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 * 4. 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 * @(#)vsnprintf.c 8.1 (Berkeley) 6/4/93 33 * $FreeBSD: src/lib/libc/stdio/vsnprintf.c,v 1.24 2008/04/17 22:17:54 jhb Exp $ 34 * $DragonFly: src/lib/libc/stdio/vsnprintf.c,v 1.9 2008/05/15 03:59:59 dillon Exp $ 35 */ 36 37 #include <limits.h> 38 #include <stdio.h> 39 #include "local.h" 40 #include "priv_stdio.h" 41 42 int 43 vsnprintf(char * __restrict str, size_t n, const char * __restrict fmt, 44 __va_list ap) 45 { 46 size_t on; 47 int ret; 48 char dummy[2]; 49 FILE f; 50 51 on = n; 52 if (n != 0) 53 n--; 54 if (n > INT_MAX) 55 n = INT_MAX; 56 /* Stdio internals do not deal correctly with zero length buffer */ 57 if (n == 0) { 58 if (on > 0) 59 *str = '\0'; 60 str = dummy; 61 n = 1; 62 } 63 f.pub._fileno = -1; 64 f.pub._flags = __SWR | __SSTR; 65 f._bf._base = f.pub._p = (unsigned char *)str; 66 f._bf._size = f.pub._w = n; 67 memset(WCIO_GET(&f), 0, sizeof(struct wchar_io_data)); 68 ret = __vfprintf(&f, fmt, ap); 69 if (on > 0) 70 *f.pub._p = '\0'; 71 return (ret); 72 } 73