lib: xpc: implement support for iterating through directories

lib/libfs/interface.h

@@ -27,7 +27,6 @@ extern kern_status_t fs_msg_read(
 	const xpc_endpoint_t *sender,
 	size_t count,
 	int *out_err,
-	size_t *out_nr_read,
 	xpc_buffer_t *out_data,
 	void *arg);
 extern kern_status_t fs_msg_write(
@@ -55,4 +54,11 @@ extern kern_status_t fs_msg_map(
 	kern_handle_t *out_vmo,
 	void *arg);
 
+extern kern_status_t fs_msg_getdents(
+	xpc_context_t *ctx,
+	const xpc_endpoint_t *sender,
+	int *out_err,
+	xpc_buffer_t *out_dents,
+	void *arg);
+
 #endif