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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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