1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 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 #if defined(LIBC_SCCS) && !defined(lint) 36 static char sccsid[] = "@(#)fwrite.c 8.1 (Berkeley) 6/4/93"; 37 #endif /* LIBC_SCCS and not lint */ 38 #include <sys/cdefs.h> 39 __FBSDID("$FreeBSD$"); 40 41 #include "namespace.h" 42 #include <errno.h> 43 #include <stdint.h> 44 #include <stdio.h> 45 #include "un-namespace.h" 46 #include "local.h" 47 #include "fvwrite.h" 48 #include "libc_private.h" 49 50 /* 51 * Write `count' objects (each size `size') from memory to the given file. 52 * Return the number of whole objects written. 53 */ 54 size_t 55 fwrite(const void * __restrict buf, size_t size, size_t count, FILE * __restrict fp) 56 { 57 size_t n; 58 struct __suio uio; 59 struct __siov iov; 60 61 /* 62 * ANSI and SUSv2 require a return value of 0 if size or count are 0. 63 */ 64 if ((count == 0) || (size == 0)) 65 return (0); 66 67 /* 68 * Check for integer overflow. As an optimization, first check that 69 * at least one of {count, size} is at least 2^16, since if both 70 * values are less than that, their product can't possibly overflow 71 * (size_t is always at least 32 bits on FreeBSD). 72 */ 73 if (((count | size) > 0xFFFF) && 74 (count > SIZE_MAX / size)) { 75 errno = EINVAL; 76 fp->_flags |= __SERR; 77 return (0); 78 } 79 80 n = count * size; 81 82 iov.iov_base = (void *)buf; 83 uio.uio_resid = iov.iov_len = n; 84 uio.uio_iov = &iov; 85 uio.uio_iovcnt = 1; 86 87 FLOCKFILE_CANCELSAFE(fp); 88 ORIENT(fp, -1); 89 /* 90 * The usual case is success (__sfvwrite returns 0); 91 * skip the divide if this happens, since divides are 92 * generally slow and since this occurs whenever size==0. 93 */ 94 if (__sfvwrite(fp, &uio) != 0) 95 count = (n - uio.uio_resid) / size; 96 FUNLOCKFILE_CANCELSAFE(); 97 return (count); 98 } 99