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
fwrite(const void * __restrict buf,size_t size,size_t count,FILE * __restrict fp)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 possible 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