Add hostName option and fix docker

examples/initrd/default.nix

@@ -25,6 +25,8 @@ nglib.makeSystem {
     };
     users.users.root.hashedPassword = "$5$Ws9piKbYzt9S6p1R$X4L6xn5UNQnufJUc/K5sKRE.0GuMR.8vp2BwIiglVYB"; # toor
 
+    networking.hostName = "initrd";
+
     services.getty."ttyS0" = {
       port = "ttyS0";
       baudrate = "115200,38400,9600";

modules/list.nix

@@ -18,6 +18,7 @@
 
     ./misc/iana.nix
 
+    ./networking.nix
     ./environment.nix
     ./users.nix
     ./ids.nix

modules/networking.nix

@@ -0,0 +1,26 @@
+# SPDX-FileCopyrightText:  2023 Richard Brežák and NixNG contributors
+#
+# SPDX-License-Identifier: MPL-2.0
+#
+#   This Source Code Form is subject to the terms of the Mozilla Public
+#   License, v. 2.0. If a copy of the MPL was not distributed with this
+#   file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+{ nglib, lib, config, ... }:
+{
+  options.networking = {
+    hostName = lib.mkOption {
+      default = null;
+      type = lib.types.nullOr (lib.types.strMatching
+        "^$|^[[:alnum:]]([[:alnum:]_-]{0,61}[[:alnum:]])?$");
+      description = ''
+        The hostname of the system. Notice that in many container engines
+        the hostname cannot be altered.
+      '';
+    };
+  };
+
+  config.system.activation.hostname = nglib.dag.dagEntryAnywhere (lib.optionalString (config.networking.hostName != null) ''
+    echo "${config.networking.hostName}" > /proc/sys/kernel/hostname
+  '');
+}

modules/system/oci-image.nix

@@ -37,23 +37,23 @@ with lib;
   config = {
     system.build.ociImage =
       let
-        config = {
-          name = cfg.name;
+        cfg = {
+          inherit (config.system) name;
           tag = "latest";
           maxLayers = 125;
 
           config = {
             StopSignal = "SIGCONT";
             Entrypoint =
               [
-                "${configFinal.system.build.toplevel}/init"
+                "${config.system.build.toplevel}/init"
               ];
           };
         };
       in
         with pkgs; {
-          build = dockerTools.buildLayeredImage config;
-          stream = dockerTools.streamLayeredImage config;
+          build = dockerTools.buildLayeredImage cfg;
+          stream = dockerTools.streamLayeredImage cfg;
         };
   };
 }