kern_conf.c revision 171181
1/*- 2 * Copyright (c) 1999-2002 Poul-Henning Kamp 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 */ 26 27#include <sys/cdefs.h> 28__FBSDID("$FreeBSD: head/sys/kern/kern_conf.c 171181 2007-07-03 17:42:37Z kib $"); 29 30#include <sys/param.h> 31#include <sys/kernel.h> 32#include <sys/systm.h> 33#include <sys/bio.h> 34#include <sys/lock.h> 35#include <sys/mutex.h> 36#include <sys/module.h> 37#include <sys/malloc.h> 38#include <sys/conf.h> 39#include <sys/vnode.h> 40#include <sys/queue.h> 41#include <sys/poll.h> 42#include <sys/sx.h> 43#include <sys/ctype.h> 44#include <sys/tty.h> 45#include <sys/ucred.h> 46#include <sys/taskqueue.h> 47#include <machine/stdarg.h> 48 49#include <fs/devfs/devfs_int.h> 50 51static MALLOC_DEFINE(M_DEVT, "cdev", "cdev storage"); 52 53struct mtx devmtx; 54static void destroy_devl(struct cdev *dev); 55 56static struct cdev *make_dev_credv(int flags, 57 struct cdevsw *devsw, int minornr, 58 struct ucred *cr, uid_t uid, gid_t gid, int mode, const char *fmt, 59 va_list ap); 60 61static struct cdev_priv_list cdevp_free_list = 62 TAILQ_HEAD_INITIALIZER(cdevp_free_list); 63 64void 65dev_lock(void) 66{ 67 68 mtx_lock(&devmtx); 69} 70 71static void 72dev_unlock_and_free(void) 73{ 74 struct cdev_priv *cdp; 75 76 mtx_assert(&devmtx, MA_OWNED); 77 while ((cdp = TAILQ_FIRST(&cdevp_free_list)) != NULL) { 78 TAILQ_REMOVE(&cdevp_free_list, cdp, cdp_list); 79 mtx_unlock(&devmtx); 80 devfs_free(&cdp->cdp_c); 81 mtx_lock(&devmtx); 82 } 83 mtx_unlock(&devmtx); 84} 85 86static void 87dev_free_devlocked(struct cdev *cdev) 88{ 89 struct cdev_priv *cdp; 90 91 mtx_assert(&devmtx, MA_OWNED); 92 cdp = cdev->si_priv; 93 TAILQ_INSERT_HEAD(&cdevp_free_list, cdp, cdp_list); 94} 95 96void 97dev_unlock(void) 98{ 99 100 mtx_unlock(&devmtx); 101} 102 103void 104dev_ref(struct cdev *dev) 105{ 106 107 mtx_assert(&devmtx, MA_NOTOWNED); 108 mtx_lock(&devmtx); 109 dev->si_refcount++; 110 mtx_unlock(&devmtx); 111} 112 113void 114dev_refl(struct cdev *dev) 115{ 116 117 mtx_assert(&devmtx, MA_OWNED); 118 dev->si_refcount++; 119} 120 121void 122dev_rel(struct cdev *dev) 123{ 124 int flag = 0; 125 126 mtx_assert(&devmtx, MA_NOTOWNED); 127 dev_lock(); 128 dev->si_refcount--; 129 KASSERT(dev->si_refcount >= 0, 130 ("dev_rel(%s) gave negative count", devtoname(dev))); 131#if 0 132 if (dev->si_usecount == 0 && 133 (dev->si_flags & SI_CHEAPCLONE) && (dev->si_flags & SI_NAMED)) 134 ; 135 else 136#endif 137 if (dev->si_devsw == NULL && dev->si_refcount == 0) { 138 LIST_REMOVE(dev, si_list); 139 flag = 1; 140 } 141 dev_unlock(); 142 if (flag) 143 devfs_free(dev); 144} 145 146struct cdevsw * 147dev_refthread(struct cdev *dev) 148{ 149 struct cdevsw *csw; 150 struct cdev_priv *cdp; 151 152 mtx_assert(&devmtx, MA_NOTOWNED); 153 dev_lock(); 154 csw = dev->si_devsw; 155 if (csw != NULL) { 156 cdp = dev->si_priv; 157 if ((cdp->cdp_flags & CDP_SCHED_DTR) == 0) 158 dev->si_threadcount++; 159 else 160 csw = NULL; 161 } 162 dev_unlock(); 163 return (csw); 164} 165 166struct cdevsw * 167devvn_refthread(struct vnode *vp, struct cdev **devp) 168{ 169 struct cdevsw *csw; 170 struct cdev_priv *cdp; 171 172 mtx_assert(&devmtx, MA_NOTOWNED); 173 csw = NULL; 174 dev_lock(); 175 *devp = vp->v_rdev; 176 if (*devp != NULL) { 177 cdp = (*devp)->si_priv; 178 if ((cdp->cdp_flags & CDP_SCHED_DTR) == 0) { 179 csw = (*devp)->si_devsw; 180 if (csw != NULL) 181 (*devp)->si_threadcount++; 182 } 183 } 184 dev_unlock(); 185 return (csw); 186} 187 188void 189dev_relthread(struct cdev *dev) 190{ 191 192 mtx_assert(&devmtx, MA_NOTOWNED); 193 dev_lock(); 194 dev->si_threadcount--; 195 dev_unlock(); 196} 197 198int 199nullop(void) 200{ 201 202 return (0); 203} 204 205int 206eopnotsupp(void) 207{ 208 209 return (EOPNOTSUPP); 210} 211 212static int 213enxio(void) 214{ 215 return (ENXIO); 216} 217 218static int 219enodev(void) 220{ 221 return (ENODEV); 222} 223 224/* Define a dead_cdevsw for use when devices leave unexpectedly. */ 225 226#define dead_open (d_open_t *)enxio 227#define dead_close (d_close_t *)enxio 228#define dead_read (d_read_t *)enxio 229#define dead_write (d_write_t *)enxio 230#define dead_ioctl (d_ioctl_t *)enxio 231#define dead_poll (d_poll_t *)enodev 232#define dead_mmap (d_mmap_t *)enodev 233 234static void 235dead_strategy(struct bio *bp) 236{ 237 238 biofinish(bp, NULL, ENXIO); 239} 240 241#define dead_dump (dumper_t *)enxio 242#define dead_kqfilter (d_kqfilter_t *)enxio 243 244static struct cdevsw dead_cdevsw = { 245 .d_version = D_VERSION, 246 .d_flags = D_NEEDGIANT, /* XXX: does dead_strategy need this ? */ 247 .d_open = dead_open, 248 .d_close = dead_close, 249 .d_read = dead_read, 250 .d_write = dead_write, 251 .d_ioctl = dead_ioctl, 252 .d_poll = dead_poll, 253 .d_mmap = dead_mmap, 254 .d_strategy = dead_strategy, 255 .d_name = "dead", 256 .d_dump = dead_dump, 257 .d_kqfilter = dead_kqfilter 258}; 259 260/* Default methods if driver does not specify method */ 261 262#define null_open (d_open_t *)nullop 263#define null_close (d_close_t *)nullop 264#define no_read (d_read_t *)enodev 265#define no_write (d_write_t *)enodev 266#define no_ioctl (d_ioctl_t *)enodev 267#define no_mmap (d_mmap_t *)enodev 268#define no_kqfilter (d_kqfilter_t *)enodev 269 270static void 271no_strategy(struct bio *bp) 272{ 273 274 biofinish(bp, NULL, ENODEV); 275} 276 277static int 278no_poll(struct cdev *dev __unused, int events, struct thread *td __unused) 279{ 280 /* 281 * Return true for read/write. If the user asked for something 282 * special, return POLLNVAL, so that clients have a way of 283 * determining reliably whether or not the extended 284 * functionality is present without hard-coding knowledge 285 * of specific filesystem implementations. 286 * Stay in sync with vop_nopoll(). 287 */ 288 if (events & ~POLLSTANDARD) 289 return (POLLNVAL); 290 291 return (events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM)); 292} 293 294#define no_dump (dumper_t *)enodev 295 296static int 297giant_open(struct cdev *dev, int oflags, int devtype, struct thread *td) 298{ 299 int retval; 300 301 mtx_lock(&Giant); 302 retval = dev->si_devsw->d_gianttrick-> 303 d_open(dev, oflags, devtype, td); 304 mtx_unlock(&Giant); 305 return (retval); 306} 307 308static int 309giant_fdopen(struct cdev *dev, int oflags, struct thread *td, struct file *fp) 310{ 311 int retval; 312 313 mtx_lock(&Giant); 314 retval = dev->si_devsw->d_gianttrick-> 315 d_fdopen(dev, oflags, td, fp); 316 mtx_unlock(&Giant); 317 return (retval); 318} 319 320static int 321giant_close(struct cdev *dev, int fflag, int devtype, struct thread *td) 322{ 323 int retval; 324 325 mtx_lock(&Giant); 326 retval = dev->si_devsw->d_gianttrick-> 327 d_close(dev, fflag, devtype, td); 328 mtx_unlock(&Giant); 329 return (retval); 330} 331 332static void 333giant_strategy(struct bio *bp) 334{ 335 336 mtx_lock(&Giant); 337 bp->bio_dev->si_devsw->d_gianttrick-> 338 d_strategy(bp); 339 mtx_unlock(&Giant); 340} 341 342static int 343giant_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int fflag, struct thread *td) 344{ 345 int retval; 346 347 mtx_lock(&Giant); 348 retval = dev->si_devsw->d_gianttrick-> 349 d_ioctl(dev, cmd, data, fflag, td); 350 mtx_unlock(&Giant); 351 return (retval); 352} 353 354static int 355giant_read(struct cdev *dev, struct uio *uio, int ioflag) 356{ 357 int retval; 358 359 mtx_lock(&Giant); 360 retval = dev->si_devsw->d_gianttrick-> 361 d_read(dev, uio, ioflag); 362 mtx_unlock(&Giant); 363 return (retval); 364} 365 366static int 367giant_write(struct cdev *dev, struct uio *uio, int ioflag) 368{ 369 int retval; 370 371 mtx_lock(&Giant); 372 retval = dev->si_devsw->d_gianttrick-> 373 d_write(dev, uio, ioflag); 374 mtx_unlock(&Giant); 375 return (retval); 376} 377 378static int 379giant_poll(struct cdev *dev, int events, struct thread *td) 380{ 381 int retval; 382 383 mtx_lock(&Giant); 384 retval = dev->si_devsw->d_gianttrick-> 385 d_poll(dev, events, td); 386 mtx_unlock(&Giant); 387 return (retval); 388} 389 390static int 391giant_kqfilter(struct cdev *dev, struct knote *kn) 392{ 393 int retval; 394 395 mtx_lock(&Giant); 396 retval = dev->si_devsw->d_gianttrick-> 397 d_kqfilter(dev, kn); 398 mtx_unlock(&Giant); 399 return (retval); 400} 401 402static int 403giant_mmap(struct cdev *dev, vm_offset_t offset, vm_paddr_t *paddr, int nprot) 404{ 405 int retval; 406 407 mtx_lock(&Giant); 408 retval = dev->si_devsw->d_gianttrick-> 409 d_mmap(dev, offset, paddr, nprot); 410 mtx_unlock(&Giant); 411 return (retval); 412} 413 414 415/* 416 * struct cdev * and u_dev_t primitives 417 */ 418 419int 420minor(struct cdev *x) 421{ 422 if (x == NULL) 423 return NODEV; 424 return(x->si_drv0 & MAXMINOR); 425} 426 427int 428dev2unit(struct cdev *x) 429{ 430 431 if (x == NULL) 432 return NODEV; 433 return (minor2unit(minor(x))); 434} 435 436u_int 437minor2unit(u_int _minor) 438{ 439 440 KASSERT((_minor & ~MAXMINOR) == 0, ("Illegal minor %x", _minor)); 441 return ((_minor & 0xff) | ((_minor >> 8) & 0xffff00)); 442} 443 444int 445unit2minor(int unit) 446{ 447 448 KASSERT(unit <= 0xffffff, ("Invalid unit (%d) in unit2minor", unit)); 449 return ((unit & 0xff) | ((unit << 8) & ~0xffff)); 450} 451 452static struct cdev * 453newdev(struct cdevsw *csw, int y, struct cdev *si) 454{ 455 struct cdev *si2; 456 dev_t udev; 457 458 mtx_assert(&devmtx, MA_OWNED); 459 udev = y; 460 LIST_FOREACH(si2, &csw->d_devs, si_list) { 461 if (si2->si_drv0 == udev) { 462 dev_free_devlocked(si); 463 return (si2); 464 } 465 } 466 si->si_drv0 = udev; 467 si->si_devsw = csw; 468 LIST_INSERT_HEAD(&csw->d_devs, si, si_list); 469 return (si); 470} 471 472int 473uminor(dev_t dev) 474{ 475 return (dev & MAXMINOR); 476} 477 478int 479umajor(dev_t dev) 480{ 481 return ((dev & ~MAXMINOR) >> 8); 482} 483 484static void 485fini_cdevsw(struct cdevsw *devsw) 486{ 487 struct cdevsw *gt; 488 489 if (devsw->d_gianttrick != NULL) { 490 gt = devsw->d_gianttrick; 491 memcpy(devsw, gt, sizeof *devsw); 492 free(gt, M_DEVT); 493 devsw->d_gianttrick = NULL; 494 } 495 devsw->d_flags &= ~D_INIT; 496} 497 498static void 499prep_cdevsw(struct cdevsw *devsw) 500{ 501 struct cdevsw *dsw2; 502 503 if (devsw->d_flags & D_NEEDGIANT) 504 dsw2 = malloc(sizeof *dsw2, M_DEVT, M_WAITOK); 505 else 506 dsw2 = NULL; 507 dev_lock(); 508 509 if (devsw->d_version != D_VERSION_01) { 510 printf( 511 "WARNING: Device driver \"%s\" has wrong version %s\n", 512 devsw->d_name == NULL ? "???" : devsw->d_name, 513 "and is disabled. Recompile KLD module."); 514 devsw->d_open = dead_open; 515 devsw->d_close = dead_close; 516 devsw->d_read = dead_read; 517 devsw->d_write = dead_write; 518 devsw->d_ioctl = dead_ioctl; 519 devsw->d_poll = dead_poll; 520 devsw->d_mmap = dead_mmap; 521 devsw->d_strategy = dead_strategy; 522 devsw->d_dump = dead_dump; 523 devsw->d_kqfilter = dead_kqfilter; 524 } 525 526 if (devsw->d_flags & D_TTY) { 527 if (devsw->d_ioctl == NULL) devsw->d_ioctl = ttyioctl; 528 if (devsw->d_read == NULL) devsw->d_read = ttyread; 529 if (devsw->d_write == NULL) devsw->d_write = ttywrite; 530 if (devsw->d_kqfilter == NULL) devsw->d_kqfilter = ttykqfilter; 531 if (devsw->d_poll == NULL) devsw->d_poll = ttypoll; 532 } 533 534 if (devsw->d_flags & D_NEEDGIANT) { 535 if (devsw->d_gianttrick == NULL) { 536 memcpy(dsw2, devsw, sizeof *dsw2); 537 devsw->d_gianttrick = dsw2; 538 } else 539 free(dsw2, M_DEVT); 540 } 541 542#define FIXUP(member, noop, giant) \ 543 do { \ 544 if (devsw->member == NULL) { \ 545 devsw->member = noop; \ 546 } else if (devsw->d_flags & D_NEEDGIANT) \ 547 devsw->member = giant; \ 548 } \ 549 while (0) 550 551 FIXUP(d_open, null_open, giant_open); 552 FIXUP(d_fdopen, NULL, giant_fdopen); 553 FIXUP(d_close, null_close, giant_close); 554 FIXUP(d_read, no_read, giant_read); 555 FIXUP(d_write, no_write, giant_write); 556 FIXUP(d_ioctl, no_ioctl, giant_ioctl); 557 FIXUP(d_poll, no_poll, giant_poll); 558 FIXUP(d_mmap, no_mmap, giant_mmap); 559 FIXUP(d_strategy, no_strategy, giant_strategy); 560 FIXUP(d_kqfilter, no_kqfilter, giant_kqfilter); 561 562 if (devsw->d_dump == NULL) devsw->d_dump = no_dump; 563 564 LIST_INIT(&devsw->d_devs); 565 566 devsw->d_flags |= D_INIT; 567 568 dev_unlock(); 569} 570 571struct cdev * 572make_dev_credv(int flags, struct cdevsw *devsw, int minornr, 573 struct ucred *cr, uid_t uid, 574 gid_t gid, int mode, const char *fmt, va_list ap) 575{ 576 struct cdev *dev; 577 int i; 578 579 KASSERT((minornr & ~MAXMINOR) == 0, 580 ("Invalid minor (0x%x) in make_dev", minornr)); 581 582 if (!(devsw->d_flags & D_INIT)) 583 prep_cdevsw(devsw); 584 dev = devfs_alloc(); 585 dev_lock(); 586 dev = newdev(devsw, minornr, dev); 587 if (flags & MAKEDEV_REF) 588 dev_refl(dev); 589 if (dev->si_flags & SI_CHEAPCLONE && 590 dev->si_flags & SI_NAMED) { 591 /* 592 * This is allowed as it removes races and generally 593 * simplifies cloning devices. 594 * XXX: still ?? 595 */ 596 dev_unlock_and_free(); 597 return (dev); 598 } 599 KASSERT(!(dev->si_flags & SI_NAMED), 600 ("make_dev() by driver %s on pre-existing device (min=%x, name=%s)", 601 devsw->d_name, minor(dev), devtoname(dev))); 602 603 i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap); 604 if (i > (sizeof dev->__si_namebuf - 1)) { 605 printf("WARNING: Device name truncated! (%s)\n", 606 dev->__si_namebuf); 607 } 608 609 dev->si_flags |= SI_NAMED; 610 if (cr != NULL) 611 dev->si_cred = crhold(cr); 612 else 613 dev->si_cred = NULL; 614 dev->si_uid = uid; 615 dev->si_gid = gid; 616 dev->si_mode = mode; 617 618 devfs_create(dev); 619 dev_unlock(); 620 return (dev); 621} 622 623struct cdev * 624make_dev(struct cdevsw *devsw, int minornr, uid_t uid, gid_t gid, int mode, 625 const char *fmt, ...) 626{ 627 struct cdev *dev; 628 va_list ap; 629 630 va_start(ap, fmt); 631 dev = make_dev_credv(0, devsw, minornr, NULL, uid, gid, mode, fmt, ap); 632 va_end(ap); 633 return (dev); 634} 635 636struct cdev * 637make_dev_cred(struct cdevsw *devsw, int minornr, struct ucred *cr, uid_t uid, 638 gid_t gid, int mode, const char *fmt, ...) 639{ 640 struct cdev *dev; 641 va_list ap; 642 643 va_start(ap, fmt); 644 dev = make_dev_credv(0, devsw, minornr, cr, uid, gid, mode, fmt, ap); 645 va_end(ap); 646 647 return (dev); 648} 649 650struct cdev * 651make_dev_credf(int flags, struct cdevsw *devsw, int minornr, 652 struct ucred *cr, uid_t uid, 653 gid_t gid, int mode, const char *fmt, ...) 654{ 655 struct cdev *dev; 656 va_list ap; 657 658 va_start(ap, fmt); 659 dev = make_dev_credv(flags, devsw, minornr, cr, uid, gid, mode, 660 fmt, ap); 661 va_end(ap); 662 663 return (dev); 664} 665 666static void 667dev_dependsl(struct cdev *pdev, struct cdev *cdev) 668{ 669 670 cdev->si_parent = pdev; 671 cdev->si_flags |= SI_CHILD; 672 LIST_INSERT_HEAD(&pdev->si_children, cdev, si_siblings); 673} 674 675 676void 677dev_depends(struct cdev *pdev, struct cdev *cdev) 678{ 679 680 dev_lock(); 681 dev_dependsl(pdev, cdev); 682 dev_unlock(); 683} 684 685struct cdev * 686make_dev_alias(struct cdev *pdev, const char *fmt, ...) 687{ 688 struct cdev *dev; 689 va_list ap; 690 int i; 691 692 dev = devfs_alloc(); 693 dev_lock(); 694 dev->si_flags |= SI_ALIAS; 695 dev->si_flags |= SI_NAMED; 696 va_start(ap, fmt); 697 i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap); 698 if (i > (sizeof dev->__si_namebuf - 1)) { 699 printf("WARNING: Device name truncated! (%s)\n", 700 dev->__si_namebuf); 701 } 702 va_end(ap); 703 704 devfs_create(dev); 705 dev_unlock(); 706 dev_depends(pdev, dev); 707 return (dev); 708} 709 710static void 711destroy_devl(struct cdev *dev) 712{ 713 struct cdevsw *csw; 714 715 mtx_assert(&devmtx, MA_OWNED); 716 KASSERT(dev->si_flags & SI_NAMED, 717 ("WARNING: Driver mistake: destroy_dev on %d\n", minor(dev))); 718 719 devfs_destroy(dev); 720 721 /* Remove name marking */ 722 dev->si_flags &= ~SI_NAMED; 723 724 /* If we are a child, remove us from the parents list */ 725 if (dev->si_flags & SI_CHILD) { 726 LIST_REMOVE(dev, si_siblings); 727 dev->si_flags &= ~SI_CHILD; 728 } 729 730 /* Kill our children */ 731 while (!LIST_EMPTY(&dev->si_children)) 732 destroy_devl(LIST_FIRST(&dev->si_children)); 733 734 /* Remove from clone list */ 735 if (dev->si_flags & SI_CLONELIST) { 736 LIST_REMOVE(dev, si_clone); 737 dev->si_flags &= ~SI_CLONELIST; 738 } 739 740 dev->si_refcount++; /* Avoid race with dev_rel() */ 741 csw = dev->si_devsw; 742 dev->si_devsw = NULL; /* already NULL for SI_ALIAS */ 743 while (csw != NULL && csw->d_purge != NULL && dev->si_threadcount) { 744 csw->d_purge(dev); 745 msleep(csw, &devmtx, PRIBIO, "devprg", hz/10); 746 if (dev->si_threadcount) 747 printf("Still %lu threads in %s\n", 748 dev->si_threadcount, devtoname(dev)); 749 } 750 while (dev->si_threadcount != 0) { 751 /* Use unique dummy wait ident */ 752 msleep(&csw, &devmtx, PRIBIO, "devdrn", hz / 10); 753 } 754 755 dev->si_drv1 = 0; 756 dev->si_drv2 = 0; 757 bzero(&dev->__si_u, sizeof(dev->__si_u)); 758 759 if (!(dev->si_flags & SI_ALIAS)) { 760 /* Remove from cdevsw list */ 761 LIST_REMOVE(dev, si_list); 762 763 /* If cdevsw has no more struct cdev *'s, clean it */ 764 if (LIST_EMPTY(&csw->d_devs)) { 765 fini_cdevsw(csw); 766 wakeup(&csw->d_devs); 767 } 768 } 769 dev->si_flags &= ~SI_ALIAS; 770 dev->si_refcount--; /* Avoid race with dev_rel() */ 771 772 if (dev->si_refcount > 0) { 773 LIST_INSERT_HEAD(&dead_cdevsw.d_devs, dev, si_list); 774 } else { 775 dev_free_devlocked(dev); 776 } 777} 778 779void 780destroy_dev(struct cdev *dev) 781{ 782 783 dev_lock(); 784 destroy_devl(dev); 785 dev_unlock_and_free(); 786} 787 788const char * 789devtoname(struct cdev *dev) 790{ 791 char *p; 792 struct cdevsw *csw; 793 int mynor; 794 795 if (dev->si_name[0] == '#' || dev->si_name[0] == '\0') { 796 p = dev->si_name; 797 csw = dev_refthread(dev); 798 if (csw != NULL) { 799 sprintf(p, "(%s)", csw->d_name); 800 dev_relthread(dev); 801 } 802 p += strlen(p); 803 mynor = minor(dev); 804 if (mynor < 0 || mynor > 255) 805 sprintf(p, "/%#x", (u_int)mynor); 806 else 807 sprintf(p, "/%d", mynor); 808 } 809 return (dev->si_name); 810} 811 812int 813dev_stdclone(char *name, char **namep, const char *stem, int *unit) 814{ 815 int u, i; 816 817 i = strlen(stem); 818 if (bcmp(stem, name, i) != 0) 819 return (0); 820 if (!isdigit(name[i])) 821 return (0); 822 u = 0; 823 if (name[i] == '0' && isdigit(name[i+1])) 824 return (0); 825 while (isdigit(name[i])) { 826 u *= 10; 827 u += name[i++] - '0'; 828 } 829 if (u > 0xffffff) 830 return (0); 831 *unit = u; 832 if (namep) 833 *namep = &name[i]; 834 if (name[i]) 835 return (2); 836 return (1); 837} 838 839/* 840 * Helper functions for cloning device drivers. 841 * 842 * The objective here is to make it unnecessary for the device drivers to 843 * use rman or similar to manage their unit number space. Due to the way 844 * we do "on-demand" devices, using rman or other "private" methods 845 * will be very tricky to lock down properly once we lock down this file. 846 * 847 * Instead we give the drivers these routines which puts the struct cdev *'s 848 * that are to be managed on their own list, and gives the driver the ability 849 * to ask for the first free unit number or a given specified unit number. 850 * 851 * In addition these routines support paired devices (pty, nmdm and similar) 852 * by respecting a number of "flag" bits in the minor number. 853 * 854 */ 855 856struct clonedevs { 857 LIST_HEAD(,cdev) head; 858}; 859 860void 861clone_setup(struct clonedevs **cdp) 862{ 863 864 *cdp = malloc(sizeof **cdp, M_DEVBUF, M_WAITOK | M_ZERO); 865 LIST_INIT(&(*cdp)->head); 866} 867 868int 869clone_create(struct clonedevs **cdp, struct cdevsw *csw, int *up, struct cdev **dp, int extra) 870{ 871 struct clonedevs *cd; 872 struct cdev *dev, *ndev, *dl, *de; 873 int unit, low, u; 874 875 KASSERT(*cdp != NULL, 876 ("clone_setup() not called in driver \"%s\"", csw->d_name)); 877 KASSERT(!(extra & CLONE_UNITMASK), 878 ("Illegal extra bits (0x%x) in clone_create", extra)); 879 KASSERT(*up <= CLONE_UNITMASK, 880 ("Too high unit (0x%x) in clone_create", *up)); 881 882 if (!(csw->d_flags & D_INIT)) 883 prep_cdevsw(csw); 884 885 /* 886 * Search the list for a lot of things in one go: 887 * A preexisting match is returned immediately. 888 * The lowest free unit number if we are passed -1, and the place 889 * in the list where we should insert that new element. 890 * The place to insert a specified unit number, if applicable 891 * the end of the list. 892 */ 893 unit = *up; 894 ndev = devfs_alloc(); 895 dev_lock(); 896 low = extra; 897 de = dl = NULL; 898 cd = *cdp; 899 LIST_FOREACH(dev, &cd->head, si_clone) { 900 KASSERT(dev->si_flags & SI_CLONELIST, 901 ("Dev %p(%s) should be on clonelist", dev, dev->si_name)); 902 u = dev2unit(dev); 903 if (u == (unit | extra)) { 904 *dp = dev; 905 dev_unlock(); 906 devfs_free(ndev); 907 return (0); 908 } 909 if (unit == -1 && u == low) { 910 low++; 911 de = dev; 912 continue; 913 } else if (u < (unit | extra)) { 914 de = dev; 915 continue; 916 } else if (u > (unit | extra)) { 917 dl = dev; 918 break; 919 } 920 } 921 if (unit == -1) 922 unit = low & CLONE_UNITMASK; 923 dev = newdev(csw, unit2minor(unit | extra), ndev); 924 if (dev->si_flags & SI_CLONELIST) { 925 printf("dev %p (%s) is on clonelist\n", dev, dev->si_name); 926 printf("unit=%d, low=%d, extra=0x%x\n", unit, low, extra); 927 LIST_FOREACH(dev, &cd->head, si_clone) { 928 printf("\t%p %s\n", dev, dev->si_name); 929 } 930 panic("foo"); 931 } 932 KASSERT(!(dev->si_flags & SI_CLONELIST), 933 ("Dev %p(%s) should not be on clonelist", dev, dev->si_name)); 934 if (dl != NULL) 935 LIST_INSERT_BEFORE(dl, dev, si_clone); 936 else if (de != NULL) 937 LIST_INSERT_AFTER(de, dev, si_clone); 938 else 939 LIST_INSERT_HEAD(&cd->head, dev, si_clone); 940 dev->si_flags |= SI_CLONELIST; 941 *up = unit; 942 dev_unlock_and_free(); 943 return (1); 944} 945 946/* 947 * Kill everything still on the list. The driver should already have 948 * disposed of any softc hung of the struct cdev *'s at this time. 949 */ 950void 951clone_cleanup(struct clonedevs **cdp) 952{ 953 struct cdev *dev; 954 struct cdev_priv *cp; 955 struct clonedevs *cd; 956 957 cd = *cdp; 958 if (cd == NULL) 959 return; 960 dev_lock(); 961 while (!LIST_EMPTY(&cd->head)) { 962 dev = LIST_FIRST(&cd->head); 963 LIST_REMOVE(dev, si_clone); 964 KASSERT(dev->si_flags & SI_CLONELIST, 965 ("Dev %p(%s) should be on clonelist", dev, dev->si_name)); 966 dev->si_flags &= ~SI_CLONELIST; 967 cp = dev->si_priv; 968 if (!(cp->cdp_flags & CDP_SCHED_DTR)) { 969 cp->cdp_flags |= CDP_SCHED_DTR; 970 KASSERT(dev->si_flags & SI_NAMED, 971 ("Driver has goofed in cloning underways udev %x", dev->si_drv0)); 972 destroy_devl(dev); 973 } 974 } 975 dev_unlock(); 976 free(cd, M_DEVBUF); 977 *cdp = NULL; 978} 979 980static TAILQ_HEAD(, cdev_priv) dev_ddtr = 981 TAILQ_HEAD_INITIALIZER(dev_ddtr); 982static struct task dev_dtr_task; 983 984static void 985destroy_dev_tq(void *ctx, int pending) 986{ 987 struct cdev_priv *cp; 988 struct cdev *dev; 989 void (*cb)(void *); 990 void *cb_arg; 991 992 dev_lock(); 993 while (!TAILQ_EMPTY(&dev_ddtr)) { 994 cp = TAILQ_FIRST(&dev_ddtr); 995 dev = &cp->cdp_c; 996 KASSERT(cp->cdp_flags & CDP_SCHED_DTR, 997 ("cdev %p in dev_destroy_tq without CDP_SCHED_DTR", cp)); 998 TAILQ_REMOVE(&dev_ddtr, cp, cdp_dtr_list); 999 cb = cp->cdp_dtr_cb; 1000 cb_arg = cp->cdp_dtr_cb_arg; 1001 destroy_devl(dev); 1002 dev_unlock(); 1003 dev_rel(dev); 1004 if (cb != NULL) 1005 cb(cb_arg); 1006 dev_lock(); 1007 } 1008 dev_unlock(); 1009} 1010 1011int 1012destroy_dev_sched_cb(struct cdev *dev, void (*cb)(void *), void *arg) 1013{ 1014 struct cdev_priv *cp; 1015 1016 cp = dev->si_priv; 1017 dev_lock(); 1018 if (cp->cdp_flags & CDP_SCHED_DTR) { 1019 dev_unlock(); 1020 return (0); 1021 } 1022 dev_refl(dev); 1023 cp->cdp_flags |= CDP_SCHED_DTR; 1024 cp->cdp_dtr_cb = cb; 1025 cp->cdp_dtr_cb_arg = arg; 1026 TAILQ_INSERT_TAIL(&dev_ddtr, cp, cdp_dtr_list); 1027 dev_unlock(); 1028 taskqueue_enqueue(taskqueue_swi_giant, &dev_dtr_task); 1029 return (1); 1030} 1031 1032int 1033destroy_dev_sched(struct cdev *dev) 1034{ 1035 return (destroy_dev_sched_cb(dev, NULL, NULL)); 1036} 1037 1038void 1039destroy_dev_drain(struct cdevsw *csw) 1040{ 1041 1042 dev_lock(); 1043 while (!LIST_EMPTY(&csw->d_devs)) { 1044 msleep(&csw->d_devs, &devmtx, PRIBIO, "devscd", hz/10); 1045 } 1046 dev_unlock(); 1047} 1048 1049void 1050drain_dev_clone_events(void) 1051{ 1052 1053 sx_xlock(&clone_drain_lock); 1054 sx_xunlock(&clone_drain_lock); 1055} 1056 1057static void 1058devdtr_init(void *dummy __unused) 1059{ 1060 1061 TASK_INIT(&dev_dtr_task, 0, destroy_dev_tq, NULL); 1062} 1063 1064SYSINIT(devdtr, SI_SUB_DEVFS, SI_ORDER_SECOND, devdtr_init, NULL); 1065