dead_vnops.c revision 273461 
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 273461 2014-10-22 09:06:36Z 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_poll_t	dead_poll;
47static vop_read_t	dead_read;
48static vop_write_t	dead_write;
49static vop_getwritemount_t dead_getwritemount;
50static vop_rename_t	dead_rename;
51
52struct vop_vector dead_vnodeops = {
53	.vop_default =		&default_vnodeops,
54
55	.vop_access =		VOP_EBADF,
56	.vop_advlock =		VOP_EBADF,
57	.vop_bmap =		VOP_EBADF,
58	.vop_create =		VOP_PANIC,
59	.vop_getattr =		VOP_EBADF,
60	.vop_getwritemount =	dead_getwritemount,
61	.vop_inactive =		VOP_NULL,
62	.vop_ioctl =		VOP_EBADF,
63	.vop_link =		VOP_PANIC,
64	.vop_lookup =		dead_lookup,
65	.vop_mkdir =		VOP_PANIC,
66	.vop_mknod =		VOP_PANIC,
67	.vop_open =		dead_open,
68	.vop_pathconf =		VOP_EBADF,	/* per pathconf(2) */
69	.vop_poll =		dead_poll,
70	.vop_read =		dead_read,
71	.vop_readdir =		VOP_EBADF,
72	.vop_readlink =		VOP_EBADF,
73	.vop_reclaim =		VOP_NULL,
74	.vop_remove =		VOP_PANIC,
75	.vop_rename =		dead_rename,
76	.vop_rmdir =		VOP_PANIC,
77	.vop_setattr =		VOP_EBADF,
78	.vop_symlink =		VOP_PANIC,
79	.vop_vptocnp =		VOP_EBADF,
80	.vop_write =		dead_write,
81};
82
83/* ARGSUSED */
84static int
85dead_getwritemount(ap)
86	struct vop_getwritemount_args /* {
87		struct vnode *a_vp;
88		struct mount **a_mpp;
89	} */ *ap;
90{
91	*(ap->a_mpp) = NULL;
92	return (0);
93}
94
95/*
96 * Trivial lookup routine that always fails.
97 */
98/* ARGSUSED */
99static int
100dead_lookup(ap)
101	struct vop_lookup_args /* {
102		struct vnode * a_dvp;
103		struct vnode ** a_vpp;
104		struct componentname * a_cnp;
105	} */ *ap;
106{
107
108	*ap->a_vpp = NULL;
109	return (ENOTDIR);
110}
111
112/*
113 * Open always fails as if device did not exist.
114 */
115/* ARGSUSED */
116static int
117dead_open(ap)
118	struct vop_open_args /* {
119		struct vnode *a_vp;
120		int  a_mode;
121		struct ucred *a_cred;
122		struct proc *a_p;
123	} */ *ap;
124{
125
126	return (ENXIO);
127}
128
129/*
130 * Vnode op for read
131 */
132/* ARGSUSED */
133static int
134dead_read(ap)
135	struct vop_read_args /* {
136		struct vnode *a_vp;
137		struct uio *a_uio;
138		int  a_ioflag;
139		struct ucred *a_cred;
140	} */ *ap;
141{
142	/*
143	 * Return EOF for tty devices, EIO for others
144	 */
145	if ((ap->a_vp->v_vflag & VV_ISTTY) == 0)
146		return (EIO);
147	return (0);
148}
149
150/*
151 * Vnode op for write
152 */
153/* ARGSUSED */
154static int
155dead_write(ap)
156	struct vop_write_args /* {
157		struct vnode *a_vp;
158		struct uio *a_uio;
159		int  a_ioflag;
160		struct ucred *a_cred;
161	} */ *ap;
162{
163	return (EIO);
164}
165
166static int
167dead_poll(ap)
168	struct vop_poll_args *ap;
169{
170
171	if (ap->a_events & ~POLLSTANDARD)
172		return (POLLNVAL);
173
174	/*
175	 * Let the user find out that the descriptor is gone.
176	 */
177	return (POLLHUP | ((POLLIN | POLLRDNORM) & ap->a_events));
178
179}
180
181static int
182dead_rename(ap)
183	struct vop_rename_args  /* {
184		struct vnode *a_fdvp;
185		struct vnode *a_fvp;
186		struct componentname *a_fcnp;
187		struct vnode *a_tdvp;
188		struct vnode *a_tvp;
189		struct componentname *a_tcnp;
190	} */ *ap;
191{
192
193	vop_rename_fail(ap);
194	return (EXDEV);
195}
196