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 * 4. 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) 34static char sccsid[] = "@(#)fread.c 8.2 (Berkeley) 12/11/93"; 35#endif /* LIBC_SCCS and not lint */ 36#include <sys/cdefs.h> 37__FBSDID("$FreeBSD: src/lib/libc/stdio/fread.c,v 1.16 2009/07/12 13:09:43 ed Exp $"); 38 39#include "namespace.h" 40#include <stdio.h> 41#include <string.h> 42#include "un-namespace.h" 43#include "local.h" 44#include "libc_private.h" 45 46/* 47 * MT-safe version 48 */ 49 50size_t 51fread(void * __restrict buf, size_t size, size_t count, FILE * __restrict fp) 52{ 53 size_t ret; 54 55 FLOCKFILE(fp); 56 ret = __fread(buf, size, count, fp); 57 FUNLOCKFILE(fp); 58 return (ret); 59} 60 61/* 62 * The maximum amount to read to avoid integer overflow. INT_MAX is odd, 63 * so it make sense to make it even. We subtract (BUFSIZ - 1) to get a 64 * whole number of BUFSIZ chunks. 65 */ 66#define MAXREAD (INT_MAX - (BUFSIZ - 1)) 67 68/* __fread0: int sized, with size = 1 */ 69static inline int 70__fread0(void * __restrict buf, int count, FILE * __restrict fp) 71{ 72 int resid; 73 char *p; 74 int r, ret; 75 76 resid = count; 77 p = buf; 78 /* first deal with anything left in buffer, plus any ungetc buffers */ 79 while (resid > (r = fp->_r)) { 80 (void)memcpy((void *)p, (void *)fp->_p, (size_t)r); 81 fp->_p += r; 82 /* fp->_r = 0 ... done in __srefill */ 83 p += r; 84 resid -= r; 85 if ((ret = __srefill0(fp)) > 0) 86 break; 87 else if (ret) { 88 /* no more input: return partial result */ 89 return (count - resid); 90 } 91 } 92 /* 93 * 5980080: don't use optimization if __SMBF not set (meaning setvbuf 94 * was called, and the buffer belongs to the user). 95 * 6180417: but for unbuffered (__SMBF is not set), so specifically 96 * test for it. 97 */ 98 if ((fp->_flags & (__SMBF | __SNBF)) && resid > fp->_bf._size) { 99 struct __sbuf save; 100 size_t n; 101 102 save = fp->_bf; 103 fp->_bf._base = (unsigned char *)p; 104 fp->_bf._size = resid; 105 while (fp->_bf._size > 0) { 106 if ((ret = __srefill1(fp)) != 0) { 107 /* no more input: return partial result */ 108 resid = fp->_bf._size; 109 fp->_bf = save; 110 fp->_p = fp->_bf._base; 111 /* fp->_r = 0; already set in __srefill1 */ 112 return (count - resid); 113 } 114 fp->_bf._base += fp->_r; 115 fp->_bf._size -= fp->_r; 116 } 117 fp->_bf = save; 118 n = fp->_bf._size * ((resid - 1) / fp->_bf._size); 119 r = resid - n; 120 (void)memcpy((void *)fp->_bf._base, (void *)(p + n), (size_t)r); 121 fp->_p = fp->_bf._base + r; 122 fp->_r = 0; 123 } else { 124 while (resid > (r = fp->_r)) { 125 (void)memcpy((void *)p, (void *)fp->_p, (size_t)r); 126 fp->_p += r; 127 /* fp->_r = 0 ... done in __srefill */ 128 p += r; 129 resid -= r; 130 if (__srefill1(fp)) { 131 /* no more input: return partial result */ 132 return (count - resid); 133 } 134 } 135 (void)memcpy((void *)p, (void *)fp->_p, resid); 136 fp->_r -= resid; 137 fp->_p += resid; 138 } 139 return (count); 140} 141 142size_t 143__fread(void * __restrict buf, size_t size, size_t count, FILE * __restrict fp) 144{ 145 size_t resid; 146 int r, ret; 147 size_t total; 148 149 /* 150 * ANSI and SUSv2 require a return value of 0 if size or count are 0. 151 */ 152 if ((resid = count * size) == 0) 153 return (0); 154 ORIENT(fp, -1); 155 if (fp->_r < 0) 156 fp->_r = 0; 157 158 for (total = resid; resid > 0; buf += r, resid -= r) { 159 r = resid > INT_MAX ? MAXREAD : (int)resid; 160 if ((ret = __fread0(buf, r, fp)) != r) { 161 count = (total - resid + ret) / size; 162 break; 163 } 164 } 165 return (count); 166} 167