list = map f' systemSpace;
          attrSet = listToAttrs list;
        in attrSet;

      forAllSystems =
        # Apply a function over all Linux and Genode systems.
        f:
        (forAllCrossSystems f) // (forAllLocalSystems (system:
          f {
            inherit system;
            localSystem = system;
            crossSystem = system;
          }));

      overlays = [ nimble.overlay eris.overlays.default self.overlay ];

    in rec {

      overlay =
        # Overlay of adjustments applied to Nixpkgs as well as
        # the "genodePackages" set which the "packages"
        # output of this flake is taken.
        import ./overlay;

      lib =
        # Local utilities merged with the Nixpkgs lib
        nixpkgs.lib.extend (final: prev: {
          inherit forAllSystems forAllLocalSystems forAllCrossSystems;

          getMainProgram = pkg:
            with builtins;
            if hasAttr "mainProgram" pkg.meta then
              pkg.meta.mainProgram
            else
              trace "${pkg.name} is missing meta.mainProgram" pkg.pname;

          getEris = filename: pkg:
            with builtins;
            let
              manifest = fromJSON (unsafeDiscardStringContext
                (readFile "${pkg}/nix-support/eris-manifest.json"));
              entry = manifest.${filename};
            in entry // {
              cap = "(${pkg}/nix-support/eris-manifest.dhall).${filename}.cap";
              path = "${pkg}${
                  substring (stringLength pkg) (stringLength entry.path)
                  entry.path
                }"; # hack to build a string with context
            };

          getErisMainProgram = pkg:
            final.getEris (final.getMainProgram pkg) (prev.getOutput "bin" pkg);

          getErisLib = filename: pkg:
            final.getEris filename (prev.getOutput "lib" pkg);

          uuidFrom = seed:
            let digest = builtins.hashString "sha256" seed;
            in (lib.lists.foldl ({ str, off }:
              n:
              let chunk = builtins.substring off n digest;
              in {
                str = if off == 0 then chunk else "${str}-${chunk}";
                off = off + n;
              }) {
                str = "";
                off = 0;
              } [ 8 4 4 4 12 ]).str;

          nixosSystem =
            # A derivative of the function for generating Linux NixOS systems.
            # This one is not so well tested…
            { modules, ... }@args:
            import "${nixpkgs}/nixos/lib/eval-config.nix" (args // {
              lib = final;

              baseModules =
                # TODO: do not blacklist modules for the Linux guests
                with builtins;
                let
                  isNotModule = suffix:
                    let x = "${nixpkgs}/nixos/modules/${suffix}";
                    in y: x != y;

                  filters = map isNotModule
                    (import ./nixos-modules/base-modules-blacklist.nix);

                  isCompatible = p:
                    let p' = toString p;
                    in all (f: f p') filters;

                in filter isCompatible
                (import "${nixpkgs}/nixos/modules/module-list.nix");

              modules = modules ++ [
                ({ config, lib, ... }: {
                  options = with lib; {

                    system.boot.loader.id = mkOption {
                      internal = true;
                      default = "";
                    };

                    system.boot.loader.kernelFile = mkOption {
                      internal = true;
                      default = pkgs.stdenv.hostPlatform.platform.kernelTarget;
                      type = types.str;
                    };

                    system.boot.loader.initrdFile = mkOption {
                      internal = true;
                      default = "initrd";
                      type = types.str;
                    };

                    systemd.defaultUnit = mkOption {
                      default = "multi-user.target";
                      type = types.str;
                    };

                  };
                  config = {

                    boot.loader.grub.enable = lib.mkDefault false;

                    fileSystems."/" = { };

                    networking.enableIPv6 = lib.mkForce false;
                    systemd.network.enable = lib.mkForce false;

                    system.nixos.versionSuffix = ".${
                        final.substring 0 8
                        (self.lastModifiedDate or self.lastModified or "19700101")
                      }.${self.shortRev or "dirty"}";

                    system.nixos.revision = final.mkIf (self ? rev) self.rev;

                    system.build.toplevel = config.system.build.initXml;

                  };

                })
              ];
            });

        });

      legacyPackages = forAllSystems ({ system, localSystem, crossSystem }:
        if builtins.hasAttr system nixpkgs.legacyPackages then
          nixpkgs.legacyPackages.${system}.appendOverlays overlays
        else
          import nixpkgs {
            inherit localSystem;
            crossSystem = {
              system = crossSystem;
              useLLVM = true;
            };
            config.allowUnsupportedSystem = true;
            inherit overlays;
          });

      packages =
        # Genode native packages, not packages in the traditional
        # sense in that these cannot be installed within a profile.
        forAllCrossSystems ({ system, localSystem, crossSystem }:
          nixpkgs.lib.filterAttrs (_: v: v != null)
          self.legacyPackages.${system}.genodePackages);

      devShell =
        # Development shell for working with the
        # upstream Genode source repositories. Some
        # things are missing but everything referred
        # to by way of #!/usr/bin/ should be here.
        forAllLocalSystems (system:
          let
            pkgs = nixpkgs.legacyPackages.${system};
            fhs = pkgs.buildFHSUserEnv {
              name = "genode-env";
              targetPkgs = pkgs:
                (with pkgs; [
                  binutils
                  bison
                  expect
                  flex
                  git
                  glibc.dev
                  gnumake
                  libxml2
                  qemu
                  rpcsvc-proto
                  subversion
                  tcl
                  wget
                  which
                  xorriso
                ]);
              runScript = "bash";
              extraBuildCommands = let
                toolchain = pkgs.fetchzip {
                  url =
                    "file://${packages.x86_64-linux-x86_64-genode.genodeSources.toolchain.src}";
                  hash = "sha256-26rPvLUPEJm40zLSqTquwuFTJ1idTB0T4VXgaHRN+4o=";
                };
              in "ln -s ${toolchain}/local usr/local";
            };
          in pkgs.stdenv.mkDerivation {
            name = "genode-fhs-shell";
            nativeBuildInputs = [ fhs ];
            shellHook = "exec genode-env";
          });

      nixosModules =
        # Modules for composing Genode and NixOS.
        import ./nixos-modules { inherit (self) legacyPackages; };

      checks =
        # Checks for continous testing.
        let tests = import ./tests;
        in with (forAllCrossSystems ({ system, localSystem, crossSystem }:
          tests {
            inherit lib system localSystem crossSystem;
            hostPkgs = nixpkgs.legacyPackages.${localSystem};
            testPkgs = self.legacyPackages.${system};
            modulesPath = "${nixpkgs}/nixos/modules";
          } // {
            ports = self.legacyPackages.${localSystem}.symlinkJoin {
              name = "ports";
              paths = (builtins.attrValues
                self.packages.${system}.genodeSources.ports);
            };
          })); {
            x86_64-linux = x86_64-linux-aarch64-genode
              // x86_64-linux-x86_64-genode;
          };

      hydraJobs = self.checks;

    };
}