20841a137b
Bug: https://code.google.com/p/android/issues/detail?id=81155 Bug: 18556607 Change-Id: Idc60976b79610e2202cc42dc393dcb4ca6c42e05
105 lines
3.3 KiB
C
105 lines
3.3 KiB
C
/* $OpenBSD: fread.c,v 1.12 2014/05/01 16:40:36 deraadt Exp $ */
|
|
/*-
|
|
* Copyright (c) 1990, 1993
|
|
* The Regents of the University of California. All rights reserved.
|
|
*
|
|
* This code is derived from software contributed to Berkeley by
|
|
* Chris Torek.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
* 3. Neither the name of the University nor the names of its contributors
|
|
* may be used to endorse or promote products derived from this software
|
|
* without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
|
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
* SUCH DAMAGE.
|
|
*/
|
|
|
|
#include <stdio.h>
|
|
#include <string.h>
|
|
#include <stdint.h>
|
|
#include <errno.h>
|
|
#include "local.h"
|
|
|
|
#define MUL_NO_OVERFLOW (1UL << (sizeof(size_t) * 4))
|
|
|
|
size_t
|
|
fread(void *buf, size_t size, size_t count, FILE *fp)
|
|
{
|
|
size_t resid;
|
|
char *p;
|
|
int r;
|
|
size_t total;
|
|
|
|
/*
|
|
* Extension: Catch integer overflow
|
|
*/
|
|
if ((size >= MUL_NO_OVERFLOW || count >= MUL_NO_OVERFLOW) &&
|
|
size > 0 && SIZE_MAX / size < count) {
|
|
errno = EOVERFLOW;
|
|
fp->_flags |= __SERR;
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* ANSI and SUSv2 require a return value of 0 if size or count are 0.
|
|
*/
|
|
if ((resid = count * size) == 0)
|
|
return (0);
|
|
FLOCKFILE(fp);
|
|
_SET_ORIENTATION(fp, -1);
|
|
if (fp->_r < 0)
|
|
fp->_r = 0;
|
|
total = resid;
|
|
p = buf;
|
|
|
|
// BEGIN android-added
|
|
// Avoid pathological behavior on unbuffered files. OpenBSD
|
|
// will loop reading one byte then memcpying one byte!
|
|
if ((fp->_flags & __SNBF) != 0) {
|
|
// We know if we're unbuffered that our buffer is empty, so
|
|
// we can just read directly.
|
|
while (resid > 0 && (r = (*fp->_read)(fp->_cookie, p, resid)) > 0) {
|
|
p += r;
|
|
resid -= r;
|
|
}
|
|
FUNLOCKFILE(fp);
|
|
return ((total - resid) / size);
|
|
}
|
|
// END android-added
|
|
|
|
while (resid > (size_t)(r = fp->_r)) {
|
|
(void)memcpy((void *)p, (void *)fp->_p, (size_t)r);
|
|
fp->_p += r;
|
|
/* fp->_r = 0 ... done in __srefill */
|
|
p += r;
|
|
resid -= r;
|
|
if (__srefill(fp)) {
|
|
/* no more input: return partial result */
|
|
FUNLOCKFILE(fp);
|
|
return ((total - resid) / size);
|
|
}
|
|
}
|
|
(void)memcpy((void *)p, (void *)fp->_p, resid);
|
|
fp->_r -= resid;
|
|
fp->_p += resid;
|
|
FUNLOCKFILE(fp);
|
|
return (count);
|
|
}
|