kern_conf.c revision 126080
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 126080 2004-02-21 21:10:55Z 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 <machine/stdarg.h> 46 47static MALLOC_DEFINE(M_DEVT, "dev_t", "dev_t storage"); 48 49/* Built at compile time from sys/conf/majors */ 50extern unsigned char reserved_majors[256]; 51 52/* 53 * This is the number of hash-buckets. Experiements with 'real-life' 54 * udev_t's show that a prime halfway between two powers of two works 55 * best. 56 */ 57#define DEVT_HASH 83 58 59/* The number of dev_t's we can create before malloc(9) kick in. */ 60#define DEVT_STASH 50 61 62static struct cdev devt_stash[DEVT_STASH]; 63 64static LIST_HEAD(, cdev) dev_hash[DEVT_HASH]; 65 66static LIST_HEAD(, cdev) dev_free; 67 68static int free_devt; 69SYSCTL_INT(_debug, OID_AUTO, free_devt, CTLFLAG_RW, &free_devt, 0, ""); 70 71int 72nullop(void) 73{ 74 75 return (0); 76} 77 78int 79eopnotsupp(void) 80{ 81 82 return (EOPNOTSUPP); 83} 84 85static int 86enxio(void) 87{ 88 return (ENXIO); 89} 90 91static int 92enodev(void) 93{ 94 return (ENODEV); 95} 96 97/* Define a dead_cdevsw for use when devices leave unexpectedly. */ 98 99#define dead_open (d_open_t *)enxio 100#define dead_close (d_close_t *)enxio 101#define dead_read (d_read_t *)enxio 102#define dead_write (d_write_t *)enxio 103#define dead_ioctl (d_ioctl_t *)enxio 104#define dead_poll (d_poll_t *)enodev 105#define dead_mmap (d_mmap_t *)enodev 106 107static void 108dead_strategy(struct bio *bp) 109{ 110 111 biofinish(bp, NULL, ENXIO); 112} 113 114#define dead_dump (dumper_t *)enxio 115#define dead_kqfilter (d_kqfilter_t *)enxio 116 117static struct cdevsw dead_cdevsw = { 118 .d_version = D_VERSION, 119 .d_flags = D_NEEDGIANT, /* XXX: does dead_strategy need this ? */ 120 .d_open = dead_open, 121 .d_close = dead_close, 122 .d_read = dead_read, 123 .d_write = dead_write, 124 .d_ioctl = dead_ioctl, 125 .d_poll = dead_poll, 126 .d_mmap = dead_mmap, 127 .d_strategy = dead_strategy, 128 .d_name = "dead", 129 .d_maj = 255, 130 .d_dump = dead_dump, 131 .d_kqfilter = dead_kqfilter 132}; 133 134/* Default methods if driver does not specify method */ 135 136#define null_open (d_open_t *)nullop 137#define null_close (d_close_t *)nullop 138#define no_read (d_read_t *)enodev 139#define no_write (d_write_t *)enodev 140#define no_ioctl (d_ioctl_t *)enodev 141#define no_mmap (d_mmap_t *)enodev 142 143static int 144no_kqfilter(dev_t dev __unused, struct knote *kn __unused) 145{ 146 147 return (1); 148} 149 150static void 151no_strategy(struct bio *bp) 152{ 153 154 biofinish(bp, NULL, ENODEV); 155} 156 157static int 158no_poll(dev_t dev __unused, int events, struct thread *td __unused) 159{ 160 /* 161 * Return true for read/write. If the user asked for something 162 * special, return POLLNVAL, so that clients have a way of 163 * determining reliably whether or not the extended 164 * functionality is present without hard-coding knowledge 165 * of specific filesystem implementations. 166 * Stay in sync with vop_nopoll(). 167 */ 168 if (events & ~POLLSTANDARD) 169 return (POLLNVAL); 170 171 return (events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM)); 172} 173 174#define no_dump (dumper_t *)enodev 175 176struct cdevsw * 177devsw(dev_t dev) 178{ 179 if (dev->si_devsw) 180 return (dev->si_devsw); 181 return (&dead_cdevsw); 182} 183 184/* 185 * dev_t and u_dev_t primitives 186 */ 187 188int 189major(dev_t x) 190{ 191 if (x == NODEV) 192 return NOUDEV; 193 return((x->si_udev >> 8) & 0xff); 194} 195 196int 197minor(dev_t x) 198{ 199 if (x == NODEV) 200 return NOUDEV; 201 return(x->si_udev & 0xffff00ff); 202} 203 204int 205dev2unit(dev_t x) 206{ 207 int i; 208 209 if (x == NODEV) 210 return NOUDEV; 211 i = minor(x); 212 return ((i & 0xff) | (i >> 8)); 213} 214 215int 216unit2minor(int unit) 217{ 218 219 KASSERT(unit <= 0xffffff, ("Invalid unit (%d) in unit2minor", unit)); 220 return ((unit & 0xff) | ((unit << 8) & ~0xffff)); 221} 222 223static dev_t 224allocdev(void) 225{ 226 static int stashed; 227 struct cdev *si; 228 229 if (LIST_FIRST(&dev_free)) { 230 si = LIST_FIRST(&dev_free); 231 LIST_REMOVE(si, si_hash); 232 } else if (stashed >= DEVT_STASH) { 233 MALLOC(si, struct cdev *, sizeof(*si), M_DEVT, 234 M_USE_RESERVE | M_ZERO | M_WAITOK); 235 } else { 236 si = devt_stash + stashed++; 237 bzero(si, sizeof *si); 238 si->si_flags |= SI_STASHED; 239 } 240 si->__si_namebuf[0] = '\0'; 241 si->si_name = si->__si_namebuf; 242 LIST_INIT(&si->si_children); 243 TAILQ_INIT(&si->si_snapshots); 244 return (si); 245} 246 247dev_t 248makedev(int x, int y) 249{ 250 struct cdev *si; 251 udev_t udev; 252 int hash; 253 254 if (x == umajor(NOUDEV) && y == uminor(NOUDEV)) 255 panic("makedev of NOUDEV"); 256 udev = (x << 8) | y; 257 hash = udev % DEVT_HASH; 258 LIST_FOREACH(si, &dev_hash[hash], si_hash) { 259 if (si->si_udev == udev) 260 return (si); 261 } 262 si = allocdev(); 263 si->si_udev = udev; 264 LIST_INSERT_HEAD(&dev_hash[hash], si, si_hash); 265 return (si); 266} 267 268void 269freedev(dev_t dev) 270{ 271 272 if (!free_devt) 273 return; 274 if (SLIST_FIRST(&dev->si_hlist)) 275 return; 276 if (dev->si_devsw || dev->si_drv1 || dev->si_drv2) 277 return; 278 LIST_REMOVE(dev, si_hash); 279 if (dev->si_flags & SI_STASHED) { 280 bzero(dev, sizeof(*dev)); 281 dev->si_flags |= SI_STASHED; 282 LIST_INSERT_HEAD(&dev_free, dev, si_hash); 283 } else { 284 FREE(dev, M_DEVT); 285 } 286} 287 288udev_t 289dev2udev(dev_t x) 290{ 291 if (x == NODEV) 292 return (NOUDEV); 293 return (x->si_udev); 294} 295 296dev_t 297udev2dev(udev_t x, int b) 298{ 299 300 if (x == NOUDEV) 301 return (NODEV); 302 switch (b) { 303 case 0: 304 return (makedev(umajor(x), uminor(x))); 305 default: 306 Debugger("udev2dev(...,X)"); 307 return (NODEV); 308 } 309} 310 311int 312uminor(udev_t dev) 313{ 314 return (dev & 0xffff00ff); 315} 316 317int 318umajor(udev_t dev) 319{ 320 return ((dev & 0xff00) >> 8); 321} 322 323udev_t 324makeudev(int x, int y) 325{ 326 return ((x << 8) | y); 327} 328 329static void 330find_major(struct cdevsw *devsw) 331{ 332 int i; 333 334 for (i = NUMCDEVSW - 1; i > 0; i--) 335 if (reserved_majors[i] != i) 336 break; 337 KASSERT(i > 0, ("Out of major numbers (%s)", devsw->d_name)); 338 devsw->d_maj = i; 339 reserved_majors[i] = i; 340} 341 342static void 343prep_cdevsw(struct cdevsw *devsw) 344{ 345 346 if (devsw->d_flags & D_TTY) { 347 if (devsw->d_read == NULL) devsw->d_read = ttyread; 348 if (devsw->d_write == NULL) devsw->d_write = ttywrite; 349 if (devsw->d_kqfilter == NULL) devsw->d_kqfilter = ttykqfilter; 350 if (devsw->d_poll == NULL) devsw->d_poll = ttypoll; 351 } 352 353 if (devsw->d_open == NULL) devsw->d_open = null_open; 354 if (devsw->d_close == NULL) devsw->d_close = null_close; 355 if (devsw->d_read == NULL) devsw->d_read = no_read; 356 if (devsw->d_write == NULL) devsw->d_write = no_write; 357 if (devsw->d_ioctl == NULL) devsw->d_ioctl = no_ioctl; 358 if (devsw->d_poll == NULL) devsw->d_poll = no_poll; 359 if (devsw->d_mmap == NULL) devsw->d_mmap = no_mmap; 360 if (devsw->d_strategy == NULL) devsw->d_strategy = no_strategy; 361 if (devsw->d_dump == NULL) devsw->d_dump = no_dump; 362 if (devsw->d_kqfilter == NULL) devsw->d_kqfilter = no_kqfilter; 363 if (devsw->d_maj == MAJOR_AUTO) { 364 find_major(devsw); 365 } else { 366 if (devsw->d_maj == 256) /* XXX: tty_cons.c is magic */ 367 devsw->d_maj = 0; 368 KASSERT(devsw->d_maj >= 0 && devsw->d_maj < 256, 369 ("Invalid major (%d) in make_dev", devsw->d_maj)); 370 if (reserved_majors[devsw->d_maj] != devsw->d_maj) { 371 printf("WARNING: driver \"%s\" used %s %d\n", 372 devsw->d_name, "unreserved major device number", 373 devsw->d_maj); 374 reserved_majors[devsw->d_maj] = devsw->d_maj; 375 } 376 } 377} 378 379dev_t 380make_dev(struct cdevsw *devsw, int minor, uid_t uid, gid_t gid, int perms, 381 const char *fmt, ...) 382{ 383 dev_t dev; 384 va_list ap; 385 int i; 386 387 KASSERT((minor & ~0xffff00ff) == 0, 388 ("Invalid minor (0x%x) in make_dev", minor)); 389 prep_cdevsw(devsw); 390 dev = makedev(devsw->d_maj, minor); 391 if (dev->si_flags & SI_CHEAPCLONE && 392 dev->si_flags & SI_NAMED && 393 dev->si_devsw == devsw) { 394 /* 395 * This is allowed as it removes races and generally 396 * simplifies cloning devices. 397 */ 398 return (dev); 399 } 400 if (dev->si_flags & SI_NAMED) { 401 printf( "WARNING: Driver mistake: repeat make_dev(\"%s\")\n", 402 dev->si_name); 403 panic("don't do that"); 404 } 405 va_start(ap, fmt); 406 i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap); 407 if (i > (sizeof dev->__si_namebuf - 1)) { 408 printf("WARNING: Device name truncated! (%s)", 409 dev->__si_namebuf); 410 } 411 va_end(ap); 412 dev->si_devsw = devsw; 413 dev->si_uid = uid; 414 dev->si_gid = gid; 415 dev->si_mode = perms; 416 dev->si_flags |= SI_NAMED; 417 418 devfs_create(dev); 419 return (dev); 420} 421 422int 423dev_named(dev_t pdev, const char *name) 424{ 425 dev_t cdev; 426 427 if (strcmp(devtoname(pdev), name) == 0) 428 return (1); 429 LIST_FOREACH(cdev, &pdev->si_children, si_siblings) 430 if (strcmp(devtoname(cdev), name) == 0) 431 return (1); 432 return (0); 433} 434 435void 436dev_depends(dev_t pdev, dev_t cdev) 437{ 438 439 cdev->si_parent = pdev; 440 cdev->si_flags |= SI_CHILD; 441 LIST_INSERT_HEAD(&pdev->si_children, cdev, si_siblings); 442} 443 444dev_t 445make_dev_alias(dev_t pdev, const char *fmt, ...) 446{ 447 dev_t dev; 448 va_list ap; 449 int i; 450 451 dev = allocdev(); 452 dev->si_flags |= SI_ALIAS; 453 dev->si_flags |= SI_NAMED; 454 dev_depends(pdev, dev); 455 va_start(ap, fmt); 456 i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap); 457 if (i > (sizeof dev->__si_namebuf - 1)) { 458 printf("WARNING: Device name truncated! (%s)", 459 dev->__si_namebuf); 460 } 461 va_end(ap); 462 463 devfs_create(dev); 464 return (dev); 465} 466 467void 468destroy_dev(dev_t dev) 469{ 470 471 if (!(dev->si_flags & SI_NAMED)) { 472 printf( "WARNING: Driver mistake: destroy_dev on %d/%d\n", 473 major(dev), minor(dev)); 474 panic("don't do that"); 475 } 476 477 devfs_destroy(dev); 478 dev->si_flags &= ~SI_NAMED; 479 480 if (dev->si_flags & SI_CHILD) { 481 LIST_REMOVE(dev, si_siblings); 482 dev->si_flags &= ~SI_CHILD; 483 } 484 while (!LIST_EMPTY(&dev->si_children)) 485 destroy_dev(LIST_FIRST(&dev->si_children)); 486 if (dev->si_flags & SI_CLONELIST) { 487 LIST_REMOVE(dev, si_clone); 488 dev->si_flags &= ~SI_CLONELIST; 489 } 490 dev->si_drv1 = 0; 491 dev->si_drv2 = 0; 492 dev->si_devsw = 0; 493 bzero(&dev->__si_u, sizeof(dev->__si_u)); 494 dev->si_flags &= ~SI_ALIAS; 495 freedev(dev); 496} 497 498const char * 499devtoname(dev_t dev) 500{ 501 char *p; 502 int mynor; 503 504 if (dev->si_name[0] == '#' || dev->si_name[0] == '\0') { 505 p = dev->si_name; 506 if (devsw(dev)) 507 sprintf(p, "#%s/", devsw(dev)->d_name); 508 else 509 sprintf(p, "#%d/", major(dev)); 510 p += strlen(p); 511 mynor = minor(dev); 512 if (mynor < 0 || mynor > 255) 513 sprintf(p, "%#x", (u_int)mynor); 514 else 515 sprintf(p, "%d", mynor); 516 } 517 return (dev->si_name); 518} 519 520int 521dev_stdclone(char *name, char **namep, const char *stem, int *unit) 522{ 523 int u, i; 524 525 i = strlen(stem); 526 if (bcmp(stem, name, i) != 0) 527 return (0); 528 if (!isdigit(name[i])) 529 return (0); 530 u = 0; 531 if (name[i] == '0' && isdigit(name[i+1])) 532 return (0); 533 while (isdigit(name[i])) { 534 u *= 10; 535 u += name[i++] - '0'; 536 } 537 if (u > 0xffffff) 538 return (0); 539 *unit = u; 540 if (namep) 541 *namep = &name[i]; 542 if (name[i]) 543 return (2); 544 return (1); 545} 546 547/* 548 * Helper functions for cloning device drivers. 549 * 550 * The objective here is to make it unnecessary for the device drivers to 551 * use rman or similar to manage their unit number space. Due to the way 552 * we do "on-demand" devices, using rman or other "private" methods 553 * will be very tricky to lock down properly once we lock down this file. 554 * 555 * Instead we give the drivers these routines which puts the dev_t's that 556 * are to be managed on their own list, and gives the driver the ability 557 * to ask for the first free unit number or a given specified unit number. 558 * 559 * In addition these routines support paired devices (pty, nmdm and similar) 560 * by respecting a number of "flag" bits in the minor number. 561 * 562 */ 563 564struct clonedevs { 565 LIST_HEAD(,cdev) head; 566}; 567 568int 569clone_create(struct clonedevs **cdp, struct cdevsw *csw, int *up, dev_t *dp, u_int extra) 570{ 571 struct clonedevs *cd; 572 dev_t dev, dl, de; 573 int unit, low, u; 574 575 KASSERT(!(extra & CLONE_UNITMASK), 576 ("Illegal extra bits (0x%x) in clone_create", extra)); 577 KASSERT(*up <= CLONE_UNITMASK, 578 ("Too high unit (0x%x) in clone_create", *up)); 579 580 if (csw->d_maj == MAJOR_AUTO) 581 find_major(csw); 582 /* if clonedevs have not been initialized, we do it here */ 583 cd = *cdp; 584 if (cd == NULL) { 585 cd = malloc(sizeof *cd, M_DEVBUF, M_WAITOK | M_ZERO); 586 LIST_INIT(&cd->head); 587 *cdp = cd; 588 } 589 590 /* 591 * Search the list for a lot of things in one go: 592 * A preexisting match is returned immediately. 593 * The lowest free unit number if we are passed -1, and the place 594 * in the list where we should insert that new element. 595 * The place to insert a specified unit number, if applicable 596 * the end of the list. 597 */ 598 unit = *up; 599 low = 0; 600 de = dl = NULL; 601 LIST_FOREACH(dev, &cd->head, si_clone) { 602 u = dev2unit(dev); 603 if (u == (unit | extra)) { 604 *dp = dev; 605 return (0); 606 } 607 if (unit == -1 && u == low) { 608 low++; 609 de = dev; 610 continue; 611 } 612 if (u > unit) { 613 dl = dev; 614 break; 615 } 616 de = dev; 617 } 618 if (unit == -1) 619 unit = low; 620 dev = makedev(csw->d_maj, unit2minor(unit | extra)); 621 KASSERT(!(dev->si_flags & SI_CLONELIST), 622 ("Dev %p should not be on clonelist", dev)); 623 if (dl != NULL) 624 LIST_INSERT_BEFORE(dl, dev, si_clone); 625 else if (de != NULL) 626 LIST_INSERT_AFTER(de, dev, si_clone); 627 else 628 LIST_INSERT_HEAD(&cd->head, dev, si_clone); 629 dev->si_flags |= SI_CLONELIST; 630 *up = unit; 631 return (1); 632} 633 634/* 635 * Kill everything still on the list. The driver should already have 636 * disposed of any softc hung of the dev_t's at this time. 637 */ 638void 639clone_cleanup(struct clonedevs **cdp) 640{ 641 dev_t dev, tdev; 642 struct clonedevs *cd; 643 644 cd = *cdp; 645 if (cd == NULL) 646 return; 647 LIST_FOREACH_SAFE(dev, &cd->head, si_clone, tdev) { 648 KASSERT(dev->si_flags & SI_NAMED, 649 ("Driver has goofed in cloning underways udev %x", dev->si_udev)); 650 destroy_dev(dev); 651 } 652 free(cd, M_DEVBUF); 653 *cdp = NULL; 654} 655 656/* 657 * Helper sysctl for devname(3). We're given a {u}dev_t and return 658 * the name, if any, registered by the device driver. 659 */ 660static int 661sysctl_devname(SYSCTL_HANDLER_ARGS) 662{ 663 int error; 664 udev_t ud; 665 dev_t dev; 666 667 error = SYSCTL_IN(req, &ud, sizeof (ud)); 668 if (error) 669 return (error); 670 if (ud == NOUDEV) 671 return(EINVAL); 672 dev = makedev(umajor(ud), uminor(ud)); 673 if (dev->si_name[0] == '\0') 674 error = ENOENT; 675 else 676 error = SYSCTL_OUT(req, dev->si_name, strlen(dev->si_name) + 1); 677 freedev(dev); 678 return (error); 679} 680 681SYSCTL_PROC(_kern, OID_AUTO, devname, CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_ANYBODY, 682 NULL, 0, sysctl_devname, "", "devname(3) handler"); 683