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