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