nixos/diod: use upstream systemd unit

nixos/modules/services/network-filesystems/diod.nix

@@ -9,20 +9,6 @@ let
 
   diodBool = b: if b then "1" else "0";
 
-  diodConfig = pkgs.writeText "diod.conf" ''
-    allsquash = ${diodBool cfg.allsquash}
-    auth_required = ${diodBool cfg.authRequired}
-    exportall = ${diodBool cfg.exportall}
-    exportopts = "${lib.concatStringsSep "," cfg.exportopts}"
-    exports = { ${lib.concatStringsSep ", " (map (s: ''"${s}"'') cfg.exports)} }
-    listen = { ${lib.concatStringsSep ", " (map (s: ''"${s}"'') cfg.listen)} }
-    logdest = "${cfg.logdest}"
-    nwthreads = ${toString cfg.nwthreads}
-    squashuser = "${cfg.squashuser}"
-    statfs_passthru = ${diodBool cfg.statfsPassthru}
-    userdb = ${diodBool cfg.userdb}
-    ${cfg.extraConfig}
-  '';
 in
 {
   options = {
@@ -150,13 +136,22 @@ in
   config = lib.mkIf config.services.diod.enable {
     environment.systemPackages = [ pkgs.diod ];
 
-    systemd.services.diod = {
-      description = "diod 9P file server";
-      wantedBy = [ "multi-user.target" ];
-      after = [ "network.target" ];
-      serviceConfig = {
-        ExecStart = "${pkgs.diod}/sbin/diod -f -c ${diodConfig}";
-      };
-    };
+    environment.etc."diod.conf".text = ''
+      allsquash = ${diodBool cfg.allsquash}
+      auth_required = ${diodBool cfg.authRequired}
+      exportall = ${diodBool cfg.exportall}
+      exportopts = "${lib.concatStringsSep "," cfg.exportopts}"
+      exports = { ${lib.concatStringsSep ", " (map (s: ''"${s}"'') cfg.exports)} }
+      listen = { ${lib.concatStringsSep ", " (map (s: ''"${s}"'') cfg.listen)} }
+      logdest = "${cfg.logdest}"
+      nwthreads = ${toString cfg.nwthreads}
+      squashuser = "${cfg.squashuser}"
+      statfs_passthru = ${diodBool cfg.statfsPassthru}
+      userdb = ${diodBool cfg.userdb}
+      ${cfg.extraConfig}
+    '';
+
+    systemd.packages = [ pkgs.diod ];
+    systemd.services.diod.wantedBy = [ "multi-user.target" ];
   };
 }