1 /*- 2 * Parts Copyright (c) 1995 Terrence R. Lambert 3 * Copyright (c) 1995 Julian R. Elischer 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. All advertising materials mentioning features or use of this software 15 * must display the following acknowledgement: 16 * This product includes software developed by Terrence R. Lambert. 17 * 4. The name Terrence R. Lambert may not be used to endorse or promote 18 * products derived from this software without specific prior written 19 * permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY Julian R. Elischer ``AS IS'' AND ANY 22 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE TERRENCE R. LAMBERT BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * $FreeBSD$ 34 */ 35 36 #include <sys/param.h> 37 #include <sys/kernel.h> 38 #include <sys/systm.h> 39 #include <sys/sysctl.h> 40 #include <sys/module.h> 41 #include <sys/malloc.h> 42 #include <sys/conf.h> 43 #include <sys/vnode.h> 44 #include <sys/queue.h> 45 #include <sys/ctype.h> 46 #include <machine/stdarg.h> 47 48 #define cdevsw_ALLOCSTART (NUMCDEVSW/2) 49 50 static struct cdevsw *cdevsw[NUMCDEVSW]; 51 52 static MALLOC_DEFINE(M_DEVT, "dev_t", "dev_t storage"); 53 54 /* 55 * This is the number of hash-buckets. Experiements with 'real-life' 56 * udev_t's show that a prime halfway between two powers of two works 57 * best. 58 */ 59 #define DEVT_HASH 83 60 61 /* The number of dev_t's we can create before malloc(9) kick in. */ 62 #define DEVT_STASH 50 63 64 static struct specinfo devt_stash[DEVT_STASH]; 65 66 static LIST_HEAD(, specinfo) dev_hash[DEVT_HASH]; 67 68 static LIST_HEAD(, specinfo) dev_free; 69 70 devfs_create_t *devfs_create_hook; 71 devfs_destroy_t *devfs_destroy_hook; 72 int devfs_present; 73 74 static int free_devt; 75 SYSCTL_INT(_debug, OID_AUTO, free_devt, CTLFLAG_RW, &free_devt, 0, ""); 76 77 /* XXX: This is a hack */ 78 void disk_dev_synth(dev_t dev); 79 80 struct cdevsw * 81 devsw(dev_t dev) 82 { 83 if (dev->si_devsw) 84 return (dev->si_devsw); 85 /* XXX: Hack around our backwards disk code */ 86 disk_dev_synth(dev); 87 if (dev->si_devsw) 88 return (dev->si_devsw); 89 if (devfs_present) 90 return (NULL); 91 return(cdevsw[major(dev)]); 92 } 93 94 /* 95 * Add a cdevsw entry 96 */ 97 98 int 99 cdevsw_add(struct cdevsw *newentry) 100 { 101 102 if (newentry->d_maj < 0 || newentry->d_maj >= NUMCDEVSW) { 103 printf("%s: ERROR: driver has bogus cdevsw->d_maj = %d\n", 104 newentry->d_name, newentry->d_maj); 105 return (EINVAL); 106 } 107 108 if (cdevsw[newentry->d_maj]) { 109 printf("WARNING: \"%s\" is usurping \"%s\"'s cdevsw[]\n", 110 newentry->d_name, cdevsw[newentry->d_maj]->d_name); 111 } 112 113 cdevsw[newentry->d_maj] = newentry; 114 115 return (0); 116 } 117 118 /* 119 * Remove a cdevsw entry 120 */ 121 122 int 123 cdevsw_remove(struct cdevsw *oldentry) 124 { 125 if (oldentry->d_maj < 0 || oldentry->d_maj >= NUMCDEVSW) { 126 printf("%s: ERROR: driver has bogus cdevsw->d_maj = %d\n", 127 oldentry->d_name, oldentry->d_maj); 128 return EINVAL; 129 } 130 131 cdevsw[oldentry->d_maj] = NULL; 132 133 return 0; 134 } 135 136 /* 137 * dev_t and u_dev_t primitives 138 */ 139 140 int 141 major(dev_t x) 142 { 143 if (x == NODEV) 144 return NOUDEV; 145 return((x->si_udev >> 8) & 0xff); 146 } 147 148 int 149 minor(dev_t x) 150 { 151 if (x == NODEV) 152 return NOUDEV; 153 return(x->si_udev & 0xffff00ff); 154 } 155 156 int 157 dev2unit(dev_t x) 158 { 159 int i; 160 161 if (x == NODEV) 162 return NOUDEV; 163 i = minor(x); 164 return ((i & 0xff) | (i >> 8)); 165 } 166 167 int 168 unit2minor(int unit) 169 { 170 171 KASSERT(unit <= 0xffffff, ("Invalid unit (%d) in unit2minor", unit)); 172 return ((unit & 0xff) | ((unit << 8) & ~0xffff)); 173 } 174 175 static dev_t 176 allocdev(void) 177 { 178 static int stashed; 179 struct specinfo *si; 180 181 if (stashed >= DEVT_STASH) { 182 MALLOC(si, struct specinfo *, sizeof(*si), M_DEVT, 183 M_USE_RESERVE | M_ZERO); 184 } else if (LIST_FIRST(&dev_free)) { 185 si = LIST_FIRST(&dev_free); 186 LIST_REMOVE(si, si_hash); 187 } else { 188 si = devt_stash + stashed++; 189 bzero(si, sizeof *si); 190 si->si_flags |= SI_STASHED; 191 } 192 LIST_INIT(&si->si_children); 193 TAILQ_INIT(&si->si_snapshots); 194 return (si); 195 } 196 197 dev_t 198 makedev(int x, int y) 199 { 200 struct specinfo *si; 201 udev_t udev; 202 int hash; 203 204 if (x == umajor(NOUDEV) && y == uminor(NOUDEV)) 205 panic("makedev of NOUDEV"); 206 udev = (x << 8) | y; 207 hash = udev % DEVT_HASH; 208 LIST_FOREACH(si, &dev_hash[hash], si_hash) { 209 if (si->si_udev == udev) 210 return (si); 211 } 212 si = allocdev(); 213 si->si_udev = udev; 214 LIST_INSERT_HEAD(&dev_hash[hash], si, si_hash); 215 return (si); 216 } 217 218 void 219 freedev(dev_t dev) 220 { 221 222 if (!free_devt) 223 return; 224 if (SLIST_FIRST(&dev->si_hlist)) 225 return; 226 if (dev->si_devsw || dev->si_drv1 || dev->si_drv2) 227 return; 228 LIST_REMOVE(dev, si_hash); 229 if (dev->si_flags & SI_STASHED) { 230 bzero(dev, sizeof(*dev)); 231 dev->si_flags |= SI_STASHED; 232 LIST_INSERT_HEAD(&dev_free, dev, si_hash); 233 } else { 234 FREE(dev, M_DEVT); 235 } 236 } 237 238 udev_t 239 dev2udev(dev_t x) 240 { 241 if (x == NODEV) 242 return NOUDEV; 243 return (x->si_udev); 244 } 245 246 dev_t 247 udev2dev(udev_t x, int b) 248 { 249 250 if (x == NOUDEV) 251 return (NODEV); 252 switch (b) { 253 case 0: 254 return makedev(umajor(x), uminor(x)); 255 case 1: 256 return (NODEV); 257 default: 258 Debugger("udev2dev(...,X)"); 259 return NODEV; 260 } 261 } 262 263 int 264 uminor(udev_t dev) 265 { 266 return(dev & 0xffff00ff); 267 } 268 269 int 270 umajor(udev_t dev) 271 { 272 return((dev & 0xff00) >> 8); 273 } 274 275 udev_t 276 makeudev(int x, int y) 277 { 278 return ((x << 8) | y); 279 } 280 281 dev_t 282 make_dev(struct cdevsw *devsw, int minor, uid_t uid, gid_t gid, int perms, const char *fmt, ...) 283 { 284 dev_t dev; 285 va_list ap; 286 int i; 287 288 KASSERT(umajor(makeudev(devsw->d_maj, minor)) == devsw->d_maj, 289 ("Invalid minor (%d) in make_dev", minor)); 290 291 dev = makedev(devsw->d_maj, minor); 292 if (dev->si_flags & SI_NAMED) { 293 printf( "WARNING: Driver mistake: repeat make_dev(\"%s\")\n", 294 dev->si_name); 295 panic("don't do that"); 296 return (dev); 297 } 298 va_start(ap, fmt); 299 i = kvprintf(fmt, NULL, dev->si_name, 32, ap); 300 dev->si_name[i] = '\0'; 301 va_end(ap); 302 dev->si_devsw = devsw; 303 dev->si_uid = uid; 304 dev->si_gid = gid; 305 dev->si_mode = perms; 306 dev->si_flags |= SI_NAMED; 307 308 if (devfs_create_hook) 309 devfs_create_hook(dev); 310 return (dev); 311 } 312 313 int 314 dev_named(dev_t pdev, const char *name) 315 { 316 dev_t cdev; 317 318 if (strcmp(devtoname(pdev), name) == 0) 319 return (1); 320 LIST_FOREACH(cdev, &pdev->si_children, si_siblings) 321 if (strcmp(devtoname(cdev), name) == 0) 322 return (1); 323 return (0); 324 } 325 326 void 327 dev_depends(dev_t pdev, dev_t cdev) 328 { 329 330 cdev->si_parent = pdev; 331 cdev->si_flags |= SI_CHILD; 332 LIST_INSERT_HEAD(&pdev->si_children, cdev, si_siblings); 333 } 334 335 dev_t 336 make_dev_alias(dev_t pdev, const char *fmt, ...) 337 { 338 dev_t dev; 339 va_list ap; 340 int i; 341 342 dev = allocdev(); 343 dev->si_flags |= SI_ALIAS; 344 dev->si_flags |= SI_NAMED; 345 dev_depends(pdev, dev); 346 va_start(ap, fmt); 347 i = kvprintf(fmt, NULL, dev->si_name, 32, ap); 348 dev->si_name[i] = '\0'; 349 va_end(ap); 350 351 if (devfs_create_hook) 352 devfs_create_hook(dev); 353 return (dev); 354 } 355 356 void 357 destroy_dev(dev_t dev) 358 { 359 360 if (!(dev->si_flags & SI_NAMED)) { 361 printf( "WARNING: Driver mistake: destroy_dev on %d/%d\n", 362 major(dev), minor(dev)); 363 panic("don't do that"); 364 return; 365 } 366 367 if (devfs_destroy_hook) 368 devfs_destroy_hook(dev); 369 if (dev->si_flags & SI_CHILD) { 370 LIST_REMOVE(dev, si_siblings); 371 dev->si_flags &= ~SI_CHILD; 372 } 373 while (!LIST_EMPTY(&dev->si_children)) 374 destroy_dev(LIST_FIRST(&dev->si_children)); 375 dev->si_drv1 = 0; 376 dev->si_drv2 = 0; 377 dev->si_devsw = 0; 378 dev->si_flags &= ~SI_NAMED; 379 dev->si_flags &= ~SI_ALIAS; 380 freedev(dev); 381 } 382 383 const char * 384 devtoname(dev_t dev) 385 { 386 char *p; 387 int mynor; 388 389 if (dev->si_name[0] == '#' || dev->si_name[0] == '\0') { 390 p = dev->si_name; 391 if (devsw(dev)) 392 sprintf(p, "#%s/", devsw(dev)->d_name); 393 else 394 sprintf(p, "#%d/", major(dev)); 395 p += strlen(p); 396 mynor = minor(dev); 397 if (mynor < 0 || mynor > 255) 398 sprintf(p, "%#x", (u_int)mynor); 399 else 400 sprintf(p, "%d", mynor); 401 } 402 return (dev->si_name); 403 } 404 405 int 406 dev_stdclone(char *name, char **namep, char *stem, int *unit) 407 { 408 int u, i; 409 410 i = strlen(stem); 411 if (bcmp(stem, name, i) != 0) 412 return (0); 413 if (!isdigit(name[i])) 414 return (0); 415 u = 0; 416 if (name[i] == '0' && isdigit(name[i+1])) 417 return (0); 418 while (isdigit(name[i])) { 419 u *= 10; 420 u += name[i++] - '0'; 421 } 422 *unit = u; 423 if (namep) 424 *namep = &name[i]; 425 if (name[i]) 426 return (2); 427 return (1); 428 } 429 430 /* 431 * Helper sysctl for devname(3). We're given a {u}dev_t and return 432 * the name, if any, registered by the device driver. 433 */ 434 static int 435 sysctl_devname(SYSCTL_HANDLER_ARGS) 436 { 437 int error; 438 udev_t ud; 439 dev_t dev; 440 441 error = SYSCTL_IN(req, &ud, sizeof (ud)); 442 if (error) 443 return (error); 444 if (ud == NOUDEV) 445 return(EINVAL); 446 dev = makedev(umajor(ud), uminor(ud)); 447 if (dev->si_name[0] == '\0') 448 error = ENOENT; 449 else 450 error = SYSCTL_OUT(req, dev->si_name, strlen(dev->si_name) + 1); 451 freedev(dev); 452 return (error); 453 } 454 455 SYSCTL_PROC(_kern, OID_AUTO, devname, CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_ANYBODY, 456 NULL, 0, sysctl_devname, "", "devname(3) handler"); 457 458