freebsd-skq/lib/libc/string/strlcat.c
jedgar 3644801234 - Reverse the order of two loop invariant to ensure strlcat() does not
attempt to read memory when siz is 0
- Clarify comments referring to strlcat() usage

PR:		24278, 24295
Submitted by:	Tony Finch <dot@dotat.at>
		Richard Kettlewell <rjk@greenend.org.uk>
Reviewed by:	-audit
2001-01-17 20:51:16 +00:00

75 lines
2.5 KiB
C

/* $OpenBSD: strlcat.c,v 1.2 1999/06/17 16:28:58 millert Exp $ */
/*
* Copyright (c) 1998 Todd C. Miller <Todd.Miller@courtesan.com>
* 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.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED ``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 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.
*
* $FreeBSD$
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char *rcsid = "$OpenBSD: strlcat.c,v 1.2 1999/06/17 16:28:58 millert Exp $";
#endif /* LIBC_SCCS and not lint */
#include <sys/types.h>
#include <string.h>
/*
* Appends src to string dst of size siz (unlike strncat, siz is the
* full size of dst, not space left). At most siz-1 characters
* will be copied. Always NUL terminates (unless siz <= strlen(dst)).
* Returns strlen(initial dst) + strlen(src); if retval >= siz,
* truncation occurred.
*/
size_t strlcat(dst, src, siz)
char *dst;
const char *src;
size_t siz;
{
register char *d = dst;
register const char *s = src;
register size_t n = siz;
size_t dlen;
/* Find the end of dst and adjust bytes left but don't go past end */
while (n-- != 0 && *d != '\0')
d++;
dlen = d - dst;
n = siz - dlen;
if (n == 0)
return(dlen + strlen(s));
while (*s != '\0') {
if (n != 1) {
*d++ = *s;
n--;
}
s++;
}
*d = '\0';
return(dlen + (s - src)); /* count does not include NUL */
}