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vsnprintf.c revision 1.21.4.1 
      1 /*	$NetBSD: vsnprintf.c,v 1.21.4.1 2007/11/06 23:11:17 matt Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1990, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * This code is derived from software contributed to Berkeley by
      8  * Chris Torek.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  * 3. Neither the name of the University nor the names of its contributors
     19  *    may be used to endorse or promote products derived from this software
     20  *    without specific prior written permission.
     21  *
     22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     32  * SUCH DAMAGE.
     33  */
     34 
     35 #include <sys/cdefs.h>
     36 #if defined(LIBC_SCCS) && !defined(lint)
     37 #if 0
     38 static char sccsid[] = "@(#)vsnprintf.c	8.1 (Berkeley) 6/4/93";
     39 #else
     40 __RCSID("$NetBSD: vsnprintf.c,v 1.21.4.1 2007/11/06 23:11:17 matt Exp $");
     41 #endif
     42 #endif /* LIBC_SCCS and not lint */
     43 
     44 #include "namespace.h"
     45 
     46 #include <assert.h>
     47 #include <errno.h>
     48 #include <stdio.h>
     49 #include "reentrant.h"
     50 #include "local.h"
     51 
     52 #if defined(_FORTIFY_SOURCE) && !defined(__lint__)
     53 #undef vsnprintf
     54 #define vsnprintf _vsnprintf
     55 #endif
     56 
     57 #ifdef __weak_alias
     58 __weak_alias(vsnprintf,_vsnprintf)
     59 #endif
     60 
     61 int
     62 vsnprintf(str, n, fmt, ap)
     63 	char *str;
     64 	size_t n;
     65 	const char *fmt;
     66 	_BSD_VA_LIST_ ap;
     67 {
     68 	int ret;
     69 	FILE f;
     70 	struct __sfileext fext;
     71 	unsigned char dummy[1];
     72 
     73 	_DIAGASSERT(n == 0 || str != NULL);
     74 	_DIAGASSERT(fmt != NULL);
     75 
     76 	if ((int)n < 0) {
     77 		errno = EINVAL;
     78 		return (-1);
     79 	}
     80 
     81 	_FILEEXT_SETUP(&f, &fext);
     82 	f._file = -1;
     83 	f._flags = __SWR | __SSTR;
     84 	if (n == 0) {
     85 		f._bf._base = f._p = dummy;
     86 		f._bf._size = f._w = 0;
     87 	} else {
     88 		f._bf._base = f._p = (unsigned char *)str;
     89 		f._bf._size = f._w = n - 1;
     90 	}
     91 	ret = __vfprintf_unlocked(&f, fmt, ap);
     92 	*f._p = 0;
     93 	return (ret);
     94 }
     95