freebsd-skq/lib/libstand/write.c
Toomas Soome 1ecc859193 dosfs support in libstand is broken since r298230
Apparently the libstand dosfs optimization is a bit too optimistic
and did introduce possible memory corruption.

This patch is backing out the bad part and since this results in
dosfs reading full blocks now, we can also remove extra offset argument
from dv_strategy callback.

The analysis of the issue and the backout patch is provided by Mikhail Kupchik.

PR:		214423
Submitted by:	Mikhail Kupchik
Reported by:	Mikhail Kupchik
Reviewed by:	bapt, allanjude
Approved by:	allanjude (mentor)
MFC after:	1 month
Differential Revision:	https://reviews.freebsd.org/D8644
2016-12-30 19:06:29 +00:00

96 lines
3.4 KiB
C

/* $NetBSD: write.c,v 1.7 1996/06/21 20:29:30 pk Exp $ */
/*-
* Copyright (c) 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* The Mach Operating System project at Carnegie-Mellon University.
*
* 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.
*
* @(#)write.c 8.1 (Berkeley) 6/11/93
*
*
* Copyright (c) 1989, 1990, 1991 Carnegie Mellon University
* All Rights Reserved.
*
* Author: Alessandro Forin
*
* Permission to use, copy, modify and distribute this software and its
* documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie the
* rights to redistribute these changes.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include "stand.h"
ssize_t
write(fd, dest, bcount)
int fd;
void *dest;
size_t bcount;
{
struct open_file *f = &files[fd];
size_t resid;
if ((unsigned)fd >= SOPEN_MAX || !(f->f_flags & F_WRITE)) {
errno = EBADF;
return (-1);
}
if (f->f_flags & F_RAW) {
twiddle(4);
errno = (f->f_dev->dv_strategy)(f->f_devdata, F_WRITE,
btodb(f->f_offset), bcount, dest, &resid);
if (errno)
return (-1);
f->f_offset += resid;
return (resid);
}
resid = bcount;
if ((errno = (f->f_ops->fo_write)(f, dest, bcount, &resid)))
return (-1);
return (bcount - resid);
}