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 * $FreeBSD$ 27 */ 28 29 #include <sys/param.h> 30 #include <sys/kernel.h> 31 #include <sys/systm.h> 32 #include <sys/lock.h> 33 #include <sys/mutex.h> 34 #include <sys/sysctl.h> 35 #include <sys/module.h> 36 #include <sys/malloc.h> 37 #include <sys/conf.h> 38 #include <sys/vnode.h> 39 #include <sys/queue.h> 40 #include <sys/ctype.h> 41 #include <machine/stdarg.h> 42 43 #ifdef NODEVFS 44 static struct cdevsw *cdevsw[NUMCDEVSW]; 45 46 #endif 47 static MALLOC_DEFINE(M_DEVT, "dev_t", "dev_t storage"); 48 49 /* 50 * This is the number of hash-buckets. Experiements with 'real-life' 51 * udev_t's show that a prime halfway between two powers of two works 52 * best. 53 */ 54 #define DEVT_HASH 83 55 56 /* The number of dev_t's we can create before malloc(9) kick in. */ 57 #define DEVT_STASH 50 58 59 static struct cdev devt_stash[DEVT_STASH]; 60 61 static LIST_HEAD(, cdev) dev_hash[DEVT_HASH]; 62 63 static LIST_HEAD(, cdev) dev_free; 64 65 devfs_create_t *devfs_create_hook; 66 devfs_destroy_t *devfs_destroy_hook; 67 68 static int ready_for_devs; 69 70 static int free_devt; 71 SYSCTL_INT(_debug, OID_AUTO, free_devt, CTLFLAG_RW, &free_devt, 0, ""); 72 73 #ifdef NO_GEOM 74 /* XXX: This is a hack */ 75 void disk_dev_synth(dev_t dev); 76 #endif 77 78 struct cdevsw * 79 devsw(dev_t dev) 80 { 81 if (dev->si_devsw) 82 return (dev->si_devsw); 83 #ifdef NO_GEOM 84 /* XXX: Hack around our backwards disk code */ 85 disk_dev_synth(dev); 86 #endif 87 if (dev->si_devsw) 88 return (dev->si_devsw); 89 #ifndef NODEVFS 90 return (NULL); 91 #else 92 return(cdevsw[major(dev)]); 93 #endif 94 } 95 96 /* 97 * Add a cdevsw entry 98 */ 99 100 int 101 cdevsw_add(struct cdevsw *newentry) 102 { 103 #ifdef NODEVFS 104 if (newentry->d_maj < 0 || newentry->d_maj >= NUMCDEVSW) { 105 printf("%s: ERROR: driver has bogus cdevsw->d_maj = %d\n", 106 newentry->d_name, newentry->d_maj); 107 return (EINVAL); 108 } 109 110 if (cdevsw[newentry->d_maj]) { 111 printf("WARNING: \"%s\" is usurping \"%s\"'s cdevsw[]\n", 112 newentry->d_name, cdevsw[newentry->d_maj]->d_name); 113 } 114 115 cdevsw[newentry->d_maj] = newentry; 116 #endif 117 118 return (0); 119 } 120 121 /* 122 * Remove a cdevsw entry 123 */ 124 125 int 126 cdevsw_remove(struct cdevsw *oldentry) 127 { 128 #ifdef NODEVFS 129 if (oldentry->d_maj < 0 || oldentry->d_maj >= NUMCDEVSW) { 130 printf("%s: ERROR: driver has bogus cdevsw->d_maj = %d\n", 131 oldentry->d_name, oldentry->d_maj); 132 return EINVAL; 133 } 134 135 cdevsw[oldentry->d_maj] = NULL; 136 #endif 137 138 return 0; 139 } 140 141 /* 142 * dev_t and u_dev_t primitives 143 */ 144 145 int 146 major(dev_t x) 147 { 148 if (x == NODEV) 149 return NOUDEV; 150 return((x->si_udev >> 8) & 0xff); 151 } 152 153 int 154 minor(dev_t x) 155 { 156 if (x == NODEV) 157 return NOUDEV; 158 return(x->si_udev & 0xffff00ff); 159 } 160 161 int 162 dev2unit(dev_t x) 163 { 164 int i; 165 166 if (x == NODEV) 167 return NOUDEV; 168 i = minor(x); 169 return ((i & 0xff) | (i >> 8)); 170 } 171 172 int 173 unit2minor(int unit) 174 { 175 176 KASSERT(unit <= 0xffffff, ("Invalid unit (%d) in unit2minor", unit)); 177 return ((unit & 0xff) | ((unit << 8) & ~0xffff)); 178 } 179 180 static dev_t 181 allocdev(void) 182 { 183 static int stashed; 184 struct cdev *si; 185 186 if (LIST_FIRST(&dev_free)) { 187 si = LIST_FIRST(&dev_free); 188 LIST_REMOVE(si, si_hash); 189 } else if (stashed >= DEVT_STASH) { 190 MALLOC(si, struct cdev *, sizeof(*si), M_DEVT, 191 M_USE_RESERVE | M_ZERO); 192 } else { 193 si = devt_stash + stashed++; 194 bzero(si, sizeof *si); 195 si->si_flags |= SI_STASHED; 196 } 197 LIST_INIT(&si->si_children); 198 TAILQ_INIT(&si->si_snapshots); 199 return (si); 200 } 201 202 dev_t 203 makedev(int x, int y) 204 { 205 struct cdev *si; 206 udev_t udev; 207 int hash; 208 209 if (x == umajor(NOUDEV) && y == uminor(NOUDEV)) 210 panic("makedev of NOUDEV"); 211 udev = (x << 8) | y; 212 hash = udev % DEVT_HASH; 213 LIST_FOREACH(si, &dev_hash[hash], si_hash) { 214 if (si->si_udev == udev) 215 return (si); 216 } 217 si = allocdev(); 218 si->si_udev = udev; 219 LIST_INSERT_HEAD(&dev_hash[hash], si, si_hash); 220 return (si); 221 } 222 223 void 224 freedev(dev_t dev) 225 { 226 227 if (!free_devt) 228 return; 229 if (SLIST_FIRST(&dev->si_hlist)) 230 return; 231 if (dev->si_devsw || dev->si_drv1 || dev->si_drv2) 232 return; 233 LIST_REMOVE(dev, si_hash); 234 if (dev->si_flags & SI_STASHED) { 235 bzero(dev, sizeof(*dev)); 236 dev->si_flags |= SI_STASHED; 237 LIST_INSERT_HEAD(&dev_free, dev, si_hash); 238 } else { 239 FREE(dev, M_DEVT); 240 } 241 } 242 243 udev_t 244 dev2udev(dev_t x) 245 { 246 if (x == NODEV) 247 return NOUDEV; 248 return (x->si_udev); 249 } 250 251 dev_t 252 udev2dev(udev_t x, int b) 253 { 254 255 if (x == NOUDEV) 256 return (NODEV); 257 switch (b) { 258 case 0: 259 return makedev(umajor(x), uminor(x)); 260 case 1: 261 return (NODEV); 262 default: 263 Debugger("udev2dev(...,X)"); 264 return NODEV; 265 } 266 } 267 268 int 269 uminor(udev_t dev) 270 { 271 return(dev & 0xffff00ff); 272 } 273 274 int 275 umajor(udev_t dev) 276 { 277 return((dev & 0xff00) >> 8); 278 } 279 280 udev_t 281 makeudev(int x, int y) 282 { 283 return ((x << 8) | y); 284 } 285 286 dev_t 287 make_dev(struct cdevsw *devsw, int minor, uid_t uid, gid_t gid, int perms, const char *fmt, ...) 288 { 289 dev_t dev; 290 va_list ap; 291 int i; 292 293 KASSERT(umajor(makeudev(devsw->d_maj, minor)) == devsw->d_maj, 294 ("Invalid minor (%d) in make_dev", minor)); 295 296 if (!ready_for_devs) { 297 printf("WARNING: Driver mistake: make_dev(%s) called before SI_SUB_DRIVERS\n", 298 fmt); 299 /* XXX panic here once drivers are cleaned up */ 300 } 301 302 dev = makedev(devsw->d_maj, minor); 303 if (dev->si_flags & SI_NAMED) { 304 printf( "WARNING: Driver mistake: repeat make_dev(\"%s\")\n", 305 dev->si_name); 306 panic("don't do that"); 307 return (dev); 308 } 309 va_start(ap, fmt); 310 i = kvprintf(fmt, NULL, dev->si_name, 32, ap); 311 dev->si_name[i] = '\0'; 312 va_end(ap); 313 dev->si_devsw = devsw; 314 dev->si_uid = uid; 315 dev->si_gid = gid; 316 dev->si_mode = perms; 317 dev->si_flags |= SI_NAMED; 318 319 if (devfs_create_hook) 320 devfs_create_hook(dev); 321 return (dev); 322 } 323 324 int 325 dev_named(dev_t pdev, const char *name) 326 { 327 dev_t cdev; 328 329 if (strcmp(devtoname(pdev), name) == 0) 330 return (1); 331 LIST_FOREACH(cdev, &pdev->si_children, si_siblings) 332 if (strcmp(devtoname(cdev), name) == 0) 333 return (1); 334 return (0); 335 } 336 337 void 338 dev_depends(dev_t pdev, dev_t cdev) 339 { 340 341 cdev->si_parent = pdev; 342 cdev->si_flags |= SI_CHILD; 343 LIST_INSERT_HEAD(&pdev->si_children, cdev, si_siblings); 344 } 345 346 dev_t 347 make_dev_alias(dev_t pdev, const char *fmt, ...) 348 { 349 dev_t dev; 350 va_list ap; 351 int i; 352 353 dev = allocdev(); 354 dev->si_flags |= SI_ALIAS; 355 dev->si_flags |= SI_NAMED; 356 dev_depends(pdev, dev); 357 va_start(ap, fmt); 358 i = kvprintf(fmt, NULL, dev->si_name, 32, ap); 359 dev->si_name[i] = '\0'; 360 va_end(ap); 361 362 if (devfs_create_hook) 363 devfs_create_hook(dev); 364 return (dev); 365 } 366 367 void 368 revoke_and_destroy_dev(dev_t dev) 369 { 370 struct vnode *vp; 371 372 GIANT_REQUIRED; 373 374 vp = SLIST_FIRST(&dev->si_hlist); 375 if (vp != NULL) 376 VOP_REVOKE(vp, REVOKEALL); 377 destroy_dev(dev); 378 } 379 380 void 381 destroy_dev(dev_t dev) 382 { 383 384 if (!(dev->si_flags & SI_NAMED)) { 385 printf( "WARNING: Driver mistake: destroy_dev on %d/%d\n", 386 major(dev), minor(dev)); 387 panic("don't do that"); 388 return; 389 } 390 391 if (devfs_destroy_hook) 392 devfs_destroy_hook(dev); 393 if (dev->si_flags & SI_CHILD) { 394 LIST_REMOVE(dev, si_siblings); 395 dev->si_flags &= ~SI_CHILD; 396 } 397 while (!LIST_EMPTY(&dev->si_children)) 398 destroy_dev(LIST_FIRST(&dev->si_children)); 399 dev->si_drv1 = 0; 400 dev->si_drv2 = 0; 401 dev->si_devsw = 0; 402 bzero(&dev->__si_u, sizeof(dev->__si_u)); 403 dev->si_flags &= ~SI_NAMED; 404 dev->si_flags &= ~SI_ALIAS; 405 freedev(dev); 406 } 407 408 const char * 409 devtoname(dev_t dev) 410 { 411 char *p; 412 int mynor; 413 414 if (dev->si_name[0] == '#' || dev->si_name[0] == '\0') { 415 p = dev->si_name; 416 if (devsw(dev)) 417 sprintf(p, "#%s/", devsw(dev)->d_name); 418 else 419 sprintf(p, "#%d/", major(dev)); 420 p += strlen(p); 421 mynor = minor(dev); 422 if (mynor < 0 || mynor > 255) 423 sprintf(p, "%#x", (u_int)mynor); 424 else 425 sprintf(p, "%d", mynor); 426 } 427 return (dev->si_name); 428 } 429 430 int 431 dev_stdclone(char *name, char **namep, const char *stem, int *unit) 432 { 433 int u, i; 434 435 i = strlen(stem); 436 if (bcmp(stem, name, i) != 0) 437 return (0); 438 if (!isdigit(name[i])) 439 return (0); 440 u = 0; 441 if (name[i] == '0' && isdigit(name[i+1])) 442 return (0); 443 while (isdigit(name[i])) { 444 u *= 10; 445 u += name[i++] - '0'; 446 } 447 if (u > 0xffffff) 448 return (0); 449 *unit = u; 450 if (namep) 451 *namep = &name[i]; 452 if (name[i]) 453 return (2); 454 return (1); 455 } 456 457 /* 458 * Helper sysctl for devname(3). We're given a {u}dev_t and return 459 * the name, if any, registered by the device driver. 460 */ 461 static int 462 sysctl_devname(SYSCTL_HANDLER_ARGS) 463 { 464 int error; 465 udev_t ud; 466 dev_t dev; 467 468 error = SYSCTL_IN(req, &ud, sizeof (ud)); 469 if (error) 470 return (error); 471 if (ud == NOUDEV) 472 return(EINVAL); 473 dev = makedev(umajor(ud), uminor(ud)); 474 if (dev->si_name[0] == '\0') 475 error = ENOENT; 476 else 477 error = SYSCTL_OUT(req, dev->si_name, strlen(dev->si_name) + 1); 478 freedev(dev); 479 return (error); 480 } 481 482 SYSCTL_PROC(_kern, OID_AUTO, devname, CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_ANYBODY, 483 NULL, 0, sysctl_devname, "", "devname(3) handler"); 484 485 /* 486 * Set ready_for_devs; prior to this point, device creation is not allowed. 487 */ 488 static void 489 dev_set_ready(void *junk) 490 { 491 ready_for_devs = 1; 492 } 493 494 SYSINIT(dev_ready, SI_SUB_DEVFS, SI_ORDER_FIRST, dev_set_ready, NULL); 495