diff --git a/lib/libukfs/ukfs.3 b/lib/libukfs/ukfs.3
index fa78c6738d05..4f6ff1d9d3ef 100644
--- a/lib/libukfs/ukfs.3
+++ b/lib/libukfs/ukfs.3
@@ -1,4 +1,4 @@
-.\"     $NetBSD: ukfs.3,v 1.2 2008/08/01 14:47:28 pooka Exp $
+.\"     $NetBSD: ukfs.3,v 1.3 2008/08/01 19:52:10 pooka Exp $
 .\"
 .\" Copyright (c) 2008 Antti Kantee.  All rights reserved.
 .\"
@@ -74,6 +74,10 @@ which should be released after use.
 .br
 .Fn ukfs_modload_dir "const char *dirname"
 .Pp
+.Ft ssize_t
+.br
+.Fn ukfs_vfstypes "char *buf, size_t buflen"
+.Pp
 .Ft struct ukfs *
 .br
 .Fo ukfs_mount
@@ -127,6 +131,20 @@ not just a specific instance of
 It is preferable to call them from only one thread, as the underlying
 dynamic library interfaces may not be threadsafe.
 .Pp
+.Fn ukfs_vfstypes
+queries the available file system types and returns a nul-terminated
+list of types separated by spaces in
+.Fa buf .
+The format of the list is equivalent to the one returned by
+.Xr sysctl 3
+on the name
+.Pa vfs.generic.fstypes .
+The function returns the length of the string without the trailing nul
+or \-1 for error.
+Notably, the return value 0 means there are no file systems available.
+If there is not enough room in the caller's buffer for all file system
+types, as many as fit will be returned.
+.Pp
 .Fn ukfs_mount
 intializes a file system image.
 The handle resulting from the operation is passed to all other routines
diff --git a/lib/libukfs/ukfs.c b/lib/libukfs/ukfs.c
index 5219cde0232f..f7080e978f23 100644
--- a/lib/libukfs/ukfs.c
+++ b/lib/libukfs/ukfs.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: ukfs.c,v 1.3 2008/08/01 14:47:28 pooka Exp $	*/
+/*	$NetBSD: ukfs.c,v 1.4 2008/08/01 19:52:10 pooka Exp $	*/
 
 /*
  * Copyright (c) 2007, 2008  Antti Kantee.  All Rights Reserved.
@@ -42,6 +42,8 @@
 #include <sys/param.h>
 #include <sys/queue.h>
 #include <sys/stat.h>
+#include <sys/sysctl.h>
+#include <sys/mount.h>
 
 #include <assert.h>
 #include <dirent.h>
@@ -656,6 +658,47 @@ ukfs_modload_dir(const char *dir)
 	return nloaded;
 }
 
+/* XXX: this code uses definitions from NetBSD, needs rumpdefs */
+ssize_t
+ukfs_vfstypes(char *buf, size_t buflen)
+{
+	int mib[3];
+	struct sysctlnode q, ans[128];
+	size_t alen;
+	int error, i;
+
+	mib[0] = CTL_VFS;
+	mib[1] = VFS_GENERIC;
+	mib[2] = CTL_QUERY;
+	alen = sizeof(ans);
+
+	memset(&q, 0, sizeof(q));
+	q.sysctl_flags = SYSCTL_VERSION;
+
+	if (rump_sys___sysctl(mib, 3, ans, &alen, &q, sizeof(q), &error) == -1){
+		errno = error;
+		return -1;
+	}
+
+	for (i = 0; i < alen/sizeof(ans[0]); i++)
+		if (strcmp("fstypes", ans[i].sysctl_name) == 0)
+			break;
+	if (i == alen/sizeof(ans[0])) {
+		errno = ENXIO;
+		return -1;
+	}
+
+	mib[0] = CTL_VFS;
+	mib[1] = VFS_GENERIC;
+	mib[2] = ans[i].sysctl_num;
+
+	if (rump_sys___sysctl(mib, 3, buf, &buflen, NULL, 0, &error) == -1) {
+		errno = error;
+		return -1;
+	}
+
+	return buflen;
+}
 
 /*
  * Utilities
diff --git a/lib/libukfs/ukfs.h b/lib/libukfs/ukfs.h
index d9168dbe3414..e1717c8b1478 100644
--- a/lib/libukfs/ukfs.h
+++ b/lib/libukfs/ukfs.h
@@ -1,4 +1,4 @@
-/*	$NetBSD: ukfs.h,v 1.5 2008/08/01 14:50:28 pooka Exp $	*/
+/*	$NetBSD: ukfs.h,v 1.6 2008/08/01 19:52:11 pooka Exp $	*/
 
 /*
  * Copyright (c) 2007, 2008  Antti Kantee.  All Rights Reserved.
@@ -95,6 +95,7 @@ struct vnode	*ukfs_getrvp(struct ukfs *);
 /* dynamic loading of library modules */
 int		ukfs_modload(const char *);
 int		ukfs_modload_dir(const char *);
+ssize_t		ukfs_vfstypes(char *, size_t);
 
 /* Utilities */
 int		ukfs_util_builddirs(struct ukfs *, const char *, mode_t);