spec_vnops.c revision 1.104
1 /* $NetBSD: spec_vnops.c,v 1.104 2007/08/03 08:45:36 pooka 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 1.104 2007/08/03 08:45:36 pooka 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(void *v) 134 { 135 struct vop_lookup_args /* { 136 struct vnode *a_dvp; 137 struct vnode **a_vpp; 138 struct componentname *a_cnp; 139 } */ *ap = v; 140 141 *ap->a_vpp = NULL; 142 return (ENOTDIR); 143 } 144 145 /* 146 * Returns true if dev is /dev/mem or /dev/kmem. 147 */ 148 int 149 iskmemdev(dev_t dev) 150 { 151 /* mem_no is emitted by config(8) to generated devsw.c */ 152 extern const int mem_no; 153 154 /* minor 14 is /dev/io on i386 with COMPAT_10 */ 155 return (major(dev) == mem_no && (minor(dev) < 2 || minor(dev) == 14)); 156 } 157 158 /* 159 * Open a special file. 160 */ 161 /* ARGSUSED */ 162 int 163 spec_open(void *v) 164 { 165 struct vop_open_args /* { 166 struct vnode *a_vp; 167 int a_mode; 168 kauth_cred_t a_cred; 169 struct lwp *a_l; 170 } */ *ap = v; 171 struct lwp *l = ap->a_l; 172 struct vnode *vp = ap->a_vp; 173 dev_t dev = (dev_t)vp->v_rdev; 174 int error; 175 struct partinfo pi; 176 enum kauth_device_req req; 177 178 /* 179 * Don't allow open if fs is mounted -nodev. 180 */ 181 if (vp->v_mount && (vp->v_mount->mnt_flag & MNT_NODEV)) 182 return (ENXIO); 183 184 #define M2K(m) (((m) & FREAD) && ((m) & FWRITE) ? \ 185 KAUTH_REQ_DEVICE_RAWIO_SPEC_RW : \ 186 (m) & FWRITE ? KAUTH_REQ_DEVICE_RAWIO_SPEC_WRITE : \ 187 KAUTH_REQ_DEVICE_RAWIO_SPEC_READ) 188 189 switch (vp->v_type) { 190 191 case VCHR: 192 req = M2K(ap->a_mode); 193 error = kauth_authorize_device_spec(ap->a_cred, req, vp); 194 if (error) 195 return (error); 196 197 if (cdev_type(dev) == D_TTY) 198 vp->v_flag |= VISTTY; 199 VOP_UNLOCK(vp, 0); 200 error = cdev_open(dev, ap->a_mode, S_IFCHR, l); 201 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 202 if (cdev_type(dev) != D_DISK) 203 return error; 204 break; 205 206 case VBLK: 207 req = M2K(ap->a_mode); 208 error = kauth_authorize_device_spec(ap->a_cred, req, vp); 209 if (error) 210 return (error); 211 error = bdev_open(dev, ap->a_mode, S_IFBLK, l); 212 break; 213 214 case VNON: 215 case VLNK: 216 case VDIR: 217 case VREG: 218 case VBAD: 219 case VFIFO: 220 case VSOCK: 221 default: 222 return 0; 223 } 224 225 #undef M2K 226 227 if (error) 228 return error; 229 if (vp->v_type == VCHR) 230 error = cdev_ioctl(vp->v_rdev, DIOCGPART, &pi, FREAD, curlwp); 231 else 232 error = bdev_ioctl(vp->v_rdev, DIOCGPART, &pi, FREAD, curlwp); 233 if (error == 0) 234 uvm_vnp_setsize(vp, 235 (voff_t)pi.disklab->d_secsize * pi.part->p_size); 236 return 0; 237 } 238 239 /* 240 * Vnode op for read 241 */ 242 /* ARGSUSED */ 243 int 244 spec_read(void *v) 245 { 246 struct vop_read_args /* { 247 struct vnode *a_vp; 248 struct uio *a_uio; 249 int a_ioflag; 250 kauth_cred_t a_cred; 251 } */ *ap = v; 252 struct vnode *vp = ap->a_vp; 253 struct uio *uio = ap->a_uio; 254 struct lwp *l = curlwp; 255 struct buf *bp; 256 daddr_t bn; 257 int bsize, bscale; 258 struct partinfo dpart; 259 int n, on; 260 int error = 0; 261 262 #ifdef DIAGNOSTIC 263 if (uio->uio_rw != UIO_READ) 264 panic("spec_read mode"); 265 if (&uio->uio_vmspace->vm_map != kernel_map && 266 uio->uio_vmspace != curproc->p_vmspace) 267 panic("spec_read proc"); 268 #endif 269 if (uio->uio_resid == 0) 270 return (0); 271 272 switch (vp->v_type) { 273 274 case VCHR: 275 VOP_UNLOCK(vp, 0); 276 error = cdev_read(vp->v_rdev, uio, ap->a_ioflag); 277 vn_lock(vp, LK_SHARED | LK_RETRY); 278 return (error); 279 280 case VBLK: 281 if (uio->uio_offset < 0) 282 return (EINVAL); 283 bsize = BLKDEV_IOSIZE; 284 if (bdev_ioctl(vp->v_rdev, DIOCGPART, &dpart, FREAD, l) == 0) { 285 if (dpart.part->p_fstype == FS_BSDFFS && 286 dpart.part->p_frag != 0 && dpart.part->p_fsize != 0) 287 bsize = dpart.part->p_frag * 288 dpart.part->p_fsize; 289 } 290 bscale = bsize >> DEV_BSHIFT; 291 do { 292 bn = (uio->uio_offset >> DEV_BSHIFT) &~ (bscale - 1); 293 on = uio->uio_offset % bsize; 294 n = min((unsigned)(bsize - on), uio->uio_resid); 295 error = bread(vp, bn, bsize, NOCRED, &bp); 296 n = min(n, bsize - bp->b_resid); 297 if (error) { 298 brelse(bp); 299 return (error); 300 } 301 error = uiomove((char *)bp->b_data + on, n, uio); 302 brelse(bp); 303 } while (error == 0 && uio->uio_resid > 0 && n != 0); 304 return (error); 305 306 default: 307 panic("spec_read type"); 308 } 309 /* NOTREACHED */ 310 } 311 312 /* 313 * Vnode op for write 314 */ 315 /* ARGSUSED */ 316 int 317 spec_write(void *v) 318 { 319 struct vop_write_args /* { 320 struct vnode *a_vp; 321 struct uio *a_uio; 322 int a_ioflag; 323 kauth_cred_t a_cred; 324 } */ *ap = v; 325 struct vnode *vp = ap->a_vp; 326 struct uio *uio = ap->a_uio; 327 struct lwp *l = curlwp; 328 struct buf *bp; 329 daddr_t bn; 330 int bsize, bscale; 331 struct partinfo dpart; 332 int n, on; 333 int error = 0; 334 335 #ifdef DIAGNOSTIC 336 if (uio->uio_rw != UIO_WRITE) 337 panic("spec_write mode"); 338 if (&uio->uio_vmspace->vm_map != kernel_map && 339 uio->uio_vmspace != curproc->p_vmspace) 340 panic("spec_write proc"); 341 #endif 342 343 switch (vp->v_type) { 344 345 case VCHR: 346 VOP_UNLOCK(vp, 0); 347 error = cdev_write(vp->v_rdev, uio, ap->a_ioflag); 348 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 349 return (error); 350 351 case VBLK: 352 if (uio->uio_resid == 0) 353 return (0); 354 if (uio->uio_offset < 0) 355 return (EINVAL); 356 bsize = BLKDEV_IOSIZE; 357 if (bdev_ioctl(vp->v_rdev, DIOCGPART, &dpart, FREAD, l) == 0) { 358 if (dpart.part->p_fstype == FS_BSDFFS && 359 dpart.part->p_frag != 0 && dpart.part->p_fsize != 0) 360 bsize = dpart.part->p_frag * 361 dpart.part->p_fsize; 362 } 363 bscale = bsize >> DEV_BSHIFT; 364 do { 365 bn = (uio->uio_offset >> DEV_BSHIFT) &~ (bscale - 1); 366 on = uio->uio_offset % bsize; 367 n = min((unsigned)(bsize - on), uio->uio_resid); 368 if (n == bsize) 369 bp = getblk(vp, bn, bsize, 0, 0); 370 else 371 error = bread(vp, bn, bsize, NOCRED, &bp); 372 if (error) { 373 brelse(bp); 374 return (error); 375 } 376 n = min(n, bsize - bp->b_resid); 377 error = uiomove((char *)bp->b_data + on, n, uio); 378 if (error) 379 brelse(bp); 380 else { 381 if (n + on == bsize) 382 bawrite(bp); 383 else 384 bdwrite(bp); 385 if (bp->b_error != 0) 386 error = bp->b_error; 387 } 388 } while (error == 0 && uio->uio_resid > 0 && n != 0); 389 return (error); 390 391 default: 392 panic("spec_write type"); 393 } 394 /* NOTREACHED */ 395 } 396 397 /* 398 * Device ioctl operation. 399 */ 400 /* ARGSUSED */ 401 int 402 spec_ioctl(void *v) 403 { 404 struct vop_ioctl_args /* { 405 struct vnode *a_vp; 406 u_long a_command; 407 void *a_data; 408 int a_fflag; 409 kauth_cred_t a_cred; 410 struct lwp *a_l; 411 } */ *ap = v; 412 struct vnode *vp; 413 dev_t dev; 414 415 /* 416 * Extract all the info we need from the vnode, taking care to 417 * avoid a race with VOP_REVOKE(). 418 */ 419 420 vp = ap->a_vp; 421 dev = NODEV; 422 simple_lock(&vp->v_interlock); 423 if ((vp->v_flag & VXLOCK) == 0 && vp->v_specinfo) { 424 dev = vp->v_rdev; 425 } 426 simple_unlock(&vp->v_interlock); 427 if (dev == NODEV) { 428 return ENXIO; 429 } 430 431 switch (vp->v_type) { 432 433 case VCHR: 434 return cdev_ioctl(dev, ap->a_command, ap->a_data, 435 ap->a_fflag, ap->a_l); 436 437 case VBLK: 438 if (ap->a_command == 0 && (long)ap->a_data == B_TAPE) { 439 if (bdev_type(dev) == D_TAPE) 440 return (0); 441 else 442 return (1); 443 } 444 return bdev_ioctl(dev, ap->a_command, ap->a_data, 445 ap->a_fflag, ap->a_l); 446 447 default: 448 panic("spec_ioctl"); 449 /* NOTREACHED */ 450 } 451 } 452 453 /* ARGSUSED */ 454 int 455 spec_poll(void *v) 456 { 457 struct vop_poll_args /* { 458 struct vnode *a_vp; 459 int a_events; 460 struct lwp *a_l; 461 } */ *ap = v; 462 struct vnode *vp; 463 dev_t dev; 464 465 /* 466 * Extract all the info we need from the vnode, taking care to 467 * avoid a race with VOP_REVOKE(). 468 */ 469 470 vp = ap->a_vp; 471 dev = NODEV; 472 simple_lock(&vp->v_interlock); 473 if ((vp->v_flag & VXLOCK) == 0 && vp->v_specinfo) { 474 dev = vp->v_rdev; 475 } 476 simple_unlock(&vp->v_interlock); 477 if (dev == NODEV) { 478 return POLLERR; 479 } 480 481 switch (vp->v_type) { 482 483 case VCHR: 484 return cdev_poll(dev, ap->a_events, ap->a_l); 485 486 default: 487 return (genfs_poll(v)); 488 } 489 } 490 491 /* ARGSUSED */ 492 int 493 spec_kqfilter(void *v) 494 { 495 struct vop_kqfilter_args /* { 496 struct vnode *a_vp; 497 struct proc *a_kn; 498 } */ *ap = v; 499 dev_t dev; 500 501 switch (ap->a_vp->v_type) { 502 503 case VCHR: 504 dev = ap->a_vp->v_rdev; 505 return cdev_kqfilter(dev, ap->a_kn); 506 default: 507 /* 508 * Block devices don't support kqfilter, and refuse it 509 * for any other files (like those vflush()ed) too. 510 */ 511 return (EOPNOTSUPP); 512 } 513 } 514 515 /* 516 * Allow mapping of only D_DISK. This is called only for VBLK. 517 */ 518 int 519 spec_mmap(void *v) 520 { 521 struct vop_mmap_args /* { 522 struct vnode *a_vp; 523 vm_prot_t a_prot; 524 kauth_cred_t a_cred; 525 struct lwp *a_l; 526 } */ *ap = v; 527 struct vnode *vp = ap->a_vp; 528 529 KASSERT(vp->v_type == VBLK); 530 if (bdev_type(vp->v_rdev) != D_DISK) 531 return EINVAL; 532 533 return 0; 534 } 535 536 /* 537 * Synch buffers associated with a block device 538 */ 539 /* ARGSUSED */ 540 int 541 spec_fsync(void *v) 542 { 543 struct vop_fsync_args /* { 544 struct vnode *a_vp; 545 kauth_cred_t a_cred; 546 int a_flags; 547 off_t offlo; 548 off_t offhi; 549 struct lwp *a_l; 550 } */ *ap = v; 551 struct vnode *vp = ap->a_vp; 552 553 if (vp->v_type == VBLK) 554 vflushbuf(vp, (ap->a_flags & FSYNC_WAIT) != 0); 555 return (0); 556 } 557 558 /* 559 * Just call the device strategy routine 560 */ 561 int 562 spec_strategy(void *v) 563 { 564 struct vop_strategy_args /* { 565 struct vnode *a_vp; 566 struct buf *a_bp; 567 } */ *ap = v; 568 struct vnode *vp = ap->a_vp; 569 struct buf *bp = ap->a_bp; 570 int error, s; 571 struct spec_cow_entry *e; 572 573 error = 0; 574 bp->b_dev = vp->v_rdev; 575 if (!(bp->b_flags & B_READ) && 576 (LIST_FIRST(&bp->b_dep)) != NULL && bioops.io_start) 577 (*bioops.io_start)(bp); 578 579 if (!(bp->b_flags & B_READ) && !SLIST_EMPTY(&vp->v_spec_cow_head)) { 580 SPEC_COW_LOCK(vp->v_specinfo, s); 581 while (vp->v_spec_cow_req > 0) 582 ltsleep(&vp->v_spec_cow_req, PRIBIO, "cowlist", 0, 583 &vp->v_spec_cow_slock); 584 vp->v_spec_cow_count++; 585 SPEC_COW_UNLOCK(vp->v_specinfo, s); 586 587 SLIST_FOREACH(e, &vp->v_spec_cow_head, ce_list) { 588 if ((error = (*e->ce_func)(e->ce_cookie, bp)) != 0) 589 break; 590 } 591 592 SPEC_COW_LOCK(vp->v_specinfo, s); 593 vp->v_spec_cow_count--; 594 if (vp->v_spec_cow_req && vp->v_spec_cow_count == 0) 595 wakeup(&vp->v_spec_cow_req); 596 SPEC_COW_UNLOCK(vp->v_specinfo, s); 597 } 598 599 if (error) { 600 bp->b_error = error; 601 biodone(bp); 602 return (error); 603 } 604 605 bdev_strategy(bp); 606 607 return (0); 608 } 609 610 int 611 spec_inactive(void *v) 612 { 613 struct vop_inactive_args /* { 614 struct vnode *a_vp; 615 struct proc *a_l; 616 } */ *ap = v; 617 618 VOP_UNLOCK(ap->a_vp, 0); 619 return (0); 620 } 621 622 /* 623 * This is a noop, simply returning what one has been given. 624 */ 625 int 626 spec_bmap(void *v) 627 { 628 struct vop_bmap_args /* { 629 struct vnode *a_vp; 630 daddr_t a_bn; 631 struct vnode **a_vpp; 632 daddr_t *a_bnp; 633 int *a_runp; 634 } */ *ap = v; 635 636 if (ap->a_vpp != NULL) 637 *ap->a_vpp = ap->a_vp; 638 if (ap->a_bnp != NULL) 639 *ap->a_bnp = ap->a_bn; 640 if (ap->a_runp != NULL) 641 *ap->a_runp = (MAXBSIZE >> DEV_BSHIFT) - 1; 642 return (0); 643 } 644 645 /* 646 * Device close routine 647 */ 648 /* ARGSUSED */ 649 int 650 spec_close(void *v) 651 { 652 struct vop_close_args /* { 653 struct vnode *a_vp; 654 int a_fflag; 655 kauth_cred_t a_cred; 656 struct lwp *a_l; 657 } */ *ap = v; 658 struct vnode *vp = ap->a_vp; 659 struct session *sess; 660 dev_t dev = vp->v_rdev; 661 int mode, error, count, flags, flags1; 662 663 count = vcount(vp); 664 flags = vp->v_flag; 665 666 switch (vp->v_type) { 667 668 case VCHR: 669 /* 670 * Hack: a tty device that is a controlling terminal 671 * has a reference from the session structure. 672 * We cannot easily tell that a character device is 673 * a controlling terminal, unless it is the closing 674 * process' controlling terminal. In that case, 675 * if the reference count is 2 (this last descriptor 676 * plus the session), release the reference from the session. 677 * Also remove the link from the tty back to the session 678 * and pgrp - due to the way consoles are handled we cannot 679 * guarantee that the vrele() will do the final close on the 680 * actual tty device. 681 */ 682 mutex_enter(&proclist_lock); 683 if (count == 2 && ap->a_l && 684 vp == (sess = ap->a_l->l_proc->p_session)->s_ttyvp) { 685 sess->s_ttyvp = NULL; 686 if (sess->s_ttyp->t_session != NULL) { 687 sess->s_ttyp->t_pgrp = NULL; 688 sess->s_ttyp->t_session = NULL; 689 mutex_exit(&proclist_lock); 690 SESSRELE(sess); 691 } else { 692 if (sess->s_ttyp->t_pgrp != NULL) 693 panic("spec_close: spurious pgrp ref"); 694 mutex_exit(&proclist_lock); 695 } 696 vrele(vp); 697 count--; 698 } else 699 mutex_exit(&proclist_lock); 700 701 /* 702 * If the vnode is locked, then we are in the midst 703 * of forcably closing the device, otherwise we only 704 * close on last reference. 705 */ 706 if (count > 1 && (flags & VXLOCK) == 0) 707 return (0); 708 mode = S_IFCHR; 709 break; 710 711 case VBLK: 712 /* 713 * On last close of a block device (that isn't mounted) 714 * we must invalidate any in core blocks, so that 715 * we can, for instance, change floppy disks. 716 */ 717 error = vinvalbuf(vp, V_SAVE, ap->a_cred, ap->a_l, 0, 0); 718 if (error) 719 return (error); 720 /* 721 * We do not want to really close the device if it 722 * is still in use unless we are trying to close it 723 * forcibly. Since every use (buffer, vnode, swap, cmap) 724 * holds a reference to the vnode, and because we mark 725 * any other vnodes that alias this device, when the 726 * sum of the reference counts on all the aliased 727 * vnodes descends to one, we are on last close. 728 */ 729 if (count > 1 && (flags & VXLOCK) == 0) 730 return (0); 731 mode = S_IFBLK; 732 break; 733 734 default: 735 panic("spec_close: not special"); 736 } 737 738 flags1 = ap->a_fflag; 739 740 /* 741 * if VXLOCK is set, then we're going away soon, so make this 742 * non-blocking. Also ensures that we won't wedge in vn_lock below. 743 */ 744 if (flags & VXLOCK) 745 flags1 |= FNONBLOCK; 746 747 /* 748 * If we're able to block, release the vnode lock & reacquire. We 749 * might end up sleeping for someone else who wants our queues. They 750 * won't get them if we hold the vnode locked. Also, if VXLOCK is 751 * set, don't release the lock as we won't be able to regain it. 752 */ 753 if (!(flags1 & FNONBLOCK)) 754 VOP_UNLOCK(vp, 0); 755 756 if (vp->v_type == VBLK) 757 error = bdev_close(dev, flags1, mode, ap->a_l); 758 else 759 error = cdev_close(dev, flags1, mode, ap->a_l); 760 761 if (!(flags1 & FNONBLOCK)) 762 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 763 764 return (error); 765 } 766 767 /* 768 * Print out the contents of a special device vnode. 769 */ 770 int 771 spec_print(void *v) 772 { 773 struct vop_print_args /* { 774 struct vnode *a_vp; 775 } */ *ap = v; 776 777 printf("tag VT_NON, dev %d, %d\n", major(ap->a_vp->v_rdev), 778 minor(ap->a_vp->v_rdev)); 779 return 0; 780 } 781 782 /* 783 * Return POSIX pathconf information applicable to special devices. 784 */ 785 int 786 spec_pathconf(void *v) 787 { 788 struct vop_pathconf_args /* { 789 struct vnode *a_vp; 790 int a_name; 791 register_t *a_retval; 792 } */ *ap = v; 793 794 switch (ap->a_name) { 795 case _PC_LINK_MAX: 796 *ap->a_retval = LINK_MAX; 797 return (0); 798 case _PC_MAX_CANON: 799 *ap->a_retval = MAX_CANON; 800 return (0); 801 case _PC_MAX_INPUT: 802 *ap->a_retval = MAX_INPUT; 803 return (0); 804 case _PC_PIPE_BUF: 805 *ap->a_retval = PIPE_BUF; 806 return (0); 807 case _PC_CHOWN_RESTRICTED: 808 *ap->a_retval = 1; 809 return (0); 810 case _PC_VDISABLE: 811 *ap->a_retval = _POSIX_VDISABLE; 812 return (0); 813 case _PC_SYNC_IO: 814 *ap->a_retval = 1; 815 return (0); 816 default: 817 return (EINVAL); 818 } 819 /* NOTREACHED */ 820 } 821 822 /* 823 * Advisory record locking support. 824 */ 825 int 826 spec_advlock(void *v) 827 { 828 struct vop_advlock_args /* { 829 struct vnode *a_vp; 830 void *a_id; 831 int a_op; 832 struct flock *a_fl; 833 int a_flags; 834 } */ *ap = v; 835 struct vnode *vp = ap->a_vp; 836 837 return lf_advlock(ap, &vp->v_speclockf, (off_t)0); 838 } 839
Indexes created Tue Sep 23 14:10:03 GMT 2025