kodi: support kernel overlays in service addon wrapper

update context is intended to be used on settings change.
This can later be extended to support selecting between
multiple overlays in an addon via config files in the
addon userdata dir.

Signed-off-by: Matthias Reichl <hias@horus.com>

packages/mediacenter/kodi/scripts/service-addon-wrapper

@@ -64,3 +64,48 @@ if [ -f "${SERVICE_FILE}" ] ; then
       ;;
   esac
 fi
+
+if [ ! -d /storage/.cache/kernel-overlays ] ; then
+  mkdir -p /storage/.cache/kernel-overlays
+fi
+
+# kernel-overlay addons built into the image have their
+# files installed in the default /usr/lib/kernel-overlays
+# location, not inside the kodi addon dir
+
+case "${ADDON_PATH}" in
+  /usr/share/kodi/addons/*)
+    OVERLAY_PATH="/usr/lib/kernel-overlays/${ADDON_ID}"
+    ;;
+  *)
+    OVERLAY_PATH="${ADDON_PATH}/kernel-overlay"
+    ;;
+esac
+
+create_overlay_conf() {
+  rm -f "${OVERLAY_CONF}"
+  echo "${OVERLAY_PATH}" > "${OVERLAY_CONF}"
+}
+
+if [ -d "${OVERLAY_PATH}" ] ; then
+  OVERLAY_CONF="/storage/.cache/kernel-overlays/50-${ADDON_ID}.conf"
+
+  case "${CONTEXT}" in
+    enable | post-install )
+      create_overlay_conf
+      ;;
+    disable | pre-uninstall )
+      rm -f "${OVERLAY_CONF}"
+      ;;
+    update )
+      if [ -e "${OVERLAY_CONF}" ] ; then
+        create_overlay_conf
+      fi
+      ;;
+    *)
+      echo "$0: unknown overlay context $CONTEXT"
+      exit 1
+      ;;
+  esac
+
+fi