dead_vnops.c revision 273462 
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 273462 2014-10-22 09:09:41Z 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
80/* ARGSUSED */
81static int
82dead_getwritemount(ap)
83	struct vop_getwritemount_args /* {
84		struct vnode *a_vp;
85		struct mount **a_mpp;
86	} */ *ap;
87{
88	*(ap->a_mpp) = NULL;
89	return (0);
90}
91
92/*
93 * Trivial lookup routine that always fails.
94 */
95/* ARGSUSED */
96static int
97dead_lookup(ap)
98	struct vop_lookup_args /* {
99		struct vnode * a_dvp;
100		struct vnode ** a_vpp;
101		struct componentname * a_cnp;
102	} */ *ap;
103{
104
105	*ap->a_vpp = NULL;
106	return (ENOTDIR);
107}
108
109/*
110 * Open always fails as if device did not exist.
111 */
112/* ARGSUSED */
113static int
114dead_open(ap)
115	struct vop_open_args /* {
116		struct vnode *a_vp;
117		int  a_mode;
118		struct ucred *a_cred;
119		struct proc *a_p;
120	} */ *ap;
121{
122
123	return (ENXIO);
124}
125
126/*
127 * Vnode op for read
128 */
129/* ARGSUSED */
130int
131dead_read(ap)
132	struct vop_read_args /* {
133		struct vnode *a_vp;
134		struct uio *a_uio;
135		int  a_ioflag;
136		struct ucred *a_cred;
137	} */ *ap;
138{
139	/*
140	 * Return EOF for tty devices, EIO for others
141	 */
142	if ((ap->a_vp->v_vflag & VV_ISTTY) == 0)
143		return (EIO);
144	return (0);
145}
146
147/*
148 * Vnode op for write
149 */
150/* ARGSUSED */
151int
152dead_write(ap)
153	struct vop_write_args /* {
154		struct vnode *a_vp;
155		struct uio *a_uio;
156		int  a_ioflag;
157		struct ucred *a_cred;
158	} */ *ap;
159{
160	return (EIO);
161}
162
163int
164dead_poll(ap)
165	struct vop_poll_args *ap;
166{
167
168	if (ap->a_events & ~POLLSTANDARD)
169		return (POLLNVAL);
170
171	/*
172	 * Let the user find out that the descriptor is gone.
173	 */
174	return (POLLHUP | ((POLLIN | POLLRDNORM) & ap->a_events));
175
176}
177
178static int
179dead_rename(ap)
180	struct vop_rename_args  /* {
181		struct vnode *a_fdvp;
182		struct vnode *a_fvp;
183		struct componentname *a_fcnp;
184		struct vnode *a_tdvp;
185		struct vnode *a_tvp;
186		struct componentname *a_tcnp;
187	} */ *ap;
188{
189
190	vop_rename_fail(ap);
191	return (EXDEV);
192}
193