xref: /freebsd/lib/libc/stdio/vsnprintf.c (revision 40a8ac8f62b535d30349faf28cf47106b7041b83)
1 /*-
2  * Copyright (c) 1990, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * This code is derived from software contributed to Berkeley by
6  * Chris Torek.
7  *
8  * Copyright (c) 2011 The FreeBSD Foundation
9  * All rights reserved.
10  * Portions of this software were developed by David Chisnall
11  * under sponsorship from the FreeBSD Foundation.
12  *
13  * Redistribution and use in source and binary forms, with or without
14  * modification, are permitted provided that the following conditions
15  * are met:
16  * 1. Redistributions of source code must retain the above copyright
17  *    notice, this list of conditions and the following disclaimer.
18  * 2. Redistributions in binary form must reproduce the above copyright
19  *    notice, this list of conditions and the following disclaimer in the
20  *    documentation and/or other materials provided with the distribution.
21  * 3. Neither the name of the University nor the names of its contributors
22  *    may be used to endorse or promote products derived from this software
23  *    without specific prior written permission.
24  *
25  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
26  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
29  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35  * SUCH DAMAGE.
36  */
37 
38 #if defined(LIBC_SCCS) && !defined(lint)
39 static char sccsid[] = "@(#)vsnprintf.c	8.1 (Berkeley) 6/4/93";
40 #endif /* LIBC_SCCS and not lint */
41 #include <sys/cdefs.h>
42 __FBSDID("$FreeBSD$");
43 
44 #include <errno.h>
45 #include <limits.h>
46 #include <stdio.h>
47 #include "local.h"
48 #include "xlocale_private.h"
49 
50 int
51 vsnprintf_l(char * __restrict str, size_t n, locale_t locale,
52 		const char * __restrict fmt, __va_list ap)
53 {
54 	size_t on;
55 	int ret;
56 	char dummy[2];
57 	FILE f = FAKE_FILE;
58 	FIX_LOCALE(locale);
59 
60 	on = n;
61 	if (n != 0)
62 		n--;
63 	if (n > INT_MAX) {
64 		errno = EOVERFLOW;
65 		*str = '\0';
66 		return (EOF);
67 	}
68 	/* Stdio internals do not deal correctly with zero length buffer */
69 	if (n == 0) {
70 		if (on > 0)
71 	  		*str = '\0';
72 		str = dummy;
73 		n = 1;
74 	}
75 	f._flags = __SWR | __SSTR;
76 	f._bf._base = f._p = (unsigned char *)str;
77 	f._bf._size = f._w = n;
78 	ret = __vfprintf(&f, locale, fmt, ap);
79 	if (on > 0)
80 		*f._p = '\0';
81 	return (ret);
82 }
83 int
84 vsnprintf(char * __restrict str, size_t n, const char * __restrict fmt,
85     __va_list ap)
86 {
87 	return vsnprintf_l(str, n, __get_locale(), fmt, ap);
88 }
89