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 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 #if defined(LIBC_SCCS) && !defined(lint) 34 static char rcsid[] = "$OpenBSD: snprintf.c,v 1.11 2005/04/30 09:25:17 espie Exp $"; 35 #endif /* LIBC_SCCS and not lint */ 36 37 #include <limits.h> 38 #include <stdio.h> 39 #include <stdarg.h> 40 #include "local.h" 41 42 int 43 snprintf(char *str, size_t n, const char *fmt, ...) 44 { 45 va_list ap; 46 int ret; 47 char dummy; 48 FILE f; 49 struct __sfileext fext; 50 51 /* While snprintf(3) specifies size_t stdio uses an int internally */ 52 if (n > INT_MAX) 53 n = INT_MAX; 54 /* Stdio internals do not deal correctly with zero length buffer */ 55 if (n == 0) { 56 str = &dummy; 57 n = 1; 58 } 59 va_start(ap, fmt); 60 _FILEEXT_SETUP(&f, &fext); 61 f._file = -1; 62 f._flags = __SWR | __SSTR; 63 f._bf._base = f._p = (unsigned char *)str; 64 f._bf._size = f._w = n - 1; 65 ret = vfprintf(&f, fmt, ap); 66 *f._p = '\0'; 67 va_end(ap); 68 return (ret); 69 } 70