spec_vnops.c revision 1.71
1 /* $NetBSD: spec_vnops.c,v 1.71 2003/11/06 08:58:04 dsl 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. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 * 31 * @(#)spec_vnops.c 8.15 (Berkeley) 7/14/95 32 */ 33 34 #include <sys/cdefs.h> 35 __KERNEL_RCSID(0, "$NetBSD: spec_vnops.c,v 1.71 2003/11/06 08:58:04 dsl Exp $"); 36 37 #include <sys/param.h> 38 #include <sys/proc.h> 39 #include <sys/systm.h> 40 #include <sys/kernel.h> 41 #include <sys/conf.h> 42 #include <sys/buf.h> 43 #include <sys/mount.h> 44 #include <sys/namei.h> 45 #include <sys/vnode.h> 46 #include <sys/stat.h> 47 #include <sys/errno.h> 48 #include <sys/ioctl.h> 49 #include <sys/file.h> 50 #include <sys/disklabel.h> 51 #include <sys/lockf.h> 52 #include <sys/tty.h> 53 54 #include <miscfs/genfs/genfs.h> 55 #include <miscfs/specfs/specdev.h> 56 57 /* symbolic sleep message strings for devices */ 58 const char devopn[] = "devopn"; 59 const char devio[] = "devio"; 60 const char devwait[] = "devwait"; 61 const char devin[] = "devin"; 62 const char devout[] = "devout"; 63 const char devioc[] = "devioc"; 64 const char devcls[] = "devcls"; 65 66 struct vnode *speclisth[SPECHSZ]; 67 68 /* 69 * This vnode operations vector is used for two things only: 70 * - special device nodes created from whole cloth by the kernel. 71 * - as a temporary vnodeops replacement for vnodes which were found to 72 * be aliased by callers of checkalias(). 73 * For the ops vector for vnodes built from special devices found in a 74 * filesystem, see (e.g) ffs_specop_entries[] in ffs_vnops.c or the 75 * equivalent for other filesystems. 76 */ 77 78 int (**spec_vnodeop_p) __P((void *)); 79 const struct vnodeopv_entry_desc spec_vnodeop_entries[] = { 80 { &vop_default_desc, vn_default_error }, 81 { &vop_lookup_desc, spec_lookup }, /* lookup */ 82 { &vop_create_desc, spec_create }, /* create */ 83 { &vop_mknod_desc, spec_mknod }, /* mknod */ 84 { &vop_open_desc, spec_open }, /* open */ 85 { &vop_close_desc, spec_close }, /* close */ 86 { &vop_access_desc, spec_access }, /* access */ 87 { &vop_getattr_desc, spec_getattr }, /* getattr */ 88 { &vop_setattr_desc, spec_setattr }, /* setattr */ 89 { &vop_read_desc, spec_read }, /* read */ 90 { &vop_write_desc, spec_write }, /* write */ 91 { &vop_lease_desc, spec_lease_check }, /* lease */ 92 { &vop_fcntl_desc, spec_fcntl }, /* fcntl */ 93 { &vop_ioctl_desc, spec_ioctl }, /* ioctl */ 94 { &vop_poll_desc, spec_poll }, /* poll */ 95 { &vop_kqfilter_desc, spec_kqfilter }, /* kqfilter */ 96 { &vop_revoke_desc, spec_revoke }, /* revoke */ 97 { &vop_mmap_desc, spec_mmap }, /* mmap */ 98 { &vop_fsync_desc, spec_fsync }, /* fsync */ 99 { &vop_seek_desc, spec_seek }, /* seek */ 100 { &vop_remove_desc, spec_remove }, /* remove */ 101 { &vop_link_desc, spec_link }, /* link */ 102 { &vop_rename_desc, spec_rename }, /* rename */ 103 { &vop_mkdir_desc, spec_mkdir }, /* mkdir */ 104 { &vop_rmdir_desc, spec_rmdir }, /* rmdir */ 105 { &vop_symlink_desc, spec_symlink }, /* symlink */ 106 { &vop_readdir_desc, spec_readdir }, /* readdir */ 107 { &vop_readlink_desc, spec_readlink }, /* readlink */ 108 { &vop_abortop_desc, spec_abortop }, /* abortop */ 109 { &vop_inactive_desc, spec_inactive }, /* inactive */ 110 { &vop_reclaim_desc, spec_reclaim }, /* reclaim */ 111 { &vop_lock_desc, spec_lock }, /* lock */ 112 { &vop_unlock_desc, spec_unlock }, /* unlock */ 113 { &vop_bmap_desc, spec_bmap }, /* bmap */ 114 { &vop_strategy_desc, spec_strategy }, /* strategy */ 115 { &vop_print_desc, spec_print }, /* print */ 116 { &vop_islocked_desc, spec_islocked }, /* islocked */ 117 { &vop_pathconf_desc, spec_pathconf }, /* pathconf */ 118 { &vop_advlock_desc, spec_advlock }, /* advlock */ 119 { &vop_blkatoff_desc, spec_blkatoff }, /* blkatoff */ 120 { &vop_valloc_desc, spec_valloc }, /* valloc */ 121 { &vop_vfree_desc, spec_vfree }, /* vfree */ 122 { &vop_truncate_desc, spec_truncate }, /* truncate */ 123 { &vop_update_desc, spec_update }, /* update */ 124 { &vop_bwrite_desc, spec_bwrite }, /* bwrite */ 125 { &vop_getpages_desc, spec_getpages }, /* getpages */ 126 { &vop_putpages_desc, spec_putpages }, /* putpages */ 127 { NULL, NULL } 128 }; 129 const struct vnodeopv_desc spec_vnodeop_opv_desc = 130 { &spec_vnodeop_p, spec_vnodeop_entries }; 131 132 /* 133 * Trivial lookup routine that always fails. 134 */ 135 int 136 spec_lookup(v) 137 void *v; 138 { 139 struct vop_lookup_args /* { 140 struct vnode *a_dvp; 141 struct vnode **a_vpp; 142 struct componentname *a_cnp; 143 } */ *ap = v; 144 145 *ap->a_vpp = NULL; 146 return (ENOTDIR); 147 } 148 149 /* 150 * Returns true if dev is /dev/mem or /dev/kmem. 151 */ 152 static int 153 iskmemdev(dev_t dev) 154 { 155 /* mem_no is emitted by config(8) to generated devsw.c */ 156 extern const int mem_no; 157 158 /* minor 14 is /dev/io on i386 with COMPAT_10 */ 159 return (major(dev) == mem_no && (minor(dev) < 2 || minor(dev) == 14)); 160 } 161 162 /* 163 * Open a special file. 164 */ 165 /* ARGSUSED */ 166 int 167 spec_open(v) 168 void *v; 169 { 170 struct vop_open_args /* { 171 struct vnode *a_vp; 172 int a_mode; 173 struct ucred *a_cred; 174 struct proc *a_p; 175 } */ *ap = v; 176 struct proc *p = ap->a_p; 177 struct vnode *bvp, *vp = ap->a_vp; 178 const struct bdevsw *bdev; 179 const struct cdevsw *cdev; 180 dev_t blkdev, dev = (dev_t)vp->v_rdev; 181 int error; 182 struct partinfo pi; 183 int (*d_ioctl)(dev_t, u_long, caddr_t, int, struct proc *); 184 185 /* 186 * Don't allow open if fs is mounted -nodev. 187 */ 188 if (vp->v_mount && (vp->v_mount->mnt_flag & MNT_NODEV)) 189 return (ENXIO); 190 191 switch (vp->v_type) { 192 193 case VCHR: 194 cdev = cdevsw_lookup(dev); 195 if (cdev == NULL) 196 return (ENXIO); 197 if (ap->a_cred != FSCRED && (ap->a_mode & FWRITE)) { 198 /* 199 * When running in very secure mode, do not allow 200 * opens for writing of any disk character devices. 201 */ 202 if (securelevel >= 2 && cdev->d_type == D_DISK) 203 return (EPERM); 204 /* 205 * When running in secure mode, do not allow opens 206 * for writing of /dev/mem, /dev/kmem, or character 207 * devices whose corresponding block devices are 208 * currently mounted. 209 */ 210 if (securelevel >= 1) { 211 blkdev = devsw_chr2blk(dev); 212 if (blkdev != (dev_t)NODEV && 213 vfinddev(blkdev, VBLK, &bvp) && 214 (error = vfs_mountedon(bvp))) 215 return (error); 216 if (iskmemdev(dev)) 217 return (EPERM); 218 } 219 } 220 if (cdev->d_type == D_TTY) 221 vp->v_flag |= VISTTY; 222 VOP_UNLOCK(vp, 0); 223 error = (*cdev->d_open)(dev, ap->a_mode, S_IFCHR, p); 224 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 225 if (cdev->d_type != D_DISK) 226 return error; 227 d_ioctl = cdev->d_ioctl; 228 break; 229 230 case VBLK: 231 bdev = bdevsw_lookup(dev); 232 if (bdev == NULL) 233 return (ENXIO); 234 /* 235 * When running in very secure mode, do not allow 236 * opens for writing of any disk block devices. 237 */ 238 if (securelevel >= 2 && ap->a_cred != FSCRED && 239 (ap->a_mode & FWRITE) && bdev->d_type == D_DISK) 240 return (EPERM); 241 /* 242 * Do not allow opens of block devices that are 243 * currently mounted. 244 */ 245 if ((error = vfs_mountedon(vp)) != 0) 246 return (error); 247 error = (*bdev->d_open)(dev, ap->a_mode, S_IFBLK, p); 248 d_ioctl = bdev->d_ioctl; 249 break; 250 251 case VNON: 252 case VLNK: 253 case VDIR: 254 case VREG: 255 case VBAD: 256 case VFIFO: 257 case VSOCK: 258 default: 259 return 0; 260 } 261 262 if (error) 263 return error; 264 if (!(*d_ioctl)(vp->v_rdev, DIOCGPART, (caddr_t)&pi, FREAD, curproc)) 265 vp->v_size = (voff_t)pi.disklab->d_secsize * pi.part->p_size; 266 return 0; 267 } 268 269 /* 270 * Vnode op for read 271 */ 272 /* ARGSUSED */ 273 int 274 spec_read(v) 275 void *v; 276 { 277 struct vop_read_args /* { 278 struct vnode *a_vp; 279 struct uio *a_uio; 280 int a_ioflag; 281 struct ucred *a_cred; 282 } */ *ap = v; 283 struct vnode *vp = ap->a_vp; 284 struct uio *uio = ap->a_uio; 285 struct proc *p = uio->uio_procp; 286 struct buf *bp; 287 const struct bdevsw *bdev; 288 const struct cdevsw *cdev; 289 daddr_t bn; 290 int bsize, bscale; 291 struct partinfo dpart; 292 int n, on; 293 int error = 0; 294 295 #ifdef DIAGNOSTIC 296 if (uio->uio_rw != UIO_READ) 297 panic("spec_read mode"); 298 if (uio->uio_segflg == UIO_USERSPACE && uio->uio_procp != curproc) 299 panic("spec_read proc"); 300 #endif 301 if (uio->uio_resid == 0) 302 return (0); 303 304 switch (vp->v_type) { 305 306 case VCHR: 307 VOP_UNLOCK(vp, 0); 308 cdev = cdevsw_lookup(vp->v_rdev); 309 if (cdev != NULL) 310 error = (*cdev->d_read)(vp->v_rdev, uio, ap->a_ioflag); 311 else 312 error = ENXIO; 313 vn_lock(vp, LK_SHARED | LK_RETRY); 314 return (error); 315 316 case VBLK: 317 if (uio->uio_offset < 0) 318 return (EINVAL); 319 bsize = BLKDEV_IOSIZE; 320 bdev = bdevsw_lookup(vp->v_rdev); 321 if (bdev != NULL && 322 (*bdev->d_ioctl)(vp->v_rdev, DIOCGPART, (caddr_t)&dpart, 323 FREAD, p) == 0) { 324 if (dpart.part->p_fstype == FS_BSDFFS && 325 dpart.part->p_frag != 0 && dpart.part->p_fsize != 0) 326 bsize = dpart.part->p_frag * 327 dpart.part->p_fsize; 328 } 329 bscale = bsize >> DEV_BSHIFT; 330 do { 331 bn = (uio->uio_offset >> DEV_BSHIFT) &~ (bscale - 1); 332 on = uio->uio_offset % bsize; 333 n = min((unsigned)(bsize - on), uio->uio_resid); 334 error = bread(vp, bn, bsize, NOCRED, &bp); 335 n = min(n, bsize - bp->b_resid); 336 if (error) { 337 brelse(bp); 338 return (error); 339 } 340 error = uiomove((char *)bp->b_data + on, n, uio); 341 brelse(bp); 342 } while (error == 0 && uio->uio_resid > 0 && n != 0); 343 return (error); 344 345 default: 346 panic("spec_read type"); 347 } 348 /* NOTREACHED */ 349 } 350 351 /* 352 * Vnode op for write 353 */ 354 /* ARGSUSED */ 355 int 356 spec_write(v) 357 void *v; 358 { 359 struct vop_write_args /* { 360 struct vnode *a_vp; 361 struct uio *a_uio; 362 int a_ioflag; 363 struct ucred *a_cred; 364 } */ *ap = v; 365 struct vnode *vp = ap->a_vp; 366 struct uio *uio = ap->a_uio; 367 struct proc *p = uio->uio_procp; 368 struct buf *bp; 369 const struct bdevsw *bdev; 370 const struct cdevsw *cdev; 371 daddr_t bn; 372 int bsize, bscale; 373 struct partinfo dpart; 374 int n, on; 375 int error = 0; 376 377 #ifdef DIAGNOSTIC 378 if (uio->uio_rw != UIO_WRITE) 379 panic("spec_write mode"); 380 if (uio->uio_segflg == UIO_USERSPACE && uio->uio_procp != curproc) 381 panic("spec_write proc"); 382 #endif 383 384 switch (vp->v_type) { 385 386 case VCHR: 387 VOP_UNLOCK(vp, 0); 388 cdev = cdevsw_lookup(vp->v_rdev); 389 if (cdev != NULL) 390 error = (*cdev->d_write)(vp->v_rdev, uio, ap->a_ioflag); 391 else 392 error = ENXIO; 393 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 394 return (error); 395 396 case VBLK: 397 if (uio->uio_resid == 0) 398 return (0); 399 if (uio->uio_offset < 0) 400 return (EINVAL); 401 bsize = BLKDEV_IOSIZE; 402 bdev = bdevsw_lookup(vp->v_rdev); 403 if (bdev != NULL && 404 (*bdev->d_ioctl)(vp->v_rdev, DIOCGPART, (caddr_t)&dpart, 405 FREAD, p) == 0) { 406 if (dpart.part->p_fstype == FS_BSDFFS && 407 dpart.part->p_frag != 0 && dpart.part->p_fsize != 0) 408 bsize = dpart.part->p_frag * 409 dpart.part->p_fsize; 410 } 411 bscale = bsize >> DEV_BSHIFT; 412 do { 413 bn = (uio->uio_offset >> DEV_BSHIFT) &~ (bscale - 1); 414 on = uio->uio_offset % bsize; 415 n = min((unsigned)(bsize - on), uio->uio_resid); 416 if (n == bsize) 417 bp = getblk(vp, bn, bsize, 0, 0); 418 else 419 error = bread(vp, bn, bsize, NOCRED, &bp); 420 if (error) { 421 brelse(bp); 422 return (error); 423 } 424 n = min(n, bsize - bp->b_resid); 425 error = uiomove((char *)bp->b_data + on, n, uio); 426 if (error) 427 brelse(bp); 428 else { 429 if (n + on == bsize) 430 bawrite(bp); 431 else 432 bdwrite(bp); 433 if (bp->b_flags & B_ERROR) 434 error = bp->b_error; 435 } 436 } while (error == 0 && uio->uio_resid > 0 && n != 0); 437 return (error); 438 439 default: 440 panic("spec_write type"); 441 } 442 /* NOTREACHED */ 443 } 444 445 /* 446 * Device ioctl operation. 447 */ 448 /* ARGSUSED */ 449 int 450 spec_ioctl(v) 451 void *v; 452 { 453 struct vop_ioctl_args /* { 454 struct vnode *a_vp; 455 u_long a_command; 456 caddr_t a_data; 457 int a_fflag; 458 struct ucred *a_cred; 459 struct proc *a_p; 460 } */ *ap = v; 461 const struct bdevsw *bdev; 462 const struct cdevsw *cdev; 463 dev_t dev = ap->a_vp->v_rdev; 464 465 switch (ap->a_vp->v_type) { 466 467 case VCHR: 468 cdev = cdevsw_lookup(dev); 469 if (cdev == NULL) 470 return (ENXIO); 471 return ((*cdev->d_ioctl)(dev, ap->a_command, ap->a_data, 472 ap->a_fflag, ap->a_p)); 473 474 case VBLK: 475 bdev = bdevsw_lookup(dev); 476 if (bdev == NULL) 477 return (ENXIO); 478 if (ap->a_command == 0 && (long)ap->a_data == B_TAPE) { 479 if (bdev->d_type == D_TAPE) 480 return (0); 481 else 482 return (1); 483 } 484 return ((*bdev->d_ioctl)(dev, ap->a_command, ap->a_data, 485 ap->a_fflag, ap->a_p)); 486 487 default: 488 panic("spec_ioctl"); 489 /* NOTREACHED */ 490 } 491 } 492 493 /* ARGSUSED */ 494 int 495 spec_poll(v) 496 void *v; 497 { 498 struct vop_poll_args /* { 499 struct vnode *a_vp; 500 int a_events; 501 struct proc *a_p; 502 } */ *ap = v; 503 const struct cdevsw *cdev; 504 dev_t dev; 505 506 switch (ap->a_vp->v_type) { 507 508 case VCHR: 509 dev = ap->a_vp->v_rdev; 510 cdev = cdevsw_lookup(dev); 511 if (cdev == NULL) 512 return (ENXIO); 513 return (*cdev->d_poll)(dev, ap->a_events, ap->a_p); 514 515 default: 516 return (genfs_poll(v)); 517 } 518 } 519 520 /* ARGSUSED */ 521 int 522 spec_kqfilter(v) 523 void *v; 524 { 525 struct vop_kqfilter_args /* { 526 struct vnode *a_vp; 527 struct proc *a_kn; 528 } */ *ap = v; 529 const struct cdevsw *cdev; 530 dev_t dev; 531 532 switch (ap->a_vp->v_type) { 533 534 case VCHR: 535 dev = ap->a_vp->v_rdev; 536 cdev = cdevsw_lookup(dev); 537 if (cdev == NULL) 538 return (ENXIO); 539 return (*cdev->d_kqfilter)(dev, ap->a_kn); 540 default: 541 /* 542 * Block devices don't support kqfilter, and refuse it 543 * for any other files (like those vflush()ed) too. 544 */ 545 return (EOPNOTSUPP); 546 } 547 } 548 549 /* 550 * Synch buffers associated with a block device 551 */ 552 /* ARGSUSED */ 553 int 554 spec_fsync(v) 555 void *v; 556 { 557 struct vop_fsync_args /* { 558 struct vnode *a_vp; 559 struct ucred *a_cred; 560 int a_flags; 561 off_t offlo; 562 off_t offhi; 563 struct proc *a_p; 564 } */ *ap = v; 565 struct vnode *vp = ap->a_vp; 566 567 if (vp->v_type == VBLK) 568 vflushbuf(vp, (ap->a_flags & FSYNC_WAIT) != 0); 569 return (0); 570 } 571 572 /* 573 * Just call the device strategy routine 574 */ 575 int 576 spec_strategy(v) 577 void *v; 578 { 579 struct vop_strategy_args /* { 580 struct buf *a_bp; 581 } */ *ap = v; 582 struct buf *bp; 583 const struct bdevsw *bdev; 584 585 bp = ap->a_bp; 586 if (!(bp->b_flags & B_READ) && 587 (LIST_FIRST(&bp->b_dep)) != NULL && bioops.io_start) 588 (*bioops.io_start)(bp); 589 bdev = bdevsw_lookup(bp->b_dev); 590 if (bdev != NULL) 591 (*bdev->d_strategy)(bp); 592 return (0); 593 } 594 595 int 596 spec_inactive(v) 597 void *v; 598 { 599 struct vop_inactive_args /* { 600 struct vnode *a_vp; 601 struct proc *a_p; 602 } */ *ap = v; 603 604 VOP_UNLOCK(ap->a_vp, 0); 605 return (0); 606 } 607 608 /* 609 * This is a noop, simply returning what one has been given. 610 */ 611 int 612 spec_bmap(v) 613 void *v; 614 { 615 struct vop_bmap_args /* { 616 struct vnode *a_vp; 617 daddr_t a_bn; 618 struct vnode **a_vpp; 619 daddr_t *a_bnp; 620 int *a_runp; 621 } */ *ap = v; 622 623 if (ap->a_vpp != NULL) 624 *ap->a_vpp = ap->a_vp; 625 if (ap->a_bnp != NULL) 626 *ap->a_bnp = ap->a_bn; 627 if (ap->a_runp != NULL) 628 *ap->a_runp = (MAXBSIZE >> DEV_BSHIFT) - 1; 629 return (0); 630 } 631 632 /* 633 * Device close routine 634 */ 635 /* ARGSUSED */ 636 int 637 spec_close(v) 638 void *v; 639 { 640 struct vop_close_args /* { 641 struct vnode *a_vp; 642 int a_fflag; 643 struct ucred *a_cred; 644 struct proc *a_p; 645 } */ *ap = v; 646 struct vnode *vp = ap->a_vp; 647 const struct bdevsw *bdev; 648 const struct cdevsw *cdev; 649 struct session *sess; 650 dev_t dev = vp->v_rdev; 651 int (*devclose) __P((dev_t, int, int, struct proc *)); 652 int mode, error, count, flags, flags1; 653 654 count = vcount(vp); 655 simple_lock(&vp->v_interlock); 656 flags = vp->v_flag; 657 simple_unlock(&vp->v_interlock); 658 659 switch (vp->v_type) { 660 661 case VCHR: 662 /* 663 * Hack: a tty device that is a controlling terminal 664 * has a reference from the session structure. 665 * We cannot easily tell that a character device is 666 * a controlling terminal, unless it is the closing 667 * process' controlling terminal. In that case, 668 * if the reference count is 2 (this last descriptor 669 * plus the session), release the reference from the session. 670 * Also remove the link from the tty back to the session 671 * and pgrp - due to the way consoles are handled we cannot 672 * guarantee that the vrele() will do the final close on the 673 * actual tty device. 674 */ 675 if (count == 2 && ap->a_p && 676 vp == (sess = ap->a_p->p_session)->s_ttyvp) { 677 sess->s_ttyvp = NULL; 678 sess->s_ttyp->t_pgrp = NULL; 679 sess->s_ttyp->t_session = NULL; 680 SESSRELE(sess); 681 vrele(vp); 682 count--; 683 } 684 /* 685 * If the vnode is locked, then we are in the midst 686 * of forcably closing the device, otherwise we only 687 * close on last reference. 688 */ 689 if (count > 1 && (flags & VXLOCK) == 0) 690 return (0); 691 cdev = cdevsw_lookup(dev); 692 if (cdev != NULL) 693 devclose = cdev->d_close; 694 else 695 devclose = NULL; 696 mode = S_IFCHR; 697 break; 698 699 case VBLK: 700 /* 701 * On last close of a block device (that isn't mounted) 702 * we must invalidate any in core blocks, so that 703 * we can, for instance, change floppy disks. 704 */ 705 error = vinvalbuf(vp, V_SAVE, ap->a_cred, ap->a_p, 0, 0); 706 if (error) 707 return (error); 708 /* 709 * We do not want to really close the device if it 710 * is still in use unless we are trying to close it 711 * forcibly. Since every use (buffer, vnode, swap, cmap) 712 * holds a reference to the vnode, and because we mark 713 * any other vnodes that alias this device, when the 714 * sum of the reference counts on all the aliased 715 * vnodes descends to one, we are on last close. 716 */ 717 if (count > 1 && (flags & VXLOCK) == 0) 718 return (0); 719 bdev = bdevsw_lookup(dev); 720 if (bdev != NULL) 721 devclose = bdev->d_close; 722 else 723 devclose = NULL; 724 mode = S_IFBLK; 725 break; 726 727 default: 728 panic("spec_close: not special"); 729 } 730 731 flags1 = ap->a_fflag; 732 733 /* 734 * if VXLOCK is set, then we're going away soon, so make this 735 * non-blocking. Also ensures that we won't wedge in vn_lock below. 736 */ 737 if (flags & VXLOCK) 738 flags1 |= FNONBLOCK; 739 740 /* 741 * If we're able to block, release the vnode lock & reacquire. We 742 * might end up sleaping for someone else who wants our queues. They 743 * won't get them if we hold the vnode locked. Also, if VXLOCK is set, 744 * don't release the lock as we won't be able to regain it. 745 */ 746 if (!(flags1 & FNONBLOCK)) 747 VOP_UNLOCK(vp, 0); 748 749 if (devclose != NULL) 750 error = (*devclose)(dev, flags1, mode, ap->a_p); 751 else 752 error = ENXIO; 753 754 if (!(flags1 & FNONBLOCK)) 755 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 756 757 return (error); 758 } 759 760 /* 761 * Print out the contents of a special device vnode. 762 */ 763 int 764 spec_print(v) 765 void *v; 766 { 767 struct vop_print_args /* { 768 struct vnode *a_vp; 769 } */ *ap = v; 770 771 printf("tag VT_NON, dev %d, %d\n", major(ap->a_vp->v_rdev), 772 minor(ap->a_vp->v_rdev)); 773 return 0; 774 } 775 776 /* 777 * Return POSIX pathconf information applicable to special devices. 778 */ 779 int 780 spec_pathconf(v) 781 void *v; 782 { 783 struct vop_pathconf_args /* { 784 struct vnode *a_vp; 785 int a_name; 786 register_t *a_retval; 787 } */ *ap = v; 788 789 switch (ap->a_name) { 790 case _PC_LINK_MAX: 791 *ap->a_retval = LINK_MAX; 792 return (0); 793 case _PC_MAX_CANON: 794 *ap->a_retval = MAX_CANON; 795 return (0); 796 case _PC_MAX_INPUT: 797 *ap->a_retval = MAX_INPUT; 798 return (0); 799 case _PC_PIPE_BUF: 800 *ap->a_retval = PIPE_BUF; 801 return (0); 802 case _PC_CHOWN_RESTRICTED: 803 *ap->a_retval = 1; 804 return (0); 805 case _PC_VDISABLE: 806 *ap->a_retval = _POSIX_VDISABLE; 807 return (0); 808 case _PC_SYNC_IO: 809 *ap->a_retval = 1; 810 return (0); 811 default: 812 return (EINVAL); 813 } 814 /* NOTREACHED */ 815 } 816 817 /* 818 * Advisory record locking support. 819 */ 820 int 821 spec_advlock(v) 822 void *v; 823 { 824 struct vop_advlock_args /* { 825 struct vnode *a_vp; 826 caddr_t a_id; 827 int a_op; 828 struct flock *a_fl; 829 int a_flags; 830 } */ *ap = v; 831 struct vnode *vp = ap->a_vp; 832 833 return lf_advlock(ap, &vp->v_speclockf, (off_t)0); 834 } 835
Indexes created Tue Sep 23 20:09:58 GMT 2025