freebsd-nq/lib/libc/stdio/fwrite.c

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/*-
* 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.
* 4. 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.
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)fwrite.c 8.1 (Berkeley) 6/4/93";
#endif /* LIBC_SCCS and not lint */
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
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#include "namespace.h"
#include <errno.h>
#include <stdint.h>
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#include <stdio.h>
#include "un-namespace.h"
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#include "local.h"
#include "fvwrite.h"
#include "libc_private.h"
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/*
* Write `count' objects (each size `size') from memory to the given file.
* Return the number of whole objects written.
*/
size_t
fwrite(buf, size, count, fp)
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const void * __restrict buf;
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size_t size, count;
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FILE * __restrict fp;
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{
size_t n;
struct __suio uio;
struct __siov iov;
/*
* ANSI and SUSv2 require a return value of 0 if size or count are 0.
*/
if ((count == 0) || (size == 0))
return (0);
/*
* Check for integer overflow. As an optimization, first check that
* at least one of {count, size} is at least 2^16, since if both
* values are less than that, their product can't possible overflow
* (size_t is always at least 32 bits on FreeBSD).
*/
if (((count | size) > 0xFFFF) &&
(count > SIZE_MAX / size)) {
errno = EINVAL;
fp->_flags |= __SERR;
return (0);
}
n = count * size;
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iov.iov_base = (void *)buf;
uio.uio_resid = iov.iov_len = n;
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uio.uio_iov = &iov;
uio.uio_iovcnt = 1;
FLOCKFILE(fp);
ORIENT(fp, -1);
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/*
* The usual case is success (__sfvwrite returns 0);
* skip the divide if this happens, since divides are
* generally slow and since this occurs whenever size==0.
*/
if (__sfvwrite(fp, &uio) != 0)
count = (n - uio.uio_resid) / size;
FUNLOCKFILE(fp);
return (count);
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}