1 /* $OpenBSD: vsnprintf.c,v 1.12 2006/01/06 18:53:04 millert Exp $ */ 2 /*- 3 * Copyright (c) 1990, 1993 4 * The Regents of the University of California. All rights reserved. 5 * 6 * This code is derived from software contributed to Berkeley by 7 * Chris Torek. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 #include <limits.h> 35 #include <stdio.h> 36 #include <string.h> 37 #include "local.h" 38 39 int 40 vsnprintf(char *str, size_t n, const char *fmt, __va_list ap) 41 { 42 int ret; 43 char dummy; 44 FILE f; 45 struct __sfileext fext; 46 47 _FILEEXT_SETUP(&f, &fext); 48 49 /* While snprintf(3) specifies size_t stdio uses an int internally */ 50 if (n > INT_MAX) 51 n = INT_MAX; 52 /* Stdio internals do not deal correctly with zero length buffer */ 53 if (n == 0) { 54 str = &dummy; 55 n = 1; 56 } 57 f._file = -1; 58 f._flags = __SWR | __SSTR; 59 f._bf._base = f._p = (unsigned char *)str; 60 f._bf._size = f._w = n - 1; 61 ret = __vfprintf(&f, fmt, ap); 62 *f._p = '\0'; 63 return (ret); 64 } 65
