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/6.0/sys/kern/kern_conf.c 151001 2005-10-06 15:17:41Z phk $"); 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 if (!mtx_initialized(&devmtx)) 61 mtx_init(&devmtx, "cdev", NULL, MTX_DEF); 62 mtx_lock(&devmtx); 63 } 64 65 void 66 dev_unlock(void) 67 { 68 69 mtx_unlock(&devmtx); 70 } 71 72 void 73 dev_ref(struct cdev *dev) 74 { 75 76 mtx_assert(&devmtx, MA_NOTOWNED); 77 mtx_lock(&devmtx); 78 dev->si_refcount++; 79 mtx_unlock(&devmtx); 80 } 81 82 void 83 dev_refl(struct cdev *dev) 84 { 85 86 mtx_assert(&devmtx, MA_OWNED); 87 dev->si_refcount++; 88 } 89 90 void 91 dev_rel(struct cdev *dev) 92 { 93 int flag = 0; 94 95 mtx_assert(&devmtx, MA_NOTOWNED); 96 dev_lock(); 97 dev->si_refcount--; 98 KASSERT(dev->si_refcount >= 0, 99 ("dev_rel(%s) gave negative count", devtoname(dev))); 100 #if 0 101 if (dev->si_usecount == 0 && 102 (dev->si_flags & SI_CHEAPCLONE) && (dev->si_flags & SI_NAMED)) 103 ; 104 else 105 #endif 106 if (dev->si_devsw == NULL && dev->si_refcount == 0) { 107 LIST_REMOVE(dev, si_list); 108 flag = 1; 109 } 110 dev_unlock(); 111 if (flag) 112 devfs_free(dev); 113 } 114 115 struct cdevsw * 116 dev_refthread(struct cdev *dev) 117 { 118 struct cdevsw *csw; 119 120 mtx_assert(&devmtx, MA_NOTOWNED); 121 dev_lock(); 122 csw = dev->si_devsw; 123 if (csw != NULL) 124 dev->si_threadcount++; 125 dev_unlock(); 126 return (csw); 127 } 128 129 void 130 dev_relthread(struct cdev *dev) 131 { 132 133 mtx_assert(&devmtx, MA_NOTOWNED); 134 dev_lock(); 135 dev->si_threadcount--; 136 dev_unlock(); 137 } 138 139 int 140 nullop(void) 141 { 142 143 return (0); 144 } 145 146 int 147 eopnotsupp(void) 148 { 149 150 return (EOPNOTSUPP); 151 } 152 153 static int 154 enxio(void) 155 { 156 return (ENXIO); 157 } 158 159 static int 160 enodev(void) 161 { 162 return (ENODEV); 163 } 164 165 /* Define a dead_cdevsw for use when devices leave unexpectedly. */ 166 167 #define dead_open (d_open_t *)enxio 168 #define dead_close (d_close_t *)enxio 169 #define dead_read (d_read_t *)enxio 170 #define dead_write (d_write_t *)enxio 171 #define dead_ioctl (d_ioctl_t *)enxio 172 #define dead_poll (d_poll_t *)enodev 173 #define dead_mmap (d_mmap_t *)enodev 174 175 static void 176 dead_strategy(struct bio *bp) 177 { 178 179 biofinish(bp, NULL, ENXIO); 180 } 181 182 #define dead_dump (dumper_t *)enxio 183 #define dead_kqfilter (d_kqfilter_t *)enxio 184 185 static struct cdevsw dead_cdevsw = { 186 .d_version = D_VERSION, 187 .d_flags = D_NEEDGIANT, /* XXX: does dead_strategy need this ? */ 188 .d_open = dead_open, 189 .d_close = dead_close, 190 .d_read = dead_read, 191 .d_write = dead_write, 192 .d_ioctl = dead_ioctl, 193 .d_poll = dead_poll, 194 .d_mmap = dead_mmap, 195 .d_strategy = dead_strategy, 196 .d_name = "dead", 197 .d_dump = dead_dump, 198 .d_kqfilter = dead_kqfilter 199 }; 200 201 /* Default methods if driver does not specify method */ 202 203 #define null_open (d_open_t *)nullop 204 #define null_close (d_close_t *)nullop 205 #define no_read (d_read_t *)enodev 206 #define no_write (d_write_t *)enodev 207 #define no_ioctl (d_ioctl_t *)enodev 208 #define no_mmap (d_mmap_t *)enodev 209 #define no_kqfilter (d_kqfilter_t *)enodev 210 211 static void 212 no_strategy(struct bio *bp) 213 { 214 215 biofinish(bp, NULL, ENODEV); 216 } 217 218 static int 219 no_poll(struct cdev *dev __unused, int events, struct thread *td __unused) 220 { 221 /* 222 * Return true for read/write. If the user asked for something 223 * special, return POLLNVAL, so that clients have a way of 224 * determining reliably whether or not the extended 225 * functionality is present without hard-coding knowledge 226 * of specific filesystem implementations. 227 * Stay in sync with vop_nopoll(). 228 */ 229 if (events & ~POLLSTANDARD) 230 return (POLLNVAL); 231 232 return (events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM)); 233 } 234 235 #define no_dump (dumper_t *)enodev 236 237 static int 238 giant_open(struct cdev *dev, int oflags, int devtype, struct thread *td) 239 { 240 int retval; 241 242 mtx_lock(&Giant); 243 retval = dev->si_devsw->d_gianttrick-> 244 d_open(dev, oflags, devtype, td); 245 mtx_unlock(&Giant); 246 return (retval); 247 } 248 249 static int 250 giant_fdopen(struct cdev *dev, int oflags, struct thread *td, int fdidx) 251 { 252 int retval; 253 254 mtx_lock(&Giant); 255 retval = dev->si_devsw->d_gianttrick-> 256 d_fdopen(dev, oflags, td, fdidx); 257 mtx_unlock(&Giant); 258 return (retval); 259 } 260 261 static int 262 giant_close(struct cdev *dev, int fflag, int devtype, struct thread *td) 263 { 264 int retval; 265 266 mtx_lock(&Giant); 267 retval = dev->si_devsw->d_gianttrick-> 268 d_close(dev, fflag, devtype, td); 269 mtx_unlock(&Giant); 270 return (retval); 271 } 272 273 static void 274 giant_strategy(struct bio *bp) 275 { 276 277 mtx_lock(&Giant); 278 bp->bio_dev->si_devsw->d_gianttrick-> 279 d_strategy(bp); 280 mtx_unlock(&Giant); 281 } 282 283 static int 284 giant_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int fflag, struct thread *td) 285 { 286 int retval; 287 288 mtx_lock(&Giant); 289 retval = dev->si_devsw->d_gianttrick-> 290 d_ioctl(dev, cmd, data, fflag, td); 291 mtx_unlock(&Giant); 292 return (retval); 293 } 294 295 static int 296 giant_read(struct cdev *dev, struct uio *uio, int ioflag) 297 { 298 int retval; 299 300 mtx_lock(&Giant); 301 retval = dev->si_devsw->d_gianttrick-> 302 d_read(dev, uio, ioflag); 303 mtx_unlock(&Giant); 304 return (retval); 305 } 306 307 static int 308 giant_write(struct cdev *dev, struct uio *uio, int ioflag) 309 { 310 int retval; 311 312 mtx_lock(&Giant); 313 retval = dev->si_devsw->d_gianttrick-> 314 d_write(dev, uio, ioflag); 315 mtx_unlock(&Giant); 316 return (retval); 317 } 318 319 static int 320 giant_poll(struct cdev *dev, int events, struct thread *td) 321 { 322 int retval; 323 324 mtx_lock(&Giant); 325 retval = dev->si_devsw->d_gianttrick-> 326 d_poll(dev, events, td); 327 mtx_unlock(&Giant); 328 return (retval); 329 } 330 331 static int 332 giant_kqfilter(struct cdev *dev, struct knote *kn) 333 { 334 int retval; 335 336 mtx_lock(&Giant); 337 retval = dev->si_devsw->d_gianttrick-> 338 d_kqfilter(dev, kn); 339 mtx_unlock(&Giant); 340 return (retval); 341 } 342 343 static int 344 giant_mmap(struct cdev *dev, vm_offset_t offset, vm_paddr_t *paddr, int nprot) 345 { 346 int retval; 347 348 mtx_lock(&Giant); 349 retval = dev->si_devsw->d_gianttrick-> 350 d_mmap(dev, offset, paddr, nprot); 351 mtx_unlock(&Giant); 352 return (retval); 353 } 354 355 356 /* 357 * struct cdev * and u_dev_t primitives 358 */ 359 360 int 361 minor(struct cdev *x) 362 { 363 if (x == NULL) 364 return NODEV; 365 return(x->si_drv0 & MAXMINOR); 366 } 367 368 int 369 dev2unit(struct cdev *x) 370 { 371 372 if (x == NULL) 373 return NODEV; 374 return (minor2unit(minor(x))); 375 } 376 377 u_int 378 minor2unit(u_int _minor) 379 { 380 381 KASSERT((_minor & ~MAXMINOR) == 0, ("Illegal minor %x", _minor)); 382 return ((_minor & 0xff) | ((_minor >> 8) & 0xffff00)); 383 } 384 385 int 386 unit2minor(int unit) 387 { 388 389 KASSERT(unit <= 0xffffff, ("Invalid unit (%d) in unit2minor", unit)); 390 return ((unit & 0xff) | ((unit << 8) & ~0xffff)); 391 } 392 393 static struct cdev * 394 newdev(struct cdevsw *csw, int y, struct cdev *si) 395 { 396 struct cdev *si2; 397 dev_t udev; 398 399 mtx_assert(&devmtx, MA_OWNED); 400 udev = y; 401 LIST_FOREACH(si2, &csw->d_devs, si_list) { 402 if (si2->si_drv0 == udev) { 403 devfs_free(si); 404 return (si2); 405 } 406 } 407 si->si_drv0 = udev; 408 si->si_devsw = csw; 409 LIST_INSERT_HEAD(&csw->d_devs, si, si_list); 410 return (si); 411 } 412 413 int 414 uminor(dev_t dev) 415 { 416 return (dev & MAXMINOR); 417 } 418 419 int 420 umajor(dev_t dev) 421 { 422 return ((dev & ~MAXMINOR) >> 8); 423 } 424 425 static void 426 fini_cdevsw(struct cdevsw *devsw) 427 { 428 struct cdevsw *gt; 429 430 if (devsw->d_gianttrick != NULL) { 431 gt = devsw->d_gianttrick; 432 memcpy(devsw, gt, sizeof *devsw); 433 free(gt, M_DEVT); 434 devsw->d_gianttrick = NULL; 435 } 436 devsw->d_flags &= ~D_INIT; 437 } 438 439 static void 440 prep_cdevsw(struct cdevsw *devsw) 441 { 442 struct cdevsw *dsw2; 443 444 if (devsw->d_flags & D_NEEDGIANT) 445 dsw2 = malloc(sizeof *dsw2, M_DEVT, M_WAITOK); 446 else 447 dsw2 = NULL; 448 dev_lock(); 449 450 if (devsw->d_version != D_VERSION_01) { 451 printf( 452 "WARNING: Device driver \"%s\" has wrong version %s\n", 453 devsw->d_name, "and is disabled. Recompile KLD module."); 454 devsw->d_open = dead_open; 455 devsw->d_close = dead_close; 456 devsw->d_read = dead_read; 457 devsw->d_write = dead_write; 458 devsw->d_ioctl = dead_ioctl; 459 devsw->d_poll = dead_poll; 460 devsw->d_mmap = dead_mmap; 461 devsw->d_strategy = dead_strategy; 462 devsw->d_dump = dead_dump; 463 devsw->d_kqfilter = dead_kqfilter; 464 } 465 466 if (devsw->d_flags & D_TTY) { 467 if (devsw->d_ioctl == NULL) devsw->d_ioctl = ttyioctl; 468 if (devsw->d_read == NULL) devsw->d_read = ttyread; 469 if (devsw->d_write == NULL) devsw->d_write = ttywrite; 470 if (devsw->d_kqfilter == NULL) devsw->d_kqfilter = ttykqfilter; 471 if (devsw->d_poll == NULL) devsw->d_poll = ttypoll; 472 } 473 474 if (devsw->d_flags & D_NEEDGIANT) { 475 if (devsw->d_gianttrick == NULL) { 476 memcpy(dsw2, devsw, sizeof *dsw2); 477 devsw->d_gianttrick = dsw2; 478 } else 479 free(dsw2, M_DEVT); 480 } 481 482 #define FIXUP(member, noop, giant) \ 483 do { \ 484 if (devsw->member == NULL) { \ 485 devsw->member = noop; \ 486 } else if (devsw->d_flags & D_NEEDGIANT) \ 487 devsw->member = giant; \ 488 } \ 489 while (0) 490 491 FIXUP(d_open, null_open, giant_open); 492 FIXUP(d_fdopen, NULL, giant_fdopen); 493 FIXUP(d_close, null_close, giant_close); 494 FIXUP(d_read, no_read, giant_read); 495 FIXUP(d_write, no_write, giant_write); 496 FIXUP(d_ioctl, no_ioctl, giant_ioctl); 497 FIXUP(d_poll, no_poll, giant_poll); 498 FIXUP(d_mmap, no_mmap, giant_mmap); 499 FIXUP(d_strategy, no_strategy, giant_strategy); 500 FIXUP(d_kqfilter, no_kqfilter, giant_kqfilter); 501 502 if (devsw->d_dump == NULL) devsw->d_dump = no_dump; 503 504 LIST_INIT(&devsw->d_devs); 505 506 devsw->d_flags |= D_INIT; 507 508 dev_unlock(); 509 } 510 511 static struct cdev * 512 make_dev_credv(struct cdevsw *devsw, int minornr, struct ucred *cr, uid_t uid, 513 gid_t gid, int mode, const char *fmt, va_list ap) 514 { 515 struct cdev *dev; 516 int i; 517 518 KASSERT((minornr & ~MAXMINOR) == 0, 519 ("Invalid minor (0x%x) in make_dev", minornr)); 520 521 if (!(devsw->d_flags & D_INIT)) 522 prep_cdevsw(devsw); 523 dev = devfs_alloc(); 524 dev_lock(); 525 dev = newdev(devsw, minornr, dev); 526 if (dev->si_flags & SI_CHEAPCLONE && 527 dev->si_flags & SI_NAMED) { 528 /* 529 * This is allowed as it removes races and generally 530 * simplifies cloning devices. 531 * XXX: still ?? 532 */ 533 dev_unlock(); 534 return (dev); 535 } 536 KASSERT(!(dev->si_flags & SI_NAMED), 537 ("make_dev() by driver %s on pre-existing device (min=%x, name=%s)", 538 devsw->d_name, minor(dev), devtoname(dev))); 539 540 i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap); 541 if (i > (sizeof dev->__si_namebuf - 1)) { 542 printf("WARNING: Device name truncated! (%s)\n", 543 dev->__si_namebuf); 544 } 545 546 dev->si_flags |= SI_NAMED; 547 if (cr != NULL) 548 dev->si_cred = crhold(cr); 549 else 550 dev->si_cred = NULL; 551 dev->si_uid = uid; 552 dev->si_gid = gid; 553 dev->si_mode = mode; 554 555 devfs_create(dev); 556 dev_unlock(); 557 return (dev); 558 } 559 560 struct cdev * 561 make_dev(struct cdevsw *devsw, int minornr, uid_t uid, gid_t gid, int mode, 562 const char *fmt, ...) 563 { 564 struct cdev *dev; 565 va_list ap; 566 567 va_start(ap, fmt); 568 dev = make_dev_credv(devsw, minornr, NULL, uid, gid, mode, fmt, ap); 569 va_end(ap); 570 return (dev); 571 } 572 573 struct cdev * 574 make_dev_cred(struct cdevsw *devsw, int minornr, struct ucred *cr, uid_t uid, 575 gid_t gid, int mode, const char *fmt, ...) 576 { 577 struct cdev *dev; 578 va_list ap; 579 580 va_start(ap, fmt); 581 dev = make_dev_credv(devsw, minornr, cr, uid, gid, mode, fmt, ap); 582 va_end(ap); 583 584 return (dev); 585 } 586 587 static void 588 dev_dependsl(struct cdev *pdev, struct cdev *cdev) 589 { 590 591 cdev->si_parent = pdev; 592 cdev->si_flags |= SI_CHILD; 593 LIST_INSERT_HEAD(&pdev->si_children, cdev, si_siblings); 594 } 595 596 597 void 598 dev_depends(struct cdev *pdev, struct cdev *cdev) 599 { 600 601 dev_lock(); 602 dev_dependsl(pdev, cdev); 603 dev_unlock(); 604 } 605 606 struct cdev * 607 make_dev_alias(struct cdev *pdev, const char *fmt, ...) 608 { 609 struct cdev *dev; 610 va_list ap; 611 int i; 612 613 dev = devfs_alloc(); 614 dev_lock(); 615 dev->si_flags |= SI_ALIAS; 616 dev->si_flags |= SI_NAMED; 617 va_start(ap, fmt); 618 i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap); 619 if (i > (sizeof dev->__si_namebuf - 1)) { 620 printf("WARNING: Device name truncated! (%s)\n", 621 dev->__si_namebuf); 622 } 623 va_end(ap); 624 625 devfs_create(dev); 626 dev_unlock(); 627 dev_depends(pdev, dev); 628 return (dev); 629 } 630 631 static void 632 destroy_devl(struct cdev *dev) 633 { 634 struct cdevsw *csw; 635 636 mtx_assert(&devmtx, MA_OWNED); 637 KASSERT(dev->si_flags & SI_NAMED, 638 ("WARNING: Driver mistake: destroy_dev on %d\n", minor(dev))); 639 640 devfs_destroy(dev); 641 642 /* Remove name marking */ 643 dev->si_flags &= ~SI_NAMED; 644 645 /* If we are a child, remove us from the parents list */ 646 if (dev->si_flags & SI_CHILD) { 647 LIST_REMOVE(dev, si_siblings); 648 dev->si_flags &= ~SI_CHILD; 649 } 650 651 /* Kill our children */ 652 while (!LIST_EMPTY(&dev->si_children)) 653 destroy_devl(LIST_FIRST(&dev->si_children)); 654 655 /* Remove from clone list */ 656 if (dev->si_flags & SI_CLONELIST) { 657 LIST_REMOVE(dev, si_clone); 658 dev->si_flags &= ~SI_CLONELIST; 659 } 660 661 csw = dev->si_devsw; 662 dev->si_devsw = NULL; /* already NULL for SI_ALIAS */ 663 while (csw != NULL && csw->d_purge != NULL && dev->si_threadcount) { 664 printf("Purging %lu threads from %s\n", 665 dev->si_threadcount, devtoname(dev)); 666 csw->d_purge(dev); 667 msleep(csw, &devmtx, PRIBIO, "devprg", hz/10); 668 } 669 if (csw != NULL && csw->d_purge != NULL) 670 printf("All threads purged from %s\n", devtoname(dev)); 671 672 dev->si_drv1 = 0; 673 dev->si_drv2 = 0; 674 bzero(&dev->__si_u, sizeof(dev->__si_u)); 675 676 if (!(dev->si_flags & SI_ALIAS)) { 677 /* Remove from cdevsw list */ 678 LIST_REMOVE(dev, si_list); 679 680 /* If cdevsw has no more struct cdev *'s, clean it */ 681 if (LIST_EMPTY(&csw->d_devs)) 682 fini_cdevsw(csw); 683 } 684 dev->si_flags &= ~SI_ALIAS; 685 686 if (dev->si_refcount > 0) { 687 LIST_INSERT_HEAD(&dead_cdevsw.d_devs, dev, si_list); 688 } else { 689 devfs_free(dev); 690 } 691 } 692 693 void 694 destroy_dev(struct cdev *dev) 695 { 696 697 dev_lock(); 698 destroy_devl(dev); 699 dev_unlock(); 700 } 701 702 const char * 703 devtoname(struct cdev *dev) 704 { 705 char *p; 706 struct cdevsw *csw; 707 int mynor; 708 709 if (dev->si_name[0] == '#' || dev->si_name[0] == '\0') { 710 p = dev->si_name; 711 csw = dev_refthread(dev); 712 if (csw != NULL) { 713 sprintf(p, "(%s)", csw->d_name); 714 dev_relthread(dev); 715 } 716 p += strlen(p); 717 mynor = minor(dev); 718 if (mynor < 0 || mynor > 255) 719 sprintf(p, "/%#x", (u_int)mynor); 720 else 721 sprintf(p, "/%d", mynor); 722 } 723 return (dev->si_name); 724 } 725 726 int 727 dev_stdclone(char *name, char **namep, const char *stem, int *unit) 728 { 729 int u, i; 730 731 i = strlen(stem); 732 if (bcmp(stem, name, i) != 0) 733 return (0); 734 if (!isdigit(name[i])) 735 return (0); 736 u = 0; 737 if (name[i] == '' && isdigit(name[i+1])) 738 return (0); 739 while (isdigit(name[i])) { 740 u *= 10; 741 u += name[i++] - ''; 742 } 743 if (u > 0xffffff) 744 return (0); 745 *unit = u; 746 if (namep) 747 *namep = &name[i]; 748 if (name[i]) 749 return (2); 750 return (1); 751 } 752 753 /* 754 * Helper functions for cloning device drivers. 755 * 756 * The objective here is to make it unnecessary for the device drivers to 757 * use rman or similar to manage their unit number space. Due to the way 758 * we do "on-demand" devices, using rman or other "private" methods 759 * will be very tricky to lock down properly once we lock down this file. 760 * 761 * Instead we give the drivers these routines which puts the struct cdev *'s 762 * that are to be managed on their own list, and gives the driver the ability 763 * to ask for the first free unit number or a given specified unit number. 764 * 765 * In addition these routines support paired devices (pty, nmdm and similar) 766 * by respecting a number of "flag" bits in the minor number. 767 * 768 */ 769 770 struct clonedevs { 771 LIST_HEAD(,cdev) head; 772 }; 773 774 void 775 clone_setup(struct clonedevs **cdp) 776 { 777 778 *cdp = malloc(sizeof **cdp, M_DEVBUF, M_WAITOK | M_ZERO); 779 LIST_INIT(&(*cdp)->head); 780 } 781 782 int 783 clone_create(struct clonedevs **cdp, struct cdevsw *csw, int *up, struct cdev **dp, u_int extra) 784 { 785 struct clonedevs *cd; 786 struct cdev *dev, *ndev, *dl, *de; 787 int unit, low, u; 788 789 KASSERT(*cdp != NULL, 790 ("clone_setup() not called in driver \"%s\"", csw->d_name)); 791 KASSERT(!(extra & CLONE_UNITMASK), 792 ("Illegal extra bits (0x%x) in clone_create", extra)); 793 KASSERT(*up <= CLONE_UNITMASK, 794 ("Too high unit (0x%x) in clone_create", *up)); 795 796 if (!(csw->d_flags & D_INIT)) 797 prep_cdevsw(csw); 798 799 /* 800 * Search the list for a lot of things in one go: 801 * A preexisting match is returned immediately. 802 * The lowest free unit number if we are passed -1, and the place 803 * in the list where we should insert that new element. 804 * The place to insert a specified unit number, if applicable 805 * the end of the list. 806 */ 807 unit = *up; 808 ndev = devfs_alloc(); 809 dev_lock(); 810 low = extra; 811 de = dl = NULL; 812 cd = *cdp; 813 LIST_FOREACH(dev, &cd->head, si_clone) { 814 KASSERT(dev->si_flags & SI_CLONELIST, 815 ("Dev %p(%s) should be on clonelist", dev, dev->si_name)); 816 u = dev2unit(dev); 817 if (u == (unit | extra)) { 818 *dp = dev; 819 devfs_free(ndev); 820 dev_unlock(); 821 return (0); 822 } 823 if (unit == -1 && u == low) { 824 low++; 825 de = dev; 826 continue; 827 } else if (u < (unit | extra)) { 828 de = dev; 829 continue; 830 } else if (u > (unit | extra)) { 831 dl = dev; 832 break; 833 } 834 } 835 if (unit == -1) 836 unit = low & CLONE_UNITMASK; 837 dev = newdev(csw, unit2minor(unit | extra), ndev); 838 if (dev->si_flags & SI_CLONELIST) { 839 printf("dev %p (%s) is on clonelist\n", dev, dev->si_name); 840 printf("unit=%d, low=%d, extra=0x%x\n", unit, low, extra); 841 LIST_FOREACH(dev, &cd->head, si_clone) { 842 printf("\t%p %s\n", dev, dev->si_name); 843 } 844 panic("foo"); 845 } 846 KASSERT(!(dev->si_flags & SI_CLONELIST), 847 ("Dev %p(%s) should not be on clonelist", dev, dev->si_name)); 848 if (dl != NULL) 849 LIST_INSERT_BEFORE(dl, dev, si_clone); 850 else if (de != NULL) 851 LIST_INSERT_AFTER(de, dev, si_clone); 852 else 853 LIST_INSERT_HEAD(&cd->head, dev, si_clone); 854 dev->si_flags |= SI_CLONELIST; 855 *up = unit; 856 dev_unlock(); 857 return (1); 858 } 859 860 /* 861 * Kill everything still on the list. The driver should already have 862 * disposed of any softc hung of the struct cdev *'s at this time. 863 */ 864 void 865 clone_cleanup(struct clonedevs **cdp) 866 { 867 struct cdev *dev, *tdev; 868 struct clonedevs *cd; 869 870 cd = *cdp; 871 if (cd == NULL) 872 return; 873 dev_lock(); 874 LIST_FOREACH_SAFE(dev, &cd->head, si_clone, tdev) { 875 KASSERT(dev->si_flags & SI_CLONELIST, 876 ("Dev %p(%s) should be on clonelist", dev, dev->si_name)); 877 KASSERT(dev->si_flags & SI_NAMED, 878 ("Driver has goofed in cloning underways udev %x", dev->si_drv0)); 879 destroy_devl(dev); 880 } 881 dev_unlock(); 882 free(cd, M_DEVBUF); 883 *cdp = NULL; 884 }
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