union.h revision 7090 
1/*
2 * Copyright (c) 1994 The Regents of the University of California.
3 * Copyright (c) 1994 Jan-Simon Pendry.
4 * All rights reserved.
5 *
6 * This code is derived from software donated to Berkeley by
7 * Jan-Simon Pendry.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in the
16 *    documentation and/or other materials provided with the distribution.
17 * 3. All advertising materials mentioning features or use of this software
18 *    must display the following acknowledgement:
19 *	This product includes software developed by the University of
20 *	California, Berkeley and its contributors.
21 * 4. Neither the name of the University nor the names of its contributors
22 *    may be used to endorse or promote products derived from this software
23 *    without specific prior written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 * SUCH DAMAGE.
36 *
37 *	@(#)union.h	8.2 (Berkeley) 2/17/94
38 * $Id: union.h,v 1.2 1994/08/02 07:45:42 davidg Exp $
39 */
40
41struct union_args {
42	char		*target;	/* Target of loopback  */
43	int		mntflags;	/* Options on the mount */
44};
45
46#define UNMNT_ABOVE	0x0001		/* Target appears below mount point */
47#define UNMNT_BELOW	0x0002		/* Target appears below mount point */
48#define UNMNT_REPLACE	0x0003		/* Target replaces mount point */
49#define UNMNT_OPMASK	0x0003
50
51struct union_mount {
52	struct vnode	*um_uppervp;
53	struct vnode	*um_lowervp;
54	struct ucred	*um_cred;	/* Credentials of user calling mount */
55	int		um_cmode;	/* cmask from mount process */
56	int		um_op;		/* Operation mode */
57};
58
59#ifdef KERNEL
60
61/*
62 * DEFDIRMODE is the mode bits used to create a shadow directory.
63 */
64#define VRWXMODE (VREAD|VWRITE|VEXEC)
65#define VRWMODE (VREAD|VWRITE)
66#define UN_DIRMODE ((VRWXMODE)|(VRWXMODE>>3)|(VRWXMODE>>6))
67#define UN_FILEMODE ((VRWMODE)|(VRWMODE>>3)|(VRWMODE>>6))
68
69/*
70 * A cache of vnode references
71 */
72struct union_node {
73	LIST_ENTRY(union_node)	un_cache;	/* Hash chain */
74	struct vnode		*un_vnode;	/* Back pointer */
75	struct vnode	        *un_uppervp;	/* overlaying object */
76	struct vnode	        *un_lowervp;	/* underlying object */
77	struct vnode		*un_dirvp;	/* Parent dir of uppervp */
78	char			*un_path;	/* saved component name */
79	int			un_hash;	/* saved un_path hash value */
80	int			un_openl;	/* # of opens on lowervp */
81	int			un_flags;
82#ifdef DIAGNOSTIC
83	pid_t			un_pid;
84#endif
85};
86
87#define UN_WANT		0x01
88#define UN_LOCKED	0x02
89#define UN_ULOCK	0x04		/* Upper node is locked */
90#define UN_KLOCK	0x08		/* Keep upper node locked on vput */
91
92extern int union_allocvp __P((struct vnode **, struct mount *,
93				struct vnode *, struct vnode *,
94				struct componentname *, struct vnode *,
95				struct vnode *));
96extern int union_freevp __P((struct vnode *));
97extern int union_copyfile __P((struct proc *, struct ucred *,
98				struct vnode *, struct vnode *));
99extern int union_mkshadow __P((struct union_mount *, struct vnode *,
100				struct componentname *, struct vnode **));
101extern int union_vn_create __P((struct vnode **, struct union_node *,
102				struct proc *));
103extern int union_vn_close __P((struct vnode *, int, struct ucred *,
104				struct proc *));
105extern int union_cn_close __P((struct vnode *, int, struct ucred *,
106				struct proc *));
107extern void union_removed_upper __P((struct union_node *un));
108extern struct vnode *union_lowervp __P((struct vnode *));
109extern void union_newlower __P((struct union_node *, struct vnode *));
110extern void union_newupper __P((struct union_node *, struct vnode *));
111
112#define	MOUNTTOUNIONMOUNT(mp) ((struct union_mount *)((mp)->mnt_data))
113#define	VTOUNION(vp) ((struct union_node *)(vp)->v_data)
114#define	UNIONTOV(un) ((un)->un_vnode)
115#define	LOWERVP(vp) (VTOUNION(vp)->un_lowervp)
116#define	UPPERVP(vp) (VTOUNION(vp)->un_uppervp)
117#define OTHERVP(vp) (UPPERVP(vp) ? UPPERVP(vp) : LOWERVP(vp))
118
119extern int (**union_vnodeop_p)();
120extern struct vfsops union_vfsops;
121#endif /* KERNEL */
122