bsd/miscfs/nullfs/null.h

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
  23 /*
  24  * Copyright (c) 1992, 1993
  25  *      The Regents of the University of California.  All rights reserved.
  26  *
  27  * This code is derived from software donated to Berkeley by
  28  * Jan-Simon Pendry.
  29  *
  30  * Redistribution and use in source and binary forms, with or without
  31  * modification, are permitted provided that the following conditions
  32  * are met:
  33  * 1. Redistributions of source code must retain the above copyright
  34  *    notice, this list of conditions and the following disclaimer.
  35  * 2. Redistributions in binary form must reproduce the above copyright
  36  *    notice, this list of conditions and the following disclaimer in the
  37  *    documentation and/or other materials provided with the distribution.
  38  * 3. All advertising materials mentioning features or use of this software
  39  *    must display the following acknowledgement:
  40  *      This product includes software developed by the University of
  41  *      California, Berkeley and its contributors.
  42  * 4. Neither the name of the University nor the names of its contributors
  43  *    may be used to endorse or promote products derived from this software
  44  *    without specific prior written permission.
  45  *
  46  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  47  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  48  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  49  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  50  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  51  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  52  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  53  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  54  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  55  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  56  * SUCH DAMAGE.
  57  *
  58  *      @(#)null.h      8.3 (Berkeley) 8/20/94
  59  *
  60  *      null.h  8.2 (Berkeley) 1/21/94
  61  */
  62
  63 struct null_args {
  64         char            *target;        /* Target of loopback  */
  65 };
  66
  67 struct null_mount {
  68         struct mount    *nullm_vfs;
  69         struct vnode    *nullm_rootvp;  /* Reference to root null_node */
  70 };
  71
  72 #ifdef KERNEL
  73 /*
  74  * A cache of vnode references
  75  */
  76 struct null_node {
  77         LIST_ENTRY(null_node)   null_hash;      /* Hash list */
  78         struct vnode            *null_lowervp;  /* VREFed once */
  79         struct vnode            *null_vnode;    /* Back pointer */
  80 };
  81
  82 extern int null_node_create __P((struct mount *mp, struct vnode *target, struct vnode **vpp));
  83
  84 #define MOUNTTONULLMOUNT(mp) ((struct null_mount *)((mp)->mnt_data))
  85 #define VTONULL(vp) ((struct null_node *)(vp)->v_data)
  86 #define NULLTOV(xp) ((xp)->null_vnode)
  87 #ifdef NULLFS_DIAGNOSTIC
  88 extern struct vnode *null_checkvp __P((struct vnode *vp, char *fil, int lno));
  89 #define NULLVPTOLOWERVP(vp) null_checkvp((vp), __FILE__, __LINE__)
  90 #else
  91 #define NULLVPTOLOWERVP(vp) (VTONULL(vp)->null_lowervp)
  92 #endif
  93
  94 extern int (**null_vnodeop_p)(void *);
  95 extern struct vfsops null_vfsops;
  96 #endif /* KERNEL */