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Replace this wcsncpy() implementation with one based on strncpy.c to fix

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two major bugs:
- off-by-one overflow when the length of the source string exceeds or
  equals the destination buffer size.
- old version was not padding the destination buffer with null wide chars
This commit is contained in:
Tim J. Robbins 2002-10-23 04:35:25 +00:00
parent 2d58d642d2
commit 4bf546e192
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=105761
1 changed files with 32 additions and 26 deletions
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58
lib/libc/string/wcsncpy.c
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@ -1,6 +1,9 @@
/*-
* Copyright (c)1999 Citrus Project,
* All rights reserved.
* Copyright (c) 1990, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Chris Torek.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
@ -10,11 +13,18 @@
* 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS 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)
@ -22,37 +32,33 @@
* 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.
*
* citrus Id: wcsncpy.c,v 1.1 1999/12/29 21:47:45 tshiozak Exp
*/
#include <sys/cdefs.h>
#if 0
#if defined(LIBC_SCCS) && !defined(lint)
__RCSID("$NetBSD: wcsncpy.c,v 1.1 2000/12/23 23:14:36 itojun Exp $");
#endif /* LIBC_SCCS and not lint */
#endif
__FBSDID("$FreeBSD$");
#include <wchar.h>
/*
* Copy src to dst, truncating or null-padding to always copy n bytes.
* Return dst.
*/
wchar_t *
wcsncpy(s1, s2, n)
wchar_t * __restrict s1;
const wchar_t * __restrict s2;
size_t n;
wcsncpy(wchar_t * __restrict dst, const wchar_t * __restrict src, size_t n)
{
wchar_t *p;
const wchar_t *q;
if (n != 0) {
wchar_t *d = dst;
const wchar_t *s = src;
*s1 = '\0';
p = s1;
q = s2;
while (n && *q) {
*p++ = *q++;
n--;
do {
if ((*d++ = *s++) == L'\0') {
/* NUL pad the remaining n-1 bytes */
while (--n != 0)
*d++ = L'\0';
break;
}
} while (--n != 0);
}
*p = '\0';
return s1;
return (dst);
}