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("$FreeBSD$"); 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 46 static MALLOC_DEFINE(M_DEVT, "dev_t", "dev_t storage"); 47 48 /* Built at compile time from sys/conf/majors */ 49 extern 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 61 static struct cdev devt_stash[DEVT_STASH]; 62 63 static LIST_HEAD(, cdev) dev_hash[DEVT_HASH]; 64 65 static LIST_HEAD(, cdev) dev_free; 66 67 static int ready_for_devs; 68 69 static int free_devt; 70 SYSCTL_INT(_debug, OID_AUTO, free_devt, CTLFLAG_RW, &free_devt, 0, ""); 71 72 int 73 nullop(void) 74 { 75 76 return (0); 77 } 78 79 int 80 eopnotsupp(void) 81 { 82 83 return (EOPNOTSUPP); 84 } 85 86 static int 87 enxio(void) 88 { 89 return (ENXIO); 90 } 91 92 static int 93 enodev(void) 94 { 95 return (ENODEV); 96 } 97 98 /* Define a dead_cdevsw for use when devices leave unexpectedly. */ 99 100 #define dead_open (d_open_t *)enxio 101 #define dead_close (d_close_t *)enxio 102 #define dead_read (d_read_t *)enxio 103 #define dead_write (d_write_t *)enxio 104 #define dead_ioctl (d_ioctl_t *)enxio 105 #define dead_poll (d_poll_t *)enodev 106 #define dead_mmap (d_mmap_t *)enodev 107 108 static void 109 dead_strategy(struct bio *bp) 110 { 111 112 biofinish(bp, NULL, ENXIO); 113 } 114 115 #define dead_dump (dumper_t *)enxio 116 #define dead_kqfilter (d_kqfilter_t *)enxio 117 118 static struct cdevsw dead_cdevsw = { 119 .d_open = dead_open, 120 .d_close = dead_close, 121 .d_read = dead_read, 122 .d_write = dead_write, 123 .d_ioctl = dead_ioctl, 124 .d_poll = dead_poll, 125 .d_mmap = dead_mmap, 126 .d_strategy = dead_strategy, 127 .d_name = "dead", 128 .d_maj = 255, 129 .d_dump = dead_dump, 130 .d_kqfilter = dead_kqfilter 131 }; 132 133 /* Default methods if driver does not specify method */ 134 135 #define null_open (d_open_t *)nullop 136 #define null_close (d_close_t *)nullop 137 #define no_read (d_read_t *)enodev 138 #define no_write (d_write_t *)enodev 139 #define no_ioctl (d_ioctl_t *)enodev 140 #define no_mmap (d_mmap_t *)enodev 141 142 static int 143 no_kqfilter(dev_t dev __unused, struct knote *kn __unused) 144 { 145 146 return (1); 147 } 148 149 static void 150 no_strategy(struct bio *bp) 151 { 152 153 biofinish(bp, NULL, ENODEV); 154 } 155 156 static int 157 no_poll(dev_t dev __unused, int events, struct thread *td __unused) 158 { 159 /* 160 * Return true for read/write. If the user asked for something 161 * special, return POLLNVAL, so that clients have a way of 162 * determining reliably whether or not the extended 163 * functionality is present without hard-coding knowledge 164 * of specific filesystem implementations. 165 * Stay in sync with vop_nopoll(). 166 */ 167 if (events & ~POLLSTANDARD) 168 return (POLLNVAL); 169 170 return (events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM)); 171 } 172 173 #define no_dump (dumper_t *)enodev 174 175 struct cdevsw * 176 devsw(dev_t dev) 177 { 178 if (dev->si_devsw) 179 return (dev->si_devsw); 180 return (&dead_cdevsw); 181 } 182 183 /* 184 * dev_t and u_dev_t primitives 185 */ 186 187 int 188 major(dev_t x) 189 { 190 if (x == NODEV) 191 return NOUDEV; 192 return((x->si_udev >> 8) & 0xff); 193 } 194 195 int 196 minor(dev_t x) 197 { 198 if (x == NODEV) 199 return NOUDEV; 200 return(x->si_udev & 0xffff00ff); 201 } 202 203 int 204 dev2unit(dev_t x) 205 { 206 int i; 207 208 if (x == NODEV) 209 return NOUDEV; 210 i = minor(x); 211 return ((i & 0xff) | (i >> 8)); 212 } 213 214 int 215 unit2minor(int unit) 216 { 217 218 KASSERT(unit <= 0xffffff, ("Invalid unit (%d) in unit2minor", unit)); 219 return ((unit & 0xff) | ((unit << 8) & ~0xffff)); 220 } 221 222 static dev_t 223 allocdev(void) 224 { 225 static int stashed; 226 struct cdev *si; 227 228 if (LIST_FIRST(&dev_free)) { 229 si = LIST_FIRST(&dev_free); 230 LIST_REMOVE(si, si_hash); 231 } else if (stashed >= DEVT_STASH) { 232 MALLOC(si, struct cdev *, sizeof(*si), M_DEVT, 233 M_USE_RESERVE | M_ZERO | M_WAITOK); 234 } else { 235 si = devt_stash + stashed++; 236 bzero(si, sizeof *si); 237 si->si_flags |= SI_STASHED; 238 } 239 si->__si_namebuf[0] = '\0'; 240 si->si_name = si->__si_namebuf; 241 LIST_INIT(&si->si_children); 242 TAILQ_INIT(&si->si_snapshots); 243 return (si); 244 } 245 246 dev_t 247 makedev(int x, int y) 248 { 249 struct cdev *si; 250 udev_t udev; 251 int hash; 252 253 if (x == umajor(NOUDEV) && y == uminor(NOUDEV)) 254 panic("makedev of NOUDEV"); 255 udev = (x << 8) | y; 256 hash = udev % DEVT_HASH; 257 LIST_FOREACH(si, &dev_hash[hash], si_hash) { 258 if (si->si_udev == udev) 259 return (si); 260 } 261 si = allocdev(); 262 si->si_udev = udev; 263 LIST_INSERT_HEAD(&dev_hash[hash], si, si_hash); 264 return (si); 265 } 266 267 void 268 freedev(dev_t dev) 269 { 270 271 if (!free_devt) 272 return; 273 if (SLIST_FIRST(&dev->si_hlist)) 274 return; 275 if (dev->si_devsw || dev->si_drv1 || dev->si_drv2) 276 return; 277 LIST_REMOVE(dev, si_hash); 278 if (dev->si_flags & SI_STASHED) { 279 bzero(dev, sizeof(*dev)); 280 dev->si_flags |= SI_STASHED; 281 LIST_INSERT_HEAD(&dev_free, dev, si_hash); 282 } else { 283 FREE(dev, M_DEVT); 284 } 285 } 286 287 udev_t 288 dev2udev(dev_t x) 289 { 290 if (x == NODEV) 291 return NOUDEV; 292 return (x->si_udev); 293 } 294 295 dev_t 296 udev2dev(udev_t x, int b) 297 { 298 299 if (x == NOUDEV) 300 return (NODEV); 301 switch (b) { 302 case 0: 303 return makedev(umajor(x), uminor(x)); 304 case 1: 305 return (NODEV); 306 default: 307 Debugger("udev2dev(...,X)"); 308 return NODEV; 309 } 310 } 311 312 int 313 uminor(udev_t dev) 314 { 315 return(dev & 0xffff00ff); 316 } 317 318 int 319 umajor(udev_t dev) 320 { 321 return((dev & 0xff00) >> 8); 322 } 323 324 udev_t 325 makeudev(int x, int y) 326 { 327 return ((x << 8) | y); 328 } 329 330 dev_t 331 make_dev(struct cdevsw *devsw, int minor, uid_t uid, gid_t gid, int perms, const char *fmt, ...) 332 { 333 dev_t dev; 334 va_list ap; 335 int i; 336 337 KASSERT((minor & ~0xffff00ff) == 0, 338 ("Invalid minor (0x%x) in make_dev", minor)); 339 340 if (devsw->d_open == NULL) devsw->d_open = null_open; 341 if (devsw->d_close == NULL) devsw->d_close = null_close; 342 if (devsw->d_read == NULL) devsw->d_read = no_read; 343 if (devsw->d_write == NULL) devsw->d_write = no_write; 344 if (devsw->d_ioctl == NULL) devsw->d_ioctl = no_ioctl; 345 if (devsw->d_poll == NULL) devsw->d_poll = no_poll; 346 if (devsw->d_mmap == NULL) devsw->d_mmap = no_mmap; 347 if (devsw->d_strategy == NULL) devsw->d_strategy = no_strategy; 348 if (devsw->d_dump == NULL) devsw->d_dump = no_dump; 349 if (devsw->d_kqfilter == NULL) devsw->d_kqfilter = no_kqfilter; 350 351 if (devsw->d_maj == MAJOR_AUTO) { 352 for (i = NUMCDEVSW - 1; i > 0; i--) 353 if (reserved_majors[i] != i) 354 break; 355 KASSERT(i > 0, ("Out of major numbers (%s)", devsw->d_name)); 356 devsw->d_maj = i; 357 reserved_majors[i] = i; 358 } else { 359 if (devsw->d_maj == 256) /* XXX: tty_cons.c is magic */ 360 devsw->d_maj = 0; 361 KASSERT(devsw->d_maj >= 0 && devsw->d_maj < 256, 362 ("Invalid major (%d) in make_dev", devsw->d_maj)); 363 if (reserved_majors[devsw->d_maj] != devsw->d_maj) { 364 printf("WARNING: driver \"%s\" used %s %d\n", 365 devsw->d_name, "unreserved major device number", 366 devsw->d_maj); 367 reserved_majors[devsw->d_maj] = devsw->d_maj; 368 } 369 } 370 371 if (!ready_for_devs) { 372 printf("WARNING: Driver mistake: make_dev(%s) called before SI_SUB_DRIVERS\n", 373 fmt); 374 /* XXX panic here once drivers are cleaned up */ 375 } 376 377 dev = makedev(devsw->d_maj, minor); 378 if (dev->si_flags & SI_CHEAPCLONE && 379 dev->si_flags & SI_NAMED && 380 dev->si_devsw == devsw) { 381 /* 382 * This is allowed as it removes races and generally 383 * simplifies cloning devices. 384 */ 385 return (dev); 386 } 387 if (dev->si_flags & SI_NAMED) { 388 printf( "WARNING: Driver mistake: repeat make_dev(\"%s\")\n", 389 dev->si_name); 390 panic("don't do that"); 391 } 392 va_start(ap, fmt); 393 i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap); 394 if (i > (sizeof dev->__si_namebuf - 1)) { 395 printf("WARNING: Device name truncated! (%s)", 396 dev->__si_namebuf); 397 } 398 va_end(ap); 399 dev->si_devsw = devsw; 400 dev->si_uid = uid; 401 dev->si_gid = gid; 402 dev->si_mode = perms; 403 dev->si_flags |= SI_NAMED; 404 405 devfs_create(dev); 406 return (dev); 407 } 408 409 int 410 dev_named(dev_t pdev, const char *name) 411 { 412 dev_t cdev; 413 414 if (strcmp(devtoname(pdev), name) == 0) 415 return (1); 416 LIST_FOREACH(cdev, &pdev->si_children, si_siblings) 417 if (strcmp(devtoname(cdev), name) == 0) 418 return (1); 419 return (0); 420 } 421 422 void 423 dev_depends(dev_t pdev, dev_t cdev) 424 { 425 426 cdev->si_parent = pdev; 427 cdev->si_flags |= SI_CHILD; 428 LIST_INSERT_HEAD(&pdev->si_children, cdev, si_siblings); 429 } 430 431 dev_t 432 make_dev_alias(dev_t pdev, const char *fmt, ...) 433 { 434 dev_t dev; 435 va_list ap; 436 int i; 437 438 dev = allocdev(); 439 dev->si_flags |= SI_ALIAS; 440 dev->si_flags |= SI_NAMED; 441 dev_depends(pdev, dev); 442 va_start(ap, fmt); 443 i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap); 444 if (i > (sizeof dev->__si_namebuf - 1)) { 445 printf("WARNING: Device name truncated! (%s)", 446 dev->__si_namebuf); 447 } 448 va_end(ap); 449 450 devfs_create(dev); 451 return (dev); 452 } 453 454 void 455 destroy_dev(dev_t dev) 456 { 457 458 if (!(dev->si_flags & SI_NAMED)) { 459 printf( "WARNING: Driver mistake: destroy_dev on %d/%d\n", 460 major(dev), minor(dev)); 461 panic("don't do that"); 462 } 463 464 devfs_destroy(dev); 465 if (dev->si_flags & SI_CHILD) { 466 LIST_REMOVE(dev, si_siblings); 467 dev->si_flags &= ~SI_CHILD; 468 } 469 while (!LIST_EMPTY(&dev->si_children)) 470 destroy_dev(LIST_FIRST(&dev->si_children)); 471 dev->si_drv1 = 0; 472 dev->si_drv2 = 0; 473 dev->si_devsw = 0; 474 bzero(&dev->__si_u, sizeof(dev->__si_u)); 475 dev->si_flags &= ~SI_NAMED; 476 dev->si_flags &= ~SI_ALIAS; 477 freedev(dev); 478 } 479 480 const char * 481 devtoname(dev_t dev) 482 { 483 char *p; 484 int mynor; 485 486 if (dev->si_name[0] == '#' || dev->si_name[0] == '\0') { 487 p = dev->si_name; 488 if (devsw(dev)) 489 sprintf(p, "#%s/", devsw(dev)->d_name); 490 else 491 sprintf(p, "#%d/", major(dev)); 492 p += strlen(p); 493 mynor = minor(dev); 494 if (mynor < 0 || mynor > 255) 495 sprintf(p, "%#x", (u_int)mynor); 496 else 497 sprintf(p, "%d", mynor); 498 } 499 return (dev->si_name); 500 } 501 502 int 503 dev_stdclone(char *name, char **namep, const char *stem, int *unit) 504 { 505 int u, i; 506 507 i = strlen(stem); 508 if (bcmp(stem, name, i) != 0) 509 return (0); 510 if (!isdigit(name[i])) 511 return (0); 512 u = 0; 513 if (name[i] == '0' && isdigit(name[i+1])) 514 return (0); 515 while (isdigit(name[i])) { 516 u *= 10; 517 u += name[i++] - '0'; 518 } 519 if (u > 0xffffff) 520 return (0); 521 *unit = u; 522 if (namep) 523 *namep = &name[i]; 524 if (name[i]) 525 return (2); 526 return (1); 527 } 528 529 /* 530 * Helper sysctl for devname(3). We're given a {u}dev_t and return 531 * the name, if any, registered by the device driver. 532 */ 533 static int 534 sysctl_devname(SYSCTL_HANDLER_ARGS) 535 { 536 int error; 537 udev_t ud; 538 dev_t dev; 539 540 error = SYSCTL_IN(req, &ud, sizeof (ud)); 541 if (error) 542 return (error); 543 if (ud == NOUDEV) 544 return(EINVAL); 545 dev = makedev(umajor(ud), uminor(ud)); 546 if (dev->si_name[0] == '\0') 547 error = ENOENT; 548 else 549 error = SYSCTL_OUT(req, dev->si_name, strlen(dev->si_name) + 1); 550 freedev(dev); 551 return (error); 552 } 553 554 SYSCTL_PROC(_kern, OID_AUTO, devname, CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_ANYBODY, 555 NULL, 0, sysctl_devname, "", "devname(3) handler"); 556 557 /* 558 * Set ready_for_devs; prior to this point, device creation is not allowed. 559 */ 560 static void 561 dev_set_ready(void *junk) 562 { 563 ready_for_devs = 1; 564 } 565 566 SYSINIT(dev_ready, SI_SUB_DEVFS, SI_ORDER_FIRST, dev_set_ready, NULL); 567