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/sysctl.h> 39 #include <sys/systm.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 struct cdevsw *cdevsw[NUMCDEVSW]; 51 52 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 struct cdevsw * 78 devsw(dev_t dev) 79 { 80 if (dev->si_devsw) 81 return (dev->si_devsw); 82 return(cdevsw[major(dev)]); 83 } 84 85 /* 86 * Add a cdevsw entry 87 */ 88 89 int 90 cdevsw_add(struct cdevsw *newentry) 91 { 92 93 if (newentry->d_maj < 0 || newentry->d_maj >= NUMCDEVSW) { 94 printf("%s: ERROR: driver has bogus cdevsw->d_maj = %d\n", 95 newentry->d_name, newentry->d_maj); 96 return (EINVAL); 97 } 98 99 if (cdevsw[newentry->d_maj]) { 100 printf("WARNING: \"%s\" is usurping \"%s\"'s cdevsw[]\n", 101 newentry->d_name, cdevsw[newentry->d_maj]->d_name); 102 } 103 104 cdevsw[newentry->d_maj] = newentry; 105 106 return (0); 107 } 108 109 /* 110 * Remove a cdevsw entry 111 */ 112 113 int 114 cdevsw_remove(struct cdevsw *oldentry) 115 { 116 if (oldentry->d_maj < 0 || oldentry->d_maj >= NUMCDEVSW) { 117 printf("%s: ERROR: driver has bogus cdevsw->d_maj = %d\n", 118 oldentry->d_name, oldentry->d_maj); 119 return EINVAL; 120 } 121 122 cdevsw[oldentry->d_maj] = NULL; 123 124 return 0; 125 } 126 127 /* 128 * dev_t and u_dev_t primitives 129 */ 130 131 int 132 major(dev_t x) 133 { 134 if (x == NODEV) 135 return NOUDEV; 136 return((x->si_udev >> 8) & 0xff); 137 } 138 139 int 140 minor(dev_t x) 141 { 142 if (x == NODEV) 143 return NOUDEV; 144 return(x->si_udev & 0xffff00ff); 145 } 146 147 int 148 dev2unit(dev_t x) 149 { 150 int i; 151 152 if (x == NODEV) 153 return NOUDEV; 154 i = minor(x); 155 return ((i & 0xff) | (i >> 8)); 156 } 157 158 int 159 unit2minor(int unit) 160 { 161 162 return ((unit & 0xff) | ((unit << 8) & ~0xffff)); 163 } 164 165 static dev_t 166 allocdev(void) 167 { 168 static int stashed; 169 struct specinfo *si; 170 171 if (stashed >= DEVT_STASH) { 172 MALLOC(si, struct specinfo *, sizeof(*si), M_DEVT, 173 M_USE_RESERVE); 174 bzero(si, sizeof(*si)); 175 } else if (LIST_FIRST(&dev_free)) { 176 si = LIST_FIRST(&dev_free); 177 LIST_REMOVE(si, si_hash); 178 } else { 179 si = devt_stash + stashed++; 180 si->si_flags |= SI_STASHED; 181 } 182 LIST_INIT(&si->si_names); 183 return (si); 184 } 185 186 dev_t 187 makedev(int x, int y) 188 { 189 struct specinfo *si; 190 udev_t udev; 191 int hash; 192 193 if (x == umajor(NOUDEV) && y == uminor(NOUDEV)) 194 Debugger("makedev of NOUDEV"); 195 udev = (x << 8) | y; 196 hash = udev % DEVT_HASH; 197 LIST_FOREACH(si, &dev_hash[hash], si_hash) { 198 if (si->si_udev == udev) 199 return (si); 200 } 201 si = allocdev(); 202 si->si_udev = udev; 203 LIST_INSERT_HEAD(&dev_hash[hash], si, si_hash); 204 return (si); 205 } 206 207 void 208 freedev(dev_t dev) 209 { 210 dev_t adev; 211 212 if (!free_devt) 213 return; 214 if (SLIST_FIRST(&dev->si_hlist)) 215 return; 216 if (dev->si_devsw || dev->si_drv1 || dev->si_drv2) 217 return; 218 while (!LIST_EMPTY(&dev->si_names)) { 219 adev = LIST_FIRST(&dev->si_names); 220 adev->si_drv1 = NULL; 221 freedev(adev); 222 } 223 LIST_REMOVE(dev, si_hash); 224 if (dev->si_flags & SI_STASHED) { 225 bzero(dev, sizeof(*dev)); 226 LIST_INSERT_HEAD(&dev_free, dev, si_hash); 227 } else { 228 FREE(dev, M_DEVT); 229 } 230 } 231 232 udev_t 233 dev2udev(dev_t x) 234 { 235 if (x == NODEV) 236 return NOUDEV; 237 return (x->si_udev); 238 } 239 240 dev_t 241 udev2dev(udev_t x, int b) 242 { 243 244 if (x == NOUDEV) 245 return (NODEV); 246 switch (b) { 247 case 0: 248 return makedev(umajor(x), uminor(x)); 249 case 1: 250 return (NODEV); 251 default: 252 Debugger("udev2dev(...,X)"); 253 return NODEV; 254 } 255 } 256 257 int 258 uminor(udev_t dev) 259 { 260 return(dev & 0xffff00ff); 261 } 262 263 int 264 umajor(udev_t dev) 265 { 266 return((dev & 0xff00) >> 8); 267 } 268 269 udev_t 270 makeudev(int x, int y) 271 { 272 return ((x << 8) | y); 273 } 274 275 dev_t 276 make_dev(struct cdevsw *devsw, int minor, uid_t uid, gid_t gid, int perms, char *fmt, ...) 277 { 278 dev_t dev; 279 va_list ap; 280 int i; 281 282 dev = makedev(devsw->d_maj, minor); 283 if (dev->si_flags & SI_NAMED) { 284 printf( "WARNING: Driver mistake: repeat make_dev(\"%s\")\n", 285 dev->si_name); 286 return (dev); 287 } 288 va_start(ap, fmt); 289 i = kvprintf(fmt, NULL, dev->si_name, 32, ap); 290 dev->si_name[i] = '\0'; 291 va_end(ap); 292 dev->si_devsw = devsw; 293 dev->si_uid = uid; 294 dev->si_gid = gid; 295 dev->si_mode = perms; 296 dev->si_flags |= SI_NAMED; 297 298 if (devfs_create_hook) 299 devfs_create_hook(dev); 300 return (dev); 301 } 302 303 dev_t 304 make_dev_alias(dev_t pdev, char *fmt, ...) 305 { 306 dev_t dev; 307 va_list ap; 308 int i; 309 310 dev = allocdev(); 311 dev->si_flags |= SI_ALIAS; 312 dev->si_flags |= SI_NAMED; 313 dev->si_drv1 = pdev; 314 LIST_INSERT_HEAD(&pdev->si_names, dev, si_hash); 315 316 va_start(ap, fmt); 317 i = kvprintf(fmt, NULL, dev->si_name, 32, ap); 318 dev->si_name[i] = '\0'; 319 va_end(ap); 320 321 if (devfs_create_hook) 322 devfs_create_hook(dev); 323 return (dev); 324 } 325 326 void 327 destroy_dev(dev_t dev) 328 { 329 330 if (!(dev->si_flags & SI_NAMED)) { 331 printf( "WARNING: Driver mistake: destroy_dev on %d/%d\n", 332 major(dev), minor(dev)); 333 return; 334 } 335 336 if (devfs_destroy_hook) 337 devfs_destroy_hook(dev); 338 dev->si_drv1 = 0; 339 dev->si_drv2 = 0; 340 dev->si_devsw = 0; 341 dev->si_flags &= ~SI_NAMED; 342 dev->si_flags &= ~SI_ALIAS; 343 freedev(dev); 344 } 345 346 const char * 347 devtoname(dev_t dev) 348 { 349 char *p; 350 int mynor; 351 352 if (dev->si_name[0] == '#' || dev->si_name[0] == '\0') { 353 p = dev->si_name; 354 if (devsw(dev)) 355 sprintf(p, "#%s/", devsw(dev)->d_name); 356 else 357 sprintf(p, "#%d/", major(dev)); 358 p += strlen(p); 359 mynor = minor(dev); 360 if (mynor < 0 || mynor > 255) 361 sprintf(p, "%#x", (u_int)mynor); 362 else 363 sprintf(p, "%d", mynor); 364 } 365 return (dev->si_name); 366 } 367 368 int 369 dev_stdclone(char *name, char **namep, char *stem, int *unit) 370 { 371 int u, i; 372 373 if (bcmp(stem, name, strlen(stem)) != 0) 374 return (0); 375 i = strlen(stem); 376 if (!isdigit(name[i])) 377 return (0); 378 u = 0; 379 while (isdigit(name[i])) { 380 u *= 10; 381 u += name[i++] - '0'; 382 } 383 *unit = u; 384 if (namep) 385 *namep = &name[i]; 386 if (name[i]) 387 return (2); 388 return (1); 389 } 390 391 /* 392 * Helper sysctl for devname(3). We're given a {u}dev_t and return 393 * the name, if any, registered by the device driver. 394 */ 395 static int 396 sysctl_devname(SYSCTL_HANDLER_ARGS) 397 { 398 int error; 399 udev_t ud; 400 dev_t dev; 401 402 error = SYSCTL_IN(req, &ud, sizeof (ud)); 403 if (error) 404 return (error); 405 dev = makedev(umajor(ud), uminor(ud)); 406 if (dev->si_name[0] == '\0') 407 error = ENOENT; 408 else 409 error = SYSCTL_OUT(req, dev->si_name, strlen(dev->si_name) + 1); 410 freedev(dev); 411 return (error); 412 } 413 414 SYSCTL_PROC(_kern, OID_AUTO, devname, CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_ANYBODY, 415 NULL, 0, sysctl_devname, "", "devname(3) handler"); 416 417