1 /* $NetBSD: spec_vnops.c,v 1.23 1995/04/10 00:48:10 mycroft Exp $ */ 2 3 /* 4 * Copyright (c) 1989, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 * 35 * @(#)spec_vnops.c 8.8 (Berkeley) 11/21/94 36 */ 37 38 #include <sys/param.h> 39 #include <sys/proc.h> 40 #include <sys/systm.h> 41 #include <sys/kernel.h> 42 #include <sys/conf.h> 43 #include <sys/buf.h> 44 #include <sys/mount.h> 45 #include <sys/namei.h> 46 #include <sys/vnode.h> 47 #include <sys/stat.h> 48 #include <sys/errno.h> 49 #include <sys/ioctl.h> 50 #include <sys/file.h> 51 #include <sys/disklabel.h> 52 #include <miscfs/specfs/specdev.h> 53 54 /* symbolic sleep message strings for devices */ 55 char devopn[] = "devopn"; 56 char devio[] = "devio"; 57 char devwait[] = "devwait"; 58 char devin[] = "devin"; 59 char devout[] = "devout"; 60 char devioc[] = "devioc"; 61 char devcls[] = "devcls"; 62 63 int (**spec_vnodeop_p)(); 64 struct vnodeopv_entry_desc spec_vnodeop_entries[] = { 65 { &vop_default_desc, vn_default_error }, 66 { &vop_lookup_desc, spec_lookup }, /* lookup */ 67 { &vop_create_desc, spec_create }, /* create */ 68 { &vop_mknod_desc, spec_mknod }, /* mknod */ 69 { &vop_open_desc, spec_open }, /* open */ 70 { &vop_close_desc, spec_close }, /* close */ 71 { &vop_access_desc, spec_access }, /* access */ 72 { &vop_getattr_desc, spec_getattr }, /* getattr */ 73 { &vop_setattr_desc, spec_setattr }, /* setattr */ 74 { &vop_read_desc, spec_read }, /* read */ 75 { &vop_write_desc, spec_write }, /* write */ 76 { &vop_lease_desc, spec_lease_check }, /* lease */ 77 { &vop_ioctl_desc, spec_ioctl }, /* ioctl */ 78 { &vop_select_desc, spec_select }, /* select */ 79 { &vop_mmap_desc, spec_mmap }, /* mmap */ 80 { &vop_fsync_desc, spec_fsync }, /* fsync */ 81 { &vop_seek_desc, spec_seek }, /* seek */ 82 { &vop_remove_desc, spec_remove }, /* remove */ 83 { &vop_link_desc, spec_link }, /* link */ 84 { &vop_rename_desc, spec_rename }, /* rename */ 85 { &vop_mkdir_desc, spec_mkdir }, /* mkdir */ 86 { &vop_rmdir_desc, spec_rmdir }, /* rmdir */ 87 { &vop_symlink_desc, spec_symlink }, /* symlink */ 88 { &vop_readdir_desc, spec_readdir }, /* readdir */ 89 { &vop_readlink_desc, spec_readlink }, /* readlink */ 90 { &vop_abortop_desc, spec_abortop }, /* abortop */ 91 { &vop_inactive_desc, spec_inactive }, /* inactive */ 92 { &vop_reclaim_desc, spec_reclaim }, /* reclaim */ 93 { &vop_lock_desc, spec_lock }, /* lock */ 94 { &vop_unlock_desc, spec_unlock }, /* unlock */ 95 { &vop_bmap_desc, spec_bmap }, /* bmap */ 96 { &vop_strategy_desc, spec_strategy }, /* strategy */ 97 { &vop_print_desc, spec_print }, /* print */ 98 { &vop_islocked_desc, spec_islocked }, /* islocked */ 99 { &vop_pathconf_desc, spec_pathconf }, /* pathconf */ 100 { &vop_advlock_desc, spec_advlock }, /* advlock */ 101 { &vop_blkatoff_desc, spec_blkatoff }, /* blkatoff */ 102 { &vop_valloc_desc, spec_valloc }, /* valloc */ 103 { &vop_vfree_desc, spec_vfree }, /* vfree */ 104 { &vop_truncate_desc, spec_truncate }, /* truncate */ 105 { &vop_update_desc, spec_update }, /* update */ 106 { &vop_bwrite_desc, spec_bwrite }, /* bwrite */ 107 { (struct vnodeop_desc*)NULL, (int(*)())NULL } 108 }; 109 struct vnodeopv_desc spec_vnodeop_opv_desc = 110 { &spec_vnodeop_p, spec_vnodeop_entries }; 111 112 /* 113 * Trivial lookup routine that always fails. 114 */ 115 int 116 spec_lookup(ap) 117 struct vop_lookup_args /* { 118 struct vnode *a_dvp; 119 struct vnode **a_vpp; 120 struct componentname *a_cnp; 121 } */ *ap; 122 { 123 124 *ap->a_vpp = NULL; 125 return (ENOTDIR); 126 } 127 128 /* 129 * Open a special file. 130 */ 131 /* ARGSUSED */ 132 spec_open(ap) 133 struct vop_open_args /* { 134 struct vnode *a_vp; 135 int a_mode; 136 struct ucred *a_cred; 137 struct proc *a_p; 138 } */ *ap; 139 { 140 struct vnode *bvp, *vp = ap->a_vp; 141 dev_t bdev, dev = (dev_t)vp->v_rdev; 142 register int maj = major(dev); 143 int error; 144 145 /* 146 * Don't allow open if fs is mounted -nodev. 147 */ 148 if (vp->v_mount && (vp->v_mount->mnt_flag & MNT_NODEV)) 149 return (ENXIO); 150 151 switch (vp->v_type) { 152 153 case VCHR: 154 if ((u_int)maj >= nchrdev) 155 return (ENXIO); 156 if (ap->a_cred != FSCRED && (ap->a_mode & FWRITE)) { 157 /* 158 * When running in very secure mode, do not allow 159 * opens for writing of any disk character devices. 160 */ 161 if (securelevel >= 2 && cdevsw[maj].d_type == D_DISK) 162 return (EPERM); 163 /* 164 * When running in secure mode, do not allow opens 165 * for writing of /dev/mem, /dev/kmem, or character 166 * devices whose corresponding block devices are 167 * currently mounted. 168 */ 169 if (securelevel >= 1) { 170 if ((bdev = chrtoblk(dev)) != NODEV && 171 vfinddev(bdev, VBLK, &bvp) && 172 bvp->v_usecount > 0 && 173 (error = vfs_mountedon(bvp))) 174 return (error); 175 if (iskmemdev(dev)) 176 return (EPERM); 177 } 178 } 179 if (cdevsw[maj].d_type == D_TTY) 180 vp->v_flag |= VISTTY; 181 VOP_UNLOCK(vp); 182 error = (*cdevsw[maj].d_open)(dev, ap->a_mode, S_IFCHR, ap->a_p); 183 VOP_LOCK(vp); 184 return (error); 185 186 case VBLK: 187 if ((u_int)maj >= nblkdev) 188 return (ENXIO); 189 /* 190 * When running in very secure mode, do not allow 191 * opens for writing of any disk block devices. 192 */ 193 if (securelevel >= 2 && ap->a_cred != FSCRED && 194 (ap->a_mode & FWRITE) && bdevsw[maj].d_type == D_DISK) 195 return (EPERM); 196 /* 197 * Do not allow opens of block devices that are 198 * currently mounted. 199 */ 200 if (error = vfs_mountedon(vp)) 201 return (error); 202 return ((*bdevsw[maj].d_open)(dev, ap->a_mode, S_IFBLK, ap->a_p)); 203 } 204 return (0); 205 } 206 207 /* 208 * Vnode op for read 209 */ 210 /* ARGSUSED */ 211 spec_read(ap) 212 struct vop_read_args /* { 213 struct vnode *a_vp; 214 struct uio *a_uio; 215 int a_ioflag; 216 struct ucred *a_cred; 217 } */ *ap; 218 { 219 register struct vnode *vp = ap->a_vp; 220 register struct uio *uio = ap->a_uio; 221 struct proc *p = uio->uio_procp; 222 struct buf *bp; 223 daddr_t bn, nextbn; 224 long bsize, bscale, ssize; 225 struct partinfo dpart; 226 int n, on, majordev, (*ioctl)(); 227 int error = 0; 228 dev_t dev; 229 230 #ifdef DIAGNOSTIC 231 if (uio->uio_rw != UIO_READ) 232 panic("spec_read mode"); 233 if (uio->uio_segflg == UIO_USERSPACE && uio->uio_procp != curproc) 234 panic("spec_read proc"); 235 #endif 236 if (uio->uio_resid == 0) 237 return (0); 238 239 switch (vp->v_type) { 240 241 case VCHR: 242 VOP_UNLOCK(vp); 243 error = (*cdevsw[major(vp->v_rdev)].d_read) 244 (vp->v_rdev, uio, ap->a_ioflag); 245 VOP_LOCK(vp); 246 return (error); 247 248 case VBLK: 249 if (uio->uio_offset < 0) 250 return (EINVAL); 251 bsize = BLKDEV_IOSIZE; 252 ssize = DEV_BSIZE; 253 dev = vp->v_rdev; 254 if ((majordev = major(dev)) < nblkdev && 255 (ioctl = bdevsw[majordev].d_ioctl) != NULL && 256 (*ioctl)(dev, DIOCGPART, (caddr_t)&dpart, FREAD, p) == 0) { 257 if (dpart.part->p_fstype == FS_BSDFFS && 258 dpart.part->p_frag != 0 && dpart.part->p_fsize != 0) 259 bsize = dpart.part->p_frag * 260 dpart.part->p_fsize; 261 if (dpart.disklab->d_secsize != 0) 262 ssize = dpart.disklab->d_secsize; 263 } 264 bscale = bsize / ssize; 265 do { 266 bn = (uio->uio_offset / ssize) &~ (bscale - 1); 267 on = uio->uio_offset % bsize; 268 n = min((unsigned)(bsize - on), uio->uio_resid); 269 if (vp->v_lastr + bscale == bn) { 270 nextbn = bn + bscale; 271 error = breadn(vp, bn, (int)bsize, &nextbn, 272 (int *)&bsize, 1, NOCRED, &bp); 273 } else 274 error = bread(vp, bn, (int)bsize, NOCRED, &bp); 275 vp->v_lastr = bn; 276 n = min(n, bsize - bp->b_resid); 277 if (error) { 278 brelse(bp); 279 return (error); 280 } 281 error = uiomove((char *)bp->b_data + on, n, uio); 282 if (n + on == bsize) 283 bp->b_flags |= B_AGE; 284 brelse(bp); 285 } while (error == 0 && uio->uio_resid > 0 && n != 0); 286 return (error); 287 288 default: 289 panic("spec_read type"); 290 } 291 /* NOTREACHED */ 292 } 293 294 /* 295 * Vnode op for write 296 */ 297 /* ARGSUSED */ 298 spec_write(ap) 299 struct vop_write_args /* { 300 struct vnode *a_vp; 301 struct uio *a_uio; 302 int a_ioflag; 303 struct ucred *a_cred; 304 } */ *ap; 305 { 306 register struct vnode *vp = ap->a_vp; 307 register struct uio *uio = ap->a_uio; 308 struct proc *p = uio->uio_procp; 309 struct buf *bp; 310 daddr_t bn; 311 int bsize, blkmask, ssize; 312 struct partinfo dpart; 313 register int n, on; 314 int error = 0; 315 316 #ifdef DIAGNOSTIC 317 if (uio->uio_rw != UIO_WRITE) 318 panic("spec_write mode"); 319 if (uio->uio_segflg == UIO_USERSPACE && uio->uio_procp != curproc) 320 panic("spec_write proc"); 321 #endif 322 323 switch (vp->v_type) { 324 325 case VCHR: 326 VOP_UNLOCK(vp); 327 error = (*cdevsw[major(vp->v_rdev)].d_write) 328 (vp->v_rdev, uio, ap->a_ioflag); 329 VOP_LOCK(vp); 330 return (error); 331 332 case VBLK: 333 if (uio->uio_resid == 0) 334 return (0); 335 if (uio->uio_offset < 0) 336 return (EINVAL); 337 bsize = BLKDEV_IOSIZE; 338 ssize = DEV_BSIZE; 339 if ((*bdevsw[major(vp->v_rdev)].d_ioctl)(vp->v_rdev, DIOCGPART, 340 (caddr_t)&dpart, FREAD, p) == 0) { 341 if (dpart.part->p_fstype == FS_BSDFFS && 342 dpart.part->p_frag != 0 && dpart.part->p_fsize != 0) 343 bsize = dpart.part->p_frag * 344 dpart.part->p_fsize; 345 if (dpart.disklab->d_secsize != 0) 346 ssize = dpart.disklab->d_secsize; 347 } 348 blkmask = (bsize / ssize) - 1; 349 do { 350 bn = (uio->uio_offset / ssize) &~ blkmask; 351 on = uio->uio_offset % bsize; 352 n = min((unsigned)(bsize - on), uio->uio_resid); 353 if (n == bsize) 354 bp = getblk(vp, bn, bsize, 0, 0); 355 else 356 error = bread(vp, bn, bsize, NOCRED, &bp); 357 n = min(n, bsize - bp->b_resid); 358 if (error) { 359 brelse(bp); 360 return (error); 361 } 362 error = uiomove((char *)bp->b_data + on, n, uio); 363 if (n + on == bsize) { 364 bp->b_flags |= B_AGE; 365 bawrite(bp); 366 } else 367 bdwrite(bp); 368 } while (error == 0 && uio->uio_resid > 0 && n != 0); 369 return (error); 370 371 default: 372 panic("spec_write type"); 373 } 374 /* NOTREACHED */ 375 } 376 377 /* 378 * Device ioctl operation. 379 */ 380 /* ARGSUSED */ 381 spec_ioctl(ap) 382 struct vop_ioctl_args /* { 383 struct vnode *a_vp; 384 u_long a_command; 385 caddr_t a_data; 386 int a_fflag; 387 struct ucred *a_cred; 388 struct proc *a_p; 389 } */ *ap; 390 { 391 dev_t dev = ap->a_vp->v_rdev; 392 int maj = major(dev); 393 394 switch (ap->a_vp->v_type) { 395 396 case VCHR: 397 return ((*cdevsw[maj].d_ioctl)(dev, ap->a_command, ap->a_data, 398 ap->a_fflag, ap->a_p)); 399 400 case VBLK: 401 if (ap->a_command == 0 && (long)ap->a_data == B_TAPE) 402 if (bdevsw[maj].d_type == D_TAPE) 403 return (0); 404 else 405 return (1); 406 return ((*bdevsw[maj].d_ioctl)(dev, ap->a_command, ap->a_data, 407 ap->a_fflag, ap->a_p)); 408 409 default: 410 panic("spec_ioctl"); 411 /* NOTREACHED */ 412 } 413 } 414 415 /* ARGSUSED */ 416 spec_select(ap) 417 struct vop_select_args /* { 418 struct vnode *a_vp; 419 int a_which; 420 int a_fflags; 421 struct ucred *a_cred; 422 struct proc *a_p; 423 } */ *ap; 424 { 425 register dev_t dev; 426 427 switch (ap->a_vp->v_type) { 428 429 default: 430 return (1); /* XXX */ 431 432 case VCHR: 433 dev = ap->a_vp->v_rdev; 434 return (*cdevsw[major(dev)].d_select)(dev, ap->a_which, ap->a_p); 435 } 436 } 437 /* 438 * Synch buffers associated with a block device 439 */ 440 /* ARGSUSED */ 441 int 442 spec_fsync(ap) 443 struct vop_fsync_args /* { 444 struct vnode *a_vp; 445 struct ucred *a_cred; 446 int a_waitfor; 447 struct proc *a_p; 448 } */ *ap; 449 { 450 register struct vnode *vp = ap->a_vp; 451 register struct buf *bp; 452 struct buf *nbp; 453 int s; 454 455 if (vp->v_type == VCHR) 456 return (0); 457 /* 458 * Flush all dirty buffers associated with a block device. 459 */ 460 loop: 461 s = splbio(); 462 for (bp = vp->v_dirtyblkhd.lh_first; bp; bp = nbp) { 463 nbp = bp->b_vnbufs.le_next; 464 if ((bp->b_flags & B_BUSY)) 465 continue; 466 if ((bp->b_flags & B_DELWRI) == 0) 467 panic("spec_fsync: not dirty"); 468 bremfree(bp); 469 bp->b_flags |= B_BUSY; 470 splx(s); 471 bawrite(bp); 472 goto loop; 473 } 474 if (ap->a_waitfor == MNT_WAIT) { 475 while (vp->v_numoutput) { 476 vp->v_flag |= VBWAIT; 477 sleep((caddr_t)&vp->v_numoutput, PRIBIO + 1); 478 } 479 #ifdef DIAGNOSTIC 480 if (vp->v_dirtyblkhd.lh_first) { 481 vprint("spec_fsync: dirty", vp); 482 goto loop; 483 } 484 #endif 485 } 486 splx(s); 487 return (0); 488 } 489 490 /* 491 * Just call the device strategy routine 492 */ 493 spec_strategy(ap) 494 struct vop_strategy_args /* { 495 struct buf *a_bp; 496 } */ *ap; 497 { 498 499 (*bdevsw[major(ap->a_bp->b_dev)].d_strategy)(ap->a_bp); 500 return (0); 501 } 502 503 /* 504 * This is a noop, simply returning what one has been given. 505 */ 506 spec_bmap(ap) 507 struct vop_bmap_args /* { 508 struct vnode *a_vp; 509 daddr_t a_bn; 510 struct vnode **a_vpp; 511 daddr_t *a_bnp; 512 } */ *ap; 513 { 514 515 if (ap->a_vpp != NULL) 516 *ap->a_vpp = ap->a_vp; 517 if (ap->a_bnp != NULL) 518 *ap->a_bnp = ap->a_bn; 519 return (0); 520 } 521 522 /* 523 * At the moment we do not do any locking. 524 */ 525 /* ARGSUSED */ 526 spec_lock(ap) 527 struct vop_lock_args /* { 528 struct vnode *a_vp; 529 } */ *ap; 530 { 531 532 return (0); 533 } 534 535 /* ARGSUSED */ 536 spec_unlock(ap) 537 struct vop_unlock_args /* { 538 struct vnode *a_vp; 539 } */ *ap; 540 { 541 542 return (0); 543 } 544 545 /* 546 * Device close routine 547 */ 548 /* ARGSUSED */ 549 spec_close(ap) 550 struct vop_close_args /* { 551 struct vnode *a_vp; 552 int a_fflag; 553 struct ucred *a_cred; 554 struct proc *a_p; 555 } */ *ap; 556 { 557 register struct vnode *vp = ap->a_vp; 558 dev_t dev = vp->v_rdev; 559 int (*devclose) __P((dev_t, int, int, struct proc *)); 560 int mode, error; 561 562 switch (vp->v_type) { 563 564 case VCHR: 565 /* 566 * Hack: a tty device that is a controlling terminal 567 * has a reference from the session structure. 568 * We cannot easily tell that a character device is 569 * a controlling terminal, unless it is the closing 570 * process' controlling terminal. In that case, 571 * if the reference count is 2 (this last descriptor 572 * plus the session), release the reference from the session. 573 */ 574 if (vcount(vp) == 2 && ap->a_p && 575 vp == ap->a_p->p_session->s_ttyvp) { 576 vrele(vp); 577 ap->a_p->p_session->s_ttyvp = NULL; 578 } 579 /* 580 * If the vnode is locked, then we are in the midst 581 * of forcably closing the device, otherwise we only 582 * close on last reference. 583 */ 584 if (vcount(vp) > 1 && (vp->v_flag & VXLOCK) == 0) 585 return (0); 586 devclose = cdevsw[major(dev)].d_close; 587 mode = S_IFCHR; 588 break; 589 590 case VBLK: 591 /* 592 * On last close of a block device (that isn't mounted) 593 * we must invalidate any in core blocks, so that 594 * we can, for instance, change floppy disks. 595 */ 596 if (error = vinvalbuf(vp, V_SAVE, ap->a_cred, ap->a_p, 0, 0)) 597 return (error); 598 /* 599 * We do not want to really close the device if it 600 * is still in use unless we are trying to close it 601 * forcibly. Since every use (buffer, vnode, swap, cmap) 602 * holds a reference to the vnode, and because we mark 603 * any other vnodes that alias this device, when the 604 * sum of the reference counts on all the aliased 605 * vnodes descends to one, we are on last close. 606 */ 607 if (vcount(vp) > 1 && (vp->v_flag & VXLOCK) == 0) 608 return (0); 609 devclose = bdevsw[major(dev)].d_close; 610 mode = S_IFBLK; 611 break; 612 613 default: 614 panic("spec_close: not special"); 615 } 616 617 return ((*devclose)(dev, ap->a_fflag, mode, ap->a_p)); 618 } 619 620 /* 621 * Print out the contents of a special device vnode. 622 */ 623 spec_print(ap) 624 struct vop_print_args /* { 625 struct vnode *a_vp; 626 } */ *ap; 627 { 628 629 printf("tag VT_NON, dev %d, %d\n", major(ap->a_vp->v_rdev), 630 minor(ap->a_vp->v_rdev)); 631 } 632 633 /* 634 * Return POSIX pathconf information applicable to special devices. 635 */ 636 spec_pathconf(ap) 637 struct vop_pathconf_args /* { 638 struct vnode *a_vp; 639 int a_name; 640 register_t *a_retval; 641 } */ *ap; 642 { 643 644 switch (ap->a_name) { 645 case _PC_LINK_MAX: 646 *ap->a_retval = LINK_MAX; 647 return (0); 648 case _PC_MAX_CANON: 649 *ap->a_retval = MAX_CANON; 650 return (0); 651 case _PC_MAX_INPUT: 652 *ap->a_retval = MAX_INPUT; 653 return (0); 654 case _PC_PIPE_BUF: 655 *ap->a_retval = PIPE_BUF; 656 return (0); 657 case _PC_CHOWN_RESTRICTED: 658 *ap->a_retval = 1; 659 return (0); 660 case _PC_VDISABLE: 661 *ap->a_retval = _POSIX_VDISABLE; 662 return (0); 663 default: 664 return (EINVAL); 665 } 666 /* NOTREACHED */ 667 } 668 669 /* 670 * Special device advisory byte-level locks. 671 */ 672 /* ARGSUSED */ 673 spec_advlock(ap) 674 struct vop_advlock_args /* { 675 struct vnode *a_vp; 676 caddr_t a_id; 677 int a_op; 678 struct flock *a_fl; 679 int a_flags; 680 } */ *ap; 681 { 682 683 return (EOPNOTSUPP); 684 } 685 686 /* 687 * Special device failed operation 688 */ 689 spec_ebadf() 690 { 691 692 return (EBADF); 693 } 694 695 /* 696 * Special device bad operation 697 */ 698 spec_badop() 699 { 700 701 panic("spec_badop called"); 702 /* NOTREACHED */ 703 } 704