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 * 3. 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[] = "@(#)fwrite.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 "namespace.h" 40 #include <errno.h> 41 #include <stdint.h> 42 #include <stdio.h> 43 #include "un-namespace.h" 44 #include "local.h" 45 #include "fvwrite.h" 46 #include "libc_private.h" 47 48 /* 49 * Write `count' objects (each size `size') from memory to the given file. 50 * Return the number of whole objects written. 51 */ 52 size_t 53 fwrite(const void * __restrict buf, size_t size, size_t count, FILE * __restrict fp) 54 { 55 size_t n; 56 struct __suio uio; 57 struct __siov iov; 58 59 /* 60 * ANSI and SUSv2 require a return value of 0 if size or count are 0. 61 */ 62 if ((count == 0) || (size == 0)) 63 return (0); 64 65 /* 66 * Check for integer overflow. As an optimization, first check that 67 * at least one of {count, size} is at least 2^16, since if both 68 * values are less than that, their product can't possibly overflow 69 * (size_t is always at least 32 bits on FreeBSD). 70 */ 71 if (((count | size) > 0xFFFF) && 72 (count > SIZE_MAX / size)) { 73 errno = EINVAL; 74 fp->_flags |= __SERR; 75 return (0); 76 } 77 78 n = count * size; 79 80 iov.iov_base = (void *)buf; 81 uio.uio_resid = iov.iov_len = n; 82 uio.uio_iov = &iov; 83 uio.uio_iovcnt = 1; 84 85 FLOCKFILE(fp); 86 ORIENT(fp, -1); 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 - uio.uio_resid) / size; 94 FUNLOCKFILE(fp); 95 return (count); 96 } 97