kern_conf.c revision 149177
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 149177 2005-08-17 08:19:52Z 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/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 50static MALLOC_DEFINE(M_DEVT, "cdev", "cdev storage"); 51 52static struct mtx devmtx; 53static void freedev(struct cdev *dev); 54static void destroy_devl(struct cdev *dev); 55static 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 59void 60dev_lock(void) 61{ 62 if (!mtx_initialized(&devmtx)) 63 mtx_init(&devmtx, "cdev", NULL, MTX_DEF); 64 mtx_lock(&devmtx); 65} 66 67void 68dev_unlock(void) 69{ 70 71 mtx_unlock(&devmtx); 72} 73 74void 75dev_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 84void 85dev_refl(struct cdev *dev) 86{ 87 88 mtx_assert(&devmtx, MA_OWNED); 89 dev->si_refcount++; 90} 91 92void 93dev_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 113struct cdevsw * 114dev_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 127void 128dev_relthread(struct cdev *dev) 129{ 130 131 mtx_assert(&devmtx, MA_NOTOWNED); 132 dev_lock(); 133 dev->si_threadcount--; 134 dev_unlock(); 135} 136 137int 138nullop(void) 139{ 140 141 return (0); 142} 143 144int 145eopnotsupp(void) 146{ 147 148 return (EOPNOTSUPP); 149} 150 151static int 152enxio(void) 153{ 154 return (ENXIO); 155} 156 157static int 158enodev(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 173static void 174dead_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 183static 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 209static void 210no_strategy(struct bio *bp) 211{ 212 213 biofinish(bp, NULL, ENODEV); 214} 215 216static int 217no_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 235static int 236giant_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 247static int 248giant_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 259static int 260giant_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 271static void 272giant_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 281static int 282giant_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 293static int 294giant_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 305static int 306giant_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 317static int 318giant_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 329static int 330giant_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 341static int 342giant_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 358int 359minor(struct cdev *x) 360{ 361 if (x == NULL) 362 return NODEV; 363 return(x->si_drv0 & MAXMINOR); 364} 365 366int 367dev2unit(struct cdev *x) 368{ 369 370 if (x == NULL) 371 return NODEV; 372 return (minor2unit(minor(x))); 373} 374 375u_int 376minor2unit(u_int _minor) 377{ 378 379 KASSERT((_minor & ~MAXMINOR) == 0, ("Illegal minor %x", _minor)); 380 return ((_minor & 0xff) | ((_minor >> 8) & 0xffff00)); 381} 382 383int 384unit2minor(int unit) 385{ 386 387 KASSERT(unit <= 0xffffff, ("Invalid unit (%d) in unit2minor", unit)); 388 return ((unit & 0xff) | ((unit << 8) & ~0xffff)); 389} 390 391static struct cdev * 392allocdev(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 403static struct cdev * 404newdev(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 422static void 423freedev(struct cdev *dev) 424{ 425 426 if (dev->si_cred != NULL) 427 crfree(dev->si_cred); 428 free(dev, M_DEVT); 429} 430 431int 432uminor(dev_t dev) 433{ 434 return (dev & MAXMINOR); 435} 436 437int 438umajor(dev_t dev) 439{ 440 return ((dev & ~MAXMINOR) >> 8); 441} 442 443static void 444fini_cdevsw(struct cdevsw *devsw) 445{ 446 447 if (devsw->d_gianttrick != NULL) 448 free(devsw->d_gianttrick, M_DEVT); 449 devsw->d_gianttrick = NULL; 450 devsw->d_flags &= ~D_INIT; 451} 452 453static void 454prep_cdevsw(struct cdevsw *devsw) 455{ 456 struct cdevsw *dsw2; 457 458 if (devsw->d_flags & D_NEEDGIANT) 459 dsw2 = malloc(sizeof *dsw2, M_DEVT, M_WAITOK); 460 else 461 dsw2 = NULL; 462 dev_lock(); 463 464 if (devsw->d_version != D_VERSION_01) { 465 printf( 466 "WARNING: Device driver \"%s\" has wrong version %s\n", 467 devsw->d_name, "and is disabled. Recompile KLD module."); 468 devsw->d_open = dead_open; 469 devsw->d_close = dead_close; 470 devsw->d_read = dead_read; 471 devsw->d_write = dead_write; 472 devsw->d_ioctl = dead_ioctl; 473 devsw->d_poll = dead_poll; 474 devsw->d_mmap = dead_mmap; 475 devsw->d_strategy = dead_strategy; 476 devsw->d_dump = dead_dump; 477 devsw->d_kqfilter = dead_kqfilter; 478 } 479 480 if (devsw->d_flags & D_TTY) { 481 if (devsw->d_ioctl == NULL) devsw->d_ioctl = ttyioctl; 482 if (devsw->d_read == NULL) devsw->d_read = ttyread; 483 if (devsw->d_write == NULL) devsw->d_write = ttywrite; 484 if (devsw->d_kqfilter == NULL) devsw->d_kqfilter = ttykqfilter; 485 if (devsw->d_poll == NULL) devsw->d_poll = ttypoll; 486 } 487 488 if (devsw->d_flags & D_NEEDGIANT) { 489 if (devsw->d_gianttrick == NULL) { 490 memcpy(dsw2, devsw, sizeof *dsw2); 491 devsw->d_gianttrick = dsw2; 492 } else 493 free(dsw2, M_DEVT); 494 } 495 496#define FIXUP(member, noop, giant) \ 497 do { \ 498 if (devsw->member == NULL) { \ 499 devsw->member = noop; \ 500 } else if (devsw->d_flags & D_NEEDGIANT) \ 501 devsw->member = giant; \ 502 } \ 503 while (0) 504 505 FIXUP(d_open, null_open, giant_open); 506 FIXUP(d_fdopen, NULL, giant_fdopen); 507 FIXUP(d_close, null_close, giant_close); 508 FIXUP(d_read, no_read, giant_read); 509 FIXUP(d_write, no_write, giant_write); 510 FIXUP(d_ioctl, no_ioctl, giant_ioctl); 511 FIXUP(d_poll, no_poll, giant_poll); 512 FIXUP(d_mmap, no_mmap, giant_mmap); 513 FIXUP(d_strategy, no_strategy, giant_strategy); 514 FIXUP(d_kqfilter, no_kqfilter, giant_kqfilter); 515 516 if (devsw->d_dump == NULL) devsw->d_dump = no_dump; 517 518 LIST_INIT(&devsw->d_devs); 519 520 devsw->d_flags |= D_INIT; 521 522 dev_unlock(); 523} 524 525static struct cdev * 526make_dev_credv(struct cdevsw *devsw, int minornr, struct ucred *cr, uid_t uid, 527 gid_t gid, int mode, const char *fmt, va_list ap) 528{ 529 struct cdev *dev; 530 int i; 531 532 KASSERT((minornr & ~MAXMINOR) == 0, 533 ("Invalid minor (0x%x) in make_dev", minornr)); 534 535 if (!(devsw->d_flags & D_INIT)) 536 prep_cdevsw(devsw); 537 dev = allocdev(); 538 dev_lock(); 539 dev = newdev(devsw, minornr, dev); 540 if (dev->si_flags & SI_CHEAPCLONE && 541 dev->si_flags & SI_NAMED && 542 dev->si_devsw == devsw) { 543 /* 544 * This is allowed as it removes races and generally 545 * simplifies cloning devices. 546 * XXX: still ?? 547 */ 548 dev_unlock(); 549 return (dev); 550 } 551 KASSERT(!(dev->si_flags & SI_NAMED), 552 ("make_dev() by driver %s on pre-existing device (min=%x, name=%s)", 553 devsw->d_name, minor(dev), devtoname(dev))); 554 555 i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap); 556 if (i > (sizeof dev->__si_namebuf - 1)) { 557 printf("WARNING: Device name truncated! (%s)\n", 558 dev->__si_namebuf); 559 } 560 561 dev->si_devsw = devsw; 562 dev->si_flags |= SI_NAMED; 563 if (cr != NULL) 564 dev->si_cred = crhold(cr); 565 else 566 dev->si_cred = NULL; 567 dev->si_uid = uid; 568 dev->si_gid = gid; 569 dev->si_mode = mode; 570 571 devfs_create(dev); 572 dev_unlock(); 573 return (dev); 574} 575 576struct cdev * 577make_dev(struct cdevsw *devsw, int minornr, uid_t uid, gid_t gid, int mode, 578 const char *fmt, ...) 579{ 580 struct cdev *dev; 581 va_list ap; 582 583 va_start(ap, fmt); 584 dev = make_dev_credv(devsw, minornr, NULL, uid, gid, mode, fmt, ap); 585 va_end(ap); 586 return (dev); 587} 588 589struct cdev * 590make_dev_cred(struct cdevsw *devsw, int minornr, struct ucred *cr, uid_t uid, 591 gid_t gid, int mode, const char *fmt, ...) 592{ 593 struct cdev *dev; 594 va_list ap; 595 596 va_start(ap, fmt); 597 dev = make_dev_credv(devsw, minornr, cr, uid, gid, mode, fmt, ap); 598 va_end(ap); 599 600 return (dev); 601} 602 603int 604dev_named(struct cdev *pdev, const char *name) 605{ 606 struct cdev *cdev; 607 608 if (strcmp(devtoname(pdev), name) == 0) 609 return (1); 610 LIST_FOREACH(cdev, &pdev->si_children, si_siblings) 611 if (strcmp(devtoname(cdev), name) == 0) 612 return (1); 613 return (0); 614} 615 616void 617dev_depends(struct cdev *pdev, struct cdev *cdev) 618{ 619 620 dev_lock(); 621 cdev->si_parent = pdev; 622 cdev->si_flags |= SI_CHILD; 623 LIST_INSERT_HEAD(&pdev->si_children, cdev, si_siblings); 624 dev_unlock(); 625} 626 627struct cdev * 628make_dev_alias(struct cdev *pdev, const char *fmt, ...) 629{ 630 struct cdev *dev; 631 va_list ap; 632 int i; 633 634 dev = allocdev(); 635 dev_lock(); 636 dev->si_flags |= SI_ALIAS; 637 dev->si_flags |= SI_NAMED; 638 va_start(ap, fmt); 639 i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap); 640 if (i > (sizeof dev->__si_namebuf - 1)) { 641 printf("WARNING: Device name truncated! (%s)\n", 642 dev->__si_namebuf); 643 } 644 va_end(ap); 645 646 devfs_create(dev); 647 dev_unlock(); 648 dev_depends(pdev, dev); 649 return (dev); 650} 651 652static void 653destroy_devl(struct cdev *dev) 654{ 655 struct cdevsw *csw; 656 657 mtx_assert(&devmtx, MA_OWNED); 658 KASSERT(dev->si_flags & SI_NAMED, 659 ("WARNING: Driver mistake: destroy_dev on %d\n", minor(dev))); 660 661 devfs_destroy(dev); 662 663 /* Remove name marking */ 664 dev->si_flags &= ~SI_NAMED; 665 666 /* If we are a child, remove us from the parents list */ 667 if (dev->si_flags & SI_CHILD) { 668 LIST_REMOVE(dev, si_siblings); 669 dev->si_flags &= ~SI_CHILD; 670 } 671 672 /* Kill our children */ 673 while (!LIST_EMPTY(&dev->si_children)) 674 destroy_devl(LIST_FIRST(&dev->si_children)); 675 676 /* Remove from clone list */ 677 if (dev->si_flags & SI_CLONELIST) { 678 LIST_REMOVE(dev, si_clone); 679 dev->si_flags &= ~SI_CLONELIST; 680 } 681 682 csw = dev->si_devsw; 683 dev->si_devsw = NULL; /* already NULL for SI_ALIAS */ 684 while (csw != NULL && csw->d_purge != NULL && dev->si_threadcount) { 685 printf("Purging %lu threads from %s\n", 686 dev->si_threadcount, devtoname(dev)); 687 csw->d_purge(dev); 688 msleep(csw, &devmtx, PRIBIO, "devprg", hz/10); 689 } 690 if (csw != NULL && csw->d_purge != NULL) 691 printf("All threads purged from %s\n", devtoname(dev)); 692 693 dev->si_drv1 = 0; 694 dev->si_drv2 = 0; 695 bzero(&dev->__si_u, sizeof(dev->__si_u)); 696 697 if (!(dev->si_flags & SI_ALIAS)) { 698 /* Remove from cdevsw list */ 699 LIST_REMOVE(dev, si_list); 700 701 /* If cdevsw has no struct cdev *'s, clean it */ 702 if (LIST_EMPTY(&csw->d_devs)) 703 fini_cdevsw(csw); 704 } 705 dev->si_flags &= ~SI_ALIAS; 706 707 if (dev->si_refcount > 0) { 708 LIST_INSERT_HEAD(&dead_cdevsw.d_devs, dev, si_list); 709 } else { 710 freedev(dev); 711 } 712} 713 714void 715destroy_dev(struct cdev *dev) 716{ 717 718 dev_lock(); 719 destroy_devl(dev); 720 dev_unlock(); 721} 722 723const char * 724devtoname(struct cdev *dev) 725{ 726 char *p; 727 struct cdevsw *csw; 728 int mynor; 729 730 if (dev->si_name[0] == '#' || dev->si_name[0] == '\0') { 731 p = dev->si_name; 732 csw = dev_refthread(dev); 733 if (csw != NULL) { 734 sprintf(p, "(%s)", csw->d_name); 735 dev_relthread(dev); 736 } 737 p += strlen(p); 738 mynor = minor(dev); 739 if (mynor < 0 || mynor > 255) 740 sprintf(p, "/%#x", (u_int)mynor); 741 else 742 sprintf(p, "/%d", mynor); 743 } 744 return (dev->si_name); 745} 746 747int 748dev_stdclone(char *name, char **namep, const char *stem, int *unit) 749{ 750 int u, i; 751 752 i = strlen(stem); 753 if (bcmp(stem, name, i) != 0) 754 return (0); 755 if (!isdigit(name[i])) 756 return (0); 757 u = 0; 758 if (name[i] == '0' && isdigit(name[i+1])) 759 return (0); 760 while (isdigit(name[i])) { 761 u *= 10; 762 u += name[i++] - '0'; 763 } 764 if (u > 0xffffff) 765 return (0); 766 *unit = u; 767 if (namep) 768 *namep = &name[i]; 769 if (name[i]) 770 return (2); 771 return (1); 772} 773 774/* 775 * Helper functions for cloning device drivers. 776 * 777 * The objective here is to make it unnecessary for the device drivers to 778 * use rman or similar to manage their unit number space. Due to the way 779 * we do "on-demand" devices, using rman or other "private" methods 780 * will be very tricky to lock down properly once we lock down this file. 781 * 782 * Instead we give the drivers these routines which puts the struct cdev *'s 783 * that are to be managed on their own list, and gives the driver the ability 784 * to ask for the first free unit number or a given specified unit number. 785 * 786 * In addition these routines support paired devices (pty, nmdm and similar) 787 * by respecting a number of "flag" bits in the minor number. 788 * 789 */ 790 791struct clonedevs { 792 LIST_HEAD(,cdev) head; 793}; 794 795void 796clone_setup(struct clonedevs **cdp) 797{ 798 799 *cdp = malloc(sizeof **cdp, M_DEVBUF, M_WAITOK | M_ZERO); 800 LIST_INIT(&(*cdp)->head); 801} 802 803int 804clone_create(struct clonedevs **cdp, struct cdevsw *csw, int *up, struct cdev **dp, u_int extra) 805{ 806 struct clonedevs *cd; 807 struct cdev *dev, *ndev, *dl, *de; 808 int unit, low, u; 809 810 KASSERT(*cdp != NULL, 811 ("clone_setup() not called in driver \"%s\"", csw->d_name)); 812 KASSERT(!(extra & CLONE_UNITMASK), 813 ("Illegal extra bits (0x%x) in clone_create", extra)); 814 KASSERT(*up <= CLONE_UNITMASK, 815 ("Too high unit (0x%x) in clone_create", *up)); 816 817 if (!(csw->d_flags & D_INIT)) 818 prep_cdevsw(csw); 819 820 /* 821 * Search the list for a lot of things in one go: 822 * A preexisting match is returned immediately. 823 * The lowest free unit number if we are passed -1, and the place 824 * in the list where we should insert that new element. 825 * The place to insert a specified unit number, if applicable 826 * the end of the list. 827 */ 828 unit = *up; 829 ndev = allocdev(); 830 dev_lock(); 831 low = extra; 832 de = dl = NULL; 833 cd = *cdp; 834 LIST_FOREACH(dev, &cd->head, si_clone) { 835 KASSERT(dev->si_flags & SI_CLONELIST, 836 ("Dev %p(%s) should be on clonelist", dev, dev->si_name)); 837 u = dev2unit(dev); 838 if (u == (unit | extra)) { 839 *dp = dev; 840 freedev(ndev); 841 dev_unlock(); 842 return (0); 843 } 844 if (unit == -1 && u == low) { 845 low++; 846 de = dev; 847 continue; 848 } 849 if (u > (unit | extra)) { 850 dl = dev; 851 break; 852 } 853 } 854 if (unit == -1) 855 unit = low & CLONE_UNITMASK; 856 dev = newdev(csw, unit2minor(unit | extra), ndev); 857 if (dev->si_flags & SI_CLONELIST) { 858 printf("dev %p (%s) is on clonelist\n", dev, dev->si_name); 859 printf("unit=%d\n", unit); 860 LIST_FOREACH(dev, &cd->head, si_clone) { 861 printf("\t%p %s\n", dev, dev->si_name); 862 } 863 panic("foo"); 864 } 865 KASSERT(!(dev->si_flags & SI_CLONELIST), 866 ("Dev %p(%s) should not be on clonelist", dev, dev->si_name)); 867 if (dl != NULL) 868 LIST_INSERT_BEFORE(dl, dev, si_clone); 869 else if (de != NULL) 870 LIST_INSERT_AFTER(de, dev, si_clone); 871 else 872 LIST_INSERT_HEAD(&cd->head, dev, si_clone); 873 dev->si_flags |= SI_CLONELIST; 874 *up = unit; 875 dev_unlock(); 876 return (1); 877} 878 879/* 880 * Kill everything still on the list. The driver should already have 881 * disposed of any softc hung of the struct cdev *'s at this time. 882 */ 883void 884clone_cleanup(struct clonedevs **cdp) 885{ 886 struct cdev *dev, *tdev; 887 struct clonedevs *cd; 888 889 cd = *cdp; 890 if (cd == NULL) 891 return; 892 dev_lock(); 893 LIST_FOREACH_SAFE(dev, &cd->head, si_clone, tdev) { 894 KASSERT(dev->si_flags & SI_CLONELIST, 895 ("Dev %p(%s) should be on clonelist", dev, dev->si_name)); 896 KASSERT(dev->si_flags & SI_NAMED, 897 ("Driver has goofed in cloning underways udev %x", dev->si_drv0)); 898 destroy_devl(dev); 899 } 900 dev_unlock(); 901 free(cd, M_DEVBUF); 902 *cdp = NULL; 903} 904