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 * $FreeBSD$
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 static int chkvnlock(struct vnode *);
42 /*
43 * Prototypes for dead operations on vnodes.
44 */
45 static int dead_bmap(struct vop_bmap_args *);
46 static int dead_ioctl(struct vop_ioctl_args *);
47 static int dead_lock(struct vop_lock_args *);
48 static int dead_lookup(struct vop_lookup_args *);
49 static int dead_open(struct vop_open_args *);
50 static int dead_poll(struct vop_poll_args *);
51 static int dead_read(struct vop_read_args *);
52 static int dead_write(struct vop_write_args *);
53
54 vop_t **dead_vnodeop_p;
55 static struct vnodeopv_entry_desc dead_vnodeop_entries[] = {
56 { &vop_default_desc, (vop_t *) vop_defaultop },
57 { &vop_access_desc, (vop_t *) vop_ebadf },
58 { &vop_advlock_desc, (vop_t *) vop_ebadf },
59 { &vop_bmap_desc, (vop_t *) dead_bmap },
60 { &vop_create_desc, (vop_t *) vop_panic },
61 { &vop_getattr_desc, (vop_t *) vop_ebadf },
62 { &vop_inactive_desc, (vop_t *) vop_null },
63 { &vop_ioctl_desc, (vop_t *) dead_ioctl },
64 { &vop_link_desc, (vop_t *) vop_panic },
65 { &vop_lock_desc, (vop_t *) dead_lock },
66 { &vop_lookup_desc, (vop_t *) dead_lookup },
67 { &vop_mkdir_desc, (vop_t *) vop_panic },
68 { &vop_mknod_desc, (vop_t *) vop_panic },
69 { &vop_open_desc, (vop_t *) dead_open },
70 { &vop_pathconf_desc, (vop_t *) vop_ebadf }, /* per pathconf(2) */
71 { &vop_poll_desc, (vop_t *) dead_poll },
72 { &vop_read_desc, (vop_t *) dead_read },
73 { &vop_readdir_desc, (vop_t *) vop_ebadf },
74 { &vop_readlink_desc, (vop_t *) vop_ebadf },
75 { &vop_reclaim_desc, (vop_t *) vop_null },
76 { &vop_remove_desc, (vop_t *) vop_panic },
77 { &vop_rename_desc, (vop_t *) vop_panic },
78 { &vop_rmdir_desc, (vop_t *) vop_panic },
79 { &vop_setattr_desc, (vop_t *) vop_ebadf },
80 { &vop_symlink_desc, (vop_t *) vop_panic },
81 { &vop_write_desc, (vop_t *) dead_write },
82 { NULL, NULL }
83 };
84 static struct vnodeopv_desc dead_vnodeop_opv_desc =
85 { &dead_vnodeop_p, dead_vnodeop_entries };
86
87 VNODEOP_SET(dead_vnodeop_opv_desc);
88
89 /*
90 * Trivial lookup routine that always fails.
91 */
92 /* ARGSUSED */
93 static int
94 dead_lookup(ap)
95 struct vop_lookup_args /* {
96 struct vnode * a_dvp;
97 struct vnode ** a_vpp;
98 struct componentname * a_cnp;
99 } */ *ap;
100 {
101
102 *ap->a_vpp = NULL;
103 return (ENOTDIR);
104 }
105
106 /*
107 * Open always fails as if device did not exist.
108 */
109 /* ARGSUSED */
110 static int
111 dead_open(ap)
112 struct vop_open_args /* {
113 struct vnode *a_vp;
114 int a_mode;
115 struct ucred *a_cred;
116 struct proc *a_p;
117 } */ *ap;
118 {
119
120 return (ENXIO);
121 }
122
123 /*
124 * Vnode op for read
125 */
126 /* ARGSUSED */
127 static int
128 dead_read(ap)
129 struct vop_read_args /* {
130 struct vnode *a_vp;
131 struct uio *a_uio;
132 int a_ioflag;
133 struct ucred *a_cred;
134 } */ *ap;
135 {
136
137 if (chkvnlock(ap->a_vp))
138 panic("dead_read: lock");
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 */
151 static int
152 dead_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
161 if (chkvnlock(ap->a_vp))
162 panic("dead_write: lock");
163 return (EIO);
164 }
165
166 /*
167 * Device ioctl operation.
168 */
169 /* ARGSUSED */
170 static int
171 dead_ioctl(ap)
172 struct vop_ioctl_args /* {
173 struct vnode *a_vp;
174 u_long a_command;
175 caddr_t a_data;
176 int a_fflag;
177 struct ucred *a_cred;
178 struct proc *a_p;
179 } */ *ap;
180 {
181
182 if (!chkvnlock(ap->a_vp))
183 return (ENOTTY);
184 /* XXX: Doesn't this just recurse back here ? */
185 return (VCALL(ap->a_vp, VOFFSET(vop_ioctl), ap));
186 }
187
188
189 /*
190 * Wait until the vnode has finished changing state.
191 */
192 static int
193 dead_lock(ap)
194 struct vop_lock_args /* {
195 struct vnode *a_vp;
196 int a_flags;
197 struct proc *a_p;
198 } */ *ap;
199 {
200 struct vnode *vp = ap->a_vp;
201
202 /*
203 * Since we are not using the lock manager, we must clear
204 * the interlock here.
205 */
206 if (ap->a_flags & LK_INTERLOCK) {
207 mtx_unlock(&vp->v_interlock);
208 ap->a_flags &= ~LK_INTERLOCK;
209 }
210 if (!chkvnlock(vp))
211 return (0);
212 return (VCALL(vp, VOFFSET(vop_lock), ap));
213 }
214
215 /*
216 * Wait until the vnode has finished changing state.
217 */
218 static int
219 dead_bmap(ap)
220 struct vop_bmap_args /* {
221 struct vnode *a_vp;
222 daddr_t a_bn;
223 struct vnode **a_vpp;
224 daddr_t *a_bnp;
225 int *a_runp;
226 int *a_runb;
227 } */ *ap;
228 {
229
230 if (!chkvnlock(ap->a_vp))
231 return (EIO);
232 return (VOP_BMAP(ap->a_vp, ap->a_bn, ap->a_vpp, ap->a_bnp, ap->a_runp, ap->a_runb));
233 }
234
235 /*
236 * We have to wait during times when the vnode is
237 * in a state of change.
238 */
239 static int
240 chkvnlock(vp)
241 register struct vnode *vp;
242 {
243 int locked = 0;
244
245 VI_LOCK(vp);
246 while (vp->v_iflag & VI_XLOCK) {
247 vp->v_iflag |= VI_XWANT;
248 (void) msleep((caddr_t)vp, VI_MTX(vp), PINOD, "ckvnlk", 0);
249 locked = 1;
250 }
251 VI_UNLOCK(vp);
252 return (locked);
253 }
254
255 /*
256 * Trivial poll routine that always returns POLLHUP.
257 * This is necessary so that a process which is polling a file
258 * gets notified when that file is revoke()d.
259 */
260 static int
261 dead_poll(ap)
262 struct vop_poll_args *ap;
263 {
264 return (POLLHUP);
265 }
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