dhcp6c readiness notification

examples/rotuer.nix

@@ -244,6 +244,7 @@ in rec {
       '';
     in longrun {
       inherit name;
+      notification-fd = 10;
       run = ''
         ${pkgs.odhcp6c}/bin/odhcp6c -s ${script} -e -v -p /run/${name}.pid -P 48 $(output ${services.wan} ifname)
         )

examples/udhcp6-script.fnl

@@ -45,3 +45,11 @@
        ]]
   (each [_ n (ipairs wanted)]
     (write-value-from-env n)))
+
+(let [ready (match state
+              "started" false
+              "unbound" false
+              "stopped" false
+              _ true)]
+  (and ready
+       (with-open [fd (io.open "/proc/self/fd/10" :w)] (fd:write "\n"))))