default.nix

@@ -25,7 +25,13 @@ let
 
   eval = evalModules {
     modules = [
-      {
+      ({ lib, pkgs, ... }: {
+        _module.args = {
+          utils = import "${nixpkgs}/nixos/lib/utils.nix" {
+            inherit lib pkgs;
+            config.systemd.globalEnvironment = {};
+          };
+        };
         nixpkgs = {
           source = nixpkgs;
           overlays = [ overlay ];
@@ -33,7 +39,7 @@ let
             "python-2.7.18.8"
           ];
         };
-      }
+      })
       device.module
       liminix-config
     ];

modules/base.nix

@@ -2,7 +2,7 @@
 ## ============
 
 
-{ lib, pkgs, config, ...}:
+{ lib, pkgs, utils, config, ...}:
 let
   inherit (lib) mkEnableOption mkOption types isDerivation hasAttr concatStringsSep mapAttrsToList;
   inherit (pkgs.pseudofile) dir symlink;
@@ -43,9 +43,15 @@ in {
         '';
       };
     };
+
+    # deprecated
     services = mkOption {
       type = types.attrsOf type_service;
     };
+
+    units = mkOption {
+      type = utils.systemdUtils.types.units;
+    };
     system.callService = mkOption {
       type = types.functionTo (types.functionTo types.anything);
     };

modules/systemd/default.nix

@@ -1,41 +1,120 @@
-{ pkgs, ... }:
+{
+  pkgs,
+  lib,
+  config,
+  utils,
+  ...
+}:
 let
+  inherit (lib)
+    mapAttrs'
+    nameValuePair
+    mkMerge
+    mapAttrsToList
+    ;
   inherit (pkgs.pseudofile) dir symlink;
-  "getty.service" = {
-    file =
-    let
-      login = pkgs.writeScript "login" ''
-        #!/bin/ash
-        exec /bin/ash
-      '';
-    in
-    ''
-      [Unit]
-      Description="Serial shell"
+  inherit (utils.systemdUtils.lib)
+    targetToUnit
+    serviceToUnit
+    ;
+
+  units-texts = mapAttrs' (
+    _: unit:
+    nameValuePair unit.name {
+      file = unit.text;
+      mode = "0644";
+    }
+  ) config.units;
+  units-aliases = mkMerge (
+    mapAttrsToList (
+      _: unit:
+      mkMerge (
+        map (aka: {
+          ${aka} = symlink "${unit.name}";
+        }) (unit.aliases or [ ])
+      )
+    ) config.units
+  );
+  units-extraWants = mkMerge (
+    mapAttrsToList (
+      _: unit:
+      mkMerge (
+        map (unit2: {
+          "${unit2}.wants" = dir {
+            ${unit.name} = symlink "../${unit.name}";
+          };
+        }) (unit.wantedBy or [ ])
+      )
+    ) config.units
+  );
+  units-extraUpholds = mkMerge (
+    mapAttrsToList (
+      _: unit:
+      mkMerge (
+        map (unit2: {
+          "${unit2}.upholds" = dir {
+            ${unit.name} = symlink "../${unit.name}";
+          };
+        }) (unit.upheldBy or [ ])
+      )
+    ) config.units
+  );
+  units-extraRequires = mkMerge (
+    mapAttrsToList (
+      _: unit:
+      mkMerge (
+        map (unit2: {
+          "${unit2}.requires" = dir {
+            ${unit.name} = symlink "../${unit.name}";
+          };
+        }) (unit.requiredBy or [ ])
+      )
+    ) config.units
+  );
 
-      [Service]
-      ExecStart=${pkgs.util-linux}/bin/agetty --login-program ${login} ttyS0
-    '';
-    mode = "0644";
-  };
-  "default.target" = {
-    file = ''
-      [Unit]
-      Description="target to boot"
-      Wants=getty.service
-      After=getty.service
-      AllowIsolate=yes
-    '';
-  };
-  "sysinit.target" = {
-    file = ''
-      [Unit]
-      Description="sysinit.target"
-    '';
-  };
 in
 {
   config = {
+    units = {
+      default-target = targetToUnit {
+        name = "default.target";
+        aliases = [];
+        wantedBy = [];
+        requiredBy = [];
+        upheldBy = [];
+        unitConfig.Description = "target to boot";
+      };
+      sysinit-target = targetToUnit {
+        name = "sysinit.target";
+        aliases = [];
+        wantedBy = [];
+        requiredBy = [];
+        upheldBy = [];
+        unitConfig.Description = "sysinit.target";
+      };
+      agetty = serviceToUnit {
+        name = "getty.service";
+        aliases = [];
+        wantedBy = [ "default.target" ];
+        requiredBy = [];
+        upheldBy = [];
+        environment = {};
+        unitConfig = {
+          Description = "Serial Shell";
+          Before = [ "default.target" ];
+        };
+        serviceConfig.ExecStart =
+          let
+            login = pkgs.writeScript "login" ''
+              #!/bin/ash
+              . /etc/profile
+              exec /bin/ash
+            '';
+          in
+          "${pkgs.util-linux}/bin/agetty --login-program ${login} ttyS0";
+      };
+    };
+
     kernel.config = {
       CGROUPS = "y";
       DEVTMPFS = "y";
@@ -55,9 +134,13 @@ in
     filesystem = dir {
       etc = dir {
         systemd = dir {
-          system = dir {
-            inherit "default.target" "getty.service" "sysinit.target";
-          };
+          system = dir (mkMerge [
+            units-texts
+            units-aliases
+            units-extraWants
+            units-extraUpholds
+            units-extraRequires
+          ]);
         };
       };
       bin = dir {