1d8053c5c0
NetBSD, OpenBSD, and Android's Bionic all number the clauses 1 through 3, so follow suit to make comparison easier. Acked-by: imp@
116 lines
3.4 KiB
C
116 lines
3.4 KiB
C
/*-
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* Copyright (c) 1990, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Chris Torek.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#if defined(LIBC_SCCS) && !defined(lint)
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static char sccsid[] = "@(#)fread.c 8.2 (Berkeley) 12/11/93";
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#endif /* LIBC_SCCS and not lint */
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "namespace.h"
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#include <errno.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <string.h>
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#include "un-namespace.h"
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#include "local.h"
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#include "libc_private.h"
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/*
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* MT-safe version
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*/
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size_t
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fread(void * __restrict buf, size_t size, size_t count, FILE * __restrict fp)
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{
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size_t ret;
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FLOCKFILE(fp);
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ret = __fread(buf, size, count, fp);
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FUNLOCKFILE(fp);
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return (ret);
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}
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size_t
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__fread(void * __restrict buf, size_t size, size_t count, FILE * __restrict fp)
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{
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size_t resid;
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char *p;
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int r;
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size_t total;
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/*
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* ANSI and SUSv2 require a return value of 0 if size or count are 0.
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*/
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if ((count == 0) || (size == 0))
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return (0);
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/*
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* Check for integer overflow. As an optimization, first check that
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* at least one of {count, size} is at least 2^16, since if both
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* values are less than that, their product can't possible overflow
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* (size_t is always at least 32 bits on FreeBSD).
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*/
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if (((count | size) > 0xFFFF) &&
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(count > SIZE_MAX / size)) {
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errno = EINVAL;
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fp->_flags |= __SERR;
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return (0);
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}
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/*
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* Compute the (now required to not overflow) number of bytes to
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* read and actually do the work.
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*/
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resid = count * size;
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ORIENT(fp, -1);
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if (fp->_r < 0)
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fp->_r = 0;
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total = resid;
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p = buf;
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while (resid > (r = fp->_r)) {
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(void)memcpy((void *)p, (void *)fp->_p, (size_t)r);
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fp->_p += r;
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/* fp->_r = 0 ... done in __srefill */
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p += r;
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resid -= r;
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if (__srefill(fp)) {
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/* no more input: return partial result */
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return ((total - resid) / size);
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}
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}
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(void)memcpy((void *)p, (void *)fp->_p, resid);
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fp->_r -= resid;
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fp->_p += resid;
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return (count);
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}
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