NetBSD/tools/compat/flock.c
lukem 171d653219 Overhaul how `build.sh tools' are used:
*	Rename "config.h" to "nbtool_config.h" and
	HAVE_CONFIG_H to HAVE_NBTOOL_CONFIG_H.
	This makes in more obvious in the source when we're using
	tools/compat/config.h versus "standard autoconf" config.h

    *	Consistently move the inclusion of nbtool_config.h to before
    	<sys/cdefs.h> so that the former can provide __RCSID() (et al),
    	and there's no need to protect those macros any more.

These changes should make it easier to "tool-ify" a program by adding:
	#if HAVE_NBTOOL_CONFIG_H
	#include "nbtool_config.h"
	#endif
to the top of the source files (for the general case).
2003-10-27 00:12:41 +00:00

84 lines
2.6 KiB
C

/* $NetBSD: flock.c,v 1.5 2003/10/27 00:12:43 lukem 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the NetBSD
* Foundation, Inc. and its contributors.
* 4. Neither the name of The NetBSD Foundation 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 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 "nbtool_config.h"
#if !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;
#endif
return rc;
}
#endif