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("$FreeBSD$");
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 */
52size_t
53fwrite(buf, size, count, fp)
54	const void * __restrict buf;
55	size_t size, count;
56	FILE * __restrict fp;
57{
58	size_t n;
59	struct __suio uio;
60	struct __siov iov;
61
62	/*
63	 * ANSI and SUSv2 require a return value of 0 if size or count are 0.
64	 */
65	if ((count == 0) || (size == 0))
66		return (0);
67
68	/*
69	 * Check for integer overflow.  As an optimization, first check that
70	 * at least one of {count, size} is at least 2^16, since if both
71	 * values are less than that, their product can't possible overflow
72	 * (size_t is always at least 32 bits on FreeBSD).
73	 */
74	if (((count | size) > 0xFFFF) &&
75	    (count > SIZE_MAX / size)) {
76		errno = EINVAL;
77		fp->_flags |= __SERR;
78		return (0);
79	}
80
81	n = count * size;
82
83	iov.iov_base = (void *)buf;
84	uio.uio_resid = iov.iov_len = n;
85	uio.uio_iov = &iov;
86	uio.uio_iovcnt = 1;
87
88	FLOCKFILE(fp);
89	ORIENT(fp, -1);
90	/*
91	 * The usual case is success (__sfvwrite returns 0);
92	 * skip the divide if this happens, since divides are
93	 * generally slow and since this occurs whenever size==0.
94	 */
95	if (__sfvwrite(fp, &uio) != 0)
96	    count = (n - uio.uio_resid) / size;
97	FUNLOCKFILE(fp);
98	return (count);
99}
100