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("$FreeBSD$"); 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/sysctl.h> 37 #include <sys/module.h> 38 #include <sys/malloc.h> 39 #include <sys/conf.h> 40 #include <sys/vnode.h> 41 #include <sys/queue.h> 42 #include <sys/poll.h> 43 #include <sys/ctype.h> 44 #include <sys/tty.h> 45 #include <sys/ucred.h> 46 #include <machine/stdarg.h> 47 48 #include <fs/devfs/devfs_int.h> 49 50 static MALLOC_DEFINE(M_DEVT, "cdev", "cdev storage"); 51 52 static struct mtx devmtx; 53 static void freedev(struct cdev *dev); 54 static void destroy_devl(struct cdev *dev); 55 static struct cdev *make_dev_credv(struct cdevsw *devsw, int minornr, 56 struct ucred *cr, uid_t uid, gid_t gid, int mode, const char *fmt, 57 va_list ap); 58 59 void 60 dev_lock(void) 61 { 62 if (!mtx_initialized(&devmtx)) 63 mtx_init(&devmtx, "cdev", NULL, MTX_DEF); 64 mtx_lock(&devmtx); 65 } 66 67 void 68 dev_unlock(void) 69 { 70 71 mtx_unlock(&devmtx); 72 } 73 74 void 75 dev_ref(struct cdev *dev) 76 { 77 78 mtx_assert(&devmtx, MA_NOTOWNED); 79 mtx_lock(&devmtx); 80 dev->si_refcount++; 81 mtx_unlock(&devmtx); 82 } 83 84 void 85 dev_refl(struct cdev *dev) 86 { 87 88 mtx_assert(&devmtx, MA_OWNED); 89 dev->si_refcount++; 90 } 91 92 void 93 dev_rel(struct cdev *dev) 94 { 95 int flag = 0; 96 97 mtx_assert(&devmtx, MA_NOTOWNED); 98 dev_lock(); 99 dev->si_refcount--; 100 KASSERT(dev->si_refcount >= 0, 101 ("dev_rel(%s) gave negative count", devtoname(dev))); 102 if (dev->si_usecount == 0 && 103 (dev->si_flags & SI_CHEAPCLONE) && (dev->si_flags & SI_NAMED)) 104 if (dev->si_devsw == NULL && dev->si_refcount == 0) { 105 LIST_REMOVE(dev, si_list); 106 flag = 1; 107 } 108 dev_unlock(); 109 if (flag) 110 freedev(dev); 111 } 112 113 struct cdevsw * 114 dev_refthread(struct cdev *dev) 115 { 116 struct cdevsw *csw; 117 118 mtx_assert(&devmtx, MA_NOTOWNED); 119 dev_lock(); 120 csw = dev->si_devsw; 121 if (csw != NULL) 122 dev->si_threadcount++; 123 dev_unlock(); 124 return (csw); 125 } 126 127 void 128 dev_relthread(struct cdev *dev) 129 { 130 131 mtx_assert(&devmtx, MA_NOTOWNED); 132 dev_lock(); 133 dev->si_threadcount--; 134 dev_unlock(); 135 } 136 137 int 138 nullop(void) 139 { 140 141 return (0); 142 } 143 144 int 145 eopnotsupp(void) 146 { 147 148 return (EOPNOTSUPP); 149 } 150 151 static int 152 enxio(void) 153 { 154 return (ENXIO); 155 } 156 157 static int 158 enodev(void) 159 { 160 return (ENODEV); 161 } 162 163 /* Define a dead_cdevsw for use when devices leave unexpectedly. */ 164 165 #define dead_open (d_open_t *)enxio 166 #define dead_close (d_close_t *)enxio 167 #define dead_read (d_read_t *)enxio 168 #define dead_write (d_write_t *)enxio 169 #define dead_ioctl (d_ioctl_t *)enxio 170 #define dead_poll (d_poll_t *)enodev 171 #define dead_mmap (d_mmap_t *)enodev 172 173 static void 174 dead_strategy(struct bio *bp) 175 { 176 177 biofinish(bp, NULL, ENXIO); 178 } 179 180 #define dead_dump (dumper_t *)enxio 181 #define dead_kqfilter (d_kqfilter_t *)enxio 182 183 static struct cdevsw dead_cdevsw = { 184 .d_version = D_VERSION, 185 .d_flags = D_NEEDGIANT, /* XXX: does dead_strategy need this ? */ 186 .d_open = dead_open, 187 .d_close = dead_close, 188 .d_read = dead_read, 189 .d_write = dead_write, 190 .d_ioctl = dead_ioctl, 191 .d_poll = dead_poll, 192 .d_mmap = dead_mmap, 193 .d_strategy = dead_strategy, 194 .d_name = "dead", 195 .d_dump = dead_dump, 196 .d_kqfilter = dead_kqfilter 197 }; 198 199 /* Default methods if driver does not specify method */ 200 201 #define null_open (d_open_t *)nullop 202 #define null_close (d_close_t *)nullop 203 #define no_read (d_read_t *)enodev 204 #define no_write (d_write_t *)enodev 205 #define no_ioctl (d_ioctl_t *)enodev 206 #define no_mmap (d_mmap_t *)enodev 207 #define no_kqfilter (d_kqfilter_t *)enodev 208 209 static void 210 no_strategy(struct bio *bp) 211 { 212 213 biofinish(bp, NULL, ENODEV); 214 } 215 216 static int 217 no_poll(struct cdev *dev __unused, int events, struct thread *td __unused) 218 { 219 /* 220 * Return true for read/write. If the user asked for something 221 * special, return POLLNVAL, so that clients have a way of 222 * determining reliably whether or not the extended 223 * functionality is present without hard-coding knowledge 224 * of specific filesystem implementations. 225 * Stay in sync with vop_nopoll(). 226 */ 227 if (events & ~POLLSTANDARD) 228 return (POLLNVAL); 229 230 return (events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM)); 231 } 232 233 #define no_dump (dumper_t *)enodev 234 235 static int 236 giant_open(struct cdev *dev, int oflags, int devtype, struct thread *td) 237 { 238 int retval; 239 240 mtx_lock(&Giant); 241 retval = dev->si_devsw->d_gianttrick-> 242 d_open(dev, oflags, devtype, td); 243 mtx_unlock(&Giant); 244 return (retval); 245 } 246 247 static int 248 giant_fdopen(struct cdev *dev, int oflags, struct thread *td, int fdidx) 249 { 250 int retval; 251 252 mtx_lock(&Giant); 253 retval = dev->si_devsw->d_gianttrick-> 254 d_fdopen(dev, oflags, td, fdidx); 255 mtx_unlock(&Giant); 256 return (retval); 257 } 258 259 static int 260 giant_close(struct cdev *dev, int fflag, int devtype, struct thread *td) 261 { 262 int retval; 263 264 mtx_lock(&Giant); 265 retval = dev->si_devsw->d_gianttrick-> 266 d_close(dev, fflag, devtype, td); 267 mtx_unlock(&Giant); 268 return (retval); 269 } 270 271 static void 272 giant_strategy(struct bio *bp) 273 { 274 275 mtx_lock(&Giant); 276 bp->bio_dev->si_devsw->d_gianttrick-> 277 d_strategy(bp); 278 mtx_unlock(&Giant); 279 } 280 281 static int 282 giant_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int fflag, struct thread *td) 283 { 284 int retval; 285 286 mtx_lock(&Giant); 287 retval = dev->si_devsw->d_gianttrick-> 288 d_ioctl(dev, cmd, data, fflag, td); 289 mtx_unlock(&Giant); 290 return (retval); 291 } 292 293 static int 294 giant_read(struct cdev *dev, struct uio *uio, int ioflag) 295 { 296 int retval; 297 298 mtx_lock(&Giant); 299 retval = dev->si_devsw->d_gianttrick-> 300 d_read(dev, uio, ioflag); 301 mtx_unlock(&Giant); 302 return (retval); 303 } 304 305 static int 306 giant_write(struct cdev *dev, struct uio *uio, int ioflag) 307 { 308 int retval; 309 310 mtx_lock(&Giant); 311 retval = dev->si_devsw->d_gianttrick-> 312 d_write(dev, uio, ioflag); 313 mtx_unlock(&Giant); 314 return (retval); 315 } 316 317 static int 318 giant_poll(struct cdev *dev, int events, struct thread *td) 319 { 320 int retval; 321 322 mtx_lock(&Giant); 323 retval = dev->si_devsw->d_gianttrick-> 324 d_poll(dev, events, td); 325 mtx_unlock(&Giant); 326 return (retval); 327 } 328 329 static int 330 giant_kqfilter(struct cdev *dev, struct knote *kn) 331 { 332 int retval; 333 334 mtx_lock(&Giant); 335 retval = dev->si_devsw->d_gianttrick-> 336 d_kqfilter(dev, kn); 337 mtx_unlock(&Giant); 338 return (retval); 339 } 340 341 static int 342 giant_mmap(struct cdev *dev, vm_offset_t offset, vm_paddr_t *paddr, int nprot) 343 { 344 int retval; 345 346 mtx_lock(&Giant); 347 retval = dev->si_devsw->d_gianttrick-> 348 d_mmap(dev, offset, paddr, nprot); 349 mtx_unlock(&Giant); 350 return (retval); 351 } 352 353 354 /* 355 * struct cdev * and u_dev_t primitives 356 */ 357 358 int 359 minor(struct cdev *x) 360 { 361 if (x == NULL) 362 return NODEV; 363 return(x->si_drv0 & MAXMINOR); 364 } 365 366 int 367 dev2unit(struct cdev *x) 368 { 369 370 if (x == NULL) 371 return NODEV; 372 return (minor2unit(minor(x))); 373 } 374 375 u_int 376 minor2unit(u_int _minor) 377 { 378 379 KASSERT((_minor & ~MAXMINOR) == 0, ("Illegal minor %x", _minor)); 380 return ((_minor & 0xff) | ((_minor >> 8) & 0xffff00)); 381 } 382 383 int 384 unit2minor(int unit) 385 { 386 387 KASSERT(unit <= 0xffffff, ("Invalid unit (%d) in unit2minor", unit)); 388 return ((unit & 0xff) | ((unit << 8) & ~0xffff)); 389 } 390 391 static struct cdev * 392 allocdev(void) 393 { 394 struct cdev *si; 395 396 si = malloc(sizeof *si, M_DEVT, M_USE_RESERVE | M_ZERO | M_WAITOK); 397 si->si_name = si->__si_namebuf; 398 LIST_INIT(&si->si_children); 399 LIST_INIT(&si->si_alist); 400 return (si); 401 } 402 403 static struct cdev * 404 newdev(struct cdevsw *csw, int y, struct cdev *si) 405 { 406 struct cdev *si2; 407 dev_t udev; 408 409 mtx_assert(&devmtx, MA_OWNED); 410 udev = y; 411 LIST_FOREACH(si2, &csw->d_devs, si_list) { 412 if (si2->si_drv0 == udev) { 413 freedev(si); 414 return (si2); 415 } 416 } 417 si->si_drv0 = udev; 418 LIST_INSERT_HEAD(&csw->d_devs, si, si_list); 419 return (si); 420 } 421 422 static void 423 freedev(struct cdev *dev) 424 { 425 426 if (dev->si_cred != NULL) 427 crfree(dev->si_cred); 428 free(dev, M_DEVT); 429 } 430 431 int 432 uminor(dev_t dev) 433 { 434 return (dev & MAXMINOR); 435 } 436 437 int 438 umajor(dev_t dev) 439 { 440 return ((dev & ~MAXMINOR) >> 8); 441 } 442 443 static void 444 fini_cdevsw(struct cdevsw *devsw) 445 { 446 struct cdevsw *gt; 447 448 if (devsw->d_gianttrick != NULL) { 449 gt = devsw->d_gianttrick; 450 memcpy(devsw, gt, sizeof *devsw); 451 free(gt, M_DEVT); 452 devsw->d_gianttrick = NULL; 453 } 454 devsw->d_flags &= ~D_INIT; 455 } 456 457 static void 458 prep_cdevsw(struct cdevsw *devsw) 459 { 460 struct cdevsw *dsw2; 461 462 if (devsw->d_flags & D_NEEDGIANT) 463 dsw2 = malloc(sizeof *dsw2, M_DEVT, M_WAITOK); 464 else 465 dsw2 = NULL; 466 dev_lock(); 467 468 if (devsw->d_version != D_VERSION_01) { 469 printf( 470 "WARNING: Device driver \"%s\" has wrong version %s\n", 471 devsw->d_name, "and is disabled. Recompile KLD module."); 472 devsw->d_open = dead_open; 473 devsw->d_close = dead_close; 474 devsw->d_read = dead_read; 475 devsw->d_write = dead_write; 476 devsw->d_ioctl = dead_ioctl; 477 devsw->d_poll = dead_poll; 478 devsw->d_mmap = dead_mmap; 479 devsw->d_strategy = dead_strategy; 480 devsw->d_dump = dead_dump; 481 devsw->d_kqfilter = dead_kqfilter; 482 } 483 484 if (devsw->d_flags & D_TTY) { 485 if (devsw->d_ioctl == NULL) devsw->d_ioctl = ttyioctl; 486 if (devsw->d_read == NULL) devsw->d_read = ttyread; 487 if (devsw->d_write == NULL) devsw->d_write = ttywrite; 488 if (devsw->d_kqfilter == NULL) devsw->d_kqfilter = ttykqfilter; 489 if (devsw->d_poll == NULL) devsw->d_poll = ttypoll; 490 } 491 492 if (devsw->d_flags & D_NEEDGIANT) { 493 if (devsw->d_gianttrick == NULL) { 494 memcpy(dsw2, devsw, sizeof *dsw2); 495 devsw->d_gianttrick = dsw2; 496 } else 497 free(dsw2, M_DEVT); 498 } 499 500 #define FIXUP(member, noop, giant) \ 501 do { \ 502 if (devsw->member == NULL) { \ 503 devsw->member = noop; \ 504 } else if (devsw->d_flags & D_NEEDGIANT) \ 505 devsw->member = giant; \ 506 } \ 507 while (0) 508 509 FIXUP(d_open, null_open, giant_open); 510 FIXUP(d_fdopen, NULL, giant_fdopen); 511 FIXUP(d_close, null_close, giant_close); 512 FIXUP(d_read, no_read, giant_read); 513 FIXUP(d_write, no_write, giant_write); 514 FIXUP(d_ioctl, no_ioctl, giant_ioctl); 515 FIXUP(d_poll, no_poll, giant_poll); 516 FIXUP(d_mmap, no_mmap, giant_mmap); 517 FIXUP(d_strategy, no_strategy, giant_strategy); 518 FIXUP(d_kqfilter, no_kqfilter, giant_kqfilter); 519 520 if (devsw->d_dump == NULL) devsw->d_dump = no_dump; 521 522 LIST_INIT(&devsw->d_devs); 523 524 devsw->d_flags |= D_INIT; 525 526 dev_unlock(); 527 } 528 529 static struct cdev * 530 make_dev_credv(struct cdevsw *devsw, int minornr, struct ucred *cr, uid_t uid, 531 gid_t gid, int mode, const char *fmt, va_list ap) 532 { 533 struct cdev *dev; 534 int i; 535 536 KASSERT((minornr & ~MAXMINOR) == 0, 537 ("Invalid minor (0x%x) in make_dev", minornr)); 538 539 if (!(devsw->d_flags & D_INIT)) 540 prep_cdevsw(devsw); 541 dev = allocdev(); 542 dev_lock(); 543 dev = newdev(devsw, minornr, dev); 544 if (dev->si_flags & SI_CHEAPCLONE && 545 dev->si_flags & SI_NAMED && 546 dev->si_devsw == devsw) { 547 /* 548 * This is allowed as it removes races and generally 549 * simplifies cloning devices. 550 * XXX: still ?? 551 */ 552 dev_unlock(); 553 return (dev); 554 } 555 KASSERT(!(dev->si_flags & SI_NAMED), 556 ("make_dev() by driver %s on pre-existing device (min=%x, name=%s)", 557 devsw->d_name, minor(dev), devtoname(dev))); 558 559 i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap); 560 if (i > (sizeof dev->__si_namebuf - 1)) { 561 printf("WARNING: Device name truncated! (%s)\n", 562 dev->__si_namebuf); 563 } 564 565 dev->si_devsw = devsw; 566 dev->si_flags |= SI_NAMED; 567 if (cr != NULL) 568 dev->si_cred = crhold(cr); 569 else 570 dev->si_cred = NULL; 571 dev->si_uid = uid; 572 dev->si_gid = gid; 573 dev->si_mode = mode; 574 575 devfs_create(dev); 576 dev_unlock(); 577 return (dev); 578 } 579 580 struct cdev * 581 make_dev(struct cdevsw *devsw, int minornr, uid_t uid, gid_t gid, int mode, 582 const char *fmt, ...) 583 { 584 struct cdev *dev; 585 va_list ap; 586 587 va_start(ap, fmt); 588 dev = make_dev_credv(devsw, minornr, NULL, uid, gid, mode, fmt, ap); 589 va_end(ap); 590 return (dev); 591 } 592 593 struct cdev * 594 make_dev_cred(struct cdevsw *devsw, int minornr, struct ucred *cr, uid_t uid, 595 gid_t gid, int mode, const char *fmt, ...) 596 { 597 struct cdev *dev; 598 va_list ap; 599 600 va_start(ap, fmt); 601 dev = make_dev_credv(devsw, minornr, cr, uid, gid, mode, fmt, ap); 602 va_end(ap); 603 604 return (dev); 605 } 606 607 void 608 dev_depends(struct cdev *pdev, struct cdev *cdev) 609 { 610 611 dev_lock(); 612 cdev->si_parent = pdev; 613 cdev->si_flags |= SI_CHILD; 614 LIST_INSERT_HEAD(&pdev->si_children, cdev, si_siblings); 615 dev_unlock(); 616 } 617 618 struct cdev * 619 make_dev_alias(struct cdev *pdev, const char *fmt, ...) 620 { 621 struct cdev *dev; 622 va_list ap; 623 int i; 624 625 dev = allocdev(); 626 dev_lock(); 627 dev->si_flags |= SI_ALIAS; 628 dev->si_flags |= SI_NAMED; 629 va_start(ap, fmt); 630 i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap); 631 if (i > (sizeof dev->__si_namebuf - 1)) { 632 printf("WARNING: Device name truncated! (%s)\n", 633 dev->__si_namebuf); 634 } 635 va_end(ap); 636 637 devfs_create(dev); 638 dev_unlock(); 639 dev_depends(pdev, dev); 640 return (dev); 641 } 642 643 static void 644 destroy_devl(struct cdev *dev) 645 { 646 struct cdevsw *csw; 647 648 mtx_assert(&devmtx, MA_OWNED); 649 KASSERT(dev->si_flags & SI_NAMED, 650 ("WARNING: Driver mistake: destroy_dev on %d\n", minor(dev))); 651 652 devfs_destroy(dev); 653 654 /* Remove name marking */ 655 dev->si_flags &= ~SI_NAMED; 656 657 /* If we are a child, remove us from the parents list */ 658 if (dev->si_flags & SI_CHILD) { 659 LIST_REMOVE(dev, si_siblings); 660 dev->si_flags &= ~SI_CHILD; 661 } 662 663 /* Kill our children */ 664 while (!LIST_EMPTY(&dev->si_children)) 665 destroy_devl(LIST_FIRST(&dev->si_children)); 666 667 /* Remove from clone list */ 668 if (dev->si_flags & SI_CLONELIST) { 669 LIST_REMOVE(dev, si_clone); 670 dev->si_flags &= ~SI_CLONELIST; 671 } 672 673 csw = dev->si_devsw; 674 dev->si_devsw = NULL; /* already NULL for SI_ALIAS */ 675 while (csw != NULL && csw->d_purge != NULL && dev->si_threadcount) { 676 printf("Purging %lu threads from %s\n", 677 dev->si_threadcount, devtoname(dev)); 678 csw->d_purge(dev); 679 msleep(csw, &devmtx, PRIBIO, "devprg", hz/10); 680 } 681 if (csw != NULL && csw->d_purge != NULL) 682 printf("All threads purged from %s\n", devtoname(dev)); 683 684 dev->si_drv1 = 0; 685 dev->si_drv2 = 0; 686 bzero(&dev->__si_u, sizeof(dev->__si_u)); 687 688 if (!(dev->si_flags & SI_ALIAS)) { 689 /* Remove from cdevsw list */ 690 LIST_REMOVE(dev, si_list); 691 692 /* If cdevsw has no struct cdev *'s, clean it */ 693 if (LIST_EMPTY(&csw->d_devs)) 694 fini_cdevsw(csw); 695 } 696 dev->si_flags &= ~SI_ALIAS; 697 698 if (dev->si_refcount > 0) { 699 LIST_INSERT_HEAD(&dead_cdevsw.d_devs, dev, si_list); 700 } else { 701 freedev(dev); 702 } 703 } 704 705 void 706 destroy_dev(struct cdev *dev) 707 { 708 709 dev_lock(); 710 destroy_devl(dev); 711 dev_unlock(); 712 } 713 714 const char * 715 devtoname(struct cdev *dev) 716 { 717 char *p; 718 struct cdevsw *csw; 719 int mynor; 720 721 if (dev->si_name[0] == '#' || dev->si_name[0] == '\0') { 722 p = dev->si_name; 723 csw = dev_refthread(dev); 724 if (csw != NULL) { 725 sprintf(p, "(%s)", csw->d_name); 726 dev_relthread(dev); 727 } 728 p += strlen(p); 729 mynor = minor(dev); 730 if (mynor < 0 || mynor > 255) 731 sprintf(p, "/%#x", (u_int)mynor); 732 else 733 sprintf(p, "/%d", mynor); 734 } 735 return (dev->si_name); 736 } 737 738 int 739 dev_stdclone(char *name, char **namep, const char *stem, int *unit) 740 { 741 int u, i; 742 743 i = strlen(stem); 744 if (bcmp(stem, name, i) != 0) 745 return (0); 746 if (!isdigit(name[i])) 747 return (0); 748 u = 0; 749 if (name[i] == '0' && isdigit(name[i+1])) 750 return (0); 751 while (isdigit(name[i])) { 752 u *= 10; 753 u += name[i++] - '0'; 754 } 755 if (u > 0xffffff) 756 return (0); 757 *unit = u; 758 if (namep) 759 *namep = &name[i]; 760 if (name[i]) 761 return (2); 762 return (1); 763 } 764 765 /* 766 * Helper functions for cloning device drivers. 767 * 768 * The objective here is to make it unnecessary for the device drivers to 769 * use rman or similar to manage their unit number space. Due to the way 770 * we do "on-demand" devices, using rman or other "private" methods 771 * will be very tricky to lock down properly once we lock down this file. 772 * 773 * Instead we give the drivers these routines which puts the struct cdev *'s 774 * that are to be managed on their own list, and gives the driver the ability 775 * to ask for the first free unit number or a given specified unit number. 776 * 777 * In addition these routines support paired devices (pty, nmdm and similar) 778 * by respecting a number of "flag" bits in the minor number. 779 * 780 */ 781 782 struct clonedevs { 783 LIST_HEAD(,cdev) head; 784 }; 785 786 void 787 clone_setup(struct clonedevs **cdp) 788 { 789 790 *cdp = malloc(sizeof **cdp, M_DEVBUF, M_WAITOK | M_ZERO); 791 LIST_INIT(&(*cdp)->head); 792 } 793 794 int 795 clone_create(struct clonedevs **cdp, struct cdevsw *csw, int *up, struct cdev **dp, u_int extra) 796 { 797 struct clonedevs *cd; 798 struct cdev *dev, *ndev, *dl, *de; 799 int unit, low, u; 800 801 KASSERT(*cdp != NULL, 802 ("clone_setup() not called in driver \"%s\"", csw->d_name)); 803 KASSERT(!(extra & CLONE_UNITMASK), 804 ("Illegal extra bits (0x%x) in clone_create", extra)); 805 KASSERT(*up <= CLONE_UNITMASK, 806 ("Too high unit (0x%x) in clone_create", *up)); 807 808 if (!(csw->d_flags & D_INIT)) 809 prep_cdevsw(csw); 810 811 /* 812 * Search the list for a lot of things in one go: 813 * A preexisting match is returned immediately. 814 * The lowest free unit number if we are passed -1, and the place 815 * in the list where we should insert that new element. 816 * The place to insert a specified unit number, if applicable 817 * the end of the list. 818 */ 819 unit = *up; 820 ndev = allocdev(); 821 dev_lock(); 822 low = extra; 823 de = dl = NULL; 824 cd = *cdp; 825 LIST_FOREACH(dev, &cd->head, si_clone) { 826 KASSERT(dev->si_flags & SI_CLONELIST, 827 ("Dev %p(%s) should be on clonelist", dev, dev->si_name)); 828 u = dev2unit(dev); 829 if (u == (unit | extra)) { 830 *dp = dev; 831 freedev(ndev); 832 dev_unlock(); 833 return (0); 834 } 835 if (unit == -1 && u == low) { 836 low++; 837 de = dev; 838 continue; 839 } 840 if (u > (unit | extra)) { 841 dl = dev; 842 break; 843 } 844 } 845 if (unit == -1) 846 unit = low & CLONE_UNITMASK; 847 dev = newdev(csw, unit2minor(unit | extra), ndev); 848 if (dev->si_flags & SI_CLONELIST) { 849 printf("dev %p (%s) is on clonelist\n", dev, dev->si_name); 850 printf("unit=%d\n", unit); 851 LIST_FOREACH(dev, &cd->head, si_clone) { 852 printf("\t%p %s\n", dev, dev->si_name); 853 } 854 panic("foo"); 855 } 856 KASSERT(!(dev->si_flags & SI_CLONELIST), 857 ("Dev %p(%s) should not be on clonelist", dev, dev->si_name)); 858 if (dl != NULL) 859 LIST_INSERT_BEFORE(dl, dev, si_clone); 860 else if (de != NULL) 861 LIST_INSERT_AFTER(de, dev, si_clone); 862 else 863 LIST_INSERT_HEAD(&cd->head, dev, si_clone); 864 dev->si_flags |= SI_CLONELIST; 865 *up = unit; 866 dev_unlock(); 867 return (1); 868 } 869 870 /* 871 * Kill everything still on the list. The driver should already have 872 * disposed of any softc hung of the struct cdev *'s at this time. 873 */ 874 void 875 clone_cleanup(struct clonedevs **cdp) 876 { 877 struct cdev *dev, *tdev; 878 struct clonedevs *cd; 879 880 cd = *cdp; 881 if (cd == NULL) 882 return; 883 dev_lock(); 884 LIST_FOREACH_SAFE(dev, &cd->head, si_clone, tdev) { 885 KASSERT(dev->si_flags & SI_CLONELIST, 886 ("Dev %p(%s) should be on clonelist", dev, dev->si_name)); 887 KASSERT(dev->si_flags & SI_NAMED, 888 ("Driver has goofed in cloning underways udev %x", dev->si_drv0)); 889 destroy_devl(dev); 890 } 891 dev_unlock(); 892 free(cd, M_DEVBUF); 893 *cdp = NULL; 894 } 895