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) 34static char sccsid[] = "@(#)fwrite.c 8.1 (Berkeley) 6/4/93"; 35#endif /* LIBC_SCCS and not lint */ 36#include <sys/cdefs.h> 37__FBSDID("$FreeBSD: src/lib/libc/stdio/fwrite.c,v 1.13 2009/07/12 13:09:43 ed Exp $"); 38 39#include "namespace.h" 40#include <stdio.h> 41#include "un-namespace.h" 42#include "local.h" 43#include "fvwrite.h" 44#include "libc_private.h" 45 46/* 47 * The maximum amount to write to avoid integer overflow (especially for 48 * uio_resid in struct __suio). INT_MAX is odd, so it make sense to make it 49 * even. We subtract (BUFSIZ - 1) to get a whole number of BUFSIZ chunks. 50 */ 51#define MAXWRITE (INT_MAX - (BUFSIZ - 1)) 52 53/* 54 * Write `count' objects (each size `size') from memory to the given file. 55 * Return the number of whole objects written. 56 */ 57size_t 58fwrite(buf, size, count, fp) 59 const void * __restrict buf; 60 size_t size, count; 61 FILE * __restrict fp; 62{ 63 size_t n, resid; 64 struct __suio uio; 65 struct __siov iov; 66 int s; 67 68 /* 69 * ANSI and SUSv2 require a return value of 0 if size or count are 0. 70 */ 71 n = count * size; 72#if __DARWIN_UNIX03 73 if (n == 0) 74 return (0); 75#endif 76 uio.uio_iov = &iov; 77 uio.uio_iovcnt = 1; 78 79 FLOCKFILE(fp); 80 ORIENT(fp, -1); 81 82 for (resid = n; resid > 0; buf += s, resid -= s) { 83 s = resid > INT_MAX ? MAXWRITE : (int)resid; 84 iov.iov_base = (void *)buf; 85 uio.uio_resid = iov.iov_len = s; 86 87 /* 88 * The usual case is success (__sfvwrite returns 0); 89 * skip the divide if this happens, since divides are 90 * generally slow and since this occurs whenever size==0. 91 */ 92 if (__sfvwrite(fp, &uio) != 0) { 93 count = (n - resid + s - uio.uio_resid) / size; 94 break; 95 } 96 } 97 FUNLOCKFILE(fp); 98 return (count); 99} 100