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/ctype.h> 43 #include <machine/stdarg.h> 44 45 static MALLOC_DEFINE(M_DEVT, "dev_t", "dev_t storage"); 46 47 /* Built at compile time from sys/conf/majors */ 48 extern unsigned char reserved_majors[256]; 49 50 /* 51 * This is the number of hash-buckets. Experiements with 'real-life' 52 * udev_t's show that a prime halfway between two powers of two works 53 * best. 54 */ 55 #define DEVT_HASH 83 56 57 /* The number of dev_t's we can create before malloc(9) kick in. */ 58 #define DEVT_STASH 50 59 60 static struct cdev devt_stash[DEVT_STASH]; 61 62 static LIST_HEAD(, cdev) dev_hash[DEVT_HASH]; 63 64 static LIST_HEAD(, cdev) dev_free; 65 66 static int ready_for_devs; 67 68 static int free_devt; 69 SYSCTL_INT(_debug, OID_AUTO, free_devt, CTLFLAG_RW, &free_devt, 0, ""); 70 71 /* Define a dead_cdevsw for use when devices leave unexpectedly. */ 72 73 static int 74 enxio(void) 75 { 76 return (ENXIO); 77 } 78 79 #define dead_open (d_open_t *)enxio 80 #define dead_close (d_close_t *)enxio 81 #define dead_read (d_read_t *)enxio 82 #define dead_write (d_write_t *)enxio 83 #define dead_ioctl (d_ioctl_t *)enxio 84 #define dead_poll nopoll 85 #define dead_mmap nommap 86 87 static void 88 dead_strategy(struct bio *bp) 89 { 90 91 biofinish(bp, NULL, ENXIO); 92 } 93 94 #define dead_dump (dumper_t *)enxio 95 96 #define dead_kqfilter (d_kqfilter_t *)enxio 97 98 static struct cdevsw dead_cdevsw = { 99 .d_open = dead_open, 100 .d_close = dead_close, 101 .d_read = dead_read, 102 .d_write = dead_write, 103 .d_ioctl = dead_ioctl, 104 .d_poll = dead_poll, 105 .d_mmap = dead_mmap, 106 .d_strategy = dead_strategy, 107 .d_name = "dead", 108 .d_maj = 255, 109 .d_dump = dead_dump, 110 .d_kqfilter = dead_kqfilter 111 }; 112 113 114 struct cdevsw * 115 devsw(dev_t dev) 116 { 117 if (dev->si_devsw) 118 return (dev->si_devsw); 119 return (&dead_cdevsw); 120 } 121 122 /* 123 * dev_t and u_dev_t primitives 124 */ 125 126 int 127 major(dev_t x) 128 { 129 if (x == NODEV) 130 return NOUDEV; 131 return((x->si_udev >> 8) & 0xff); 132 } 133 134 int 135 minor(dev_t x) 136 { 137 if (x == NODEV) 138 return NOUDEV; 139 return(x->si_udev & 0xffff00ff); 140 } 141 142 int 143 dev2unit(dev_t x) 144 { 145 int i; 146 147 if (x == NODEV) 148 return NOUDEV; 149 i = minor(x); 150 return ((i & 0xff) | (i >> 8)); 151 } 152 153 int 154 unit2minor(int unit) 155 { 156 157 KASSERT(unit <= 0xffffff, ("Invalid unit (%d) in unit2minor", unit)); 158 return ((unit & 0xff) | ((unit << 8) & ~0xffff)); 159 } 160 161 static dev_t 162 allocdev(void) 163 { 164 static int stashed; 165 struct cdev *si; 166 167 if (LIST_FIRST(&dev_free)) { 168 si = LIST_FIRST(&dev_free); 169 LIST_REMOVE(si, si_hash); 170 } else if (stashed >= DEVT_STASH) { 171 MALLOC(si, struct cdev *, sizeof(*si), M_DEVT, 172 M_USE_RESERVE | M_ZERO | M_WAITOK); 173 } else { 174 si = devt_stash + stashed++; 175 bzero(si, sizeof *si); 176 si->si_flags |= SI_STASHED; 177 } 178 si->__si_namebuf[0] = '\0'; 179 si->si_name = si->__si_namebuf; 180 LIST_INIT(&si->si_children); 181 TAILQ_INIT(&si->si_snapshots); 182 return (si); 183 } 184 185 dev_t 186 makedev(int x, int y) 187 { 188 struct cdev *si; 189 udev_t udev; 190 int hash; 191 192 if (x == umajor(NOUDEV) && y == uminor(NOUDEV)) 193 panic("makedev of NOUDEV"); 194 udev = (x << 8) | y; 195 hash = udev % DEVT_HASH; 196 LIST_FOREACH(si, &dev_hash[hash], si_hash) { 197 if (si->si_udev == udev) 198 return (si); 199 } 200 si = allocdev(); 201 si->si_udev = udev; 202 LIST_INSERT_HEAD(&dev_hash[hash], si, si_hash); 203 return (si); 204 } 205 206 void 207 freedev(dev_t dev) 208 { 209 210 if (!free_devt) 211 return; 212 if (SLIST_FIRST(&dev->si_hlist)) 213 return; 214 if (dev->si_devsw || dev->si_drv1 || dev->si_drv2) 215 return; 216 LIST_REMOVE(dev, si_hash); 217 if (dev->si_flags & SI_STASHED) { 218 bzero(dev, sizeof(*dev)); 219 dev->si_flags |= SI_STASHED; 220 LIST_INSERT_HEAD(&dev_free, dev, si_hash); 221 } else { 222 FREE(dev, M_DEVT); 223 } 224 } 225 226 udev_t 227 dev2udev(dev_t x) 228 { 229 if (x == NODEV) 230 return NOUDEV; 231 return (x->si_udev); 232 } 233 234 dev_t 235 udev2dev(udev_t x, int b) 236 { 237 238 if (x == NOUDEV) 239 return (NODEV); 240 switch (b) { 241 case 0: 242 return makedev(umajor(x), uminor(x)); 243 case 1: 244 return (NODEV); 245 default: 246 Debugger("udev2dev(...,X)"); 247 return NODEV; 248 } 249 } 250 251 int 252 uminor(udev_t dev) 253 { 254 return(dev & 0xffff00ff); 255 } 256 257 int 258 umajor(udev_t dev) 259 { 260 return((dev & 0xff00) >> 8); 261 } 262 263 udev_t 264 makeudev(int x, int y) 265 { 266 return ((x << 8) | y); 267 } 268 269 dev_t 270 make_dev(struct cdevsw *devsw, int minor, uid_t uid, gid_t gid, int perms, const char *fmt, ...) 271 { 272 dev_t dev; 273 va_list ap; 274 int i; 275 276 KASSERT((minor & ~0xffff00ff) == 0, 277 ("Invalid minor (0x%x) in make_dev", minor)); 278 279 if (devsw->d_open == NULL) devsw->d_open = noopen; 280 if (devsw->d_close == NULL) devsw->d_close = noclose; 281 if (devsw->d_read == NULL) devsw->d_read = noread; 282 if (devsw->d_write == NULL) devsw->d_write = nowrite; 283 if (devsw->d_ioctl == NULL) devsw->d_ioctl = noioctl; 284 if (devsw->d_poll == NULL) devsw->d_poll = nopoll; 285 if (devsw->d_mmap == NULL) devsw->d_mmap = nommap; 286 if (devsw->d_strategy == NULL) devsw->d_strategy = nostrategy; 287 if (devsw->d_dump == NULL) devsw->d_dump = nodump; 288 if (devsw->d_kqfilter == NULL) devsw->d_kqfilter = nokqfilter; 289 290 if (devsw->d_maj == MAJOR_AUTO) { 291 for (i = NUMCDEVSW - 1; i > 0; i--) 292 if (reserved_majors[i] != i) 293 break; 294 KASSERT(i > 0, ("Out of major numbers (%s)", devsw->d_name)); 295 devsw->d_maj = i; 296 reserved_majors[i] = i; 297 } else { 298 if (devsw->d_maj == 256) /* XXX: tty_cons.c is magic */ 299 devsw->d_maj = 0; 300 KASSERT(devsw->d_maj >= 0 && devsw->d_maj < 256, 301 ("Invalid major (%d) in make_dev", devsw->d_maj)); 302 if (reserved_majors[devsw->d_maj] != devsw->d_maj) { 303 printf("WARNING: driver \"%s\" used %s %d\n", 304 devsw->d_name, "unreserved major device number", 305 devsw->d_maj); 306 reserved_majors[devsw->d_maj] = devsw->d_maj; 307 } 308 } 309 310 if (!ready_for_devs) { 311 printf("WARNING: Driver mistake: make_dev(%s) called before SI_SUB_DRIVERS\n", 312 fmt); 313 /* XXX panic here once drivers are cleaned up */ 314 } 315 316 dev = makedev(devsw->d_maj, minor); 317 if (dev->si_flags & SI_NAMED) { 318 printf( "WARNING: Driver mistake: repeat make_dev(\"%s\")\n", 319 dev->si_name); 320 panic("don't do that"); 321 } 322 va_start(ap, fmt); 323 i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap); 324 if (i > (sizeof dev->__si_namebuf - 1)) { 325 printf("WARNING: Device name truncated! (%s)", 326 dev->__si_namebuf); 327 } 328 va_end(ap); 329 dev->si_devsw = devsw; 330 dev->si_uid = uid; 331 dev->si_gid = gid; 332 dev->si_mode = perms; 333 dev->si_flags |= SI_NAMED; 334 335 devfs_create(dev); 336 return (dev); 337 } 338 339 int 340 dev_named(dev_t pdev, const char *name) 341 { 342 dev_t cdev; 343 344 if (strcmp(devtoname(pdev), name) == 0) 345 return (1); 346 LIST_FOREACH(cdev, &pdev->si_children, si_siblings) 347 if (strcmp(devtoname(cdev), name) == 0) 348 return (1); 349 return (0); 350 } 351 352 void 353 dev_depends(dev_t pdev, dev_t cdev) 354 { 355 356 cdev->si_parent = pdev; 357 cdev->si_flags |= SI_CHILD; 358 LIST_INSERT_HEAD(&pdev->si_children, cdev, si_siblings); 359 } 360 361 dev_t 362 make_dev_alias(dev_t pdev, const char *fmt, ...) 363 { 364 dev_t dev; 365 va_list ap; 366 int i; 367 368 dev = allocdev(); 369 dev->si_flags |= SI_ALIAS; 370 dev->si_flags |= SI_NAMED; 371 dev_depends(pdev, dev); 372 va_start(ap, fmt); 373 i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap); 374 if (i > (sizeof dev->__si_namebuf - 1)) { 375 printf("WARNING: Device name truncated! (%s)", 376 dev->__si_namebuf); 377 } 378 va_end(ap); 379 380 devfs_create(dev); 381 return (dev); 382 } 383 384 void 385 revoke_and_destroy_dev(dev_t dev) 386 { 387 struct vnode *vp; 388 389 GIANT_REQUIRED; 390 391 vp = SLIST_FIRST(&dev->si_hlist); 392 if (vp != NULL) 393 VOP_REVOKE(vp, REVOKEALL); 394 destroy_dev(dev); 395 } 396 397 void 398 destroy_dev(dev_t dev) 399 { 400 401 if (!(dev->si_flags & SI_NAMED)) { 402 printf( "WARNING: Driver mistake: destroy_dev on %d/%d\n", 403 major(dev), minor(dev)); 404 panic("don't do that"); 405 } 406 407 devfs_destroy(dev); 408 if (dev->si_flags & SI_CHILD) { 409 LIST_REMOVE(dev, si_siblings); 410 dev->si_flags &= ~SI_CHILD; 411 } 412 while (!LIST_EMPTY(&dev->si_children)) 413 destroy_dev(LIST_FIRST(&dev->si_children)); 414 dev->si_drv1 = 0; 415 dev->si_drv2 = 0; 416 dev->si_devsw = 0; 417 bzero(&dev->__si_u, sizeof(dev->__si_u)); 418 dev->si_flags &= ~SI_NAMED; 419 dev->si_flags &= ~SI_ALIAS; 420 freedev(dev); 421 } 422 423 const char * 424 devtoname(dev_t dev) 425 { 426 char *p; 427 int mynor; 428 429 if (dev->si_name[0] == '#' || dev->si_name[0] == '\0') { 430 p = dev->si_name; 431 if (devsw(dev)) 432 sprintf(p, "#%s/", devsw(dev)->d_name); 433 else 434 sprintf(p, "#%d/", major(dev)); 435 p += strlen(p); 436 mynor = minor(dev); 437 if (mynor < 0 || mynor > 255) 438 sprintf(p, "%#x", (u_int)mynor); 439 else 440 sprintf(p, "%d", mynor); 441 } 442 return (dev->si_name); 443 } 444 445 int 446 dev_stdclone(char *name, char **namep, const char *stem, int *unit) 447 { 448 int u, i; 449 450 i = strlen(stem); 451 if (bcmp(stem, name, i) != 0) 452 return (0); 453 if (!isdigit(name[i])) 454 return (0); 455 u = 0; 456 if (name[i] == '0' && isdigit(name[i+1])) 457 return (0); 458 while (isdigit(name[i])) { 459 u *= 10; 460 u += name[i++] - '0'; 461 } 462 if (u > 0xffffff) 463 return (0); 464 *unit = u; 465 if (namep) 466 *namep = &name[i]; 467 if (name[i]) 468 return (2); 469 return (1); 470 } 471 472 /* 473 * Helper sysctl for devname(3). We're given a {u}dev_t and return 474 * the name, if any, registered by the device driver. 475 */ 476 static int 477 sysctl_devname(SYSCTL_HANDLER_ARGS) 478 { 479 int error; 480 udev_t ud; 481 dev_t dev; 482 483 error = SYSCTL_IN(req, &ud, sizeof (ud)); 484 if (error) 485 return (error); 486 if (ud == NOUDEV) 487 return(EINVAL); 488 dev = makedev(umajor(ud), uminor(ud)); 489 if (dev->si_name[0] == '\0') 490 error = ENOENT; 491 else 492 error = SYSCTL_OUT(req, dev->si_name, strlen(dev->si_name) + 1); 493 freedev(dev); 494 return (error); 495 } 496 497 SYSCTL_PROC(_kern, OID_AUTO, devname, CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_ANYBODY, 498 NULL, 0, sysctl_devname, "", "devname(3) handler"); 499 500 /* 501 * Set ready_for_devs; prior to this point, device creation is not allowed. 502 */ 503 static void 504 dev_set_ready(void *junk) 505 { 506 ready_for_devs = 1; 507 } 508 509 SYSINIT(dev_ready, SI_SUB_DEVFS, SI_ORDER_FIRST, dev_set_ready, NULL); 510