charybdis service: add option to configure MOTD (#25512)

Read MOTD files from /etc/charybdis.

nixos/modules/services/networking/charybdis.nix

@@ -51,6 +51,17 @@ in
         '';
       };
 
+      motd = mkOption {
+        type = types.nullOr types.lines;
+        default = null;
+        description = ''
+          Charybdis MOTD text.
+
+          Charybdis will read its MOTD from /etc/charybdis/ircd.motd .
+          If set, the value of this option will be written to this path.
+        '';
+      };
+
     };
 
   };
@@ -58,8 +69,8 @@ in
 
   ###### implementation
 
-  config = mkIf cfg.enable {
-
+  config = mkIf cfg.enable (lib.mkMerge [
+    {
       users.extraUsers = singleton {
         name = cfg.user;
         description = "Charybdis IRC daemon user";
@@ -88,9 +99,12 @@ in
           ${coreutils}/bin/mkdir -p ${cfg.statedir}
           ${coreutils}/bin/chown ${cfg.user}:${cfg.group} ${cfg.statedir}
         '';
-
-    };
-
       };
 
     }
+    
+    (mkIf (cfg.motd != null) {
+      environment.etc."charybdis/ircd.motd".text = cfg.motd;
+    })
+  ]);
+}

pkgs/servers/irc/charybdis/default.nix

@@ -19,6 +19,7 @@ stdenv.mkDerivation rec {
     "--enable-ipv6"
     "--enable-openssl=${openssl.dev}"
     "--with-program-prefix=charybdis-"
+    "--sysconfdir=/etc/charybdis"
   ];
 
   buildInputs = [ bison flex openssl ];