diff --git a/include/wchar.h b/include/wchar.h
index c1aaf7812e71..39b74e8637ef 100644
--- a/include/wchar.h
+++ b/include/wchar.h
@@ -209,6 +209,10 @@ int	wcwidth(wchar_t);
 
 #if __BSD_VISIBLE
 wchar_t	*fgetwln(struct __sFILE * __restrict, size_t * __restrict);
+size_t	mbsnrtowcs(wchar_t * __restrict, const char ** __restrict, size_t,
+	    size_t, mbstate_t * __restrict);
+size_t	wcsnrtombs(char * __restrict, const wchar_t ** __restrict, size_t,
+	    size_t, mbstate_t * __restrict);
 size_t	wcslcat(wchar_t *, const wchar_t *, size_t);
 size_t	wcslcpy(wchar_t *, const wchar_t *, size_t);
 #endif
diff --git a/lib/libc/locale/Makefile.inc b/lib/libc/locale/Makefile.inc
index 1e8a36322288..cf02a3fa5cbf 100644
--- a/lib/libc/locale/Makefile.inc
+++ b/lib/libc/locale/Makefile.inc
@@ -8,11 +8,13 @@ SRCS+=	big5.c btowc.c collate.c collcmp.c euc.c fix_grouping.c frune.c \
 	gb18030.c gb2312.c gbk.c isctype.c iswctype.c \
 	ldpart.c lmessages.c lmonetary.c lnumeric.c localeconv.c mblen.c \
 	mbrlen.c \
-	mbrtowc.c mbrune.c mbsinit.c mbsrtowcs.c mbtowc.c mbstowcs.c \
+	mbrtowc.c mbrune.c mbsinit.c mbsnrtowcs.c \
+	mbsrtowcs.c mbtowc.c mbstowcs.c \
 	mskanji.c nextwctype.c nl_langinfo.c nomacros.c none.c rune.c \
 	runetype.c setinvalidrune.c setlocale.c setrunelocale.c srune.c \
 	table.c \
-	tolower.c toupper.c utf2.c utf8.c wcrtomb.c wcsrtombs.c wcsftime.c \
+	tolower.c toupper.c utf2.c utf8.c wcrtomb.c wcsnrtombs.c \
+	wcsrtombs.c wcsftime.c \
 	wcstof.c wcstod.c \
 	wcstoimax.c wcstol.c wcstold.c wcstoll.c \
 	wcstombs.c \
@@ -47,9 +49,11 @@ MLINKS+=iswalnum.3 iswalpha.3 iswalnum.3 iswascii.3 iswalnum.3 iswblank.3 \
 	iswalnum.3 iswupper.3 iswalnum.3 iswxdigit.3
 MLINKS+=isxdigit.3 ishexnumber.3
 MLINKS+=mbrune.3 mbmb.3 mbrune.3 mbrrune.3
+MLINKS+=mbsrtowcs.3 mbsnrtowcs.3
 MLINKS+=rune.3 fgetrune.3 rune.3 fputrune.3 rune.3 fungetrune.3 \
 	rune.3 setinvalidrune.3 rune.3 setrunelocale.3 rune.3 sgetrune.3 \
 	rune.3 sputrune.3
+MLINKS+=wcsrtombs.3 wcsnrtombs.3
 MLINKS+=wcstod.3 wcstof.3 wcstod.3 wcstold.3
 MLINKS+=wcstol.3 wcstoul.3 wcstol.3 wcstoll.3 wcstol.3 wcstoull.3 \
 	wcstol.3 wcstoimax.3 wcstol.3 wcstoumax.3
diff --git a/lib/libc/locale/mblocal.h b/lib/libc/locale/mblocal.h
index 8e36ad5ea2a2..3727b72c0742 100644
--- a/lib/libc/locale/mblocal.h
+++ b/lib/libc/locale/mblocal.h
@@ -37,11 +37,11 @@
 extern size_t (*__mbrtowc)(wchar_t * __restrict, const char * __restrict,
     size_t, mbstate_t * __restrict);
 extern int (*__mbsinit)(const mbstate_t *);
-extern size_t (*__mbsrtowcs)(wchar_t * __restrict, const char ** __restrict,
-    size_t, mbstate_t * __restrict);
+extern size_t (*__mbsnrtowcs)(wchar_t * __restrict, const char ** __restrict,
+    size_t, size_t, mbstate_t * __restrict);
 extern size_t (*__wcrtomb)(char * __restrict, wchar_t, mbstate_t * __restrict);
-extern size_t (*__wcsrtombs)(char * __restrict, const wchar_t ** __restrict,
-    size_t, mbstate_t * __restrict);
+extern size_t (*__wcsnrtombs)(char * __restrict, const wchar_t ** __restrict,
+    size_t, size_t, mbstate_t * __restrict);
 
 /*
  * Conversion functions for "NONE"/C/POSIX encoding.
@@ -49,17 +49,17 @@ extern size_t (*__wcsrtombs)(char * __restrict, const wchar_t ** __restrict,
 extern size_t _none_mbrtowc(wchar_t * __restrict, const char * __restrict,
     size_t, mbstate_t * __restrict);
 extern int _none_mbsinit(const mbstate_t *);
-extern size_t _none_mbsrtowcs(wchar_t * __restrict, const char ** __restrict,
-    size_t, mbstate_t * __restrict);
+extern size_t _none_mbsnrtowcs(wchar_t * __restrict, const char ** __restrict,
+    size_t, size_t, mbstate_t * __restrict);
 extern size_t _none_wcrtomb(char * __restrict, wchar_t,
     mbstate_t * __restrict);
-extern size_t _none_wcsrtombs(char * __restrict, const wchar_t ** __restrict,
-    size_t, mbstate_t * __restrict);
+extern size_t _none_wcsnrtombs(char * __restrict, const wchar_t ** __restrict,
+    size_t, size_t, mbstate_t * __restrict);
 
-extern size_t __mbsrtowcs_std(wchar_t * __restrict, const char ** __restrict,
-    size_t, mbstate_t * __restrict);
-extern size_t __wcsrtombs_std(char * __restrict, const wchar_t ** __restrict,
-    size_t, mbstate_t * __restrict);
+extern size_t __mbsnrtowcs_std(wchar_t * __restrict, const char ** __restrict,
+    size_t, size_t, mbstate_t * __restrict);
+extern size_t __wcsnrtombs_std(char * __restrict, const wchar_t ** __restrict,
+    size_t, size_t, mbstate_t * __restrict);
 
 /*
  * Rune emulation functions.
diff --git a/lib/libc/locale/mbsnrtowcs.c b/lib/libc/locale/mbsnrtowcs.c
new file mode 100644
index 000000000000..5284087fb4c1
--- /dev/null
+++ b/lib/libc/locale/mbsnrtowcs.c
@@ -0,0 +1,91 @@
+/*-
+ * Copyright (c) 2002-2004 Tim J. Robbins.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <errno.h>
+#include <limits.h>
+#include <stdlib.h>
+#include <wchar.h>
+#include "mblocal.h"
+
+size_t
+mbsnrtowcs(wchar_t * __restrict dst, const char ** __restrict src,
+    size_t nms, size_t len, mbstate_t * __restrict ps)
+{
+	static mbstate_t mbs;
+
+	if (ps == NULL)
+		ps = &mbs;
+	return (__mbsnrtowcs(dst, src, nms, len, ps));
+}
+
+size_t
+__mbsnrtowcs_std(wchar_t * __restrict dst, const char ** __restrict src,
+    size_t nms, size_t len, mbstate_t * __restrict ps)
+{
+	const char *s;
+	size_t nchr;
+	wchar_t wc;
+	size_t nb;
+
+	s = *src;
+	nchr = 0;
+
+	if (dst == NULL) {
+		for (;;) {
+			if ((nb = __mbrtowc(&wc, s, nms, ps)) == (size_t)-1)
+				/* Invalid sequence - mbrtowc() sets errno. */
+				return ((size_t)-1);
+			else if (nb == 0 || nb == (size_t)-2)
+				return (nchr);
+			s += nb;
+			nms -= nb;
+			nchr++;
+		}
+		/*NOTREACHED*/
+	}
+
+	while (len-- > 0) {
+		if ((nb = __mbrtowc(dst, s, nms, ps)) == (size_t)-1) {
+			*src = s;
+			return ((size_t)-1);
+		} else if (nb == (size_t)-2) {
+			*src = s + nms;
+			return (nchr);
+		} else if (nb == 0) {
+			*src = NULL;
+			return (nchr);
+		}
+		s += nb;
+		nms -= nb;
+		nchr++;
+		dst++;
+	}
+	*src = s;
+	return (nchr);
+}
diff --git a/lib/libc/locale/mbsrtowcs.3 b/lib/libc/locale/mbsrtowcs.3
index 9963d8552088..f54e419139e2 100644
--- a/lib/libc/locale/mbsrtowcs.3
+++ b/lib/libc/locale/mbsrtowcs.3
@@ -23,11 +23,12 @@
 .\" SUCH DAMAGE.
 .\"
 .\" $FreeBSD$
-.Dd April 8, 2004
+.Dd July 21, 2004
 .Dt MBSRTOWCS 3
 .Os
 .Sh NAME
-.Nm mbsrtowcs
+.Nm mbsrtowcs ,
+.Nm mbsnrtowcs
 .Nd "convert a character string to a wide-character string (restartable)"
 .Sh LIBRARY
 .Lb libc
@@ -38,6 +39,11 @@
 .Fa "wchar_t * restrict dst" "const char ** restrict src" "size_t len"
 .Fa "mbstate_t * restrict ps"
 .Fc
+.Ft size_t
+.Fo mbsnrtowcs
+.Fa "wchar_t * restrict dst" "const char ** restrict src" "size_t nms"
+.Fa "size_t len" "mbstate_t * restrict ps"
+.Fc
 .Sh DESCRIPTION
 The
 .Fn mbsrtowcs
@@ -82,10 +88,21 @@ uses an internal, static
 .Vt mbstate_t
 object, which is initialized to the initial conversion state
 at program startup.
+.Pp
+The
+.Fn mbsnrtowcs
+function behaves identically to
+.Fn mbsrtowcs ,
+except that conversion stops after reading at most
+.Fa nms
+bytes from the buffer pointed to by 
+.Fa src .
 .Sh RETURN VALUES
 The
 .Fn mbsrtowcs
-function returns the number of wide characters stored in
+and
+.Fn mbsnrtowcs
+functions return the number of wide characters stored in
 the array pointed to by
 .Fa dst
 if successful, otherwise it returns
@@ -93,7 +110,9 @@ if successful, otherwise it returns
 .Sh ERRORS
 The
 .Fn mbsrtowcs
-function will fail if:
+and
+.Fn mbsnrtowcs
+functions will fail if:
 .Bl -tag -width Er
 .It Bq Er EILSEQ
 An invalid multibyte character sequence was encountered.
@@ -110,3 +129,7 @@ The
 .Fn mbsrtowcs
 function conforms to
 .St -isoC-99 .
+.Pp
+The
+.Fn mbsnrtowcs
+function is an extension to the standard.
diff --git a/lib/libc/locale/mbsrtowcs.c b/lib/libc/locale/mbsrtowcs.c
index a90c65563f7a..1239c82c337f 100644
--- a/lib/libc/locale/mbsrtowcs.c
+++ b/lib/libc/locale/mbsrtowcs.c
@@ -41,46 +41,5 @@ mbsrtowcs(wchar_t * __restrict dst, const char ** __restrict src, size_t len,
 
 	if (ps == NULL)
 		ps = &mbs;
-	return (__mbsrtowcs(dst, src, len, ps));
-}
-
-size_t
-__mbsrtowcs_std(wchar_t * __restrict dst, const char ** __restrict src,
-    size_t len, mbstate_t * __restrict ps)
-{
-	const char *s;
-	size_t nchr;
-	wchar_t wc;
-	int nb;
-
-	s = *src;
-	nchr = 0;
-
-	if (dst == NULL) {
-		for (;;) {
-			if ((nb = (int)__mbrtowc(&wc, s, MB_CUR_MAX, ps)) < 0)
-				/* Invalid sequence - mbrtowc() sets errno. */
-				return ((size_t)-1);
-			else if (nb == 0)
-				return (nchr);
-			s += nb;
-			nchr++;
-		}
-		/*NOTREACHED*/
-	}
-
-	while (len-- > 0) {
-		if ((nb = (int)__mbrtowc(dst, s, MB_CUR_MAX, ps)) < 0) {
-			*src = s;
-			return ((size_t)-1);
-		} else if (nb == 0) {
-			*src = NULL;
-			return (nchr);
-		}
-		s += nb;
-		nchr++;
-		dst++;
-	}
-	*src = s;
-	return (nchr);
+	return (__mbsnrtowcs(dst, src, SIZE_T_MAX, len, ps));
 }
diff --git a/lib/libc/locale/mbstowcs.c b/lib/libc/locale/mbstowcs.c
index 4623535457dd..ad259d84dab3 100644
--- a/lib/libc/locale/mbstowcs.c
+++ b/lib/libc/locale/mbstowcs.c
@@ -27,6 +27,7 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
+#include <limits.h>
 #include <stdlib.h>
 #include <wchar.h>
 #include "mblocal.h"
@@ -38,5 +39,5 @@ mbstowcs(wchar_t * __restrict pwcs, const char * __restrict s, size_t n)
 	mbstate_t mbs;
 
 	mbs = initial;
-	return (__mbsrtowcs(pwcs, &s, n, &mbs));
+	return (__mbsnrtowcs(pwcs, &s, SIZE_T_MAX, n, &mbs));
 }
diff --git a/lib/libc/locale/none.c b/lib/libc/locale/none.c
index 2a3ada6b3ee6..d964233e45e0 100644
--- a/lib/libc/locale/none.c
+++ b/lib/libc/locale/none.c
@@ -55,11 +55,12 @@ int	_none_init(_RuneLocale *);
 size_t	_none_mbrtowc(wchar_t * __restrict, const char * __restrict, size_t,
 	    mbstate_t * __restrict);
 int	_none_mbsinit(const mbstate_t *);
-size_t	_none_mbsrtowcs(wchar_t * __restrict, const char ** __restrict,
-	    size_t, mbstate_t * __restrict);
+size_t	_none_mbsnrtowcs(wchar_t * __restrict dst,
+	    const char ** __restrict src, size_t nms, size_t len,
+	    mbstate_t * __restrict ps __unused);
 size_t	_none_wcrtomb(char * __restrict, wchar_t, mbstate_t * __restrict);
-size_t	_none_wcsrtombs(char * __restrict, const wchar_t ** __restrict,
-	    size_t, mbstate_t * __restrict);
+size_t	_none_wcsnrtombs(char * __restrict, const wchar_t ** __restrict,
+	    size_t, size_t, mbstate_t * __restrict);
 
 int
 _none_init(_RuneLocale *rl)
@@ -67,9 +68,9 @@ _none_init(_RuneLocale *rl)
 
 	__mbrtowc = _none_mbrtowc;
 	__mbsinit = _none_mbsinit;
-	__mbsrtowcs = _none_mbsrtowcs;
+	__mbsnrtowcs = _none_mbsnrtowcs;
 	__wcrtomb = _none_wcrtomb;
-	__wcsrtombs = _none_wcsrtombs;
+	__wcsnrtombs = _none_wcsnrtombs;
 	_CurrentRuneLocale = rl;
 	__mb_cur_max = 1;
 	return(0);
@@ -119,18 +120,20 @@ _none_wcrtomb(char * __restrict s, wchar_t wc,
 }
 
 size_t
-_none_mbsrtowcs(wchar_t * __restrict dst, const char ** __restrict src,
-    size_t len, mbstate_t * __restrict ps __unused)
+_none_mbsnrtowcs(wchar_t * __restrict dst, const char ** __restrict src,
+    size_t nms, size_t len, mbstate_t * __restrict ps __unused)
 {
 	const char *s;
 	size_t nchr;
 
-	if (dst == NULL)
-		return (strlen(*src));
+	if (dst == NULL) {
+		s = memchr(*src, '\0', nms);
+		return (s != NULL ? s - *src : nms);
+	}
 
 	s = *src;
 	nchr = 0;
-	while (len-- > 0) {
+	while (len-- > 0 && nms-- > 0) {
 		if ((*dst++ = (unsigned char)*s++) == L'\0') {
 			*src = NULL;
 			return (nchr);
@@ -142,14 +145,14 @@ _none_mbsrtowcs(wchar_t * __restrict dst, const char ** __restrict src,
 }
 
 size_t
-_none_wcsrtombs(char * __restrict dst, const wchar_t ** __restrict src,
-    size_t len, mbstate_t * __restrict ps __unused)
+_none_wcsnrtombs(char * __restrict dst, const wchar_t ** __restrict src,
+    size_t nwc, size_t len, mbstate_t * __restrict ps __unused)
 {
 	const wchar_t *s;
 	size_t nchr;
 
 	if (dst == NULL) {
-		for (s = *src; *s != L'\0'; s++) {
+		for (s = *src; nwc > 0 && *s != L'\0'; s++, nwc--) {
 			if (*s < 0 || *s > UCHAR_MAX) {
 				errno = EILSEQ;
 				return ((size_t)-1);
@@ -160,7 +163,7 @@ _none_wcsrtombs(char * __restrict dst, const wchar_t ** __restrict src,
 
 	s = *src;
 	nchr = 0;
-	while (len-- > 0) {
+	while (len-- > 0 && nwc-- > 0) {
 		if (*s < 0 || *s > UCHAR_MAX) {
 			errno = EILSEQ;
 			return ((size_t)-1);
diff --git a/lib/libc/locale/setrunelocale.c b/lib/libc/locale/setrunelocale.c
index de3ee06d7c37..4c19ff76a178 100644
--- a/lib/libc/locale/setrunelocale.c
+++ b/lib/libc/locale/setrunelocale.c
@@ -100,10 +100,11 @@ __setrunelocale(const char *encoding)
 	static size_t (*Cached__wcrtomb)(char * __restrict, wchar_t,
 	    mbstate_t * __restrict);
 	static int (*Cached__mbsinit)(const mbstate_t *);
-	static size_t (*Cached__mbsrtowcs)(wchar_t * __restrict,
-	    const char ** __restrict, size_t, mbstate_t * __restrict);
-	static size_t (*Cached__wcsrtombs)(char * __restrict,
-	    const wchar_t ** __restrict, size_t, mbstate_t * __restrict);
+	static size_t (*Cached__mbsnrtowcs)(wchar_t * __restrict,
+	    const char ** __restrict, size_t, size_t, mbstate_t * __restrict);
+	static size_t (*Cached__wcsnrtombs)(char * __restrict,
+	    const wchar_t ** __restrict, size_t, size_t,
+	    mbstate_t * __restrict);
 
 	/*
 	 * The "C" and "POSIX" locale are always here.
@@ -113,9 +114,9 @@ __setrunelocale(const char *encoding)
 		__mb_cur_max = 1;
 		__mbrtowc = _none_mbrtowc;
 		__mbsinit = _none_mbsinit;
-		__mbsrtowcs = _none_mbsrtowcs;
+		__mbsnrtowcs = _none_mbsnrtowcs;
 		__wcrtomb = _none_wcrtomb;
-		__wcsrtombs = _none_wcsrtombs;
+		__wcsnrtombs = _none_wcsnrtombs;
 		return (0);
 	}
 
@@ -128,9 +129,9 @@ __setrunelocale(const char *encoding)
 		__mb_cur_max = Cached__mb_cur_max;
 		__mbrtowc = Cached__mbrtowc;
 		__mbsinit = Cached__mbsinit;
-		__mbsrtowcs = Cached__mbsrtowcs;
+		__mbsnrtowcs = Cached__mbsnrtowcs;
 		__wcrtomb = Cached__wcrtomb;
-		__wcsrtombs = Cached__wcsrtombs;
+		__wcsnrtombs = Cached__wcsnrtombs;
 		return (0);
 	}
 
@@ -156,9 +157,9 @@ __setrunelocale(const char *encoding)
 
 	__mbrtowc = NULL;
 	__mbsinit = NULL;
-	__mbsrtowcs = __mbsrtowcs_std;
+	__mbsnrtowcs = __mbsnrtowcs_std;
 	__wcrtomb = NULL;
-	__wcsrtombs = __wcsrtombs_std;
+	__wcsnrtombs = __wcsnrtombs_std;
 	rl->__sputrune = __emulated_sputrune;
 	rl->__sgetrune = __emulated_sgetrune;
 	if (strcmp(rl->__encoding, "NONE") == 0)
@@ -192,9 +193,9 @@ __setrunelocale(const char *encoding)
 		Cached__mb_cur_max = __mb_cur_max;
 		Cached__mbrtowc = __mbrtowc;
 		Cached__mbsinit = __mbsinit;
-		Cached__mbsrtowcs = __mbsrtowcs;
+		Cached__mbsnrtowcs = __mbsnrtowcs;
 		Cached__wcrtomb = __wcrtomb;
-		Cached__wcsrtombs = __wcsrtombs;
+		Cached__wcsnrtombs = __wcsnrtombs;
 		(void)strcpy(ctype_encoding, encoding);
 	} else
 		free(rl);
diff --git a/lib/libc/locale/table.c b/lib/libc/locale/table.c
index 4d72959505b3..de71a4b820b8 100644
--- a/lib/libc/locale/table.c
+++ b/lib/libc/locale/table.c
@@ -255,9 +255,9 @@ int __mb_cur_max = 1;
 size_t (*__mbrtowc)(wchar_t * __restrict, const char * __restrict, size_t,
     mbstate_t * __restrict) = _none_mbrtowc;
 int (*__mbsinit)(const mbstate_t *) = _none_mbsinit;
-size_t (*__mbsrtowcs)(wchar_t * __restrict, const char ** __restrict,
-    size_t, mbstate_t * __restrict) = _none_mbsrtowcs;
+size_t (*__mbsnrtowcs)(wchar_t * __restrict, const char ** __restrict,
+    size_t, size_t, mbstate_t * __restrict) = _none_mbsnrtowcs;
 size_t (*__wcrtomb)(char * __restrict, wchar_t, mbstate_t * __restrict) =
     _none_wcrtomb;
-size_t (*__wcsrtombs)(char * __restrict, const wchar_t ** __restrict,
-    size_t, mbstate_t * __restrict) = _none_wcsrtombs;
+size_t (*__wcsnrtombs)(char * __restrict, const wchar_t ** __restrict,
+    size_t, size_t, mbstate_t * __restrict) = _none_wcsnrtombs;
diff --git a/lib/libc/locale/wcsnrtombs.c b/lib/libc/locale/wcsnrtombs.c
new file mode 100644
index 000000000000..6f2d5b0c88c0
--- /dev/null
+++ b/lib/libc/locale/wcsnrtombs.c
@@ -0,0 +1,111 @@
+/*-
+ * Copyright (c) 2002-2004 Tim J. Robbins.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <limits.h>
+#include <stdlib.h>
+#include <string.h>
+#include <wchar.h>
+#include "mblocal.h"
+
+size_t
+wcsnrtombs(char * __restrict dst, const wchar_t ** __restrict src, size_t nwc,
+    size_t len, mbstate_t * __restrict ps)
+{
+	static mbstate_t mbs;
+
+	if (ps == NULL)
+		ps = &mbs;
+	return (__wcsnrtombs(dst, src, nwc, len, ps));
+}
+
+size_t
+__wcsnrtombs_std(char * __restrict dst, const wchar_t ** __restrict src,
+    size_t nwc, size_t len, mbstate_t * __restrict ps)
+{
+	mbstate_t mbsbak;
+	char buf[MB_LEN_MAX];
+	const wchar_t *s;
+	size_t nbytes;
+	size_t nb;
+
+	s = *src;
+	nbytes = 0;
+
+	if (dst == NULL) {
+		while (nwc-- > 0) {
+			if ((nb = __wcrtomb(buf, *s, ps)) == (size_t)-1)
+				/* Invalid character - wcrtomb() sets errno. */
+				return ((size_t)-1);
+			else if (*s == L'\0')
+				break;
+			s++;
+			nbytes += nb;
+		}
+		return (nbytes + nb - 1);
+	}
+
+	while (len > 0 && nwc-- > 0) {
+		if (len > (size_t)MB_CUR_MAX) {
+			/* Enough space to translate in-place. */
+			if ((nb = (int)__wcrtomb(dst, *s, ps)) < 0) {
+				*src = s;
+				return ((size_t)-1);
+			}
+		} else {
+			/*
+			 * May not be enough space; use temp. buffer.
+			 *
+			 * We need to save a copy of the conversion state
+			 * here so we can restore it if the multibyte
+			 * character is too long for the buffer.
+			 */
+			mbsbak = *ps;
+			if ((nb = (int)__wcrtomb(buf, *s, ps)) < 0) {
+				*src = s;
+				return ((size_t)-1);
+			}
+			if (nb > (int)len) {
+				/* MB sequence for character won't fit. */
+				*ps = mbsbak;
+				break;
+			}
+			memcpy(dst, buf, nb);
+		}
+		if (*s == L'\0') {
+			*src = NULL;
+			return (nbytes + nb - 1);
+		}
+		s++;
+		dst += nb;
+		len -= nb;
+		nbytes += nb;
+	}
+	*src = s;
+	return (nbytes);
+}
diff --git a/lib/libc/locale/wcsrtombs.3 b/lib/libc/locale/wcsrtombs.3
index 91e61fde5086..ff607c2dad11 100644
--- a/lib/libc/locale/wcsrtombs.3
+++ b/lib/libc/locale/wcsrtombs.3
@@ -24,11 +24,12 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd April 8, 2004
+.Dd July 21, 2004
 .Dt WCSRTOMBS 3
 .Os
 .Sh NAME
-.Nm wcsrtombs
+.Nm wcsrtombs ,
+.Nm wcsnrtombs
 .Nd "convert a wide-character string to a character string (restartable)"
 .Sh LIBRARY
 .Lb libc
@@ -39,6 +40,11 @@
 .Fa "char * restrict dst" "const wchar_t ** restrict src"
 .Fa "size_t len" "mbstate_t * restrict ps"
 .Fc
+.Ft size_t
+.Fo wcsnrtombs
+.Fa "char * restrict dst" "const wchar_t ** restrict src" "size_t nwc"
+.Fa "size_t len" "mbstate_t * restrict ps"
+.Fc
 .Sh DESCRIPTION
 The
 .Fn wcsrtombs
@@ -82,10 +88,21 @@ uses an internal, static
 .Vt mbstate_t
 object, which is initialized to the initial conversion state
 at program startup.
+.Pp
+The
+.Fn wcsnrtombs
+function behaves identically to
+.Fn wcsrtombs ,
+except that conversion stops after reading at most
+.Fa nwc
+characters from the buffer pointed to by
+.Fa src .
 .Sh RETURN VALUES
 The
 .Fn wcsrtombs
-function returns the number of bytes stored in
+and
+.Fn wcsnrtombs
+functions return the number of bytes stored in
 the array pointed to by
 .Fa dst
 (not including any terminating null), if successful, otherwise it returns
@@ -93,7 +110,9 @@ the array pointed to by
 .Sh ERRORS
 The
 .Fn wcsrtombs
-function will fail if:
+and
+.Fn wcsnrtombs
+functions will fail if:
 .Bl -tag -width Er
 .It Bq Er EILSEQ
 An invalid wide character was encountered.
@@ -109,3 +128,7 @@ The
 .Fn wcsrtombs
 function conforms to
 .St -isoC-99 .
+.Pp
+The
+.Fn wcsnrtombs
+function is an extension to the standard.
diff --git a/lib/libc/locale/wcsrtombs.c b/lib/libc/locale/wcsrtombs.c
index a03f0d33f83d..f3b38b71c4d8 100644
--- a/lib/libc/locale/wcsrtombs.c
+++ b/lib/libc/locale/wcsrtombs.c
@@ -41,71 +41,5 @@ wcsrtombs(char * __restrict dst, const wchar_t ** __restrict src, size_t len,
 
 	if (ps == NULL)
 		ps = &mbs;
-	return (__wcsrtombs(dst, src, len, ps));
-}
-
-size_t
-__wcsrtombs_std(char * __restrict dst, const wchar_t ** __restrict src,
-    size_t len, mbstate_t * __restrict ps)
-{
-	mbstate_t mbsbak;
-	char buf[MB_LEN_MAX];
-	const wchar_t *s;
-	size_t nbytes;
-	int nb;
-
-	s = *src;
-	nbytes = 0;
-
-	if (dst == NULL) {
-		for (;;) {
-			if ((nb = (int)__wcrtomb(buf, *s, ps)) < 0)
-				/* Invalid character - wcrtomb() sets errno. */
-				return ((size_t)-1);
-			else if (*s == L'\0')
-				return (nbytes + nb - 1);
-			s++;
-			nbytes += nb;
-		}
-		/*NOTREACHED*/
-	}
-
-	while (len > 0) {
-		if (len > (size_t)MB_CUR_MAX) {
-			/* Enough space to translate in-place. */
-			if ((nb = (int)__wcrtomb(dst, *s, ps)) < 0) {
-				*src = s;
-				return ((size_t)-1);
-			}
-		} else {
-			/*
-			 * May not be enough space; use temp. buffer.
-			 *
-			 * We need to save a copy of the conversion state
-			 * here so we can restore it if the multibyte
-			 * character is too long for the buffer.
-			 */
-			mbsbak = *ps;
-			if ((nb = (int)__wcrtomb(buf, *s, ps)) < 0) {
-				*src = s;
-				return ((size_t)-1);
-			}
-			if (nb > (int)len) {
-				/* MB sequence for character won't fit. */
-				*ps = mbsbak;
-				break;
-			}
-			memcpy(dst, buf, nb);
-		}
-		if (*s == L'\0') {
-			*src = NULL;
-			return (nbytes + nb - 1);
-		}
-		s++;
-		dst += nb;
-		len -= nb;
-		nbytes += nb;
-	}
-	*src = s;
-	return (nbytes);
+	return (__wcsnrtombs(dst, src, SIZE_T_MAX, len, ps));
 }
diff --git a/lib/libc/locale/wcstombs.c b/lib/libc/locale/wcstombs.c
index 5bb5954a7cde..acd0051463b3 100644
--- a/lib/libc/locale/wcstombs.c
+++ b/lib/libc/locale/wcstombs.c
@@ -27,6 +27,7 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
+#include <limits.h>
 #include <stdlib.h>
 #include <wchar.h>
 #include "mblocal.h"
@@ -38,5 +39,5 @@ wcstombs(char * __restrict s, const wchar_t * __restrict pwcs, size_t n)
 	mbstate_t mbs;
 
 	mbs = initial;
-	return (__wcsrtombs(s, &pwcs, n, &mbs));
+	return (__wcsnrtombs(s, &pwcs, SIZE_T_MAX, n, &mbs));
 }
diff --git a/lib/libc/stdio/fputws.c b/lib/libc/stdio/fputws.c
index b5be7317ba72..025e1c00d198 100644
--- a/lib/libc/stdio/fputws.c
+++ b/lib/libc/stdio/fputws.c
@@ -29,6 +29,7 @@ __FBSDID("$FreeBSD$");
 
 #include "namespace.h"
 #include <errno.h>
+#include <limits.h>
 #include <stdio.h>
 #include <wchar.h>
 #include "un-namespace.h"
@@ -53,7 +54,7 @@ fputws(const wchar_t * __restrict ws, FILE * __restrict fp)
 	uio.uio_iovcnt = 1;
 	iov.iov_base = buf;
 	do {
-		nbytes = __wcsrtombs(buf, &ws, sizeof(buf),
+		nbytes = __wcsnrtombs(buf, &ws, SIZE_T_MAX, sizeof(buf),
 		    &fp->_extra->mbstate);
 		if (nbytes == (size_t)-1)
 			goto error;