kern_conf.c revision 126077
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 126077 2004-02-21 20:29:52Z 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 <machine/stdarg.h> 45 46static MALLOC_DEFINE(M_DEVT, "dev_t", "dev_t storage"); 47 48/* Built at compile time from sys/conf/majors */ 49extern unsigned char reserved_majors[256]; 50 51/* 52 * This is the number of hash-buckets. Experiements with 'real-life' 53 * udev_t's show that a prime halfway between two powers of two works 54 * best. 55 */ 56#define DEVT_HASH 83 57 58/* The number of dev_t's we can create before malloc(9) kick in. */ 59#define DEVT_STASH 50 60 61static struct cdev devt_stash[DEVT_STASH]; 62 63static LIST_HEAD(, cdev) dev_hash[DEVT_HASH]; 64 65static LIST_HEAD(, cdev) dev_free; 66 67static int free_devt; 68SYSCTL_INT(_debug, OID_AUTO, free_devt, CTLFLAG_RW, &free_devt, 0, ""); 69 70int 71nullop(void) 72{ 73 74 return (0); 75} 76 77int 78eopnotsupp(void) 79{ 80 81 return (EOPNOTSUPP); 82} 83 84static int 85enxio(void) 86{ 87 return (ENXIO); 88} 89 90static int 91enodev(void) 92{ 93 return (ENODEV); 94} 95 96/* Define a dead_cdevsw for use when devices leave unexpectedly. */ 97 98#define dead_open (d_open_t *)enxio 99#define dead_close (d_close_t *)enxio 100#define dead_read (d_read_t *)enxio 101#define dead_write (d_write_t *)enxio 102#define dead_ioctl (d_ioctl_t *)enxio 103#define dead_poll (d_poll_t *)enodev 104#define dead_mmap (d_mmap_t *)enodev 105 106static void 107dead_strategy(struct bio *bp) 108{ 109 110 biofinish(bp, NULL, ENXIO); 111} 112 113#define dead_dump (dumper_t *)enxio 114#define dead_kqfilter (d_kqfilter_t *)enxio 115 116static struct cdevsw dead_cdevsw = { 117 .d_open = dead_open, 118 .d_close = dead_close, 119 .d_read = dead_read, 120 .d_write = dead_write, 121 .d_ioctl = dead_ioctl, 122 .d_poll = dead_poll, 123 .d_mmap = dead_mmap, 124 .d_strategy = dead_strategy, 125 .d_name = "dead", 126 .d_maj = 255, 127 .d_dump = dead_dump, 128 .d_kqfilter = dead_kqfilter 129}; 130 131/* Default methods if driver does not specify method */ 132 133#define null_open (d_open_t *)nullop 134#define null_close (d_close_t *)nullop 135#define no_read (d_read_t *)enodev 136#define no_write (d_write_t *)enodev 137#define no_ioctl (d_ioctl_t *)enodev 138#define no_mmap (d_mmap_t *)enodev 139 140static int 141no_kqfilter(dev_t dev __unused, struct knote *kn __unused) 142{ 143 144 return (1); 145} 146 147static void 148no_strategy(struct bio *bp) 149{ 150 151 biofinish(bp, NULL, ENODEV); 152} 153 154static int 155no_poll(dev_t dev __unused, int events, struct thread *td __unused) 156{ 157 /* 158 * Return true for read/write. If the user asked for something 159 * special, return POLLNVAL, so that clients have a way of 160 * determining reliably whether or not the extended 161 * functionality is present without hard-coding knowledge 162 * of specific filesystem implementations. 163 * Stay in sync with vop_nopoll(). 164 */ 165 if (events & ~POLLSTANDARD) 166 return (POLLNVAL); 167 168 return (events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM)); 169} 170 171#define no_dump (dumper_t *)enodev 172 173struct cdevsw * 174devsw(dev_t dev) 175{ 176 if (dev->si_devsw) 177 return (dev->si_devsw); 178 return (&dead_cdevsw); 179} 180 181/* 182 * dev_t and u_dev_t primitives 183 */ 184 185int 186major(dev_t x) 187{ 188 if (x == NODEV) 189 return NOUDEV; 190 return((x->si_udev >> 8) & 0xff); 191} 192 193int 194minor(dev_t x) 195{ 196 if (x == NODEV) 197 return NOUDEV; 198 return(x->si_udev & 0xffff00ff); 199} 200 201int 202dev2unit(dev_t x) 203{ 204 int i; 205 206 if (x == NODEV) 207 return NOUDEV; 208 i = minor(x); 209 return ((i & 0xff) | (i >> 8)); 210} 211 212int 213unit2minor(int unit) 214{ 215 216 KASSERT(unit <= 0xffffff, ("Invalid unit (%d) in unit2minor", unit)); 217 return ((unit & 0xff) | ((unit << 8) & ~0xffff)); 218} 219 220static dev_t 221allocdev(void) 222{ 223 static int stashed; 224 struct cdev *si; 225 226 if (LIST_FIRST(&dev_free)) { 227 si = LIST_FIRST(&dev_free); 228 LIST_REMOVE(si, si_hash); 229 } else if (stashed >= DEVT_STASH) { 230 MALLOC(si, struct cdev *, sizeof(*si), M_DEVT, 231 M_USE_RESERVE | M_ZERO | M_WAITOK); 232 } else { 233 si = devt_stash + stashed++; 234 bzero(si, sizeof *si); 235 si->si_flags |= SI_STASHED; 236 } 237 si->__si_namebuf[0] = '\0'; 238 si->si_name = si->__si_namebuf; 239 LIST_INIT(&si->si_children); 240 TAILQ_INIT(&si->si_snapshots); 241 return (si); 242} 243 244dev_t 245makedev(int x, int y) 246{ 247 struct cdev *si; 248 udev_t udev; 249 int hash; 250 251 if (x == umajor(NOUDEV) && y == uminor(NOUDEV)) 252 panic("makedev of NOUDEV"); 253 udev = (x << 8) | y; 254 hash = udev % DEVT_HASH; 255 LIST_FOREACH(si, &dev_hash[hash], si_hash) { 256 if (si->si_udev == udev) 257 return (si); 258 } 259 si = allocdev(); 260 si->si_udev = udev; 261 LIST_INSERT_HEAD(&dev_hash[hash], si, si_hash); 262 return (si); 263} 264 265void 266freedev(dev_t dev) 267{ 268 269 if (!free_devt) 270 return; 271 if (SLIST_FIRST(&dev->si_hlist)) 272 return; 273 if (dev->si_devsw || dev->si_drv1 || dev->si_drv2) 274 return; 275 LIST_REMOVE(dev, si_hash); 276 if (dev->si_flags & SI_STASHED) { 277 bzero(dev, sizeof(*dev)); 278 dev->si_flags |= SI_STASHED; 279 LIST_INSERT_HEAD(&dev_free, dev, si_hash); 280 } else { 281 FREE(dev, M_DEVT); 282 } 283} 284 285udev_t 286dev2udev(dev_t x) 287{ 288 if (x == NODEV) 289 return (NOUDEV); 290 return (x->si_udev); 291} 292 293dev_t 294udev2dev(udev_t x, int b) 295{ 296 297 if (x == NOUDEV) 298 return (NODEV); 299 switch (b) { 300 case 0: 301 return (makedev(umajor(x), uminor(x))); 302 default: 303 Debugger("udev2dev(...,X)"); 304 return (NODEV); 305 } 306} 307 308int 309uminor(udev_t dev) 310{ 311 return (dev & 0xffff00ff); 312} 313 314int 315umajor(udev_t dev) 316{ 317 return ((dev & 0xff00) >> 8); 318} 319 320udev_t 321makeudev(int x, int y) 322{ 323 return ((x << 8) | y); 324} 325 326static void 327find_major(struct cdevsw *devsw) 328{ 329 int i; 330 331 for (i = NUMCDEVSW - 1; i > 0; i--) 332 if (reserved_majors[i] != i) 333 break; 334 KASSERT(i > 0, ("Out of major numbers (%s)", devsw->d_name)); 335 devsw->d_maj = i; 336 reserved_majors[i] = i; 337} 338 339static void 340prep_cdevsw(struct cdevsw *devsw) 341{ 342 343 if (devsw->d_open == NULL) devsw->d_open = null_open; 344 if (devsw->d_close == NULL) devsw->d_close = null_close; 345 if (devsw->d_read == NULL) devsw->d_read = no_read; 346 if (devsw->d_write == NULL) devsw->d_write = no_write; 347 if (devsw->d_ioctl == NULL) devsw->d_ioctl = no_ioctl; 348 if (devsw->d_poll == NULL) devsw->d_poll = no_poll; 349 if (devsw->d_mmap == NULL) devsw->d_mmap = no_mmap; 350 if (devsw->d_strategy == NULL) devsw->d_strategy = no_strategy; 351 if (devsw->d_dump == NULL) devsw->d_dump = no_dump; 352 if (devsw->d_kqfilter == NULL) devsw->d_kqfilter = no_kqfilter; 353 if (devsw->d_maj == MAJOR_AUTO) { 354 find_major(devsw); 355 } else { 356 if (devsw->d_maj == 256) /* XXX: tty_cons.c is magic */ 357 devsw->d_maj = 0; 358 KASSERT(devsw->d_maj >= 0 && devsw->d_maj < 256, 359 ("Invalid major (%d) in make_dev", devsw->d_maj)); 360 if (reserved_majors[devsw->d_maj] != devsw->d_maj) { 361 printf("WARNING: driver \"%s\" used %s %d\n", 362 devsw->d_name, "unreserved major device number", 363 devsw->d_maj); 364 reserved_majors[devsw->d_maj] = devsw->d_maj; 365 } 366 } 367} 368 369dev_t 370make_dev(struct cdevsw *devsw, int minor, uid_t uid, gid_t gid, int perms, 371 const char *fmt, ...) 372{ 373 dev_t dev; 374 va_list ap; 375 int i; 376 377 KASSERT((minor & ~0xffff00ff) == 0, 378 ("Invalid minor (0x%x) in make_dev", minor)); 379 prep_cdevsw(devsw); 380 dev = makedev(devsw->d_maj, minor); 381 if (dev->si_flags & SI_CHEAPCLONE && 382 dev->si_flags & SI_NAMED && 383 dev->si_devsw == devsw) { 384 /* 385 * This is allowed as it removes races and generally 386 * simplifies cloning devices. 387 */ 388 return (dev); 389 } 390 if (dev->si_flags & SI_NAMED) { 391 printf( "WARNING: Driver mistake: repeat make_dev(\"%s\")\n", 392 dev->si_name); 393 panic("don't do that"); 394 } 395 va_start(ap, fmt); 396 i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap); 397 if (i > (sizeof dev->__si_namebuf - 1)) { 398 printf("WARNING: Device name truncated! (%s)", 399 dev->__si_namebuf); 400 } 401 va_end(ap); 402 dev->si_devsw = devsw; 403 dev->si_uid = uid; 404 dev->si_gid = gid; 405 dev->si_mode = perms; 406 dev->si_flags |= SI_NAMED; 407 408 devfs_create(dev); 409 return (dev); 410} 411 412int 413dev_named(dev_t pdev, const char *name) 414{ 415 dev_t cdev; 416 417 if (strcmp(devtoname(pdev), name) == 0) 418 return (1); 419 LIST_FOREACH(cdev, &pdev->si_children, si_siblings) 420 if (strcmp(devtoname(cdev), name) == 0) 421 return (1); 422 return (0); 423} 424 425void 426dev_depends(dev_t pdev, dev_t cdev) 427{ 428 429 cdev->si_parent = pdev; 430 cdev->si_flags |= SI_CHILD; 431 LIST_INSERT_HEAD(&pdev->si_children, cdev, si_siblings); 432} 433 434dev_t 435make_dev_alias(dev_t pdev, const char *fmt, ...) 436{ 437 dev_t dev; 438 va_list ap; 439 int i; 440 441 dev = allocdev(); 442 dev->si_flags |= SI_ALIAS; 443 dev->si_flags |= SI_NAMED; 444 dev_depends(pdev, dev); 445 va_start(ap, fmt); 446 i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap); 447 if (i > (sizeof dev->__si_namebuf - 1)) { 448 printf("WARNING: Device name truncated! (%s)", 449 dev->__si_namebuf); 450 } 451 va_end(ap); 452 453 devfs_create(dev); 454 return (dev); 455} 456 457void 458destroy_dev(dev_t dev) 459{ 460 461 if (!(dev->si_flags & SI_NAMED)) { 462 printf( "WARNING: Driver mistake: destroy_dev on %d/%d\n", 463 major(dev), minor(dev)); 464 panic("don't do that"); 465 } 466 467 devfs_destroy(dev); 468 dev->si_flags &= ~SI_NAMED; 469 470 if (dev->si_flags & SI_CHILD) { 471 LIST_REMOVE(dev, si_siblings); 472 dev->si_flags &= ~SI_CHILD; 473 } 474 while (!LIST_EMPTY(&dev->si_children)) 475 destroy_dev(LIST_FIRST(&dev->si_children)); 476 if (dev->si_flags & SI_CLONELIST) { 477 LIST_REMOVE(dev, si_clone); 478 dev->si_flags &= ~SI_CLONELIST; 479 } 480 dev->si_drv1 = 0; 481 dev->si_drv2 = 0; 482 dev->si_devsw = 0; 483 bzero(&dev->__si_u, sizeof(dev->__si_u)); 484 dev->si_flags &= ~SI_ALIAS; 485 freedev(dev); 486} 487 488const char * 489devtoname(dev_t dev) 490{ 491 char *p; 492 int mynor; 493 494 if (dev->si_name[0] == '#' || dev->si_name[0] == '\0') { 495 p = dev->si_name; 496 if (devsw(dev)) 497 sprintf(p, "#%s/", devsw(dev)->d_name); 498 else 499 sprintf(p, "#%d/", major(dev)); 500 p += strlen(p); 501 mynor = minor(dev); 502 if (mynor < 0 || mynor > 255) 503 sprintf(p, "%#x", (u_int)mynor); 504 else 505 sprintf(p, "%d", mynor); 506 } 507 return (dev->si_name); 508} 509 510int 511dev_stdclone(char *name, char **namep, const char *stem, int *unit) 512{ 513 int u, i; 514 515 i = strlen(stem); 516 if (bcmp(stem, name, i) != 0) 517 return (0); 518 if (!isdigit(name[i])) 519 return (0); 520 u = 0; 521 if (name[i] == '0' && isdigit(name[i+1])) 522 return (0); 523 while (isdigit(name[i])) { 524 u *= 10; 525 u += name[i++] - '0'; 526 } 527 if (u > 0xffffff) 528 return (0); 529 *unit = u; 530 if (namep) 531 *namep = &name[i]; 532 if (name[i]) 533 return (2); 534 return (1); 535} 536 537/* 538 * Helper functions for cloning device drivers. 539 * 540 * The objective here is to make it unnecessary for the device drivers to 541 * use rman or similar to manage their unit number space. Due to the way 542 * we do "on-demand" devices, using rman or other "private" methods 543 * will be very tricky to lock down properly once we lock down this file. 544 * 545 * Instead we give the drivers these routines which puts the dev_t's that 546 * are to be managed on their own list, and gives the driver the ability 547 * to ask for the first free unit number or a given specified unit number. 548 * 549 * In addition these routines support paired devices (pty, nmdm and similar) 550 * by respecting a number of "flag" bits in the minor number. 551 * 552 */ 553 554struct clonedevs { 555 LIST_HEAD(,cdev) head; 556}; 557 558int 559clone_create(struct clonedevs **cdp, struct cdevsw *csw, int *up, dev_t *dp, u_int extra) 560{ 561 struct clonedevs *cd; 562 dev_t dev, dl, de; 563 int unit, low, u; 564 565 KASSERT(!(extra & CLONE_UNITMASK), 566 ("Illegal extra bits (0x%x) in clone_create", extra)); 567 KASSERT(*up <= CLONE_UNITMASK, 568 ("Too high unit (0x%x) in clone_create", *up)); 569 570 if (csw->d_maj == MAJOR_AUTO) 571 find_major(csw); 572 /* if clonedevs have not been initialized, we do it here */ 573 cd = *cdp; 574 if (cd == NULL) { 575 cd = malloc(sizeof *cd, M_DEVBUF, M_WAITOK | M_ZERO); 576 LIST_INIT(&cd->head); 577 *cdp = cd; 578 } 579 580 /* 581 * Search the list for a lot of things in one go: 582 * A preexisting match is returned immediately. 583 * The lowest free unit number if we are passed -1, and the place 584 * in the list where we should insert that new element. 585 * The place to insert a specified unit number, if applicable 586 * the end of the list. 587 */ 588 unit = *up; 589 low = 0; 590 de = dl = NULL; 591 LIST_FOREACH(dev, &cd->head, si_clone) { 592 u = dev2unit(dev); 593 if (u == (unit | extra)) { 594 *dp = dev; 595 return (0); 596 } 597 if (unit == -1 && u == low) { 598 low++; 599 de = dev; 600 continue; 601 } 602 if (u > unit) { 603 dl = dev; 604 break; 605 } 606 de = dev; 607 } 608 if (unit == -1) 609 unit = low; 610 dev = makedev(csw->d_maj, unit2minor(unit | extra)); 611 KASSERT(!(dev->si_flags & SI_CLONELIST), 612 ("Dev %p should not be on clonelist", dev)); 613 if (dl != NULL) 614 LIST_INSERT_BEFORE(dl, dev, si_clone); 615 else if (de != NULL) 616 LIST_INSERT_AFTER(de, dev, si_clone); 617 else 618 LIST_INSERT_HEAD(&cd->head, dev, si_clone); 619 dev->si_flags |= SI_CLONELIST; 620 *up = unit; 621 return (1); 622} 623 624/* 625 * Kill everything still on the list. The driver should already have 626 * disposed of any softc hung of the dev_t's at this time. 627 */ 628void 629clone_cleanup(struct clonedevs **cdp) 630{ 631 dev_t dev, tdev; 632 struct clonedevs *cd; 633 634 cd = *cdp; 635 if (cd == NULL) 636 return; 637 LIST_FOREACH_SAFE(dev, &cd->head, si_clone, tdev) { 638 KASSERT(dev->si_flags & SI_NAMED, 639 ("Driver has goofed in cloning underways udev %x", dev->si_udev)); 640 destroy_dev(dev); 641 } 642 free(cd, M_DEVBUF); 643 *cdp = NULL; 644} 645 646/* 647 * Helper sysctl for devname(3). We're given a {u}dev_t and return 648 * the name, if any, registered by the device driver. 649 */ 650static int 651sysctl_devname(SYSCTL_HANDLER_ARGS) 652{ 653 int error; 654 udev_t ud; 655 dev_t dev; 656 657 error = SYSCTL_IN(req, &ud, sizeof (ud)); 658 if (error) 659 return (error); 660 if (ud == NOUDEV) 661 return(EINVAL); 662 dev = makedev(umajor(ud), uminor(ud)); 663 if (dev->si_name[0] == '\0') 664 error = ENOENT; 665 else 666 error = SYSCTL_OUT(req, dev->si_name, strlen(dev->si_name) + 1); 667 freedev(dev); 668 return (error); 669} 670 671SYSCTL_PROC(_kern, OID_AUTO, devname, CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_ANYBODY, 672 NULL, 0, sysctl_devname, "", "devname(3) handler"); 673