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