fa11ebb133
however, susv2 adds the same to fwrite(3), so add the explicit check. document this for both fread & fwrite. move diagassert for buf!=NULL to after the (size * nmembs) == 0 check. this has the helpful side effect of preventing the _DIAGASSERT()ion in fwrite() being triggered by lots of 3rdparty code that calls fwrite() with buf=NULL count=0
94 lines
3.2 KiB
C
94 lines
3.2 KiB
C
/* $NetBSD: fwrite.c,v 1.13 2001/01/25 02:06:25 lukem Exp $ */
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/*-
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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. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. 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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#include <sys/cdefs.h>
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#if defined(LIBC_SCCS) && !defined(lint)
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#if 0
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static char sccsid[] = "@(#)fwrite.c 8.1 (Berkeley) 6/4/93";
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#else
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__RCSID("$NetBSD: fwrite.c,v 1.13 2001/01/25 02:06:25 lukem Exp $");
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#endif
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#endif /* LIBC_SCCS and not lint */
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#include <assert.h>
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#include <errno.h>
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#include <stdio.h>
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#include "local.h"
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#include "fvwrite.h"
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#include "reentrant.h"
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/*
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* Write `count' objects (each size `size') from memory to the given file.
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* Return the number of whole objects written.
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*/
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size_t
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fwrite(buf, size, count, fp)
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const void *buf;
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size_t size, count;
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FILE *fp;
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{
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size_t n;
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struct __suio uio;
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struct __siov iov;
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_DIAGASSERT(fp != NULL);
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/*
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* SUSv2 requires a return value of 0 for a count or a size of 0.
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*/
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if ((n = count * size) == 0)
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return (0);
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_DIAGASSERT(buf != NULL);
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/* LINTED we don't play with buf */
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iov.iov_base = (void *)buf;
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uio.uio_resid = iov.iov_len = n;
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uio.uio_iov = &iov;
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uio.uio_iovcnt = 1;
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/*
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* The usual case is success (__sfvwrite returns 0);
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* skip the divide if this happens, since divides are
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* generally slow and since this occurs whenever size==0.
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*/
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FLOCKFILE(fp);
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if (__sfvwrite(fp, &uio) != 0)
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count = ((n - uio.uio_resid) / size);
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FUNLOCKFILE(fp);
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return (count);
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}
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