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 <string.h>
40 #include <ssp/ssp.h>
41 #include "un-namespace.h"
42 #include "local.h"
43 #include "libc_private.h"
44
45 /*
46 * MT-safe version
47 */
48
49 size_t
__ssp_real(fread)50 __ssp_real(fread)(void * __restrict buf, size_t size, size_t count,
51 FILE * __restrict fp)
52 {
53 size_t ret;
54
55 FLOCKFILE_CANCELSAFE(fp);
56 ret = __fread(buf, size, count, fp);
57 FUNLOCKFILE_CANCELSAFE();
58 return (ret);
59 }
60
61 size_t
__fread(void * __restrict buf,size_t size,size_t count,FILE * __restrict fp)62 __fread(void * __restrict buf, size_t size, size_t count, FILE * __restrict fp)
63 {
64 size_t resid;
65 char *p;
66 int r;
67 size_t total;
68
69 /*
70 * ANSI and SUSv2 require a return value of 0 if size or count are 0.
71 */
72 if ((count == 0) || (size == 0))
73 return (0);
74
75 /*
76 * Check for integer overflow. As an optimization, first check that
77 * at least one of {count, size} is at least 2^16, since if both
78 * values are less than that, their product can't possible overflow
79 * (size_t is always at least 32 bits on FreeBSD).
80 */
81 if (((count | size) > 0xFFFF) &&
82 (count > SIZE_MAX / size)) {
83 errno = EINVAL;
84 fp->_flags |= __SERR;
85 return (0);
86 }
87
88 /*
89 * Compute the (now required to not overflow) number of bytes to
90 * read and actually do the work.
91 */
92 resid = count * size;
93 ORIENT(fp, -1);
94 if (fp->_r < 0)
95 fp->_r = 0;
96 total = resid;
97 p = buf;
98
99 /*
100 * If we're unbuffered we know that the buffer in fp is empty so
101 * we can read directly into buf. This is much faster than a
102 * series of one byte reads into fp->_nbuf.
103 */
104 if ((fp->_flags & __SNBF) != 0 && buf != NULL) {
105 while (resid > 0) {
106 /* set up the buffer */
107 fp->_bf._base = fp->_p = p;
108 fp->_bf._size = resid;
109
110 if (__srefill(fp)) {
111 /* no more input: return partial result */
112 count = (total - resid) / size;
113 break;
114 }
115 p += fp->_r;
116 resid -= fp->_r;
117 }
118
119 /* restore the old buffer (see __smakebuf) */
120 fp->_bf._base = fp->_p = fp->_nbuf;
121 fp->_bf._size = 1;
122 fp->_r = 0;
123
124 return (count);
125 }
126
127 while (resid > (r = fp->_r)) {
128 if (r != 0) {
129 (void)memcpy((void *)p, (void *)fp->_p, (size_t)r);
130 fp->_p += r;
131 /* fp->_r = 0 ... done in __srefill */
132 p += r;
133 resid -= r;
134 }
135 if (__srefill(fp)) {
136 /* no more input: return partial result */
137 return ((total - resid) / size);
138 }
139 }
140 (void)memcpy((void *)p, (void *)fp->_p, resid);
141 fp->_r -= resid;
142 fp->_p += resid;
143 return (count);
144 }
145
146 __weak_reference(__fread, fread_unlocked);
147