Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_conf.c
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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: releng/6.1/sys/kern/kern_conf.c 158179 2006-04-30 16:44:43Z cvs2svn $"); 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/ctype.h> 43 #include <sys/tty.h> 44 #include <sys/ucred.h> 45 #include <machine/stdarg.h> 46 47 #include <fs/devfs/devfs_int.h> 48 49 static MALLOC_DEFINE(M_DEVT, "cdev", "cdev storage"); 50 51 struct mtx devmtx; 52 static void destroy_devl(struct cdev *dev); 53 static struct cdev *make_dev_credv(struct cdevsw *devsw, int minornr, 54 struct ucred *cr, uid_t uid, gid_t gid, int mode, const char *fmt, 55 va_list ap); 56 57 void 58 dev_lock(void) 59 { 60 61 mtx_lock(&devmtx); 62 } 63 64 void 65 dev_unlock(void) 66 { 67 68 mtx_unlock(&devmtx); 69 } 70 71 void 72 dev_ref(struct cdev *dev) 73 { 74 75 mtx_assert(&devmtx, MA_NOTOWNED); 76 mtx_lock(&devmtx); 77 dev->si_refcount++; 78 mtx_unlock(&devmtx); 79 } 80 81 void 82 dev_refl(struct cdev *dev) 83 { 84 85 mtx_assert(&devmtx, MA_OWNED); 86 dev->si_refcount++; 87 } 88 89 void 90 dev_rel(struct cdev *dev) 91 { 92 int flag = 0; 93 94 mtx_assert(&devmtx, MA_NOTOWNED); 95 dev_lock(); 96 dev->si_refcount--; 97 KASSERT(dev->si_refcount >= 0, 98 ("dev_rel(%s) gave negative count", devtoname(dev))); 99 #if 0 100 if (dev->si_usecount == 0 && 101 (dev->si_flags & SI_CHEAPCLONE) && (dev->si_flags & SI_NAMED)) 102 ; 103 else 104 #endif 105 if (dev->si_devsw == NULL && dev->si_refcount == 0) { 106 LIST_REMOVE(dev, si_list); 107 flag = 1; 108 } 109 dev_unlock(); 110 if (flag) 111 devfs_free(dev); 112 } 113 114 struct cdevsw * 115 dev_refthread(struct cdev *dev) 116 { 117 struct cdevsw *csw; 118 119 mtx_assert(&devmtx, MA_NOTOWNED); 120 dev_lock(); 121 csw = dev->si_devsw; 122 if (csw != NULL) 123 dev->si_threadcount++; 124 dev_unlock(); 125 return (csw); 126 } 127 128 void 129 dev_relthread(struct cdev *dev) 130 { 131 132 mtx_assert(&devmtx, MA_NOTOWNED); 133 dev_lock(); 134 dev->si_threadcount--; 135 dev_unlock(); 136 } 137 138 int 139 nullop(void) 140 { 141 142 return (0); 143 } 144 145 int 146 eopnotsupp(void) 147 { 148 149 return (EOPNOTSUPP); 150 } 151 152 static int 153 enxio(void) 154 { 155 return (ENXIO); 156 } 157 158 static int 159 enodev(void) 160 { 161 return (ENODEV); 162 } 163 164 /* Define a dead_cdevsw for use when devices leave unexpectedly. */ 165 166 #define dead_open (d_open_t *)enxio 167 #define dead_close (d_close_t *)enxio 168 #define dead_read (d_read_t *)enxio 169 #define dead_write (d_write_t *)enxio 170 #define dead_ioctl (d_ioctl_t *)enxio 171 #define dead_poll (d_poll_t *)enodev 172 #define dead_mmap (d_mmap_t *)enodev 173 174 static void 175 dead_strategy(struct bio *bp) 176 { 177 178 biofinish(bp, NULL, ENXIO); 179 } 180 181 #define dead_dump (dumper_t *)enxio 182 #define dead_kqfilter (d_kqfilter_t *)enxio 183 184 static struct cdevsw dead_cdevsw = { 185 .d_version = D_VERSION, 186 .d_flags = D_NEEDGIANT, /* XXX: does dead_strategy need this ? */ 187 .d_open = dead_open, 188 .d_close = dead_close, 189 .d_read = dead_read, 190 .d_write = dead_write, 191 .d_ioctl = dead_ioctl, 192 .d_poll = dead_poll, 193 .d_mmap = dead_mmap, 194 .d_strategy = dead_strategy, 195 .d_name = "dead", 196 .d_dump = dead_dump, 197 .d_kqfilter = dead_kqfilter 198 }; 199 200 /* Default methods if driver does not specify method */ 201 202 #define null_open (d_open_t *)nullop 203 #define null_close (d_close_t *)nullop 204 #define no_read (d_read_t *)enodev 205 #define no_write (d_write_t *)enodev 206 #define no_ioctl (d_ioctl_t *)enodev 207 #define no_mmap (d_mmap_t *)enodev 208 #define no_kqfilter (d_kqfilter_t *)enodev 209 210 static void 211 no_strategy(struct bio *bp) 212 { 213 214 biofinish(bp, NULL, ENODEV); 215 } 216 217 static int 218 no_poll(struct cdev *dev __unused, int events, struct thread *td __unused) 219 { 220 /* 221 * Return true for read/write. If the user asked for something 222 * special, return POLLNVAL, so that clients have a way of 223 * determining reliably whether or not the extended 224 * functionality is present without hard-coding knowledge 225 * of specific filesystem implementations. 226 * Stay in sync with vop_nopoll(). 227 */ 228 if (events & ~POLLSTANDARD) 229 return (POLLNVAL); 230 231 return (events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM)); 232 } 233 234 #define no_dump (dumper_t *)enodev 235 236 static int 237 giant_open(struct cdev *dev, int oflags, int devtype, struct thread *td) 238 { 239 int retval; 240 241 mtx_lock(&Giant); 242 retval = dev->si_devsw->d_gianttrick-> 243 d_open(dev, oflags, devtype, td); 244 mtx_unlock(&Giant); 245 return (retval); 246 } 247 248 static int 249 giant_fdopen(struct cdev *dev, int oflags, struct thread *td, int fdidx) 250 { 251 int retval; 252 253 mtx_lock(&Giant); 254 retval = dev->si_devsw->d_gianttrick-> 255 d_fdopen(dev, oflags, td, fdidx); 256 mtx_unlock(&Giant); 257 return (retval); 258 } 259 260 static int 261 giant_close(struct cdev *dev, int fflag, int devtype, struct thread *td) 262 { 263 int retval; 264 265 mtx_lock(&Giant); 266 retval = dev->si_devsw->d_gianttrick-> 267 d_close(dev, fflag, devtype, td); 268 mtx_unlock(&Giant); 269 return (retval); 270 } 271 272 static void 273 giant_strategy(struct bio *bp) 274 { 275 276 mtx_lock(&Giant); 277 bp->bio_dev->si_devsw->d_gianttrick-> 278 d_strategy(bp); 279 mtx_unlock(&Giant); 280 } 281 282 static int 283 giant_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int fflag, struct thread *td) 284 { 285 int retval; 286 287 mtx_lock(&Giant); 288 retval = dev->si_devsw->d_gianttrick-> 289 d_ioctl(dev, cmd, data, fflag, td); 290 mtx_unlock(&Giant); 291 return (retval); 292 } 293 294 static int 295 giant_read(struct cdev *dev, struct uio *uio, int ioflag) 296 { 297 int retval; 298 299 mtx_lock(&Giant); 300 retval = dev->si_devsw->d_gianttrick-> 301 d_read(dev, uio, ioflag); 302 mtx_unlock(&Giant); 303 return (retval); 304 } 305 306 static int 307 giant_write(struct cdev *dev, struct uio *uio, int ioflag) 308 { 309 int retval; 310 311 mtx_lock(&Giant); 312 retval = dev->si_devsw->d_gianttrick-> 313 d_write(dev, uio, ioflag); 314 mtx_unlock(&Giant); 315 return (retval); 316 } 317 318 static int 319 giant_poll(struct cdev *dev, int events, struct thread *td) 320 { 321 int retval; 322 323 mtx_lock(&Giant); 324 retval = dev->si_devsw->d_gianttrick-> 325 d_poll(dev, events, td); 326 mtx_unlock(&Giant); 327 return (retval); 328 } 329 330 static int 331 giant_kqfilter(struct cdev *dev, struct knote *kn) 332 { 333 int retval; 334 335 mtx_lock(&Giant); 336 retval = dev->si_devsw->d_gianttrick-> 337 d_kqfilter(dev, kn); 338 mtx_unlock(&Giant); 339 return (retval); 340 } 341 342 static int 343 giant_mmap(struct cdev *dev, vm_offset_t offset, vm_paddr_t *paddr, int nprot) 344 { 345 int retval; 346 347 mtx_lock(&Giant); 348 retval = dev->si_devsw->d_gianttrick-> 349 d_mmap(dev, offset, paddr, nprot); 350 mtx_unlock(&Giant); 351 return (retval); 352 } 353 354 355 /* 356 * struct cdev * and u_dev_t primitives 357 */ 358 359 int 360 minor(struct cdev *x) 361 { 362 if (x == NULL) 363 return NODEV; 364 return(x->si_drv0 & MAXMINOR); 365 } 366 367 int 368 dev2unit(struct cdev *x) 369 { 370 371 if (x == NULL) 372 return NODEV; 373 return (minor2unit(minor(x))); 374 } 375 376 u_int 377 minor2unit(u_int _minor) 378 { 379 380 KASSERT((_minor & ~MAXMINOR) == 0, ("Illegal minor %x", _minor)); 381 return ((_minor & 0xff) | ((_minor >> 8) & 0xffff00)); 382 } 383 384 int 385 unit2minor(int unit) 386 { 387 388 KASSERT(unit <= 0xffffff, ("Invalid unit (%d) in unit2minor", unit)); 389 return ((unit & 0xff) | ((unit << 8) & ~0xffff)); 390 } 391 392 static struct cdev * 393 newdev(struct cdevsw *csw, int y, struct cdev *si) 394 { 395 struct cdev *si2; 396 dev_t udev; 397 398 mtx_assert(&devmtx, MA_OWNED); 399 udev = y; 400 LIST_FOREACH(si2, &csw->d_devs, si_list) { 401 if (si2->si_drv0 == udev) { 402 devfs_free(si); 403 return (si2); 404 } 405 } 406 si->si_drv0 = udev; 407 si->si_devsw = csw; 408 LIST_INSERT_HEAD(&csw->d_devs, si, si_list); 409 return (si); 410 } 411 412 int 413 uminor(dev_t dev) 414 { 415 return (dev & MAXMINOR); 416 } 417 418 int 419 umajor(dev_t dev) 420 { 421 return ((dev & ~MAXMINOR) >> 8); 422 } 423 424 static void 425 fini_cdevsw(struct cdevsw *devsw) 426 { 427 struct cdevsw *gt; 428 429 if (devsw->d_gianttrick != NULL) { 430 gt = devsw->d_gianttrick; 431 memcpy(devsw, gt, sizeof *devsw); 432 free(gt, M_DEVT); 433 devsw->d_gianttrick = NULL; 434 } 435 devsw->d_flags &= ~D_INIT; 436 } 437 438 static void 439 prep_cdevsw(struct cdevsw *devsw) 440 { 441 struct cdevsw *dsw2; 442 443 if (devsw->d_flags & D_NEEDGIANT) 444 dsw2 = malloc(sizeof *dsw2, M_DEVT, M_WAITOK); 445 else 446 dsw2 = NULL; 447 dev_lock(); 448 449 if (devsw->d_version != D_VERSION_01) { 450 printf( 451 "WARNING: Device driver \"%s\" has wrong version %s\n", 452 devsw->d_name, "and is disabled. Recompile KLD module."); 453 devsw->d_open = dead_open; 454 devsw->d_close = dead_close; 455 devsw->d_read = dead_read; 456 devsw->d_write = dead_write; 457 devsw->d_ioctl = dead_ioctl; 458 devsw->d_poll = dead_poll; 459 devsw->d_mmap = dead_mmap; 460 devsw->d_strategy = dead_strategy; 461 devsw->d_dump = dead_dump; 462 devsw->d_kqfilter = dead_kqfilter; 463 } 464 465 if (devsw->d_flags & D_TTY) { 466 if (devsw->d_ioctl == NULL) devsw->d_ioctl = ttyioctl; 467 if (devsw->d_read == NULL) devsw->d_read = ttyread; 468 if (devsw->d_write == NULL) devsw->d_write = ttywrite; 469 if (devsw->d_kqfilter == NULL) devsw->d_kqfilter = ttykqfilter; 470 if (devsw->d_poll == NULL) devsw->d_poll = ttypoll; 471 } 472 473 if (devsw->d_flags & D_NEEDGIANT) { 474 if (devsw->d_gianttrick == NULL) { 475 memcpy(dsw2, devsw, sizeof *dsw2); 476 devsw->d_gianttrick = dsw2; 477 } else 478 free(dsw2, M_DEVT); 479 } 480 481 #define FIXUP(member, noop, giant) \ 482 do { \ 483 if (devsw->member == NULL) { \ 484 devsw->member = noop; \ 485 } else if (devsw->d_flags & D_NEEDGIANT) \ 486 devsw->member = giant; \ 487 } \ 488 while (0) 489 490 FIXUP(d_open, null_open, giant_open); 491 FIXUP(d_fdopen, NULL, giant_fdopen); 492 FIXUP(d_close, null_close, giant_close); 493 FIXUP(d_read, no_read, giant_read); 494 FIXUP(d_write, no_write, giant_write); 495 FIXUP(d_ioctl, no_ioctl, giant_ioctl); 496 FIXUP(d_poll, no_poll, giant_poll); 497 FIXUP(d_mmap, no_mmap, giant_mmap); 498 FIXUP(d_strategy, no_strategy, giant_strategy); 499 FIXUP(d_kqfilter, no_kqfilter, giant_kqfilter); 500 501 if (devsw->d_dump == NULL) devsw->d_dump = no_dump; 502 503 LIST_INIT(&devsw->d_devs); 504 505 devsw->d_flags |= D_INIT; 506 507 dev_unlock(); 508 } 509 510 static struct cdev * 511 make_dev_credv(struct cdevsw *devsw, int minornr, struct ucred *cr, uid_t uid, 512 gid_t gid, int mode, const char *fmt, va_list ap) 513 { 514 struct cdev *dev; 515 int i; 516 517 KASSERT((minornr & ~MAXMINOR) == 0, 518 ("Invalid minor (0x%x) in make_dev", minornr)); 519 520 if (!(devsw->d_flags & D_INIT)) 521 prep_cdevsw(devsw); 522 dev = devfs_alloc(); 523 dev_lock(); 524 dev = newdev(devsw, minornr, dev); 525 if (dev->si_flags & SI_CHEAPCLONE && 526 dev->si_flags & SI_NAMED) { 527 /* 528 * This is allowed as it removes races and generally 529 * simplifies cloning devices. 530 * XXX: still ?? 531 */ 532 dev_unlock(); 533 return (dev); 534 } 535 KASSERT(!(dev->si_flags & SI_NAMED), 536 ("make_dev() by driver %s on pre-existing device (min=%x, name=%s)", 537 devsw->d_name, minor(dev), devtoname(dev))); 538 539 i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap); 540 if (i > (sizeof dev->__si_namebuf - 1)) { 541 printf("WARNING: Device name truncated! (%s)\n", 542 dev->__si_namebuf); 543 } 544 545 dev->si_flags |= SI_NAMED; 546 if (cr != NULL) 547 dev->si_cred = crhold(cr); 548 else 549 dev->si_cred = NULL; 550 dev->si_uid = uid; 551 dev->si_gid = gid; 552 dev->si_mode = mode; 553 554 devfs_create(dev); 555 dev_unlock(); 556 return (dev); 557 } 558 559 struct cdev * 560 make_dev(struct cdevsw *devsw, int minornr, uid_t uid, gid_t gid, int mode, 561 const char *fmt, ...) 562 { 563 struct cdev *dev; 564 va_list ap; 565 566 va_start(ap, fmt); 567 dev = make_dev_credv(devsw, minornr, NULL, uid, gid, mode, fmt, ap); 568 va_end(ap); 569 return (dev); 570 } 571 572 struct cdev * 573 make_dev_cred(struct cdevsw *devsw, int minornr, struct ucred *cr, uid_t uid, 574 gid_t gid, int mode, const char *fmt, ...) 575 { 576 struct cdev *dev; 577 va_list ap; 578 579 va_start(ap, fmt); 580 dev = make_dev_credv(devsw, minornr, cr, uid, gid, mode, fmt, ap); 581 va_end(ap); 582 583 return (dev); 584 } 585 586 static void 587 dev_dependsl(struct cdev *pdev, struct cdev *cdev) 588 { 589 590 cdev->si_parent = pdev; 591 cdev->si_flags |= SI_CHILD; 592 LIST_INSERT_HEAD(&pdev->si_children, cdev, si_siblings); 593 } 594 595 596 void 597 dev_depends(struct cdev *pdev, struct cdev *cdev) 598 { 599 600 dev_lock(); 601 dev_dependsl(pdev, cdev); 602 dev_unlock(); 603 } 604 605 struct cdev * 606 make_dev_alias(struct cdev *pdev, const char *fmt, ...) 607 { 608 struct cdev *dev; 609 va_list ap; 610 int i; 611 612 dev = devfs_alloc(); 613 dev_lock(); 614 dev->si_flags |= SI_ALIAS; 615 dev->si_flags |= SI_NAMED; 616 va_start(ap, fmt); 617 i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap); 618 if (i > (sizeof dev->__si_namebuf - 1)) { 619 printf("WARNING: Device name truncated! (%s)\n", 620 dev->__si_namebuf); 621 } 622 va_end(ap); 623 624 devfs_create(dev); 625 dev_unlock(); 626 dev_depends(pdev, dev); 627 return (dev); 628 } 629 630 static void 631 destroy_devl(struct cdev *dev) 632 { 633 struct cdevsw *csw; 634 635 mtx_assert(&devmtx, MA_OWNED); 636 KASSERT(dev->si_flags & SI_NAMED, 637 ("WARNING: Driver mistake: destroy_dev on %d\n", minor(dev))); 638 639 devfs_destroy(dev); 640 641 /* Remove name marking */ 642 dev->si_flags &= ~SI_NAMED; 643 644 /* If we are a child, remove us from the parents list */ 645 if (dev->si_flags & SI_CHILD) { 646 LIST_REMOVE(dev, si_siblings); 647 dev->si_flags &= ~SI_CHILD; 648 } 649 650 /* Kill our children */ 651 while (!LIST_EMPTY(&dev->si_children)) 652 destroy_devl(LIST_FIRST(&dev->si_children)); 653 654 /* Remove from clone list */ 655 if (dev->si_flags & SI_CLONELIST) { 656 LIST_REMOVE(dev, si_clone); 657 dev->si_flags &= ~SI_CLONELIST; 658 } 659 660 csw = dev->si_devsw; 661 dev->si_devsw = NULL; /* already NULL for SI_ALIAS */ 662 while (csw != NULL && csw->d_purge != NULL && dev->si_threadcount) { 663 printf("Purging %lu threads from %s\n", 664 dev->si_threadcount, devtoname(dev)); 665 csw->d_purge(dev); 666 msleep(csw, &devmtx, PRIBIO, "devprg", hz/10); 667 } 668 if (csw != NULL && csw->d_purge != NULL) 669 printf("All threads purged from %s\n", devtoname(dev)); 670 671 dev->si_drv1 = 0; 672 dev->si_drv2 = 0; 673 bzero(&dev->__si_u, sizeof(dev->__si_u)); 674 675 if (!(dev->si_flags & SI_ALIAS)) { 676 /* Remove from cdevsw list */ 677 LIST_REMOVE(dev, si_list); 678 679 /* If cdevsw has no more struct cdev *'s, clean it */ 680 if (LIST_EMPTY(&csw->d_devs)) 681 fini_cdevsw(csw); 682 } 683 dev->si_flags &= ~SI_ALIAS; 684 685 if (dev->si_refcount > 0) { 686 LIST_INSERT_HEAD(&dead_cdevsw.d_devs, dev, si_list); 687 } else { 688 devfs_free(dev); 689 } 690 } 691 692 void 693 destroy_dev(struct cdev *dev) 694 { 695 696 dev_lock(); 697 destroy_devl(dev); 698 dev_unlock(); 699 } 700 701 const char * 702 devtoname(struct cdev *dev) 703 { 704 char *p; 705 struct cdevsw *csw; 706 int mynor; 707 708 if (dev->si_name[0] == '#' || dev->si_name[0] == '\0') { 709 p = dev->si_name; 710 csw = dev_refthread(dev); 711 if (csw != NULL) { 712 sprintf(p, "(%s)", csw->d_name); 713 dev_relthread(dev); 714 } 715 p += strlen(p); 716 mynor = minor(dev); 717 if (mynor < 0 || mynor > 255) 718 sprintf(p, "/%#x", (u_int)mynor); 719 else 720 sprintf(p, "/%d", mynor); 721 } 722 return (dev->si_name); 723 } 724 725 int 726 dev_stdclone(char *name, char **namep, const char *stem, int *unit) 727 { 728 int u, i; 729 730 i = strlen(stem); 731 if (bcmp(stem, name, i) != 0) 732 return (0); 733 if (!isdigit(name[i])) 734 return (0); 735 u = 0; 736 if (name[i] == '' && isdigit(name[i+1])) 737 return (0); 738 while (isdigit(name[i])) { 739 u *= 10; 740 u += name[i++] - ''; 741 } 742 if (u > 0xffffff) 743 return (0); 744 *unit = u; 745 if (namep) 746 *namep = &name[i]; 747 if (name[i]) 748 return (2); 749 return (1); 750 } 751 752 /* 753 * Helper functions for cloning device drivers. 754 * 755 * The objective here is to make it unnecessary for the device drivers to 756 * use rman or similar to manage their unit number space. Due to the way 757 * we do "on-demand" devices, using rman or other "private" methods 758 * will be very tricky to lock down properly once we lock down this file. 759 * 760 * Instead we give the drivers these routines which puts the struct cdev *'s 761 * that are to be managed on their own list, and gives the driver the ability 762 * to ask for the first free unit number or a given specified unit number. 763 * 764 * In addition these routines support paired devices (pty, nmdm and similar) 765 * by respecting a number of "flag" bits in the minor number. 766 * 767 */ 768 769 struct clonedevs { 770 LIST_HEAD(,cdev) head; 771 }; 772 773 void 774 clone_setup(struct clonedevs **cdp) 775 { 776 777 *cdp = malloc(sizeof **cdp, M_DEVBUF, M_WAITOK | M_ZERO); 778 LIST_INIT(&(*cdp)->head); 779 } 780 781 int 782 clone_create(struct clonedevs **cdp, struct cdevsw *csw, int *up, struct cdev **dp, u_int extra) 783 { 784 struct clonedevs *cd; 785 struct cdev *dev, *ndev, *dl, *de; 786 int unit, low, u; 787 788 KASSERT(*cdp != NULL, 789 ("clone_setup() not called in driver \"%s\"", csw->d_name)); 790 KASSERT(!(extra & CLONE_UNITMASK), 791 ("Illegal extra bits (0x%x) in clone_create", extra)); 792 KASSERT(*up <= CLONE_UNITMASK, 793 ("Too high unit (0x%x) in clone_create", *up)); 794 795 if (!(csw->d_flags & D_INIT)) 796 prep_cdevsw(csw); 797 798 /* 799 * Search the list for a lot of things in one go: 800 * A preexisting match is returned immediately. 801 * The lowest free unit number if we are passed -1, and the place 802 * in the list where we should insert that new element. 803 * The place to insert a specified unit number, if applicable 804 * the end of the list. 805 */ 806 unit = *up; 807 ndev = devfs_alloc(); 808 dev_lock(); 809 low = extra; 810 de = dl = NULL; 811 cd = *cdp; 812 LIST_FOREACH(dev, &cd->head, si_clone) { 813 KASSERT(dev->si_flags & SI_CLONELIST, 814 ("Dev %p(%s) should be on clonelist", dev, dev->si_name)); 815 u = dev2unit(dev); 816 if (u == (unit | extra)) { 817 *dp = dev; 818 devfs_free(ndev); 819 dev_unlock(); 820 return (0); 821 } 822 if (unit == -1 && u == low) { 823 low++; 824 de = dev; 825 continue; 826 } else if (u < (unit | extra)) { 827 de = dev; 828 continue; 829 } else if (u > (unit | extra)) { 830 dl = dev; 831 break; 832 } 833 } 834 if (unit == -1) 835 unit = low & CLONE_UNITMASK; 836 dev = newdev(csw, unit2minor(unit | extra), ndev); 837 if (dev->si_flags & SI_CLONELIST) { 838 printf("dev %p (%s) is on clonelist\n", dev, dev->si_name); 839 printf("unit=%d, low=%d, extra=0x%x\n", unit, low, extra); 840 LIST_FOREACH(dev, &cd->head, si_clone) { 841 printf("\t%p %s\n", dev, dev->si_name); 842 } 843 panic("foo"); 844 } 845 KASSERT(!(dev->si_flags & SI_CLONELIST), 846 ("Dev %p(%s) should not be on clonelist", dev, dev->si_name)); 847 if (dl != NULL) 848 LIST_INSERT_BEFORE(dl, dev, si_clone); 849 else if (de != NULL) 850 LIST_INSERT_AFTER(de, dev, si_clone); 851 else 852 LIST_INSERT_HEAD(&cd->head, dev, si_clone); 853 dev->si_flags |= SI_CLONELIST; 854 *up = unit; 855 dev_unlock(); 856 return (1); 857 } 858 859 /* 860 * Kill everything still on the list. The driver should already have 861 * disposed of any softc hung of the struct cdev *'s at this time. 862 */ 863 void 864 clone_cleanup(struct clonedevs **cdp) 865 { 866 struct cdev *dev, *tdev; 867 struct clonedevs *cd; 868 869 cd = *cdp; 870 if (cd == NULL) 871 return; 872 dev_lock(); 873 LIST_FOREACH_SAFE(dev, &cd->head, si_clone, tdev) { 874 KASSERT(dev->si_flags & SI_CLONELIST, 875 ("Dev %p(%s) should be on clonelist", dev, dev->si_name)); 876 KASSERT(dev->si_flags & SI_NAMED, 877 ("Driver has goofed in cloning underways udev %x", dev->si_drv0)); 878 destroy_devl(dev); 879 } 880 dev_unlock(); 881 free(cd, M_DEVBUF); 882 *cdp = NULL; 883 }
Cache object: 68993dd221cbdb878f17b400c932eb9c
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