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lockf.c revision 1.3.8.2 
      1  1.3.8.2  martin /*	$NetBSD: lockf.c,v 1.3.8.2 2008/04/28 20:23:00 martin Exp $	*/
      2  1.3.8.2  martin 
      3  1.3.8.2  martin /*-
      4  1.3.8.2  martin  * Copyright (c) 1997 The NetBSD Foundation, Inc.
      5  1.3.8.2  martin  * All rights reserved.
      6  1.3.8.2  martin  *
      7  1.3.8.2  martin  * This code is derived from software contributed to The NetBSD Foundation
      8  1.3.8.2  martin  * by Klaus Klein.
      9  1.3.8.2  martin  *
     10  1.3.8.2  martin  * Redistribution and use in source and binary forms, with or without
     11  1.3.8.2  martin  * modification, are permitted provided that the following conditions
     12  1.3.8.2  martin  * are met:
     13  1.3.8.2  martin  * 1. Redistributions of source code must retain the above copyright
     14  1.3.8.2  martin  *    notice, this list of conditions and the following disclaimer.
     15  1.3.8.2  martin  * 2. Redistributions in binary form must reproduce the above copyright
     16  1.3.8.2  martin  *    notice, this list of conditions and the following disclaimer in the
     17  1.3.8.2  martin  *    documentation and/or other materials provided with the distribution.
     18  1.3.8.2  martin  *
     19  1.3.8.2  martin  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  1.3.8.2  martin  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  1.3.8.2  martin  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  1.3.8.2  martin  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  1.3.8.2  martin  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  1.3.8.2  martin  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  1.3.8.2  martin  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  1.3.8.2  martin  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  1.3.8.2  martin  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  1.3.8.2  martin  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  1.3.8.2  martin  * POSSIBILITY OF SUCH DAMAGE.
     30  1.3.8.2  martin  */
     31  1.3.8.2  martin 
     32  1.3.8.2  martin #include <sys/cdefs.h>
     33  1.3.8.2  martin #if defined(LIBC_SCCS) && !defined(lint)
     34  1.3.8.2  martin __RCSID("$NetBSD: lockf.c,v 1.3.8.2 2008/04/28 20:23:00 martin Exp $");
     35  1.3.8.2  martin #endif
     36  1.3.8.2  martin 
     37  1.3.8.2  martin #include "namespace.h"
     38  1.3.8.2  martin #include <errno.h>
     39  1.3.8.2  martin #include <fcntl.h>
     40  1.3.8.2  martin #include <unistd.h>
     41  1.3.8.2  martin 
     42  1.3.8.2  martin #ifdef __weak_alias
     43  1.3.8.2  martin __weak_alias(lockf,_lockf)
     44  1.3.8.2  martin #endif
     45  1.3.8.2  martin 
     46  1.3.8.2  martin 
     47  1.3.8.2  martin int
     48  1.3.8.2  martin lockf(filedes, function, size)
     49  1.3.8.2  martin 	int filedes;
     50  1.3.8.2  martin 	int function;
     51  1.3.8.2  martin 	off_t size;
     52  1.3.8.2  martin {
     53  1.3.8.2  martin 	struct flock fl;
     54  1.3.8.2  martin 	int cmd;
     55  1.3.8.2  martin 
     56  1.3.8.2  martin 	fl.l_start = 0;
     57  1.3.8.2  martin 	fl.l_len = size;
     58  1.3.8.2  martin 	fl.l_whence = SEEK_CUR;
     59  1.3.8.2  martin 
     60  1.3.8.2  martin 	switch (function) {
     61  1.3.8.2  martin 	case F_ULOCK:
     62  1.3.8.2  martin 		cmd = F_SETLK;
     63  1.3.8.2  martin 		fl.l_type = F_UNLCK;
     64  1.3.8.2  martin 		break;
     65  1.3.8.2  martin 	case F_LOCK:
     66  1.3.8.2  martin 		cmd = F_SETLKW;
     67  1.3.8.2  martin 		fl.l_type = F_WRLCK;
     68  1.3.8.2  martin 		break;
     69  1.3.8.2  martin 	case F_TLOCK:
     70  1.3.8.2  martin 		cmd = F_SETLK;
     71  1.3.8.2  martin 		fl.l_type = F_WRLCK;
     72  1.3.8.2  martin 		break;
     73  1.3.8.2  martin 	case F_TEST:
     74  1.3.8.2  martin 		fl.l_type = F_WRLCK;
     75  1.3.8.2  martin 		if (fcntl(filedes, F_GETLK, &fl) == -1)
     76  1.3.8.2  martin 			return (-1);
     77  1.3.8.2  martin 		if (fl.l_type == F_UNLCK || fl.l_pid == getpid())
     78  1.3.8.2  martin 			return (0);
     79  1.3.8.2  martin 		errno = EAGAIN;
     80  1.3.8.2  martin 		return (-1);
     81  1.3.8.2  martin 		/* NOTREACHED */
     82  1.3.8.2  martin 	default:
     83  1.3.8.2  martin 		errno = EINVAL;
     84  1.3.8.2  martin 		return (-1);
     85  1.3.8.2  martin 		/* NOTREACHED */
     86  1.3.8.2  martin 	}
     87  1.3.8.2  martin 
     88  1.3.8.2  martin 	return (fcntl(filedes, cmd, &fl));
     89  1.3.8.2  martin }
     90