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mirror of https://git.FreeBSD.org/src.git synced 2024-12-22 11:17:19 +00:00
freebsd/lib/libc/stdio/vsnprintf.c
Jordan K. Hubbard b0a06af596 When size is 1 should just null terminate the string. The dummy variable
is made an array of two, to explicitly avoid stack corruption due to
null-terminating (which is doesn't actually happen due to stack alignment
padding).

Submitted by: Ed Moy <emoy@apple.com>
Obtained from: Apple Computer, Inc.
2003-07-02 07:08:44 +00:00

80 lines
2.7 KiB
C

/*-
* 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
* 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. 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 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 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)
* 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.
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)vsnprintf.c 8.1 (Berkeley) 6/4/93";
#endif /* LIBC_SCCS and not lint */
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <limits.h>
#include <stdio.h>
#include "local.h"
int
vsnprintf(char * __restrict str, size_t n, const char * __restrict fmt,
__va_list ap)
{
size_t on;
int ret;
char dummy[2];
FILE f;
struct __sFILEX ext;
on = n;
if (n != 0)
n--;
if (n > INT_MAX)
n = INT_MAX;
/* Stdio internals do not deal correctly with zero length buffer */
if (n == 0) {
if (on > 0)
*str = '\0';
str = dummy;
n = 1;
}
f._file = -1;
f._flags = __SWR | __SSTR;
f._bf._base = f._p = (unsigned char *)str;
f._bf._size = f._w = n;
f._extra = &ext;
INITEXTRA(&f);
ret = __vfprintf(&f, fmt, ap);
if (on > 0)
*f._p = '\0';
return (ret);
}