add a type definiton for s6-rc modules

modules/base.nix

@@ -1,12 +1,19 @@
 { lib, ...}:
-let inherit (lib) mkEnableOption mkOption types;
+let
+  inherit (lib) mkEnableOption mkOption types isDerivation hasAttr ;
+  type_service = types.package // {
+    name = "service";
+    description = "s6-rc service";
+    check = x: isDerivation x && hasAttr "serviceType" x;
+  };
+
 in {
   options = {
     systemPackages = mkOption {
       type = types.listOf types.package;
     };
     services = mkOption {
-      type = types.anything;
+      type = types.attrsOf type_service;
     };
     kernel = mkOption {
       type = types.anything;

pkgs/liminix-tools/builder.sh

@@ -1,6 +1,6 @@
 source $stdenv/setup
 mkdir -p $out/${name}
-echo $type > $out/${name}/type
+echo $serviceType > $out/${name}/type
 mkdir -p $out/${name}/dependencies.d
 echo $buildInputs > $out/buildInputs
 test -n "$dependencies" && for d in $dependencies; do

pkgs/liminix-tools/default.nix

@@ -15,7 +15,7 @@
     , dependencies ? []
   } @ args: stdenvNoCC.mkDerivation {
     name = "${name}.service";
-    type = "longrun";
+    serviceType = "longrun";
     buildInputs = dependencies;
     dependencies = builtins.map (d: d.name) dependencies;
     shell = "${busybox}/bin/sh";
@@ -34,7 +34,7 @@
     # stdenvNoCC is to avoid generating derivations with names
     # like foo.service-mips-linux-musl
     name = "${name}.service";
-    type = "oneshot";
+    serviceType = "oneshot";
     # does this suffice to make sure dependencies are included
     # even though the built output has no references to their
     # store directories?
@@ -53,7 +53,7 @@
     , ...
   }: stdenvNoCC.mkDerivation {
     inherit name;
-    type = "bundle";
+    serviceType = "bundle";
     contents = builtins.map (d: d.name) contents;
     buildInputs = dependencies ++ contents;
     dependencies = builtins.map (d: d.name) dependencies;