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 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 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