bsd/sys/lockf.h

   1 /*
   2  * Copyright (c) 2004-2006 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 /*
  29  * Copyright (c) 1991, 1993
  30  *      The Regents of the University of California.  All rights reserved.
  31  *
  32  * This code is derived from software contributed to Berkeley by
  33  * Scooter Morris at Genentech Inc.
  34  *
  35  * Redistribution and use in source and binary forms, with or without
  36  * modification, are permitted provided that the following conditions
  37  * are met:
  38  * 1. Redistributions of source code must retain the above copyright
  39  *    notice, this list of conditions and the following disclaimer.
  40  * 2. Redistributions in binary form must reproduce the above copyright
  41  *    notice, this list of conditions and the following disclaimer in the
  42  *    documentation and/or other materials provided with the distribution.
  43  * 4. Neither the name of the University nor the names of its contributors
  44  *    may be used to endorse or promote products derived from this software
  45  *    without specific prior written permission.
  46  *
  47  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  48  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  49  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  50  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  51  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  52  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  53  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  54  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  55  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  56  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  57  * SUCH DAMAGE.
  58  *
  59  *      @(#)lockf.h     8.1 (Berkeley) 6/11/93
  60  * $FreeBSD: src/sys/sys/lockf.h,v 1.16 2004/04/07 04:19:49 imp Exp $
  61  */
  62
  63 #ifndef _SYS_LOCKF_H_
  64 #define _SYS_LOCKF_H_
  65
  66 #include <sys/queue.h>
  67 #include <sys/cdefs.h>
  68
  69 struct vnop_advlock_args;
  70 struct vnode;
  71
  72 #ifdef MALLOC_DECLARE
  73 MALLOC_DECLARE(M_LOCKF);
  74 #endif
  75
  76 /*
  77  * The lockf structure is a kernel structure which contains the information
  78  * associated with a byte range lock.  The lockf structures are linked into
  79  * the vnode structure.  Locks are sorted by the starting byte of the lock for
  80  * efficiency after they have been committed; uncommitted locks are on the list
  81  * head so they may quickly be accessed, and are both short lived and transient.
  82  */
  83 TAILQ_HEAD(locklist, lockf);
  84
  85 #pragma pack(4)
  86
  87 struct lockf {
  88         short   lf_flags;           /* Semantics: F_POSIX, F_FLOCK, F_WAIT */
  89         short   lf_type;         /* Lock type: F_RDLCK, F_WRLCK */
  90         off_t   lf_start;           /* Byte # of the start of the lock */
  91         off_t   lf_end;             /* Byte # of the end of the lock (-1=EOF) */
  92         caddr_t lf_id;              /* Id of the resource holding the lock */
  93         struct  lockf **lf_head;    /* Back pointer to the head of the locf list */
  94         struct vnode *lf_vnode;     /* Back pointer to the inode */
  95         struct  lockf *lf_next;     /* Pointer to the next lock on this inode */
  96         struct  locklist lf_blkhd;  /* List of requests blocked on this lock */
  97         TAILQ_ENTRY(lockf) lf_block;/* A request waiting for a lock */
  98 };
  99
 100 #pragma pack()
 101
 102 /* Maximum length of sleep chains to traverse to try and detect deadlock. */
 103 #define MAXDEPTH 50
 104
 105 __BEGIN_DECLS
 106
 107 #ifdef KERNEL_PRIVATE
 108 int     lf_advlock(struct vnop_advlock_args *);
 109 int     lf_assert(struct vnop_advlock_args *, void **);
 110 void    lf_commit(void *, int);
 111
 112 #ifdef LOCKF_DEBUG
 113 void    lf_print(char *, struct lockf *);
 114 void    lf_printlist(char *, struct lockf *);
 115 #endif
 116 #endif /* KERNEL_PRIVATE */
 117
 118 __END_DECLS
 119
 120 #endif /* !_SYS_LOCKF_H_ */