1 /* $OpenBSD: dead_vnops.c,v 1.35 2021/04/28 09:53:53 claudio Exp $ */ 2 /* $NetBSD: dead_vnops.c,v 1.16 1996/02/13 13:12:48 mycroft Exp $ */ 3 4 /* 5 * Copyright (c) 1989, 1993 6 * The Regents of the University of California. All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 * 32 * @(#)dead_vnops.c 8.2 (Berkeley) 11/21/94 33 */ 34 35 #include <sys/param.h> 36 #include <sys/systm.h> 37 #include <sys/event.h> 38 #include <sys/time.h> 39 #include <sys/vnode.h> 40 #include <sys/lock.h> 41 #include <sys/errno.h> 42 #include <sys/buf.h> 43 #include <sys/poll.h> 44 45 /* 46 * Prototypes for dead operations on vnodes. 47 */ 48 int dead_badop(void *); 49 int dead_ebadf(void *); 50 51 int dead_open(void *); 52 int dead_read(void *); 53 int dead_write(void *); 54 int dead_ioctl(void *); 55 int dead_poll(void *); 56 int dead_kqfilter(void *v); 57 int dead_inactive(void *); 58 int dead_lock(void *); 59 int dead_bmap(void *); 60 int dead_strategy(void *); 61 int dead_print(void *); 62 63 int chkvnlock(struct vnode *); 64 65 const struct vops dead_vops = { 66 .vop_lookup = vop_generic_lookup, 67 .vop_create = dead_badop, 68 .vop_mknod = dead_badop, 69 .vop_open = dead_open, 70 .vop_close = nullop, 71 .vop_access = dead_ebadf, 72 .vop_getattr = dead_ebadf, 73 .vop_setattr = dead_ebadf, 74 .vop_read = dead_read, 75 .vop_write = dead_write, 76 .vop_ioctl = dead_ioctl, 77 .vop_poll = dead_poll, 78 .vop_kqfilter = dead_kqfilter, 79 .vop_revoke = NULL, 80 .vop_fsync = nullop, 81 .vop_remove = dead_badop, 82 .vop_link = dead_badop, 83 .vop_rename = dead_badop, 84 .vop_mkdir = dead_badop, 85 .vop_rmdir = dead_badop, 86 .vop_symlink = dead_badop, 87 .vop_readdir = dead_ebadf, 88 .vop_readlink = dead_ebadf, 89 .vop_abortop = dead_badop, 90 .vop_inactive = dead_inactive, 91 .vop_reclaim = nullop, 92 .vop_lock = dead_lock, 93 .vop_unlock = vop_generic_unlock, 94 .vop_bmap = dead_bmap, 95 .vop_strategy = dead_strategy, 96 .vop_print = dead_print, 97 .vop_islocked = vop_generic_islocked, 98 .vop_pathconf = dead_ebadf, 99 .vop_advlock = dead_ebadf, 100 .vop_bwrite = nullop, 101 }; 102 103 /* 104 * Open always fails as if device did not exist. 105 */ 106 /* ARGSUSED */ 107 int 108 dead_open(void *v) 109 { 110 return (ENXIO); 111 } 112 113 /* 114 * Vnode op for read 115 */ 116 /* ARGSUSED */ 117 int 118 dead_read(void *v) 119 { 120 struct vop_read_args *ap = v; 121 122 if (chkvnlock(ap->a_vp)) 123 panic("dead_read: lock"); 124 /* 125 * Return EOF for tty devices, EIO for others 126 */ 127 if ((ap->a_vp->v_flag & VISTTY) == 0) 128 return (EIO); 129 return (0); 130 } 131 132 /* 133 * Vnode op for write 134 */ 135 /* ARGSUSED */ 136 int 137 dead_write(void *v) 138 { 139 struct vop_write_args *ap = v; 140 141 if (chkvnlock(ap->a_vp)) 142 panic("dead_write: lock"); 143 return (EIO); 144 } 145 146 /* 147 * Device ioctl operation. 148 */ 149 /* ARGSUSED */ 150 int 151 dead_ioctl(void *v) 152 { 153 struct vop_ioctl_args *ap = v; 154 155 if (!chkvnlock(ap->a_vp)) 156 return (EBADF); 157 return ((ap->a_vp->v_op->vop_ioctl)(ap)); 158 } 159 160 /* ARGSUSED */ 161 int 162 dead_poll(void *v) 163 { 164 #if 0 165 struct vop_poll_args *ap = v; 166 #endif 167 168 /* 169 * Let the user find out that the descriptor is gone. 170 */ 171 return (POLLHUP); 172 } 173 174 int 175 dead_kqfilter(void *v) 176 { 177 struct vop_kqfilter_args *ap = v; 178 179 switch (ap->a_kn->kn_filter) { 180 case EVFILT_READ: 181 case EVFILT_WRITE: 182 ap->a_kn->kn_fop = &dead_filtops; 183 break; 184 default: 185 return (EINVAL); 186 } 187 188 return (0); 189 } 190 191 /* 192 * Just call the device strategy routine 193 */ 194 int 195 dead_strategy(void *v) 196 { 197 struct vop_strategy_args *ap = v; 198 int s; 199 200 if (ap->a_bp->b_vp == NULL || !chkvnlock(ap->a_bp->b_vp)) { 201 ap->a_bp->b_flags |= B_ERROR; 202 s = splbio(); 203 biodone(ap->a_bp); 204 splx(s); 205 return (EIO); 206 } 207 return (VOP_STRATEGY(ap->a_bp)); 208 } 209 210 int 211 dead_inactive(void *v) 212 { 213 struct vop_inactive_args *ap = v; 214 215 VOP_UNLOCK(ap->a_vp); 216 return (0); 217 } 218 219 /* 220 * Wait until the vnode has finished changing state. 221 */ 222 int 223 dead_lock(void *v) 224 { 225 struct vop_lock_args *ap = v; 226 struct vnode *vp = ap->a_vp; 227 228 if (ap->a_flags & LK_DRAIN || !chkvnlock(vp)) 229 return (0); 230 231 return ((vp->v_op->vop_lock)(ap)); 232 } 233 234 /* 235 * Wait until the vnode has finished changing state. 236 */ 237 int 238 dead_bmap(void *v) 239 { 240 struct vop_bmap_args *ap = v; 241 242 if (!chkvnlock(ap->a_vp)) 243 return (EIO); 244 return (VOP_BMAP(ap->a_vp, ap->a_bn, ap->a_vpp, ap->a_bnp, ap->a_runp)); 245 } 246 247 /* 248 * Print out the contents of a dead vnode. 249 */ 250 /* ARGSUSED */ 251 int 252 dead_print(void *v) 253 { 254 printf("tag VT_NON, dead vnode\n"); 255 return 0; 256 } 257 258 /* 259 * Empty vnode failed operation 260 */ 261 /*ARGSUSED*/ 262 int 263 dead_ebadf(void *v) 264 { 265 return (EBADF); 266 } 267 268 /* 269 * Empty vnode bad operation 270 */ 271 /*ARGSUSED*/ 272 int 273 dead_badop(void *v) 274 { 275 panic("dead_badop called"); 276 /* NOTREACHED */ 277 } 278 279 /* 280 * We have to wait during times when the vnode is 281 * in a state of change. 282 */ 283 int 284 chkvnlock(struct vnode *vp) 285 { 286 int locked = 0; 287 288 mtx_enter(&vnode_mtx); 289 while (vp->v_lflag & VXLOCK) { 290 vp->v_lflag |= VXWANT; 291 msleep_nsec(vp, &vnode_mtx, PINOD, "chkvnlock", INFSLP); 292 locked = 1; 293 } 294 mtx_leave(&vnode_mtx); 295 return (locked); 296 } 297