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 #include "namespace.h"
36 #include <errno.h>
37 #include <stdint.h>
38 #include <stdio.h>
39 #include "un-namespace.h"
40 #include "local.h"
41 #include "fvwrite.h"
42 #include "libc_private.h"
43
44 /*
45 * Write `count' objects (each size `size') from memory to the given file.
46 * Return the number of whole objects written.
47 */
48 size_t
fwrite_unlocked(const void * __restrict buf,size_t size,size_t count,FILE * __restrict fp)49 fwrite_unlocked(const void * __restrict buf, size_t size, size_t count,
50 FILE * __restrict fp)
51 {
52 size_t n;
53 struct __suio uio;
54 struct __siov iov;
55
56 /*
57 * ANSI and SUSv2 require a return value of 0 if size or count are 0.
58 */
59 if ((count == 0) || (size == 0))
60 return (0);
61
62 /*
63 * Check for integer overflow. As an optimization, first check that
64 * at least one of {count, size} is at least 2^16, since if both
65 * values are less than that, their product can't possibly overflow
66 * (size_t is always at least 32 bits on FreeBSD).
67 */
68 if (((count | size) > 0xFFFF) &&
69 (count > SIZE_MAX / size)) {
70 errno = EINVAL;
71 fp->_flags |= __SERR;
72 return (0);
73 }
74
75 n = count * size;
76
77 iov.iov_base = (void *)buf;
78 uio.uio_resid = iov.iov_len = n;
79 uio.uio_iov = &iov;
80 uio.uio_iovcnt = 1;
81
82 ORIENT(fp, -1);
83 /*
84 * The usual case is success (__sfvwrite returns 0);
85 * skip the divide if this happens, since divides are
86 * generally slow and since this occurs whenever size==0.
87 */
88 if (__sfvwrite(fp, &uio) != 0)
89 count = (n - uio.uio_resid) / size;
90 return (count);
91 }
92
93 size_t
fwrite(const void * __restrict buf,size_t size,size_t count,FILE * __restrict fp)94 fwrite(const void * __restrict buf, size_t size, size_t count,
95 FILE * __restrict fp)
96 {
97 size_t n;
98
99 FLOCKFILE_CANCELSAFE(fp);
100 n = fwrite_unlocked(buf, size, count, fp);
101 FUNLOCKFILE_CANCELSAFE();
102 return (n);
103 }
104