1 /* $NetBSD: fwrite.c,v 1.19 2021/02/01 17:50:53 jdolecek Exp $ */ 2 3 /*- 4 * Copyright (c) 1990, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Chris Torek. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 #include <sys/cdefs.h> 36 #if defined(LIBC_SCCS) && !defined(lint) 37 #if 0 38 static char sccsid[] = "@(#)fwrite.c 8.1 (Berkeley) 6/4/93"; 39 #else 40 __RCSID("$NetBSD: fwrite.c,v 1.19 2021/02/01 17:50:53 jdolecek Exp $"); 41 #endif 42 #endif /* LIBC_SCCS and not lint */ 43 44 #include <assert.h> 45 #include <errno.h> 46 #include <stdio.h> 47 #include "reentrant.h" 48 #include "local.h" 49 #include "fvwrite.h" 50 51 #define MUL_NO_OVERFLOW (1UL << (sizeof(size_t) * 4)) 52 53 /* 54 * Write `count' objects (each size `size') from memory to the given file. 55 * Return the number of whole objects written. 56 */ 57 size_t 58 fwrite(const void *buf, size_t size, size_t count, FILE *fp) 59 { 60 size_t n; 61 struct __suio uio; 62 struct __siov iov; 63 64 /* 65 * Extension: Catch integer overflow 66 */ 67 if ((size >= MUL_NO_OVERFLOW || count >= MUL_NO_OVERFLOW) && 68 size > 0 && count > SIZE_MAX / size) { 69 errno = EOVERFLOW; 70 fp->_flags |= __SERR; 71 return (0); 72 } 73 74 /* 75 * SUSv2 requires a return value of 0 for a count or a size of 0. 76 */ 77 if ((n = count * size) == 0) 78 return 0; 79 80 iov.iov_base = __UNCONST(buf); 81 uio.uio_resid = iov.iov_len = n; 82 uio.uio_iov = &iov; 83 uio.uio_iovcnt = 1; 84 85 /* 86 * The usual case is success (__sfvwrite returns 0); 87 * skip the divide if this happens, since divides are 88 * generally slow and since this occurs whenever size==0. 89 */ 90 FLOCKFILE(fp); 91 if (__sfvwrite(fp, &uio) != 0) 92 count = ((n - uio.uio_resid) / size); 93 FUNLOCKFILE(fp); 94 return count; 95 } 96