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 33 #if defined(LIBC_SCCS) && !defined(lint) 34 static char sccsid[] = "@(#)vsnprintf.c 8.1 (Berkeley) 6/4/93"; 35 #endif /* LIBC_SCCS and not lint */ 36 #include <sys/cdefs.h> 37 __FBSDID("$FreeBSD$"); 38 39 #include <limits.h> 40 #include <stdio.h> 41 #include "local.h" 42 43 int 44 vsnprintf(char * __restrict str, size_t n, const char * __restrict fmt, 45 __va_list ap) 46 { 47 size_t on; 48 int ret; 49 char dummy[2]; 50 FILE f; 51 struct __sFILEX ext; 52 53 on = n; 54 if (n != 0) 55 n--; 56 if (n > INT_MAX) 57 n = INT_MAX; 58 /* Stdio internals do not deal correctly with zero length buffer */ 59 if (n == 0) { 60 if (on > 0) 61 *str = '\0'; 62 str = dummy; 63 n = 1; 64 } 65 f._file = -1; 66 f._flags = __SWR | __SSTR; 67 f._bf._base = f._p = (unsigned char *)str; 68 f._bf._size = f._w = n; 69 f._extra = &ext; 70 INITEXTRA(&f); 71 ret = __vfprintf(&f, fmt, ap); 72 if (on > 0) 73 *f._p = '\0'; 74 return (ret); 75 } 76