kern_conf.c revision 126078
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 126078 2004-02-21 20:41:11Z 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_open = dead_open, 119 .d_close = dead_close, 120 .d_read = dead_read, 121 .d_write = dead_write, 122 .d_ioctl = dead_ioctl, 123 .d_poll = dead_poll, 124 .d_mmap = dead_mmap, 125 .d_strategy = dead_strategy, 126 .d_name = "dead", 127 .d_maj = 255, 128 .d_dump = dead_dump, 129 .d_kqfilter = dead_kqfilter 130}; 131 132/* Default methods if driver does not specify method */ 133 134#define null_open (d_open_t *)nullop 135#define null_close (d_close_t *)nullop 136#define no_read (d_read_t *)enodev 137#define no_write (d_write_t *)enodev 138#define no_ioctl (d_ioctl_t *)enodev 139#define no_mmap (d_mmap_t *)enodev 140 141static int 142no_kqfilter(dev_t dev __unused, struct knote *kn __unused) 143{ 144 145 return (1); 146} 147 148static void 149no_strategy(struct bio *bp) 150{ 151 152 biofinish(bp, NULL, ENODEV); 153} 154 155static int 156no_poll(dev_t dev __unused, int events, struct thread *td __unused) 157{ 158 /* 159 * Return true for read/write. If the user asked for something 160 * special, return POLLNVAL, so that clients have a way of 161 * determining reliably whether or not the extended 162 * functionality is present without hard-coding knowledge 163 * of specific filesystem implementations. 164 * Stay in sync with vop_nopoll(). 165 */ 166 if (events & ~POLLSTANDARD) 167 return (POLLNVAL); 168 169 return (events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM)); 170} 171 172#define no_dump (dumper_t *)enodev 173 174struct cdevsw * 175devsw(dev_t dev) 176{ 177 if (dev->si_devsw) 178 return (dev->si_devsw); 179 return (&dead_cdevsw); 180} 181 182/* 183 * dev_t and u_dev_t primitives 184 */ 185 186int 187major(dev_t x) 188{ 189 if (x == NODEV) 190 return NOUDEV; 191 return((x->si_udev >> 8) & 0xff); 192} 193 194int 195minor(dev_t x) 196{ 197 if (x == NODEV) 198 return NOUDEV; 199 return(x->si_udev & 0xffff00ff); 200} 201 202int 203dev2unit(dev_t x) 204{ 205 int i; 206 207 if (x == NODEV) 208 return NOUDEV; 209 i = minor(x); 210 return ((i & 0xff) | (i >> 8)); 211} 212 213int 214unit2minor(int unit) 215{ 216 217 KASSERT(unit <= 0xffffff, ("Invalid unit (%d) in unit2minor", unit)); 218 return ((unit & 0xff) | ((unit << 8) & ~0xffff)); 219} 220 221static dev_t 222allocdev(void) 223{ 224 static int stashed; 225 struct cdev *si; 226 227 if (LIST_FIRST(&dev_free)) { 228 si = LIST_FIRST(&dev_free); 229 LIST_REMOVE(si, si_hash); 230 } else if (stashed >= DEVT_STASH) { 231 MALLOC(si, struct cdev *, sizeof(*si), M_DEVT, 232 M_USE_RESERVE | M_ZERO | M_WAITOK); 233 } else { 234 si = devt_stash + stashed++; 235 bzero(si, sizeof *si); 236 si->si_flags |= SI_STASHED; 237 } 238 si->__si_namebuf[0] = '\0'; 239 si->si_name = si->__si_namebuf; 240 LIST_INIT(&si->si_children); 241 TAILQ_INIT(&si->si_snapshots); 242 return (si); 243} 244 245dev_t 246makedev(int x, int y) 247{ 248 struct cdev *si; 249 udev_t udev; 250 int hash; 251 252 if (x == umajor(NOUDEV) && y == uminor(NOUDEV)) 253 panic("makedev of NOUDEV"); 254 udev = (x << 8) | y; 255 hash = udev % DEVT_HASH; 256 LIST_FOREACH(si, &dev_hash[hash], si_hash) { 257 if (si->si_udev == udev) 258 return (si); 259 } 260 si = allocdev(); 261 si->si_udev = udev; 262 LIST_INSERT_HEAD(&dev_hash[hash], si, si_hash); 263 return (si); 264} 265 266void 267freedev(dev_t dev) 268{ 269 270 if (!free_devt) 271 return; 272 if (SLIST_FIRST(&dev->si_hlist)) 273 return; 274 if (dev->si_devsw || dev->si_drv1 || dev->si_drv2) 275 return; 276 LIST_REMOVE(dev, si_hash); 277 if (dev->si_flags & SI_STASHED) { 278 bzero(dev, sizeof(*dev)); 279 dev->si_flags |= SI_STASHED; 280 LIST_INSERT_HEAD(&dev_free, dev, si_hash); 281 } else { 282 FREE(dev, M_DEVT); 283 } 284} 285 286udev_t 287dev2udev(dev_t x) 288{ 289 if (x == NODEV) 290 return (NOUDEV); 291 return (x->si_udev); 292} 293 294dev_t 295udev2dev(udev_t x, int b) 296{ 297 298 if (x == NOUDEV) 299 return (NODEV); 300 switch (b) { 301 case 0: 302 return (makedev(umajor(x), uminor(x))); 303 default: 304 Debugger("udev2dev(...,X)"); 305 return (NODEV); 306 } 307} 308 309int 310uminor(udev_t dev) 311{ 312 return (dev & 0xffff00ff); 313} 314 315int 316umajor(udev_t dev) 317{ 318 return ((dev & 0xff00) >> 8); 319} 320 321udev_t 322makeudev(int x, int y) 323{ 324 return ((x << 8) | y); 325} 326 327static void 328find_major(struct cdevsw *devsw) 329{ 330 int i; 331 332 for (i = NUMCDEVSW - 1; i > 0; i--) 333 if (reserved_majors[i] != i) 334 break; 335 KASSERT(i > 0, ("Out of major numbers (%s)", devsw->d_name)); 336 devsw->d_maj = i; 337 reserved_majors[i] = i; 338} 339 340static void 341prep_cdevsw(struct cdevsw *devsw) 342{ 343 344 if (devsw->d_flags & D_TTY) { 345 if (devsw->d_read == NULL) devsw->d_read = ttyread; 346 if (devsw->d_write == NULL) devsw->d_write = ttywrite; 347 if (devsw->d_kqfilter == NULL) devsw->d_kqfilter = ttykqfilter; 348 if (devsw->d_poll == NULL) devsw->d_poll = ttypoll; 349 } 350 351 if (devsw->d_open == NULL) devsw->d_open = null_open; 352 if (devsw->d_close == NULL) devsw->d_close = null_close; 353 if (devsw->d_read == NULL) devsw->d_read = no_read; 354 if (devsw->d_write == NULL) devsw->d_write = no_write; 355 if (devsw->d_ioctl == NULL) devsw->d_ioctl = no_ioctl; 356 if (devsw->d_poll == NULL) devsw->d_poll = no_poll; 357 if (devsw->d_mmap == NULL) devsw->d_mmap = no_mmap; 358 if (devsw->d_strategy == NULL) devsw->d_strategy = no_strategy; 359 if (devsw->d_dump == NULL) devsw->d_dump = no_dump; 360 if (devsw->d_kqfilter == NULL) devsw->d_kqfilter = no_kqfilter; 361 if (devsw->d_maj == MAJOR_AUTO) { 362 find_major(devsw); 363 } else { 364 if (devsw->d_maj == 256) /* XXX: tty_cons.c is magic */ 365 devsw->d_maj = 0; 366 KASSERT(devsw->d_maj >= 0 && devsw->d_maj < 256, 367 ("Invalid major (%d) in make_dev", devsw->d_maj)); 368 if (reserved_majors[devsw->d_maj] != devsw->d_maj) { 369 printf("WARNING: driver \"%s\" used %s %d\n", 370 devsw->d_name, "unreserved major device number", 371 devsw->d_maj); 372 reserved_majors[devsw->d_maj] = devsw->d_maj; 373 } 374 } 375} 376 377dev_t 378make_dev(struct cdevsw *devsw, int minor, uid_t uid, gid_t gid, int perms, 379 const char *fmt, ...) 380{ 381 dev_t dev; 382 va_list ap; 383 int i; 384 385 KASSERT((minor & ~0xffff00ff) == 0, 386 ("Invalid minor (0x%x) in make_dev", minor)); 387 prep_cdevsw(devsw); 388 dev = makedev(devsw->d_maj, minor); 389 if (dev->si_flags & SI_CHEAPCLONE && 390 dev->si_flags & SI_NAMED && 391 dev->si_devsw == devsw) { 392 /* 393 * This is allowed as it removes races and generally 394 * simplifies cloning devices. 395 */ 396 return (dev); 397 } 398 if (dev->si_flags & SI_NAMED) { 399 printf( "WARNING: Driver mistake: repeat make_dev(\"%s\")\n", 400 dev->si_name); 401 panic("don't do that"); 402 } 403 va_start(ap, fmt); 404 i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap); 405 if (i > (sizeof dev->__si_namebuf - 1)) { 406 printf("WARNING: Device name truncated! (%s)", 407 dev->__si_namebuf); 408 } 409 va_end(ap); 410 dev->si_devsw = devsw; 411 dev->si_uid = uid; 412 dev->si_gid = gid; 413 dev->si_mode = perms; 414 dev->si_flags |= SI_NAMED; 415 416 devfs_create(dev); 417 return (dev); 418} 419 420int 421dev_named(dev_t pdev, const char *name) 422{ 423 dev_t cdev; 424 425 if (strcmp(devtoname(pdev), name) == 0) 426 return (1); 427 LIST_FOREACH(cdev, &pdev->si_children, si_siblings) 428 if (strcmp(devtoname(cdev), name) == 0) 429 return (1); 430 return (0); 431} 432 433void 434dev_depends(dev_t pdev, dev_t cdev) 435{ 436 437 cdev->si_parent = pdev; 438 cdev->si_flags |= SI_CHILD; 439 LIST_INSERT_HEAD(&pdev->si_children, cdev, si_siblings); 440} 441 442dev_t 443make_dev_alias(dev_t pdev, const char *fmt, ...) 444{ 445 dev_t dev; 446 va_list ap; 447 int i; 448 449 dev = allocdev(); 450 dev->si_flags |= SI_ALIAS; 451 dev->si_flags |= SI_NAMED; 452 dev_depends(pdev, dev); 453 va_start(ap, fmt); 454 i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap); 455 if (i > (sizeof dev->__si_namebuf - 1)) { 456 printf("WARNING: Device name truncated! (%s)", 457 dev->__si_namebuf); 458 } 459 va_end(ap); 460 461 devfs_create(dev); 462 return (dev); 463} 464 465void 466destroy_dev(dev_t dev) 467{ 468 469 if (!(dev->si_flags & SI_NAMED)) { 470 printf( "WARNING: Driver mistake: destroy_dev on %d/%d\n", 471 major(dev), minor(dev)); 472 panic("don't do that"); 473 } 474 475 devfs_destroy(dev); 476 dev->si_flags &= ~SI_NAMED; 477 478 if (dev->si_flags & SI_CHILD) { 479 LIST_REMOVE(dev, si_siblings); 480 dev->si_flags &= ~SI_CHILD; 481 } 482 while (!LIST_EMPTY(&dev->si_children)) 483 destroy_dev(LIST_FIRST(&dev->si_children)); 484 if (dev->si_flags & SI_CLONELIST) { 485 LIST_REMOVE(dev, si_clone); 486 dev->si_flags &= ~SI_CLONELIST; 487 } 488 dev->si_drv1 = 0; 489 dev->si_drv2 = 0; 490 dev->si_devsw = 0; 491 bzero(&dev->__si_u, sizeof(dev->__si_u)); 492 dev->si_flags &= ~SI_ALIAS; 493 freedev(dev); 494} 495 496const char * 497devtoname(dev_t dev) 498{ 499 char *p; 500 int mynor; 501 502 if (dev->si_name[0] == '#' || dev->si_name[0] == '\0') { 503 p = dev->si_name; 504 if (devsw(dev)) 505 sprintf(p, "#%s/", devsw(dev)->d_name); 506 else 507 sprintf(p, "#%d/", major(dev)); 508 p += strlen(p); 509 mynor = minor(dev); 510 if (mynor < 0 || mynor > 255) 511 sprintf(p, "%#x", (u_int)mynor); 512 else 513 sprintf(p, "%d", mynor); 514 } 515 return (dev->si_name); 516} 517 518int 519dev_stdclone(char *name, char **namep, const char *stem, int *unit) 520{ 521 int u, i; 522 523 i = strlen(stem); 524 if (bcmp(stem, name, i) != 0) 525 return (0); 526 if (!isdigit(name[i])) 527 return (0); 528 u = 0; 529 if (name[i] == '0' && isdigit(name[i+1])) 530 return (0); 531 while (isdigit(name[i])) { 532 u *= 10; 533 u += name[i++] - '0'; 534 } 535 if (u > 0xffffff) 536 return (0); 537 *unit = u; 538 if (namep) 539 *namep = &name[i]; 540 if (name[i]) 541 return (2); 542 return (1); 543} 544 545/* 546 * Helper functions for cloning device drivers. 547 * 548 * The objective here is to make it unnecessary for the device drivers to 549 * use rman or similar to manage their unit number space. Due to the way 550 * we do "on-demand" devices, using rman or other "private" methods 551 * will be very tricky to lock down properly once we lock down this file. 552 * 553 * Instead we give the drivers these routines which puts the dev_t's that 554 * are to be managed on their own list, and gives the driver the ability 555 * to ask for the first free unit number or a given specified unit number. 556 * 557 * In addition these routines support paired devices (pty, nmdm and similar) 558 * by respecting a number of "flag" bits in the minor number. 559 * 560 */ 561 562struct clonedevs { 563 LIST_HEAD(,cdev) head; 564}; 565 566int 567clone_create(struct clonedevs **cdp, struct cdevsw *csw, int *up, dev_t *dp, u_int extra) 568{ 569 struct clonedevs *cd; 570 dev_t dev, dl, de; 571 int unit, low, u; 572 573 KASSERT(!(extra & CLONE_UNITMASK), 574 ("Illegal extra bits (0x%x) in clone_create", extra)); 575 KASSERT(*up <= CLONE_UNITMASK, 576 ("Too high unit (0x%x) in clone_create", *up)); 577 578 if (csw->d_maj == MAJOR_AUTO) 579 find_major(csw); 580 /* if clonedevs have not been initialized, we do it here */ 581 cd = *cdp; 582 if (cd == NULL) { 583 cd = malloc(sizeof *cd, M_DEVBUF, M_WAITOK | M_ZERO); 584 LIST_INIT(&cd->head); 585 *cdp = cd; 586 } 587 588 /* 589 * Search the list for a lot of things in one go: 590 * A preexisting match is returned immediately. 591 * The lowest free unit number if we are passed -1, and the place 592 * in the list where we should insert that new element. 593 * The place to insert a specified unit number, if applicable 594 * the end of the list. 595 */ 596 unit = *up; 597 low = 0; 598 de = dl = NULL; 599 LIST_FOREACH(dev, &cd->head, si_clone) { 600 u = dev2unit(dev); 601 if (u == (unit | extra)) { 602 *dp = dev; 603 return (0); 604 } 605 if (unit == -1 && u == low) { 606 low++; 607 de = dev; 608 continue; 609 } 610 if (u > unit) { 611 dl = dev; 612 break; 613 } 614 de = dev; 615 } 616 if (unit == -1) 617 unit = low; 618 dev = makedev(csw->d_maj, unit2minor(unit | extra)); 619 KASSERT(!(dev->si_flags & SI_CLONELIST), 620 ("Dev %p should not be on clonelist", dev)); 621 if (dl != NULL) 622 LIST_INSERT_BEFORE(dl, dev, si_clone); 623 else if (de != NULL) 624 LIST_INSERT_AFTER(de, dev, si_clone); 625 else 626 LIST_INSERT_HEAD(&cd->head, dev, si_clone); 627 dev->si_flags |= SI_CLONELIST; 628 *up = unit; 629 return (1); 630} 631 632/* 633 * Kill everything still on the list. The driver should already have 634 * disposed of any softc hung of the dev_t's at this time. 635 */ 636void 637clone_cleanup(struct clonedevs **cdp) 638{ 639 dev_t dev, tdev; 640 struct clonedevs *cd; 641 642 cd = *cdp; 643 if (cd == NULL) 644 return; 645 LIST_FOREACH_SAFE(dev, &cd->head, si_clone, tdev) { 646 KASSERT(dev->si_flags & SI_NAMED, 647 ("Driver has goofed in cloning underways udev %x", dev->si_udev)); 648 destroy_dev(dev); 649 } 650 free(cd, M_DEVBUF); 651 *cdp = NULL; 652} 653 654/* 655 * Helper sysctl for devname(3). We're given a {u}dev_t and return 656 * the name, if any, registered by the device driver. 657 */ 658static int 659sysctl_devname(SYSCTL_HANDLER_ARGS) 660{ 661 int error; 662 udev_t ud; 663 dev_t dev; 664 665 error = SYSCTL_IN(req, &ud, sizeof (ud)); 666 if (error) 667 return (error); 668 if (ud == NOUDEV) 669 return(EINVAL); 670 dev = makedev(umajor(ud), uminor(ud)); 671 if (dev->si_name[0] == '\0') 672 error = ENOENT; 673 else 674 error = SYSCTL_OUT(req, dev->si_name, strlen(dev->si_name) + 1); 675 freedev(dev); 676 return (error); 677} 678 679SYSCTL_PROC(_kern, OID_AUTO, devname, CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_ANYBODY, 680 NULL, 0, sysctl_devname, "", "devname(3) handler"); 681