first pass at a hostapd service, rough around the edges

pkgs/liminix-tools/networking/default.nix

@@ -28,6 +28,7 @@ in {
   };
   pppoe = callPackage ./pppoe.nix {};
   dnsmasq = callPackage ./dnsmasq.nix {};
+  hostapd = callPackage ./hostapd.nix {};
   route = { name, target, via, dependencies }:
     oneshot {
       inherit name;

pkgs/liminix-tools/networking/hostapd.nix

@@ -0,0 +1,39 @@
+# This is not a friendly interface to configuring a wireless AP: it
+# just passes everything straight through to the hostapd config.  When
+# we've worked out what the sensible options are to expose, we'll add
+# them as top-level attributes and rename params to extraParams
+
+{
+  liminix
+, hostapd
+, lib
+, writeText
+}:
+interface:
+{
+  params ? {}
+}:
+let
+  inherit (liminix.services) longrun;
+  inherit (lib) concatStringsSep mapAttrsToList;
+  inherit (builtins) toString;
+
+  name = "${interface.device}.hostapd";
+  defaults =  {
+    driver = "nl80211";
+    logger_syslog = "-1";
+    logger_syslog_level = 1;
+    ctrl_interface = "/run/hostapd";
+    ctrl_interface_group = 0;
+  };
+
+  conf = writeText "hostapd.conf"
+    (concatStringsSep
+      "\n"
+      (mapAttrsToList
+        (name: value: "${name}=${toString value}")
+        (defaults // params)));
+in longrun {
+  inherit name;
+  run = "${hostapd}/bin/hostapd -d -i ${interface.device}  -P /run/hostapd.pid -S ${conf}";
+}