diff --git a/compat/sys/tree.3 b/compat/sys/tree.3
index ffb39ef..ead02ea 100644
--- a/compat/sys/tree.3
+++ b/compat/sys/tree.3
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: tree.3,v 1.20 2009/01/28 12:22:48 stsp Exp $
+.\"	$OpenBSD: tree.3,v 1.26 2014/09/08 01:27:55 schwarze Exp $
 .\"/*
 .\" * Copyright 2002 Niels Provos <provos@citi.umich.edu>
 .\" * All rights reserved.
@@ -23,7 +23,7 @@
 .\" * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 .\" * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 .\" */
-.Dd $Mdocdate: January 28 2009 $
+.Dd $Mdocdate: September 8 2014 $
 .Dt TREE 3
 .Os
 .Sh NAME
@@ -63,13 +63,15 @@
 .Nm RB_RIGHT ,
 .Nm RB_PARENT ,
 .Nm RB_FOREACH ,
+.Nm RB_FOREACH_SAFE ,
 .Nm RB_FOREACH_REVERSE ,
+.Nm RB_FOREACH_REVERSE_SAFE ,
 .Nm RB_INIT ,
 .Nm RB_INSERT ,
 .Nm RB_REMOVE
-.Nd "implementations of splay and red-black trees"
+.Nd implementations of splay and red-black trees
 .Sh SYNOPSIS
-.Fd #include <sys/tree.h>
+.In sys/tree.h
 .Pp
 .Fn SPLAY_PROTOTYPE "NAME" "TYPE" "FIELD" "CMP"
 .Fn SPLAY_GENERATE "NAME" "TYPE" "FIELD" "CMP"
@@ -130,7 +132,9 @@
 .Ft "struct TYPE *"
 .Fn RB_PARENT "struct TYPE *elm" "RB_ENTRY NAME"
 .Fn RB_FOREACH "VARNAME" "NAME" "RB_HEAD *head"
+.Fn RB_FOREACH_SAFE "VARNAME" "NAME" "RB_HEAD *head" "TEMP_VARNAME"
 .Fn RB_FOREACH_REVERSE "VARNAME" "NAME" "RB_HEAD *head"
+.Fn RB_FOREACH_REVERSE_SAFE "VARNAME" "NAME" "RB_HEAD *head" "TEMP_VARNAME"
 .Ft void
 .Fn RB_INIT "RB_HEAD *head"
 .Ft "struct TYPE *"
@@ -258,6 +262,11 @@ The
 macro inserts the new element
 .Fa elm
 into the tree.
+Upon success,
+.Va NULL
+is returned.
+If a matching element already exists in the tree, the insertion is
+aborted, and a pointer to the existing element is returned.
 .Pp
 The
 .Fn SPLAY_REMOVE
@@ -265,6 +274,11 @@ macro removes the element
 .Fa elm
 from the tree pointed by
 .Fa head .
+Upon success, a pointer to the removed element is returned.
+.Va NULL
+is returned if
+.Fa elm
+is not present in the tree.
 .Pp
 The
 .Fn SPLAY_FIND
@@ -405,6 +419,9 @@ macro removes the element
 .Fa elm
 from the tree pointed by
 .Fa head .
+.Fn RB_REMOVE
+returns
+.Fa elm .
 .Pp
 The
 .Fn RB_FIND
@@ -443,6 +460,18 @@ macros:
 RB_FOREACH(np, NAME, &head)
 .Ed
 .Pp
+The macros
+.Fn RB_FOREACH_SAFE
+and
+.Fn RB_FOREACH_REVERSE_SAFE
+traverse the tree referenced by head
+in a forward or reverse direction respectively,
+assigning each element in turn to np.
+However, unlike their unsafe counterparts,
+they permit both the removal of np
+as well as freeing it from within the loop safely
+without interfering with the traversal.
+.Pp
 The
 .Fn RB_EMPTY
 macro should be used to check whether a red-black tree is empty.
@@ -543,22 +572,6 @@ for (var = SPLAY_MIN(NAME, &head); var != NULL; var = nxt) {
 	free(var);
 }
 .Ed
-.Pp
-Both
-.Fn RB_INSERT
-and
-.Fn SPLAY_INSERT
-return
-.Va NULL
-if the element was inserted in the tree successfully, otherwise they
-return a pointer to the element with the colliding key.
-.Pp
-Accordingly,
-.Fn RB_REMOVE
-and
-.Fn SPLAY_REMOVE
-return the pointer to the removed element, otherwise they return
-.Va NULL
-to indicate an error.
 .Sh AUTHORS
-The author of the tree macros is Niels Provos.
+The author of the tree macros is
+.An Niels Provos .
diff --git a/compat/sys/tree.h b/compat/sys/tree.h
index 08b1b2e..80d0f53 100644
--- a/compat/sys/tree.h
+++ b/compat/sys/tree.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: tree.h,v 1.11 2008/05/11 22:19:09 millert Exp $	*/
+/*	$OpenBSD: tree.h,v 1.13 2011/07/09 00:19:45 pirofti Exp $	*/
 /*
  * Copyright 2002 Niels Provos <provos@citi.umich.edu>
  * All rights reserved.
@@ -329,7 +329,7 @@ struct {								\
 } while (0)
 
 #ifndef RB_AUGMENT
-#define RB_AUGMENT(x)
+#define RB_AUGMENT(x)	do {} while (0)
 #endif
 
 #define RB_ROTATE_LEFT(head, elm, tmp, field) do {			\
@@ -730,9 +730,19 @@ name##_RB_MINMAX(struct name *head, int val)				\
 	     (x) != NULL;						\
 	     (x) = name##_RB_NEXT(x))
 
+#define RB_FOREACH_SAFE(x, name, head, y)				\
+	for ((x) = RB_MIN(name, head);					\
+	    ((x) != NULL) && ((y) = name##_RB_NEXT(x), 1);		\
+	     (x) = (y))
+
 #define RB_FOREACH_REVERSE(x, name, head)				\
 	for ((x) = RB_MAX(name, head);					\
 	     (x) != NULL;						\
 	     (x) = name##_RB_PREV(x))
 
+#define RB_FOREACH_REVERSE_SAFE(x, name, head, y)			\
+	for ((x) = RB_MAX(name, head);					\
+	    ((x) != NULL) && ((y) = name##_RB_PREV(x), 1);		\
+	     (x) = (y))
+
 #endif	/* _SYS_TREE_H_ */