From df4e6b697e38aec85ebef589b675651a892a74bb Mon Sep 17 00:00:00 2001
From: Malo Bourgon <mbourgon@gmail.com>
Date: Mon, 31 Aug 2020 18:01:41 -0700
Subject: [PATCH] Add separate options for ComputerName, HostName, and
 LocalHostName

---
 modules/networking/default.nix | 63 ++++++++++++++++++++++++++++------
 tests/networking-hostname.nix  |  3 +-
 2 files changed, 55 insertions(+), 11 deletions(-)

diff --git a/modules/networking/default.nix b/modules/networking/default.nix
index b5456905..46cd982e 100644
--- a/modules/networking/default.nix
+++ b/modules/networking/default.nix
@@ -5,15 +5,11 @@ with lib;
 let
   cfg = config.networking;
 
+  hostnameRegEx = ''^(([a-zA-Z0-9]|[a-zA-Z0-9][a-zA-Z0-9\-]*[a-zA-Z0-9])\.)*([A-Za-z0-9]|[A-Za-z0-9][A-Za-z0-9\-]*[A-Za-z0-9])$'';
+
   emptyList = lst: if lst != [] then lst else ["empty"];
   quoteStrings = concatMapStringsSep " " (str: "'${str}'");
 
-  setHostName = optionalString (cfg.hostName != null) ''
-    scutil --set ComputerName '${cfg.hostName}'
-    scutil --set LocalHostName '${cfg.hostName}'
-    scutil --set HostName '${cfg.hostName}'
-  '';
-
   setNetworkServices = optionalString (cfg.knownNetworkServices != []) ''
     networkservices=$(networksetup -listallnetworkservices)
     ${concatMapStringsSep "\n" (srv: ''
@@ -29,11 +25,49 @@ in
 
 {
   options = {
-    networking.hostName = mkOption {
+    networking.computerName = mkOption {
       type = types.nullOr types.str;
       default = null;
-      example = "myhostname";
-      description = "Hostname for your machine.";
+      example = "John’s MacBook Pro";
+      description = ''
+        The user-friendly name for the system, set in System Preferences > Sharing > Computer Name.
+
+        Setting this option is equivalent to running `scutil --set ComputerName`.
+
+        This name can contain spaces and Unicode characters.
+      '';
+    };
+
+    networking.hostName = mkOption {
+      type = types.nullOr (types.strMatching hostnameRegEx);
+      default = null;
+      example = "Johns-MacBook-Pro";
+      description = ''
+        The hostname of your system, as visible from the command line and used by local and remote
+        networks when connecting through SSH and Remote Login.
+
+        Setting this option is equivalent to running the command `scutil --set HostName`.
+
+        (Note that networking.localHostName defaults to the value of this option.)
+      '';
+    };
+
+    networking.localHostName = mkOption {
+      type = types.nullOr (types.strMatching hostnameRegEx);
+      default = cfg.hostName;
+      example = "Johns-MacBook-Pro";
+      description = ''
+        The local hostname, or local network name, is displayed beneath the computer's name at the
+        top of the Sharing preferences pane. It identifies your Mac to Bonjour-compatible services.
+
+        Setting this option is equivalent to running the command `scutil --set LocalHostName`, where
+        running, e.g., `scutil --set LocalHostName 'Johns-MacBook-Pro'`, would set
+        the systems local hostname to "Johns-MacBook-Pro.local". The value of this option defaults
+        to the value of the networking.hostName option.
+
+        By default on macOS the local hostname is your computer's name with ".local" appended, with
+        any spaces replaced with hyphens, and invalid characters omitted.
+      '';
     };
 
     networking.knownNetworkServices = mkOption {
@@ -72,7 +106,16 @@ in
     system.activationScripts.networking.text = ''
       echo "configuring networking..." >&2
 
-      ${setHostName}
+      ${optionalString (cfg.computerName != null) ''
+        scutil --set ComputerName '${cfg.computerName}'
+      ''}
+      ${optionalString (cfg.hostName != null) ''
+        scutil --set HostName '${cfg.hostName}'
+      ''}
+      ${optionalString (cfg.localHostName != null) ''
+        scutil --set LocalHostName '${cfg.localHostName}'
+      ''}
+
       ${setNetworkServices}
     '';
 
diff --git a/tests/networking-hostname.nix b/tests/networking-hostname.nix
index 450c955a..3793958c 100644
--- a/tests/networking-hostname.nix
+++ b/tests/networking-hostname.nix
@@ -2,10 +2,11 @@
 
 {
   networking.hostName = "EVE";
+  networking.computerName = "EVE’s MacBook Pro";
 
   test = ''
     echo checking hostname in /activate >&2
-    grep "scutil --set ComputerName 'EVE'" ${config.out}/activate
+    grep "scutil --set ComputerName 'EVE’s MacBook Pro'" ${config.out}/activate
     grep "scutil --set LocalHostName 'EVE'" ${config.out}/activate
     grep "scutil --set HostName 'EVE'" ${config.out}/activate
     echo checking defaults write in ${config.out}/activate-user >&2