diff --git a/src/lib9/nulldir.c b/src/lib9/nulldir.c
new file mode 100644
index 0000000..612725d
--- /dev/null
+++ b/src/lib9/nulldir.c
@@ -0,0 +1,9 @@
+#include <u.h>
+#include <libc.h>
+
+void
+nulldir(Dir *d)
+{
+	memset(d, ~0, sizeof(Dir));
+	d->name = d->uid = d->gid = d->muid = "";
+}