dead_vnops.c revision 273463 
1/*-
2 * Copyright (c) 1989, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 4. Neither the name of the University nor the names of its contributors
14 *    may be used to endorse or promote products derived from this software
15 *    without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 *	@(#)dead_vnops.c	8.1 (Berkeley) 6/10/93
30 * $FreeBSD: stable/10/sys/fs/deadfs/dead_vnops.c 273463 2014-10-22 09:12:20Z kib $
31 */
32
33#include <sys/param.h>
34#include <sys/systm.h>
35#include <sys/kernel.h>
36#include <sys/lock.h>
37#include <sys/mutex.h>
38#include <sys/poll.h>
39#include <sys/vnode.h>
40
41/*
42 * Prototypes for dead operations on vnodes.
43 */
44static vop_lookup_t	dead_lookup;
45static vop_open_t	dead_open;
46static vop_getwritemount_t dead_getwritemount;
47static vop_rename_t	dead_rename;
48
49struct vop_vector dead_vnodeops = {
50	.vop_default =		&default_vnodeops,
51
52	.vop_access =		VOP_EBADF,
53	.vop_advlock =		VOP_EBADF,
54	.vop_bmap =		VOP_EBADF,
55	.vop_create =		VOP_PANIC,
56	.vop_getattr =		VOP_EBADF,
57	.vop_getwritemount =	dead_getwritemount,
58	.vop_inactive =		VOP_NULL,
59	.vop_ioctl =		VOP_EBADF,
60	.vop_link =		VOP_PANIC,
61	.vop_lookup =		dead_lookup,
62	.vop_mkdir =		VOP_PANIC,
63	.vop_mknod =		VOP_PANIC,
64	.vop_open =		dead_open,
65	.vop_pathconf =		VOP_EBADF,	/* per pathconf(2) */
66	.vop_poll =		dead_poll,
67	.vop_read =		dead_read,
68	.vop_readdir =		VOP_EBADF,
69	.vop_readlink =		VOP_EBADF,
70	.vop_reclaim =		VOP_NULL,
71	.vop_remove =		VOP_PANIC,
72	.vop_rename =		dead_rename,
73	.vop_rmdir =		VOP_PANIC,
74	.vop_setattr =		VOP_EBADF,
75	.vop_symlink =		VOP_PANIC,
76	.vop_vptocnp =		VOP_EBADF,
77	.vop_write =		dead_write,
78};
79
80static int
81dead_getwritemount(struct vop_getwritemount_args *ap)
82{
83
84	*(ap->a_mpp) = NULL;
85	return (0);
86}
87
88/*
89 * Trivial lookup routine that always fails.
90 */
91static int
92dead_lookup(struct vop_lookup_args *ap)
93{
94
95	*ap->a_vpp = NULL;
96	return (ENOTDIR);
97}
98
99/*
100 * Open always fails as if device did not exist.
101 */
102static int
103dead_open(struct vop_open_args *ap)
104{
105
106	return (ENXIO);
107}
108
109int
110dead_read(struct vop_read_args *ap)
111{
112
113	/*
114	 * Return EOF for tty devices, EIO for others
115	 */
116	if ((ap->a_vp->v_vflag & VV_ISTTY) == 0)
117		return (EIO);
118	return (0);
119}
120
121int
122dead_write(struct vop_write_args *ap)
123{
124
125	return (EIO);
126}
127
128int
129dead_poll(struct vop_poll_args *ap)
130{
131
132	if (ap->a_events & ~POLLSTANDARD)
133		return (POLLNVAL);
134
135	/*
136	 * Let the user find out that the descriptor is gone.
137	 */
138	return (POLLHUP | ((POLLIN | POLLRDNORM) & ap->a_events));
139
140}
141
142static int
143dead_rename(struct vop_rename_args *ap)
144{
145
146	vop_rename_fail(ap);
147	return (EXDEV);
148}
149