diff --git a/libc/bionic/realpath.c b/libc/bionic/realpath.c
index 4cb847b..b909831 100644
--- a/libc/bionic/realpath.c
+++ b/libc/bionic/realpath.c
@@ -1,4 +1,3 @@
-/*	$OpenBSD: realpath.c,v 1.13 2005/08/08 08:05:37 espie Exp $ */
 /*
  * Copyright (c) 2003 Constantin S. Svintsoff <kostik@iclub.nsu.ru>
  *
@@ -27,6 +26,12 @@
  * SUCH DAMAGE.
  */
 
+#if defined(LIBC_SCCS) && !defined(lint)
+static char sccsid[] = "@(#)realpath.c	8.1 (Berkeley) 2/16/94";
+#endif /* LIBC_SCCS and not lint */
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD: release/9.0.0/lib/libc/stdlib/realpath.c 217144 2011-01-08 11:04:30Z kib $");
+
 #include <sys/param.h>
 #include <sys/stat.h>
 
@@ -36,23 +41,36 @@
 #include <unistd.h>
 
 /*
- * char *realpath(const char *path, char resolved[PATH_MAX]);
- *
  * Find the real name of path, by removing all ".", ".." and symlink
  * components.  Returns (resolved) on success, or (NULL) on failure,
  * in which case the path which caused trouble is left in (resolved).
  */
 char *
-realpath(const char *path, char resolved[PATH_MAX])
+realpath(const char * __restrict path, char * __restrict resolved)
 {
 	struct stat sb;
 	char *p, *q, *s;
 	size_t left_len, resolved_len;
 	unsigned symlinks;
-	int serrno, slen;
+	int m, serrno, slen;
 	char left[PATH_MAX], next_token[PATH_MAX], symlink[PATH_MAX];
 
+	if (path == NULL) {
+		errno = EINVAL;
+		return (NULL);
+	}
+	if (path[0] == '\0') {
+		errno = ENOENT;
+		return (NULL);
+	}
 	serrno = errno;
+	if (resolved == NULL) {
+		resolved = malloc(PATH_MAX);
+		if (resolved == NULL)
+			return (NULL);
+		m = 1;
+	} else
+		m = 0;
 	symlinks = 0;
 	if (path[0] == '/') {
 		resolved[0] = '/';
@@ -63,13 +81,20 @@
 		left_len = strlcpy(left, path + 1, sizeof(left));
 	} else {
 		if (getcwd(resolved, PATH_MAX) == NULL) {
-			strlcpy(resolved, ".", PATH_MAX);
+			if (m)
+				free(resolved);
+			else {
+				resolved[0] = '.';
+				resolved[1] = '\0';
+			}
 			return (NULL);
 		}
 		resolved_len = strlen(resolved);
 		left_len = strlcpy(left, path, sizeof(left));
 	}
 	if (left_len >= sizeof(left) || resolved_len >= PATH_MAX) {
+		if (m)
+			free(resolved);
 		errno = ENAMETOOLONG;
 		return (NULL);
 	}
@@ -85,6 +110,8 @@
 		p = strchr(left, '/');
 		s = p ? p : left + left_len;
 		if (s - left >= sizeof(next_token)) {
+			if (m)
+				free(resolved);
 			errno = ENAMETOOLONG;
 			return (NULL);
 		}
@@ -95,6 +122,8 @@
 			memmove(left, s + 1, left_len + 1);
 		if (resolved[resolved_len - 1] != '/') {
 			if (resolved_len + 1 >= PATH_MAX) {
+				if (m)
+					free(resolved);
 				errno = ENAMETOOLONG;
 				return (NULL);
 			}
@@ -126,6 +155,8 @@
 		 */
 		resolved_len = strlcat(resolved, next_token, PATH_MAX);
 		if (resolved_len >= PATH_MAX) {
+			if (m)
+				free(resolved);
 			errno = ENAMETOOLONG;
 			return (NULL);
 		}
@@ -134,16 +165,23 @@
 				errno = serrno;
 				return (resolved);
 			}
+			if (m)
+				free(resolved);
 			return (NULL);
 		}
 		if (S_ISLNK(sb.st_mode)) {
 			if (symlinks++ > MAXSYMLINKS) {
+				if (m)
+					free(resolved);
 				errno = ELOOP;
 				return (NULL);
 			}
 			slen = readlink(resolved, symlink, sizeof(symlink) - 1);
-			if (slen < 0)
+			if (slen < 0) {
+				if (m)
+					free(resolved);
 				return (NULL);
+			}
 			symlink[slen] = '\0';
 			if (symlink[0] == '/') {
 				resolved[1] = 0;
@@ -164,6 +202,8 @@
 			if (p != NULL) {
 				if (symlink[slen - 1] != '/') {
 					if (slen + 1 >= sizeof(symlink)) {
+						if (m)
+							free(resolved);
 						errno = ENAMETOOLONG;
 						return (NULL);
 					}
@@ -172,6 +212,8 @@
 				}
 				left_len = strlcat(symlink, left, sizeof(left));
 				if (left_len >= sizeof(left)) {
+					if (m)
+						free(resolved);
 					errno = ENAMETOOLONG;
 					return (NULL);
 				}
diff --git a/libc/bionic/tdelete.c b/libc/bionic/tdelete.c
new file mode 100644
index 0000000..b64b47a
--- /dev/null
+++ b/libc/bionic/tdelete.c
@@ -0,0 +1,71 @@
+/*	$NetBSD: tdelete.c,v 1.2 1999/09/16 11:45:37 lukem Exp $	*/
+
+/*
+ * Tree search generalized from Knuth (6.2.2) Algorithm T just like
+ * the AT&T man page says.
+ *
+ * The node_t structure is for internal use only, lint doesn't grok it.
+ *
+ * Written by reading the System V Interface Definition, not the code.
+ *
+ * Totally public domain.
+ */
+
+#include <sys/cdefs.h>
+#if 0
+#if defined(LIBC_SCCS) && !defined(lint)
+__RCSID("$NetBSD: tdelete.c,v 1.2 1999/09/16 11:45:37 lukem Exp $");
+#endif /* LIBC_SCCS and not lint */
+#endif
+__FBSDID("$FreeBSD: release/9.0.0/lib/libc/stdlib/tdelete.c 108694 2003-01-05 02:43:18Z tjr $");
+
+#define _SEARCH_PRIVATE
+#include <search.h>
+#include <stdlib.h>
+
+
+/*
+ * delete node with given key
+ *
+ * vkey:   key to be deleted
+ * vrootp: address of the root of the tree
+ * compar: function to carry out node comparisons
+ */
+void *
+tdelete(const void * __restrict vkey, void ** __restrict vrootp,
+    int (*compar)(const void *, const void *))
+{
+	node_t **rootp = (node_t **)vrootp;
+	node_t *p, *q, *r;
+	int cmp;
+
+	if (rootp == NULL || (p = *rootp) == NULL)
+		return NULL;
+
+	while ((cmp = (*compar)(vkey, (*rootp)->key)) != 0) {
+		p = *rootp;
+		rootp = (cmp < 0) ?
+		    &(*rootp)->llink :		/* follow llink branch */
+		    &(*rootp)->rlink;		/* follow rlink branch */
+		if (*rootp == NULL)
+			return NULL;		/* key not found */
+	}
+	r = (*rootp)->rlink;			/* D1: */
+	if ((q = (*rootp)->llink) == NULL)	/* Left NULL? */
+		q = r;
+	else if (r != NULL) {			/* Right link is NULL? */
+		if (r->llink == NULL) {		/* D2: Find successor */
+			r->llink = q;
+			q = r;
+		} else {			/* D3: Find NULL link */
+			for (q = r->llink; q->llink != NULL; q = r->llink)
+				r = q;
+			r->llink = q->rlink;
+			q->llink = (*rootp)->llink;
+			q->rlink = (*rootp)->rlink;
+		}
+	}
+	free(*rootp);				/* D4: Free node */
+	*rootp = q;				/* link parent to new node */
+	return p;
+}
diff --git a/libc/bionic/tdestroy.c b/libc/bionic/tdestroy.c
new file mode 100644
index 0000000..70b71f4
--- /dev/null
+++ b/libc/bionic/tdestroy.c
@@ -0,0 +1,33 @@
+/*
+ * Copyright 2012, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define _SEARCH_PRIVATE
+#include <search.h>
+#include <stdlib.h>
+
+/* destroy a tree and free all allocated resources */
+void
+tdestroy(void *root, void (*destroy_func)(void *))
+{
+    node_t *root_node = (node_t *) root;
+    if (root_node == NULL) return;
+    if (root_node->llink)
+        tdestroy(root_node->llink, destroy_func);
+    if (root_node->rlink)
+        tdestroy(root_node->rlink, destroy_func);
+    (*destroy_func)(root_node->key);
+    free(root);
+}
diff --git a/libc/bionic/tfind.c b/libc/bionic/tfind.c
new file mode 100644
index 0000000..7e2bb0c
--- /dev/null
+++ b/libc/bionic/tfind.c
@@ -0,0 +1,48 @@
+/*	$NetBSD: tfind.c,v 1.2 1999/09/16 11:45:37 lukem Exp $	*/
+
+/*
+ * Tree search generalized from Knuth (6.2.2) Algorithm T just like
+ * the AT&T man page says.
+ *
+ * The node_t structure is for internal use only, lint doesn't grok it.
+ *
+ * Written by reading the System V Interface Definition, not the code.
+ *
+ * Totally public domain.
+ */
+
+#include <sys/cdefs.h>
+#if 0
+#if defined(LIBC_SCCS) && !defined(lint)
+__RCSID("$NetBSD: tfind.c,v 1.2 1999/09/16 11:45:37 lukem Exp $");
+#endif /* LIBC_SCCS and not lint */
+#endif
+__FBSDID("$FreeBSD: release/9.0.0/lib/libc/stdlib/tfind.c 108694 2003-01-05 02:43:18Z tjr $");
+
+#define _SEARCH_PRIVATE
+#include <stdlib.h>
+#include <search.h>
+
+/* find a node, or return 0 */
+void *
+tfind(vkey, vrootp, compar)
+	const void *vkey;		/* key to be found */
+	void * const *vrootp;		/* address of the tree root */
+	int (*compar)(const void *, const void *);
+{
+	node_t **rootp = (node_t **)vrootp;
+
+	if (rootp == NULL)
+		return NULL;
+
+	while (*rootp != NULL) {		/* T1: */
+		int r;
+
+		if ((r = (*compar)(vkey, (*rootp)->key)) == 0)	/* T2: */
+			return *rootp;		/* key found */
+		rootp = (r < 0) ?
+		    &(*rootp)->llink :		/* T3: follow left branch */
+		    &(*rootp)->rlink;		/* T4: follow right branch */
+	}
+	return NULL;
+}
diff --git a/libc/bionic/tsearch.c b/libc/bionic/tsearch.c
new file mode 100644
index 0000000..4270e6b
--- /dev/null
+++ b/libc/bionic/tsearch.c
@@ -0,0 +1,58 @@
+/*	$NetBSD: tsearch.c,v 1.3 1999/09/16 11:45:37 lukem Exp $	*/
+
+/*
+ * Tree search generalized from Knuth (6.2.2) Algorithm T just like
+ * the AT&T man page says.
+ *
+ * The node_t structure is for internal use only, lint doesn't grok it.
+ *
+ * Written by reading the System V Interface Definition, not the code.
+ *
+ * Totally public domain.
+ */
+
+#include <sys/cdefs.h>
+#if 0
+#if defined(LIBC_SCCS) && !defined(lint)
+__RCSID("$NetBSD: tsearch.c,v 1.3 1999/09/16 11:45:37 lukem Exp $");
+#endif /* LIBC_SCCS and not lint */
+#endif
+__FBSDID("$FreeBSD: release/9.0.0/lib/libc/stdlib/tsearch.c 108694 2003-01-05 02:43:18Z tjr $");
+
+#define _SEARCH_PRIVATE
+#include <search.h>
+#include <stdlib.h>
+
+/* find or insert datum into search tree */
+void *
+tsearch(vkey, vrootp, compar)
+	const void *vkey;		/* key to be located */
+	void **vrootp;			/* address of tree root */
+	int (*compar)(const void *, const void *);
+{
+	node_t *q;
+	node_t **rootp = (node_t **)vrootp;
+
+	if (rootp == NULL)
+		return NULL;
+
+	while (*rootp != NULL) {	/* Knuth's T1: */
+		int r;
+
+		if ((r = (*compar)(vkey, (*rootp)->key)) == 0)	/* T2: */
+			return *rootp;		/* we found it! */
+
+		rootp = (r < 0) ?
+		    &(*rootp)->llink :		/* T3: follow left branch */
+		    &(*rootp)->rlink;		/* T4: follow right branch */
+	}
+
+	q = malloc(sizeof(node_t));		/* T5: key not found */
+	if (q != 0) {				/* make new node */
+		*rootp = q;			/* link new node to old */
+		/* LINTED const castaway ok */
+		q->key = (void *)vkey;		/* initialize new node */
+		q->llink = q->rlink = NULL;
+	}
+	return q;
+}