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/* $NetBSD: flock.c,v 1.6 2008/04/28 20:24:12 martin Exp $ */
/*-
* Copyright (c) 2001 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Todd Vierling.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
*/
/*
* Emulate flock() with fcntl(), where available.
* Otherwise, don't do locking; just pretend success.
*/
#include "includes.h"
#ifndef HAVE_FLOCK
#include <errno.h>
#include <fcntl.h>
int
flock(int fd, int op)
{
int rc = 0;
#if defined(F_SETLK) && defined(F_SETLKW)
struct flock fl = {0};
switch (op & (LOCK_EX|LOCK_SH|LOCK_UN)) {
case LOCK_EX:
fl.l_type = F_WRLCK;
break;
case LOCK_SH:
fl.l_type = F_RDLCK;
break;
case LOCK_UN:
fl.l_type = F_UNLCK;
break;
default:
errno = EINVAL;
return -1;
}
fl.l_whence = SEEK_SET;
rc = fcntl(fd, op & LOCK_NB ? F_SETLK : F_SETLKW, &fl);
if (rc && (errno == EAGAIN))
errno = EWOULDBLOCK;
#else
rc = -1;
errno = ENOSYS;
#endif
return rc;
}
#endif
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