kern_conf.c revision 149324
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 149324 2005-08-20 12:13:51Z 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 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 457static void 458prep_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 529static struct cdev * 530make_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 580struct cdev * 581make_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 593struct cdev * 594make_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 607int 608dev_named(struct cdev *pdev, const char *name) 609{ 610 struct cdev *cdev; 611 612 if (strcmp(devtoname(pdev), name) == 0) 613 return (1); 614 LIST_FOREACH(cdev, &pdev->si_children, si_siblings) 615 if (strcmp(devtoname(cdev), name) == 0) 616 return (1); 617 return (0); 618} 619 620void 621dev_depends(struct cdev *pdev, struct cdev *cdev) 622{ 623 624 dev_lock(); 625 cdev->si_parent = pdev; 626 cdev->si_flags |= SI_CHILD; 627 LIST_INSERT_HEAD(&pdev->si_children, cdev, si_siblings); 628 dev_unlock(); 629} 630 631struct cdev * 632make_dev_alias(struct cdev *pdev, const char *fmt, ...) 633{ 634 struct cdev *dev; 635 va_list ap; 636 int i; 637 638 dev = allocdev(); 639 dev_lock(); 640 dev->si_flags |= SI_ALIAS; 641 dev->si_flags |= SI_NAMED; 642 va_start(ap, fmt); 643 i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap); 644 if (i > (sizeof dev->__si_namebuf - 1)) { 645 printf("WARNING: Device name truncated! (%s)\n", 646 dev->__si_namebuf); 647 } 648 va_end(ap); 649 650 devfs_create(dev); 651 dev_unlock(); 652 dev_depends(pdev, dev); 653 return (dev); 654} 655 656static void 657destroy_devl(struct cdev *dev) 658{ 659 struct cdevsw *csw; 660 661 mtx_assert(&devmtx, MA_OWNED); 662 KASSERT(dev->si_flags & SI_NAMED, 663 ("WARNING: Driver mistake: destroy_dev on %d\n", minor(dev))); 664 665 devfs_destroy(dev); 666 667 /* Remove name marking */ 668 dev->si_flags &= ~SI_NAMED; 669 670 /* If we are a child, remove us from the parents list */ 671 if (dev->si_flags & SI_CHILD) { 672 LIST_REMOVE(dev, si_siblings); 673 dev->si_flags &= ~SI_CHILD; 674 } 675 676 /* Kill our children */ 677 while (!LIST_EMPTY(&dev->si_children)) 678 destroy_devl(LIST_FIRST(&dev->si_children)); 679 680 /* Remove from clone list */ 681 if (dev->si_flags & SI_CLONELIST) { 682 LIST_REMOVE(dev, si_clone); 683 dev->si_flags &= ~SI_CLONELIST; 684 } 685 686 csw = dev->si_devsw; 687 dev->si_devsw = NULL; /* already NULL for SI_ALIAS */ 688 while (csw != NULL && csw->d_purge != NULL && dev->si_threadcount) { 689 printf("Purging %lu threads from %s\n", 690 dev->si_threadcount, devtoname(dev)); 691 csw->d_purge(dev); 692 msleep(csw, &devmtx, PRIBIO, "devprg", hz/10); 693 } 694 if (csw != NULL && csw->d_purge != NULL) 695 printf("All threads purged from %s\n", devtoname(dev)); 696 697 dev->si_drv1 = 0; 698 dev->si_drv2 = 0; 699 bzero(&dev->__si_u, sizeof(dev->__si_u)); 700 701 if (!(dev->si_flags & SI_ALIAS)) { 702 /* Remove from cdevsw list */ 703 LIST_REMOVE(dev, si_list); 704 705 /* If cdevsw has no struct cdev *'s, clean it */ 706 if (LIST_EMPTY(&csw->d_devs)) 707 fini_cdevsw(csw); 708 } 709 dev->si_flags &= ~SI_ALIAS; 710 711 if (dev->si_refcount > 0) { 712 LIST_INSERT_HEAD(&dead_cdevsw.d_devs, dev, si_list); 713 } else { 714 freedev(dev); 715 } 716} 717 718void 719destroy_dev(struct cdev *dev) 720{ 721 722 dev_lock(); 723 destroy_devl(dev); 724 dev_unlock(); 725} 726 727const char * 728devtoname(struct cdev *dev) 729{ 730 char *p; 731 struct cdevsw *csw; 732 int mynor; 733 734 if (dev->si_name[0] == '#' || dev->si_name[0] == '\0') { 735 p = dev->si_name; 736 csw = dev_refthread(dev); 737 if (csw != NULL) { 738 sprintf(p, "(%s)", csw->d_name); 739 dev_relthread(dev); 740 } 741 p += strlen(p); 742 mynor = minor(dev); 743 if (mynor < 0 || mynor > 255) 744 sprintf(p, "/%#x", (u_int)mynor); 745 else 746 sprintf(p, "/%d", mynor); 747 } 748 return (dev->si_name); 749} 750 751int 752dev_stdclone(char *name, char **namep, const char *stem, int *unit) 753{ 754 int u, i; 755 756 i = strlen(stem); 757 if (bcmp(stem, name, i) != 0) 758 return (0); 759 if (!isdigit(name[i])) 760 return (0); 761 u = 0; 762 if (name[i] == '0' && isdigit(name[i+1])) 763 return (0); 764 while (isdigit(name[i])) { 765 u *= 10; 766 u += name[i++] - '0'; 767 } 768 if (u > 0xffffff) 769 return (0); 770 *unit = u; 771 if (namep) 772 *namep = &name[i]; 773 if (name[i]) 774 return (2); 775 return (1); 776} 777 778/* 779 * Helper functions for cloning device drivers. 780 * 781 * The objective here is to make it unnecessary for the device drivers to 782 * use rman or similar to manage their unit number space. Due to the way 783 * we do "on-demand" devices, using rman or other "private" methods 784 * will be very tricky to lock down properly once we lock down this file. 785 * 786 * Instead we give the drivers these routines which puts the struct cdev *'s 787 * that are to be managed on their own list, and gives the driver the ability 788 * to ask for the first free unit number or a given specified unit number. 789 * 790 * In addition these routines support paired devices (pty, nmdm and similar) 791 * by respecting a number of "flag" bits in the minor number. 792 * 793 */ 794 795struct clonedevs { 796 LIST_HEAD(,cdev) head; 797}; 798 799void 800clone_setup(struct clonedevs **cdp) 801{ 802 803 *cdp = malloc(sizeof **cdp, M_DEVBUF, M_WAITOK | M_ZERO); 804 LIST_INIT(&(*cdp)->head); 805} 806 807int 808clone_create(struct clonedevs **cdp, struct cdevsw *csw, int *up, struct cdev **dp, u_int extra) 809{ 810 struct clonedevs *cd; 811 struct cdev *dev, *ndev, *dl, *de; 812 int unit, low, u; 813 814 KASSERT(*cdp != NULL, 815 ("clone_setup() not called in driver \"%s\"", csw->d_name)); 816 KASSERT(!(extra & CLONE_UNITMASK), 817 ("Illegal extra bits (0x%x) in clone_create", extra)); 818 KASSERT(*up <= CLONE_UNITMASK, 819 ("Too high unit (0x%x) in clone_create", *up)); 820 821 if (!(csw->d_flags & D_INIT)) 822 prep_cdevsw(csw); 823 824 /* 825 * Search the list for a lot of things in one go: 826 * A preexisting match is returned immediately. 827 * The lowest free unit number if we are passed -1, and the place 828 * in the list where we should insert that new element. 829 * The place to insert a specified unit number, if applicable 830 * the end of the list. 831 */ 832 unit = *up; 833 ndev = allocdev(); 834 dev_lock(); 835 low = extra; 836 de = dl = NULL; 837 cd = *cdp; 838 LIST_FOREACH(dev, &cd->head, si_clone) { 839 KASSERT(dev->si_flags & SI_CLONELIST, 840 ("Dev %p(%s) should be on clonelist", dev, dev->si_name)); 841 u = dev2unit(dev); 842 if (u == (unit | extra)) { 843 *dp = dev; 844 freedev(ndev); 845 dev_unlock(); 846 return (0); 847 } 848 if (unit == -1 && u == low) { 849 low++; 850 de = dev; 851 continue; 852 } 853 if (u > (unit | extra)) { 854 dl = dev; 855 break; 856 } 857 } 858 if (unit == -1) 859 unit = low & CLONE_UNITMASK; 860 dev = newdev(csw, unit2minor(unit | extra), ndev); 861 if (dev->si_flags & SI_CLONELIST) { 862 printf("dev %p (%s) is on clonelist\n", dev, dev->si_name); 863 printf("unit=%d\n", unit); 864 LIST_FOREACH(dev, &cd->head, si_clone) { 865 printf("\t%p %s\n", dev, dev->si_name); 866 } 867 panic("foo"); 868 } 869 KASSERT(!(dev->si_flags & SI_CLONELIST), 870 ("Dev %p(%s) should not be on clonelist", dev, dev->si_name)); 871 if (dl != NULL) 872 LIST_INSERT_BEFORE(dl, dev, si_clone); 873 else if (de != NULL) 874 LIST_INSERT_AFTER(de, dev, si_clone); 875 else 876 LIST_INSERT_HEAD(&cd->head, dev, si_clone); 877 dev->si_flags |= SI_CLONELIST; 878 *up = unit; 879 dev_unlock(); 880 return (1); 881} 882 883/* 884 * Kill everything still on the list. The driver should already have 885 * disposed of any softc hung of the struct cdev *'s at this time. 886 */ 887void 888clone_cleanup(struct clonedevs **cdp) 889{ 890 struct cdev *dev, *tdev; 891 struct clonedevs *cd; 892 893 cd = *cdp; 894 if (cd == NULL) 895 return; 896 dev_lock(); 897 LIST_FOREACH_SAFE(dev, &cd->head, si_clone, tdev) { 898 KASSERT(dev->si_flags & SI_CLONELIST, 899 ("Dev %p(%s) should be on clonelist", dev, dev->si_name)); 900 KASSERT(dev->si_flags & SI_NAMED, 901 ("Driver has goofed in cloning underways udev %x", dev->si_drv0)); 902 destroy_devl(dev); 903 } 904 dev_unlock(); 905 free(cd, M_DEVBUF); 906 *cdp = NULL; 907} 908