raven/labsync: declaratively build tftp env

Fixes #8.

machines/raven/services/default.nix

@@ -3,7 +3,7 @@
     ./asterisk.nix
     ./dnsmasq.nix
     ./dyndns.nix
-    ./labsync.nix
+    ./labsync
     ./unifi-controller.nix
   ];
 }

machines/raven/services/labsync/default.nix

@@ -1,11 +1,13 @@
 # legacy labsync, currently partly implemented in docker outside of this configuration
+{ pkgs, ... }:
+
 {
   services.opentracker.enable = true;
 
   services.nginx.virtualHosts."labsync.lab.fablab-nea.de" = {
     locations = {
       "/" = {
-        root = "/opt/docker/tftpgen/data/labsync";
+        root = "/opt/docker/tftpgen/data";
         extraConfig = ''
           autoindex on;
         '';
@@ -16,7 +18,14 @@
 
   services.atftpd = {
     enable = true;
-    root = "/opt/docker/tftpgen/data";
+    root = pkgs.runCommand "pxelinux-tftproot" { } ''
+      mkdir -p $out/pxelinux.cfg
+      cp ${pkgs.syslinux}/share/syslinux/{ldlinux.c32,libcom32.c32,libutil.c32,lpxelinux.0,vesamenu.c32} $out
+      cp ${./splash.png} $out/splash.png
+      cp ${./pxelinux.cfg} $out/pxelinux.cfg/default
+      # required to serve labsync/labsync.cfg, which is generated dynamically by a docker container
+      ln -s /opt/docker/tftpgen/data $out/labsync
+    '';
   };
 
   networking.firewall.allowedTCPPorts = [

machines/raven/services/labsync/pxelinux.cfg

@@ -0,0 +1,21 @@
+# default menu settings
+menu width 100
+menu height 24
+menu title labsync
+
+# can be overwriten by mounting another image; has to be 1024×768 in 16:9
+menu background splash.png
+menu color border	* #00000000 #00000000 none
+menu color sel		* #ffffffff #76a1d0ff *
+menu color hotsel	1;7;37;40 #ffffffff #76a1d0ff *
+menu cmdlinerow 16
+menu timeoutrow 16
+menu tabmsgrow 18
+# do not show “press tab to edit options…” entry (empty)
+menu tabmsg
+
+include labsync/labsync.cfg
+default vesamenu.c32
+
+# disable timeout (explicitly)
+timeout 0