kern_conf.c revision 110060
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: head/sys/kern/kern_conf.c 110060 2003-01-29 21:54:03Z phk $ 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 43static 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 55static struct cdev devt_stash[DEVT_STASH]; 56 57static LIST_HEAD(, cdev) dev_hash[DEVT_HASH]; 58 59static LIST_HEAD(, cdev) dev_free; 60 61devfs_create_t *devfs_create_hook; 62devfs_destroy_t *devfs_destroy_hook; 63 64static int ready_for_devs; 65 66static int free_devt; 67SYSCTL_INT(_debug, OID_AUTO, free_devt, CTLFLAG_RW, &free_devt, 0, ""); 68 69#ifdef NO_GEOM 70/* XXX: This is a hack */ 71void disk_dev_synth(dev_t dev); 72#endif 73 74struct cdevsw * 75devsw(dev_t dev) 76{ 77 if (dev->si_devsw) 78 return (dev->si_devsw); 79#ifdef NO_GEOM 80 /* XXX: Hack around our backwards disk code */ 81 disk_dev_synth(dev); 82#endif 83 if (dev->si_devsw) 84 return (dev->si_devsw); 85 return (NULL); 86} 87 88/* 89 * Add a cdevsw entry 90 */ 91 92int 93cdevsw_add(struct cdevsw *newentry) 94{ 95 96 return (0); 97} 98 99/* 100 * Remove a cdevsw entry 101 */ 102 103int 104cdevsw_remove(struct cdevsw *oldentry) 105{ 106 107 return 0; 108} 109 110/* 111 * dev_t and u_dev_t primitives 112 */ 113 114int 115major(dev_t x) 116{ 117 if (x == NODEV) 118 return NOUDEV; 119 return((x->si_udev >> 8) & 0xff); 120} 121 122int 123minor(dev_t x) 124{ 125 if (x == NODEV) 126 return NOUDEV; 127 return(x->si_udev & 0xffff00ff); 128} 129 130int 131dev2unit(dev_t x) 132{ 133 int i; 134 135 if (x == NODEV) 136 return NOUDEV; 137 i = minor(x); 138 return ((i & 0xff) | (i >> 8)); 139} 140 141int 142unit2minor(int unit) 143{ 144 145 KASSERT(unit <= 0xffffff, ("Invalid unit (%d) in unit2minor", unit)); 146 return ((unit & 0xff) | ((unit << 8) & ~0xffff)); 147} 148 149static dev_t 150allocdev(void) 151{ 152 static int stashed; 153 struct cdev *si; 154 155 if (LIST_FIRST(&dev_free)) { 156 si = LIST_FIRST(&dev_free); 157 LIST_REMOVE(si, si_hash); 158 } else if (stashed >= DEVT_STASH) { 159 MALLOC(si, struct cdev *, sizeof(*si), M_DEVT, 160 M_USE_RESERVE | M_ZERO); 161 } else { 162 si = devt_stash + stashed++; 163 bzero(si, sizeof *si); 164 si->si_flags |= SI_STASHED; 165 } 166 LIST_INIT(&si->si_children); 167 TAILQ_INIT(&si->si_snapshots); 168 return (si); 169} 170 171dev_t 172makedev(int x, int y) 173{ 174 struct cdev *si; 175 udev_t udev; 176 int hash; 177 178 if (x == umajor(NOUDEV) && y == uminor(NOUDEV)) 179 panic("makedev of NOUDEV"); 180 udev = (x << 8) | y; 181 hash = udev % DEVT_HASH; 182 LIST_FOREACH(si, &dev_hash[hash], si_hash) { 183 if (si->si_udev == udev) 184 return (si); 185 } 186 si = allocdev(); 187 si->si_udev = udev; 188 LIST_INSERT_HEAD(&dev_hash[hash], si, si_hash); 189 return (si); 190} 191 192void 193freedev(dev_t dev) 194{ 195 196 if (!free_devt) 197 return; 198 if (SLIST_FIRST(&dev->si_hlist)) 199 return; 200 if (dev->si_devsw || dev->si_drv1 || dev->si_drv2) 201 return; 202 LIST_REMOVE(dev, si_hash); 203 if (dev->si_flags & SI_STASHED) { 204 bzero(dev, sizeof(*dev)); 205 dev->si_flags |= SI_STASHED; 206 LIST_INSERT_HEAD(&dev_free, dev, si_hash); 207 } else { 208 FREE(dev, M_DEVT); 209 } 210} 211 212udev_t 213dev2udev(dev_t x) 214{ 215 if (x == NODEV) 216 return NOUDEV; 217 return (x->si_udev); 218} 219 220dev_t 221udev2dev(udev_t x, int b) 222{ 223 224 if (x == NOUDEV) 225 return (NODEV); 226 switch (b) { 227 case 0: 228 return makedev(umajor(x), uminor(x)); 229 case 1: 230 return (NODEV); 231 default: 232 Debugger("udev2dev(...,X)"); 233 return NODEV; 234 } 235} 236 237int 238uminor(udev_t dev) 239{ 240 return(dev & 0xffff00ff); 241} 242 243int 244umajor(udev_t dev) 245{ 246 return((dev & 0xff00) >> 8); 247} 248 249udev_t 250makeudev(int x, int y) 251{ 252 return ((x << 8) | y); 253} 254 255dev_t 256make_dev(struct cdevsw *devsw, int minor, uid_t uid, gid_t gid, int perms, const char *fmt, ...) 257{ 258 dev_t dev; 259 va_list ap; 260 int i; 261 262 KASSERT(umajor(makeudev(devsw->d_maj, minor)) == devsw->d_maj, 263 ("Invalid minor (%d) in make_dev", minor)); 264 265 if (!ready_for_devs) { 266 printf("WARNING: Driver mistake: make_dev(%s) called before SI_SUB_DRIVERS\n", 267 fmt); 268 /* XXX panic here once drivers are cleaned up */ 269 } 270 271 dev = makedev(devsw->d_maj, minor); 272 if (dev->si_flags & SI_NAMED) { 273 printf( "WARNING: Driver mistake: repeat make_dev(\"%s\")\n", 274 dev->si_name); 275 panic("don't do that"); 276 return (dev); 277 } 278 va_start(ap, fmt); 279 i = kvprintf(fmt, NULL, dev->si_name, 32, ap); 280 dev->si_name[i] = '\0'; 281 va_end(ap); 282 dev->si_devsw = devsw; 283 dev->si_uid = uid; 284 dev->si_gid = gid; 285 dev->si_mode = perms; 286 dev->si_flags |= SI_NAMED; 287 288 if (devfs_create_hook) 289 devfs_create_hook(dev); 290 return (dev); 291} 292 293int 294dev_named(dev_t pdev, const char *name) 295{ 296 dev_t cdev; 297 298 if (strcmp(devtoname(pdev), name) == 0) 299 return (1); 300 LIST_FOREACH(cdev, &pdev->si_children, si_siblings) 301 if (strcmp(devtoname(cdev), name) == 0) 302 return (1); 303 return (0); 304} 305 306void 307dev_depends(dev_t pdev, dev_t cdev) 308{ 309 310 cdev->si_parent = pdev; 311 cdev->si_flags |= SI_CHILD; 312 LIST_INSERT_HEAD(&pdev->si_children, cdev, si_siblings); 313} 314 315dev_t 316make_dev_alias(dev_t pdev, const char *fmt, ...) 317{ 318 dev_t dev; 319 va_list ap; 320 int i; 321 322 dev = allocdev(); 323 dev->si_flags |= SI_ALIAS; 324 dev->si_flags |= SI_NAMED; 325 dev_depends(pdev, dev); 326 va_start(ap, fmt); 327 i = kvprintf(fmt, NULL, dev->si_name, 32, ap); 328 dev->si_name[i] = '\0'; 329 va_end(ap); 330 331 if (devfs_create_hook) 332 devfs_create_hook(dev); 333 return (dev); 334} 335 336void 337revoke_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 349void 350destroy_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 377const char * 378devtoname(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 399int 400dev_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 */ 430static int 431sysctl_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 451SYSCTL_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 */ 457static void 458dev_set_ready(void *junk) 459{ 460 ready_for_devs = 1; 461} 462 463SYSINIT(dev_ready, SI_SUB_DEVFS, SI_ORDER_FIRST, dev_set_ready, NULL); 464