spec_vnops.c revision 1.99
1 /* $NetBSD: spec_vnops.c,v 1.99 2007/06/05 12:31:32 yamt 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 1.99 2007/06/05 12:31:32 yamt 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/poll.h> 50 #include <sys/file.h> 51 #include <sys/disklabel.h> 52 #include <sys/lockf.h> 53 #include <sys/tty.h> 54 #include <sys/kauth.h> 55 56 #include <miscfs/genfs/genfs.h> 57 #include <miscfs/specfs/specdev.h> 58 59 /* symbolic sleep message strings for devices */ 60 const char devopn[] = "devopn"; 61 const char devio[] = "devio"; 62 const char devwait[] = "devwait"; 63 const char devin[] = "devin"; 64 const char devout[] = "devout"; 65 const char devioc[] = "devioc"; 66 const char devcls[] = "devcls"; 67 68 struct vnode *speclisth[SPECHSZ]; 69 70 /* 71 * This vnode operations vector is used for two things only: 72 * - special device nodes created from whole cloth by the kernel. 73 * - as a temporary vnodeops replacement for vnodes which were found to 74 * be aliased by callers of checkalias(). 75 * For the ops vector for vnodes built from special devices found in a 76 * filesystem, see (e.g) ffs_specop_entries[] in ffs_vnops.c or the 77 * equivalent for other filesystems. 78 */ 79 80 int (**spec_vnodeop_p)(void *); 81 const struct vnodeopv_entry_desc spec_vnodeop_entries[] = { 82 { &vop_default_desc, vn_default_error }, 83 { &vop_lookup_desc, spec_lookup }, /* lookup */ 84 { &vop_create_desc, spec_create }, /* create */ 85 { &vop_mknod_desc, spec_mknod }, /* mknod */ 86 { &vop_open_desc, spec_open }, /* open */ 87 { &vop_close_desc, spec_close }, /* close */ 88 { &vop_access_desc, spec_access }, /* access */ 89 { &vop_getattr_desc, spec_getattr }, /* getattr */ 90 { &vop_setattr_desc, spec_setattr }, /* setattr */ 91 { &vop_read_desc, spec_read }, /* read */ 92 { &vop_write_desc, spec_write }, /* write */ 93 { &vop_lease_desc, spec_lease_check }, /* lease */ 94 { &vop_fcntl_desc, spec_fcntl }, /* fcntl */ 95 { &vop_ioctl_desc, spec_ioctl }, /* ioctl */ 96 { &vop_poll_desc, spec_poll }, /* poll */ 97 { &vop_kqfilter_desc, spec_kqfilter }, /* kqfilter */ 98 { &vop_revoke_desc, spec_revoke }, /* revoke */ 99 { &vop_mmap_desc, spec_mmap }, /* mmap */ 100 { &vop_fsync_desc, spec_fsync }, /* fsync */ 101 { &vop_seek_desc, spec_seek }, /* seek */ 102 { &vop_remove_desc, spec_remove }, /* remove */ 103 { &vop_link_desc, spec_link }, /* link */ 104 { &vop_rename_desc, spec_rename }, /* rename */ 105 { &vop_mkdir_desc, spec_mkdir }, /* mkdir */ 106 { &vop_rmdir_desc, spec_rmdir }, /* rmdir */ 107 { &vop_symlink_desc, spec_symlink }, /* symlink */ 108 { &vop_readdir_desc, spec_readdir }, /* readdir */ 109 { &vop_readlink_desc, spec_readlink }, /* readlink */ 110 { &vop_abortop_desc, spec_abortop }, /* abortop */ 111 { &vop_inactive_desc, spec_inactive }, /* inactive */ 112 { &vop_reclaim_desc, spec_reclaim }, /* reclaim */ 113 { &vop_lock_desc, spec_lock }, /* lock */ 114 { &vop_unlock_desc, spec_unlock }, /* unlock */ 115 { &vop_bmap_desc, spec_bmap }, /* bmap */ 116 { &vop_strategy_desc, spec_strategy }, /* strategy */ 117 { &vop_print_desc, spec_print }, /* print */ 118 { &vop_islocked_desc, spec_islocked }, /* islocked */ 119 { &vop_pathconf_desc, spec_pathconf }, /* pathconf */ 120 { &vop_advlock_desc, spec_advlock }, /* advlock */ 121 { &vop_bwrite_desc, spec_bwrite }, /* bwrite */ 122 { &vop_getpages_desc, spec_getpages }, /* getpages */ 123 { &vop_putpages_desc, spec_putpages }, /* putpages */ 124 { NULL, NULL } 125 }; 126 const struct vnodeopv_desc spec_vnodeop_opv_desc = 127 { &spec_vnodeop_p, spec_vnodeop_entries }; 128 129 /* 130 * Trivial lookup routine that always fails. 131 */ 132 int 133 spec_lookup(v) 134 void *v; 135 { 136 struct vop_lookup_args /* { 137 struct vnode *a_dvp; 138 struct vnode **a_vpp; 139 struct componentname *a_cnp; 140 } */ *ap = v; 141 142 *ap->a_vpp = NULL; 143 return (ENOTDIR); 144 } 145 146 /* 147 * Returns true if dev is /dev/mem or /dev/kmem. 148 */ 149 int 150 iskmemdev(dev_t dev) 151 { 152 /* mem_no is emitted by config(8) to generated devsw.c */ 153 extern const int mem_no; 154 155 /* minor 14 is /dev/io on i386 with COMPAT_10 */ 156 return (major(dev) == mem_no && (minor(dev) < 2 || minor(dev) == 14)); 157 } 158 159 /* 160 * Open a special file. 161 */ 162 /* ARGSUSED */ 163 int 164 spec_open(v) 165 void *v; 166 { 167 struct vop_open_args /* { 168 struct vnode *a_vp; 169 int a_mode; 170 kauth_cred_t a_cred; 171 struct lwp *a_l; 172 } */ *ap = v; 173 struct lwp *l = ap->a_l; 174 struct vnode *vp = ap->a_vp; 175 const struct bdevsw *bdev; 176 const struct cdevsw *cdev; 177 dev_t dev = (dev_t)vp->v_rdev; 178 int error; 179 struct partinfo pi; 180 int (*d_ioctl)(dev_t, u_long, void *, int, struct lwp *); 181 enum kauth_device_req req; 182 183 /* 184 * Don't allow open if fs is mounted -nodev. 185 */ 186 if (vp->v_mount && (vp->v_mount->mnt_flag & MNT_NODEV)) 187 return (ENXIO); 188 189 #define M2K(m) (((m) & FREAD) && ((m) & FWRITE) ? \ 190 KAUTH_REQ_DEVICE_RAWIO_SPEC_RW : \ 191 (m) & FWRITE ? KAUTH_REQ_DEVICE_RAWIO_SPEC_WRITE : \ 192 KAUTH_REQ_DEVICE_RAWIO_SPEC_READ) 193 194 switch (vp->v_type) { 195 196 case VCHR: 197 cdev = cdevsw_lookup(dev); 198 if (cdev == NULL) 199 return (ENXIO); 200 201 req = M2K(ap->a_mode); 202 203 error = kauth_authorize_device_spec(ap->a_cred, req, vp); 204 if (error) 205 return (error); 206 207 if (cdev->d_type == D_TTY) 208 vp->v_flag |= VISTTY; 209 VOP_UNLOCK(vp, 0); 210 error = (*cdev->d_open)(dev, ap->a_mode, S_IFCHR, l); 211 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 212 if (cdev->d_type != D_DISK) 213 return error; 214 d_ioctl = cdev->d_ioctl; 215 break; 216 217 case VBLK: 218 bdev = bdevsw_lookup(dev); 219 if (bdev == NULL) 220 return (ENXIO); 221 222 req = M2K(ap->a_mode); 223 224 error = kauth_authorize_device_spec(ap->a_cred, req, vp); 225 if (error) 226 return (error); 227 228 error = (*bdev->d_open)(dev, ap->a_mode, S_IFBLK, l); 229 d_ioctl = bdev->d_ioctl; 230 break; 231 232 case VNON: 233 case VLNK: 234 case VDIR: 235 case VREG: 236 case VBAD: 237 case VFIFO: 238 case VSOCK: 239 default: 240 return 0; 241 } 242 243 #undef M2K 244 245 if (error) 246 return error; 247 if (!(*d_ioctl)(vp->v_rdev, DIOCGPART, (void *)&pi, FREAD, curlwp)) 248 uvm_vnp_setsize(vp, 249 (voff_t)pi.disklab->d_secsize * pi.part->p_size); 250 return 0; 251 } 252 253 /* 254 * Vnode op for read 255 */ 256 /* ARGSUSED */ 257 int 258 spec_read(v) 259 void *v; 260 { 261 struct vop_read_args /* { 262 struct vnode *a_vp; 263 struct uio *a_uio; 264 int a_ioflag; 265 kauth_cred_t a_cred; 266 } */ *ap = v; 267 struct vnode *vp = ap->a_vp; 268 struct uio *uio = ap->a_uio; 269 struct lwp *l = curlwp; 270 struct buf *bp; 271 const struct bdevsw *bdev; 272 const struct cdevsw *cdev; 273 daddr_t bn; 274 int bsize, bscale; 275 struct partinfo dpart; 276 int n, on; 277 int error = 0; 278 279 #ifdef DIAGNOSTIC 280 if (uio->uio_rw != UIO_READ) 281 panic("spec_read mode"); 282 if (&uio->uio_vmspace->vm_map != kernel_map && 283 uio->uio_vmspace != curproc->p_vmspace) 284 panic("spec_read proc"); 285 #endif 286 if (uio->uio_resid == 0) 287 return (0); 288 289 switch (vp->v_type) { 290 291 case VCHR: 292 VOP_UNLOCK(vp, 0); 293 cdev = cdevsw_lookup(vp->v_rdev); 294 if (cdev != NULL) 295 error = (*cdev->d_read)(vp->v_rdev, uio, ap->a_ioflag); 296 else 297 error = ENXIO; 298 vn_lock(vp, LK_SHARED | LK_RETRY); 299 return (error); 300 301 case VBLK: 302 if (uio->uio_offset < 0) 303 return (EINVAL); 304 bsize = BLKDEV_IOSIZE; 305 bdev = bdevsw_lookup(vp->v_rdev); 306 if (bdev != NULL && 307 (*bdev->d_ioctl)(vp->v_rdev, DIOCGPART, (void *)&dpart, 308 FREAD, l) == 0) { 309 if (dpart.part->p_fstype == FS_BSDFFS && 310 dpart.part->p_frag != 0 && dpart.part->p_fsize != 0) 311 bsize = dpart.part->p_frag * 312 dpart.part->p_fsize; 313 } 314 bscale = bsize >> DEV_BSHIFT; 315 do { 316 bn = (uio->uio_offset >> DEV_BSHIFT) &~ (bscale - 1); 317 on = uio->uio_offset % bsize; 318 n = min((unsigned)(bsize - on), uio->uio_resid); 319 error = bread(vp, bn, bsize, NOCRED, &bp); 320 n = min(n, bsize - bp->b_resid); 321 if (error) { 322 brelse(bp); 323 return (error); 324 } 325 error = uiomove((char *)bp->b_data + on, n, uio); 326 brelse(bp); 327 } while (error == 0 && uio->uio_resid > 0 && n != 0); 328 return (error); 329 330 default: 331 panic("spec_read type"); 332 } 333 /* NOTREACHED */ 334 } 335 336 /* 337 * Vnode op for write 338 */ 339 /* ARGSUSED */ 340 int 341 spec_write(v) 342 void *v; 343 { 344 struct vop_write_args /* { 345 struct vnode *a_vp; 346 struct uio *a_uio; 347 int a_ioflag; 348 kauth_cred_t a_cred; 349 } */ *ap = v; 350 struct vnode *vp = ap->a_vp; 351 struct uio *uio = ap->a_uio; 352 struct lwp *l = curlwp; 353 struct buf *bp; 354 const struct bdevsw *bdev; 355 const struct cdevsw *cdev; 356 daddr_t bn; 357 int bsize, bscale; 358 struct partinfo dpart; 359 int n, on; 360 int error = 0; 361 362 #ifdef DIAGNOSTIC 363 if (uio->uio_rw != UIO_WRITE) 364 panic("spec_write mode"); 365 if (&uio->uio_vmspace->vm_map != kernel_map && 366 uio->uio_vmspace != curproc->p_vmspace) 367 panic("spec_write proc"); 368 #endif 369 370 switch (vp->v_type) { 371 372 case VCHR: 373 VOP_UNLOCK(vp, 0); 374 cdev = cdevsw_lookup(vp->v_rdev); 375 if (cdev != NULL) 376 error = (*cdev->d_write)(vp->v_rdev, uio, ap->a_ioflag); 377 else 378 error = ENXIO; 379 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 380 return (error); 381 382 case VBLK: 383 if (uio->uio_resid == 0) 384 return (0); 385 if (uio->uio_offset < 0) 386 return (EINVAL); 387 bsize = BLKDEV_IOSIZE; 388 bdev = bdevsw_lookup(vp->v_rdev); 389 if (bdev != NULL && 390 (*bdev->d_ioctl)(vp->v_rdev, DIOCGPART, (void *)&dpart, 391 FREAD, l) == 0) { 392 if (dpart.part->p_fstype == FS_BSDFFS && 393 dpart.part->p_frag != 0 && dpart.part->p_fsize != 0) 394 bsize = dpart.part->p_frag * 395 dpart.part->p_fsize; 396 } 397 bscale = bsize >> DEV_BSHIFT; 398 do { 399 bn = (uio->uio_offset >> DEV_BSHIFT) &~ (bscale - 1); 400 on = uio->uio_offset % bsize; 401 n = min((unsigned)(bsize - on), uio->uio_resid); 402 if (n == bsize) 403 bp = getblk(vp, bn, bsize, 0, 0); 404 else 405 error = bread(vp, bn, bsize, NOCRED, &bp); 406 if (error) { 407 brelse(bp); 408 return (error); 409 } 410 n = min(n, bsize - bp->b_resid); 411 error = uiomove((char *)bp->b_data + on, n, uio); 412 if (error) 413 brelse(bp); 414 else { 415 if (n + on == bsize) 416 bawrite(bp); 417 else 418 bdwrite(bp); 419 if (bp->b_flags & B_ERROR) 420 error = bp->b_error; 421 } 422 } while (error == 0 && uio->uio_resid > 0 && n != 0); 423 return (error); 424 425 default: 426 panic("spec_write type"); 427 } 428 /* NOTREACHED */ 429 } 430 431 /* 432 * Device ioctl operation. 433 */ 434 /* ARGSUSED */ 435 int 436 spec_ioctl(v) 437 void *v; 438 { 439 struct vop_ioctl_args /* { 440 struct vnode *a_vp; 441 u_long a_command; 442 void *a_data; 443 int a_fflag; 444 kauth_cred_t a_cred; 445 struct lwp *a_l; 446 } */ *ap = v; 447 const struct bdevsw *bdev; 448 const struct cdevsw *cdev; 449 struct vnode *vp; 450 dev_t dev; 451 452 /* 453 * Extract all the info we need from the vnode, taking care to 454 * avoid a race with VOP_REVOKE(). 455 */ 456 457 vp = ap->a_vp; 458 dev = NODEV; 459 simple_lock(&vp->v_interlock); 460 if ((vp->v_flag & VXLOCK) == 0 && vp->v_specinfo) { 461 dev = vp->v_rdev; 462 } 463 simple_unlock(&vp->v_interlock); 464 if (dev == NODEV) { 465 return ENXIO; 466 } 467 468 switch (vp->v_type) { 469 470 case VCHR: 471 cdev = cdevsw_lookup(dev); 472 if (cdev == NULL) 473 return (ENXIO); 474 return ((*cdev->d_ioctl)(dev, ap->a_command, ap->a_data, 475 ap->a_fflag, ap->a_l)); 476 477 case VBLK: 478 bdev = bdevsw_lookup(dev); 479 if (bdev == NULL) 480 return (ENXIO); 481 if (ap->a_command == 0 && (long)ap->a_data == B_TAPE) { 482 if (bdev->d_type == D_TAPE) 483 return (0); 484 else 485 return (1); 486 } 487 return ((*bdev->d_ioctl)(dev, ap->a_command, ap->a_data, 488 ap->a_fflag, ap->a_l)); 489 490 default: 491 panic("spec_ioctl"); 492 /* NOTREACHED */ 493 } 494 } 495 496 /* ARGSUSED */ 497 int 498 spec_poll(v) 499 void *v; 500 { 501 struct vop_poll_args /* { 502 struct vnode *a_vp; 503 int a_events; 504 struct lwp *a_l; 505 } */ *ap = v; 506 const struct cdevsw *cdev; 507 struct vnode *vp; 508 dev_t dev; 509 510 /* 511 * Extract all the info we need from the vnode, taking care to 512 * avoid a race with VOP_REVOKE(). 513 */ 514 515 vp = ap->a_vp; 516 dev = NODEV; 517 simple_lock(&vp->v_interlock); 518 if ((vp->v_flag & VXLOCK) == 0 && vp->v_specinfo) { 519 dev = vp->v_rdev; 520 } 521 simple_unlock(&vp->v_interlock); 522 if (dev == NODEV) { 523 return POLLERR; 524 } 525 526 switch (vp->v_type) { 527 528 case VCHR: 529 cdev = cdevsw_lookup(dev); 530 if (cdev == NULL) 531 return (POLLERR); 532 return (*cdev->d_poll)(dev, ap->a_events, ap->a_l); 533 534 default: 535 return (genfs_poll(v)); 536 } 537 } 538 539 /* ARGSUSED */ 540 int 541 spec_kqfilter(v) 542 void *v; 543 { 544 struct vop_kqfilter_args /* { 545 struct vnode *a_vp; 546 struct proc *a_kn; 547 } */ *ap = v; 548 const struct cdevsw *cdev; 549 dev_t dev; 550 551 switch (ap->a_vp->v_type) { 552 553 case VCHR: 554 dev = ap->a_vp->v_rdev; 555 cdev = cdevsw_lookup(dev); 556 if (cdev == NULL) 557 return (ENXIO); 558 return (*cdev->d_kqfilter)(dev, ap->a_kn); 559 default: 560 /* 561 * Block devices don't support kqfilter, and refuse it 562 * for any other files (like those vflush()ed) too. 563 */ 564 return (EOPNOTSUPP); 565 } 566 } 567 568 /* 569 * Synch buffers associated with a block device 570 */ 571 /* ARGSUSED */ 572 int 573 spec_fsync(v) 574 void *v; 575 { 576 struct vop_fsync_args /* { 577 struct vnode *a_vp; 578 kauth_cred_t a_cred; 579 int a_flags; 580 off_t offlo; 581 off_t offhi; 582 struct lwp *a_l; 583 } */ *ap = v; 584 struct vnode *vp = ap->a_vp; 585 586 if (vp->v_type == VBLK) 587 vflushbuf(vp, (ap->a_flags & FSYNC_WAIT) != 0); 588 return (0); 589 } 590 591 /* 592 * Just call the device strategy routine 593 */ 594 int 595 spec_strategy(v) 596 void *v; 597 { 598 struct vop_strategy_args /* { 599 struct vnode *a_vp; 600 struct buf *a_bp; 601 } */ *ap = v; 602 struct vnode *vp = ap->a_vp; 603 struct buf *bp = ap->a_bp; 604 int error, s; 605 struct spec_cow_entry *e; 606 607 error = 0; 608 bp->b_dev = vp->v_rdev; 609 if (!(bp->b_flags & B_READ) && 610 (LIST_FIRST(&bp->b_dep)) != NULL && bioops.io_start) 611 (*bioops.io_start)(bp); 612 613 if (!(bp->b_flags & B_READ) && !SLIST_EMPTY(&vp->v_spec_cow_head)) { 614 SPEC_COW_LOCK(vp->v_specinfo, s); 615 while (vp->v_spec_cow_req > 0) 616 ltsleep(&vp->v_spec_cow_req, PRIBIO, "cowlist", 0, 617 &vp->v_spec_cow_slock); 618 vp->v_spec_cow_count++; 619 SPEC_COW_UNLOCK(vp->v_specinfo, s); 620 621 SLIST_FOREACH(e, &vp->v_spec_cow_head, ce_list) { 622 if ((error = (*e->ce_func)(e->ce_cookie, bp)) != 0) 623 break; 624 } 625 626 SPEC_COW_LOCK(vp->v_specinfo, s); 627 vp->v_spec_cow_count--; 628 if (vp->v_spec_cow_req && vp->v_spec_cow_count == 0) 629 wakeup(&vp->v_spec_cow_req); 630 SPEC_COW_UNLOCK(vp->v_specinfo, s); 631 } 632 633 if (error) { 634 bp->b_error = error; 635 bp->b_flags |= B_ERROR; 636 biodone(bp); 637 return (error); 638 } 639 640 DEV_STRATEGY(bp); 641 642 return (0); 643 } 644 645 int 646 spec_inactive(v) 647 void *v; 648 { 649 struct vop_inactive_args /* { 650 struct vnode *a_vp; 651 struct proc *a_l; 652 } */ *ap = v; 653 654 VOP_UNLOCK(ap->a_vp, 0); 655 return (0); 656 } 657 658 /* 659 * This is a noop, simply returning what one has been given. 660 */ 661 int 662 spec_bmap(v) 663 void *v; 664 { 665 struct vop_bmap_args /* { 666 struct vnode *a_vp; 667 daddr_t a_bn; 668 struct vnode **a_vpp; 669 daddr_t *a_bnp; 670 int *a_runp; 671 } */ *ap = v; 672 673 if (ap->a_vpp != NULL) 674 *ap->a_vpp = ap->a_vp; 675 if (ap->a_bnp != NULL) 676 *ap->a_bnp = ap->a_bn; 677 if (ap->a_runp != NULL) 678 *ap->a_runp = (MAXBSIZE >> DEV_BSHIFT) - 1; 679 return (0); 680 } 681 682 /* 683 * Device close routine 684 */ 685 /* ARGSUSED */ 686 int 687 spec_close(v) 688 void *v; 689 { 690 struct vop_close_args /* { 691 struct vnode *a_vp; 692 int a_fflag; 693 kauth_cred_t a_cred; 694 struct lwp *a_l; 695 } */ *ap = v; 696 struct vnode *vp = ap->a_vp; 697 const struct bdevsw *bdev; 698 const struct cdevsw *cdev; 699 struct session *sess; 700 dev_t dev = vp->v_rdev; 701 int (*devclose)(dev_t, int, int, struct lwp *); 702 int mode, error, count, flags, flags1; 703 704 count = vcount(vp); 705 flags = vp->v_flag; 706 707 switch (vp->v_type) { 708 709 case VCHR: 710 /* 711 * Hack: a tty device that is a controlling terminal 712 * has a reference from the session structure. 713 * We cannot easily tell that a character device is 714 * a controlling terminal, unless it is the closing 715 * process' controlling terminal. In that case, 716 * if the reference count is 2 (this last descriptor 717 * plus the session), release the reference from the session. 718 * Also remove the link from the tty back to the session 719 * and pgrp - due to the way consoles are handled we cannot 720 * guarantee that the vrele() will do the final close on the 721 * actual tty device. 722 */ 723 if (count == 2 && ap->a_l && 724 vp == (sess = ap->a_l->l_proc->p_session)->s_ttyvp) { 725 sess->s_ttyvp = NULL; 726 if (sess->s_ttyp->t_session != NULL) { 727 sess->s_ttyp->t_pgrp = NULL; 728 sess->s_ttyp->t_session = NULL; 729 SESSRELE(sess); 730 } else if (sess->s_ttyp->t_pgrp != NULL) 731 panic("spec_close: spurious pgrp ref"); 732 vrele(vp); 733 count--; 734 } 735 /* 736 * If the vnode is locked, then we are in the midst 737 * of forcably closing the device, otherwise we only 738 * close on last reference. 739 */ 740 if (count > 1 && (flags & VXLOCK) == 0) 741 return (0); 742 cdev = cdevsw_lookup(dev); 743 if (cdev != NULL) 744 devclose = cdev->d_close; 745 else 746 devclose = NULL; 747 mode = S_IFCHR; 748 break; 749 750 case VBLK: 751 /* 752 * On last close of a block device (that isn't mounted) 753 * we must invalidate any in core blocks, so that 754 * we can, for instance, change floppy disks. 755 */ 756 error = vinvalbuf(vp, V_SAVE, ap->a_cred, ap->a_l, 0, 0); 757 if (error) 758 return (error); 759 /* 760 * We do not want to really close the device if it 761 * is still in use unless we are trying to close it 762 * forcibly. Since every use (buffer, vnode, swap, cmap) 763 * holds a reference to the vnode, and because we mark 764 * any other vnodes that alias this device, when the 765 * sum of the reference counts on all the aliased 766 * vnodes descends to one, we are on last close. 767 */ 768 if (count > 1 && (flags & VXLOCK) == 0) 769 return (0); 770 bdev = bdevsw_lookup(dev); 771 if (bdev != NULL) 772 devclose = bdev->d_close; 773 else 774 devclose = NULL; 775 mode = S_IFBLK; 776 break; 777 778 default: 779 panic("spec_close: not special"); 780 } 781 782 flags1 = ap->a_fflag; 783 784 /* 785 * if VXLOCK is set, then we're going away soon, so make this 786 * non-blocking. Also ensures that we won't wedge in vn_lock below. 787 */ 788 if (flags & VXLOCK) 789 flags1 |= FNONBLOCK; 790 791 /* 792 * If we're able to block, release the vnode lock & reacquire. We 793 * might end up sleeping for someone else who wants our queues. They 794 * won't get them if we hold the vnode locked. Also, if VXLOCK is set, 795 * don't release the lock as we won't be able to regain it. 796 */ 797 if (!(flags1 & FNONBLOCK)) 798 VOP_UNLOCK(vp, 0); 799 800 if (devclose != NULL) 801 error = (*devclose)(dev, flags1, mode, ap->a_l); 802 else 803 error = ENXIO; 804 805 if (!(flags1 & FNONBLOCK)) 806 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 807 808 return (error); 809 } 810 811 /* 812 * Print out the contents of a special device vnode. 813 */ 814 int 815 spec_print(v) 816 void *v; 817 { 818 struct vop_print_args /* { 819 struct vnode *a_vp; 820 } */ *ap = v; 821 822 printf("tag VT_NON, dev %d, %d\n", major(ap->a_vp->v_rdev), 823 minor(ap->a_vp->v_rdev)); 824 return 0; 825 } 826 827 /* 828 * Return POSIX pathconf information applicable to special devices. 829 */ 830 int 831 spec_pathconf(v) 832 void *v; 833 { 834 struct vop_pathconf_args /* { 835 struct vnode *a_vp; 836 int a_name; 837 register_t *a_retval; 838 } */ *ap = v; 839 840 switch (ap->a_name) { 841 case _PC_LINK_MAX: 842 *ap->a_retval = LINK_MAX; 843 return (0); 844 case _PC_MAX_CANON: 845 *ap->a_retval = MAX_CANON; 846 return (0); 847 case _PC_MAX_INPUT: 848 *ap->a_retval = MAX_INPUT; 849 return (0); 850 case _PC_PIPE_BUF: 851 *ap->a_retval = PIPE_BUF; 852 return (0); 853 case _PC_CHOWN_RESTRICTED: 854 *ap->a_retval = 1; 855 return (0); 856 case _PC_VDISABLE: 857 *ap->a_retval = _POSIX_VDISABLE; 858 return (0); 859 case _PC_SYNC_IO: 860 *ap->a_retval = 1; 861 return (0); 862 default: 863 return (EINVAL); 864 } 865 /* NOTREACHED */ 866 } 867 868 /* 869 * Advisory record locking support. 870 */ 871 int 872 spec_advlock(v) 873 void *v; 874 { 875 struct vop_advlock_args /* { 876 struct vnode *a_vp; 877 void *a_id; 878 int a_op; 879 struct flock *a_fl; 880 int a_flags; 881 } */ *ap = v; 882 struct vnode *vp = ap->a_vp; 883 884 return lf_advlock(ap, &vp->v_speclockf, (off_t)0); 885 } 886
Indexes created Thu Sep 25 16:09:42 GMT 2025