xref: /netbsd-src/lib/libc/stdio/snprintf_ss.c (revision c0179c282a5968435315a82f4128c61372c68fc3)
1 /*	$NetBSD: snprintf_ss.c,v 1.3 2006/11/22 17:23:25 christos 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[] = "@(#)snprintf.c	8.1 (Berkeley) 6/4/93";
39 #else
40 __RCSID("$NetBSD: snprintf_ss.c,v 1.3 2006/11/22 17:23:25 christos 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 <stdarg.h>
49 #include <stdio.h>
50 
51 #include "reentrant.h"
52 #include "extern.h"
53 #include "local.h"
54 
55 #ifdef __weak_alias
56 __weak_alias(snprintf_ss,_snprintf_ss)
57 #endif
58 
59 int
60 snprintf_ss(char *str, size_t n, char const *fmt, ...)
61 {
62 	int ret;
63 	va_list ap;
64 	FILE f;
65 	struct __sfileext fext;
66 	unsigned char dummy[1];
67 
68 	_DIAGASSERT(n == 0 || str != NULL);
69 	_DIAGASSERT(fmt != NULL);
70 
71 	if ((int)n < 0) {
72 		errno = EINVAL;
73 		return (-1);
74 	}
75 	va_start(ap, fmt);
76 	_FILEEXT_SETUP(&f, &fext);
77 	f._file = -1;
78 	f._flags = __SWR | __SSTR | __SAFE;
79 	if (n == 0) {
80 		f._bf._base = f._p = dummy;
81 		f._bf._size = f._w = 0;
82 	} else {
83 		f._bf._base = f._p = (unsigned char *)str;
84 		f._bf._size = f._w = n - 1;
85 	}
86 	ret = __vfprintf_unlocked(&f, fmt, ap);
87 	*f._p = 0;
88 	va_end(ap);
89 	return (ret);
90 }
91