kern_conf.c revision 111735
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 111735 2003-03-02 14:43:46Z phk $ 27 */ 28 29#include <sys/param.h> 30#include <sys/kernel.h> 31#include <sys/systm.h> 32#include <sys/bio.h> 33#include <sys/lock.h> 34#include <sys/mutex.h> 35#include <sys/sysctl.h> 36#include <sys/module.h> 37#include <sys/malloc.h> 38#include <sys/conf.h> 39#include <sys/vnode.h> 40#include <sys/queue.h> 41#include <sys/ctype.h> 42#include <machine/stdarg.h> 43 44static MALLOC_DEFINE(M_DEVT, "dev_t", "dev_t storage"); 45 46/* Built at compile time from sys/conf/majors */ 47extern unsigned char reserved_majors[256]; 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 59static struct cdev devt_stash[DEVT_STASH]; 60 61static LIST_HEAD(, cdev) dev_hash[DEVT_HASH]; 62 63static LIST_HEAD(, cdev) dev_free; 64 65static int ready_for_devs; 66 67static int free_devt; 68SYSCTL_INT(_debug, OID_AUTO, free_devt, CTLFLAG_RW, &free_devt, 0, ""); 69 70/* Define a dead_cdevsw for use when devices leave unexpectedly. */ 71 72static int 73enxio(void) 74{ 75 return (ENXIO); 76} 77 78#define dead_open (d_open_t *)enxio 79#define dead_close (d_close_t *)enxio 80#define dead_read (d_read_t *)enxio 81#define dead_write (d_write_t *)enxio 82#define dead_ioctl (d_ioctl_t *)enxio 83#define dead_poll nopoll 84#define dead_mmap nommap 85 86static void 87dead_strategy(struct bio *bp) 88{ 89 90 biofinish(bp, NULL, ENXIO); 91} 92 93#define dead_dump (dumper_t *)enxio 94 95#define dead_kqfilter (d_kqfilter_t *)enxio 96 97static struct cdevsw dead_cdevsw = { 98 /* open */ dead_open, 99 /* close */ dead_close, 100 /* read */ dead_read, 101 /* write */ dead_write, 102 /* ioctl */ dead_ioctl, 103 /* poll */ dead_poll, 104 /* mmap */ dead_mmap, 105 /* strategy */ dead_strategy, 106 /* name */ "dead", 107 /* maj */ 255, 108 /* dump */ dead_dump, 109 /* psize */ nopsize, 110 /* flags */ 0, 111 /* kqfilter */ dead_kqfilter 112}; 113 114 115struct cdevsw * 116devsw(dev_t dev) 117{ 118 if (dev->si_devsw) 119 return (dev->si_devsw); 120 return (&dead_cdevsw); 121} 122 123/* 124 * dev_t and u_dev_t primitives 125 */ 126 127int 128major(dev_t x) 129{ 130 if (x == NODEV) 131 return NOUDEV; 132 return((x->si_udev >> 8) & 0xff); 133} 134 135int 136minor(dev_t x) 137{ 138 if (x == NODEV) 139 return NOUDEV; 140 return(x->si_udev & 0xffff00ff); 141} 142 143int 144dev2unit(dev_t x) 145{ 146 int i; 147 148 if (x == NODEV) 149 return NOUDEV; 150 i = minor(x); 151 return ((i & 0xff) | (i >> 8)); 152} 153 154int 155unit2minor(int unit) 156{ 157 158 KASSERT(unit <= 0xffffff, ("Invalid unit (%d) in unit2minor", unit)); 159 return ((unit & 0xff) | ((unit << 8) & ~0xffff)); 160} 161 162static dev_t 163allocdev(void) 164{ 165 static int stashed; 166 struct cdev *si; 167 168 if (LIST_FIRST(&dev_free)) { 169 si = LIST_FIRST(&dev_free); 170 LIST_REMOVE(si, si_hash); 171 } else if (stashed >= DEVT_STASH) { 172 MALLOC(si, struct cdev *, sizeof(*si), M_DEVT, 173 M_USE_RESERVE | M_ZERO | M_WAITOK); 174 } else { 175 si = devt_stash + stashed++; 176 bzero(si, sizeof *si); 177 si->si_flags |= SI_STASHED; 178 } 179 si->__si_namebuf[0] = '\0'; 180 si->si_name = si->__si_namebuf; 181 LIST_INIT(&si->si_children); 182 TAILQ_INIT(&si->si_snapshots); 183 return (si); 184} 185 186dev_t 187makedev(int x, int y) 188{ 189 struct cdev *si; 190 udev_t udev; 191 int hash; 192 193 if (x == umajor(NOUDEV) && y == uminor(NOUDEV)) 194 panic("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 207void 208freedev(dev_t dev) 209{ 210 211 if (!free_devt) 212 return; 213 if (SLIST_FIRST(&dev->si_hlist)) 214 return; 215 if (dev->si_devsw || dev->si_drv1 || dev->si_drv2) 216 return; 217 LIST_REMOVE(dev, si_hash); 218 if (dev->si_flags & SI_STASHED) { 219 bzero(dev, sizeof(*dev)); 220 dev->si_flags |= SI_STASHED; 221 LIST_INSERT_HEAD(&dev_free, dev, si_hash); 222 } else { 223 FREE(dev, M_DEVT); 224 } 225} 226 227udev_t 228dev2udev(dev_t x) 229{ 230 if (x == NODEV) 231 return NOUDEV; 232 return (x->si_udev); 233} 234 235dev_t 236udev2dev(udev_t x, int b) 237{ 238 239 if (x == NOUDEV) 240 return (NODEV); 241 switch (b) { 242 case 0: 243 return makedev(umajor(x), uminor(x)); 244 case 1: 245 return (NODEV); 246 default: 247 Debugger("udev2dev(...,X)"); 248 return NODEV; 249 } 250} 251 252int 253uminor(udev_t dev) 254{ 255 return(dev & 0xffff00ff); 256} 257 258int 259umajor(udev_t dev) 260{ 261 return((dev & 0xff00) >> 8); 262} 263 264udev_t 265makeudev(int x, int y) 266{ 267 return ((x << 8) | y); 268} 269 270dev_t 271make_dev(struct cdevsw *devsw, int minor, uid_t uid, gid_t gid, int perms, const char *fmt, ...) 272{ 273 dev_t dev; 274 va_list ap; 275 int i; 276 277 KASSERT((minor & ~0xffff00ff) == 0, 278 ("Invalid minor (0x%x) in make_dev", minor)); 279 280 if (devsw->d_maj == MAJOR_AUTO) { 281 for (i = NUMCDEVSW - 1; i > 0; i--) 282 if (reserved_majors[i] != i) 283 break; 284 KASSERT(i > 0, ("Out of major numbers (%s)", devsw->d_name)); 285 printf("Allocating major#%d to \"%s\"\n", i, devsw->d_name); 286 devsw->d_maj = i; 287 reserved_majors[i] = i; 288 } else { 289 KASSERT(devsw->d_maj >= 0 && devsw->d_maj < 256, 290 ("Invalid major (%d) in make_dev", devsw->d_maj)); 291 if (reserved_majors[devsw->d_maj] != devsw->d_maj) { 292 printf("WARNING: driver \"%s\" used %s %d\n", 293 devsw->d_name, "unreserved major device number", 294 devsw->d_maj); 295 reserved_majors[devsw->d_maj] = devsw->d_maj; 296 } 297 } 298 299 if (!ready_for_devs) { 300 printf("WARNING: Driver mistake: make_dev(%s) called before SI_SUB_DRIVERS\n", 301 fmt); 302 /* XXX panic here once drivers are cleaned up */ 303 } 304 305 dev = makedev(devsw->d_maj, minor); 306 if (dev->si_flags & SI_NAMED) { 307 printf( "WARNING: Driver mistake: repeat make_dev(\"%s\")\n", 308 dev->si_name); 309 panic("don't do that"); 310 return (dev); 311 } 312 va_start(ap, fmt); 313 i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap); 314 if (i > (sizeof dev->__si_namebuf - 1)) { 315 printf("WARNING: Device name truncated! (%s)", 316 dev->__si_namebuf); 317 } 318 va_end(ap); 319 dev->si_devsw = devsw; 320 dev->si_uid = uid; 321 dev->si_gid = gid; 322 dev->si_mode = perms; 323 dev->si_flags |= SI_NAMED; 324 325 devfs_create(dev); 326 return (dev); 327} 328 329int 330dev_named(dev_t pdev, const char *name) 331{ 332 dev_t cdev; 333 334 if (strcmp(devtoname(pdev), name) == 0) 335 return (1); 336 LIST_FOREACH(cdev, &pdev->si_children, si_siblings) 337 if (strcmp(devtoname(cdev), name) == 0) 338 return (1); 339 return (0); 340} 341 342void 343dev_depends(dev_t pdev, dev_t cdev) 344{ 345 346 cdev->si_parent = pdev; 347 cdev->si_flags |= SI_CHILD; 348 LIST_INSERT_HEAD(&pdev->si_children, cdev, si_siblings); 349} 350 351dev_t 352make_dev_alias(dev_t pdev, const char *fmt, ...) 353{ 354 dev_t dev; 355 va_list ap; 356 int i; 357 358 dev = allocdev(); 359 dev->si_flags |= SI_ALIAS; 360 dev->si_flags |= SI_NAMED; 361 dev_depends(pdev, dev); 362 va_start(ap, fmt); 363 i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap); 364 if (i > (sizeof dev->__si_namebuf - 1)) { 365 printf("WARNING: Device name truncated! (%s)", 366 dev->__si_namebuf); 367 } 368 va_end(ap); 369 370 devfs_create(dev); 371 return (dev); 372} 373 374void 375revoke_and_destroy_dev(dev_t dev) 376{ 377 struct vnode *vp; 378 379 GIANT_REQUIRED; 380 381 vp = SLIST_FIRST(&dev->si_hlist); 382 if (vp != NULL) 383 VOP_REVOKE(vp, REVOKEALL); 384 destroy_dev(dev); 385} 386 387void 388destroy_dev(dev_t dev) 389{ 390 391 if (!(dev->si_flags & SI_NAMED)) { 392 printf( "WARNING: Driver mistake: destroy_dev on %d/%d\n", 393 major(dev), minor(dev)); 394 panic("don't do that"); 395 return; 396 } 397 398 devfs_destroy(dev); 399 if (dev->si_flags & SI_CHILD) { 400 LIST_REMOVE(dev, si_siblings); 401 dev->si_flags &= ~SI_CHILD; 402 } 403 while (!LIST_EMPTY(&dev->si_children)) 404 destroy_dev(LIST_FIRST(&dev->si_children)); 405 dev->si_drv1 = 0; 406 dev->si_drv2 = 0; 407 dev->si_devsw = 0; 408 bzero(&dev->__si_u, sizeof(dev->__si_u)); 409 dev->si_flags &= ~SI_NAMED; 410 dev->si_flags &= ~SI_ALIAS; 411 freedev(dev); 412} 413 414const char * 415devtoname(dev_t dev) 416{ 417 char *p; 418 int mynor; 419 420 if (dev->si_name[0] == '#' || dev->si_name[0] == '\0') { 421 p = dev->si_name; 422 if (devsw(dev)) 423 sprintf(p, "#%s/", devsw(dev)->d_name); 424 else 425 sprintf(p, "#%d/", major(dev)); 426 p += strlen(p); 427 mynor = minor(dev); 428 if (mynor < 0 || mynor > 255) 429 sprintf(p, "%#x", (u_int)mynor); 430 else 431 sprintf(p, "%d", mynor); 432 } 433 return (dev->si_name); 434} 435 436int 437dev_stdclone(char *name, char **namep, const char *stem, int *unit) 438{ 439 int u, i; 440 441 i = strlen(stem); 442 if (bcmp(stem, name, i) != 0) 443 return (0); 444 if (!isdigit(name[i])) 445 return (0); 446 u = 0; 447 if (name[i] == '0' && isdigit(name[i+1])) 448 return (0); 449 while (isdigit(name[i])) { 450 u *= 10; 451 u += name[i++] - '0'; 452 } 453 if (u > 0xffffff) 454 return (0); 455 *unit = u; 456 if (namep) 457 *namep = &name[i]; 458 if (name[i]) 459 return (2); 460 return (1); 461} 462 463/* 464 * Helper sysctl for devname(3). We're given a {u}dev_t and return 465 * the name, if any, registered by the device driver. 466 */ 467static int 468sysctl_devname(SYSCTL_HANDLER_ARGS) 469{ 470 int error; 471 udev_t ud; 472 dev_t dev; 473 474 error = SYSCTL_IN(req, &ud, sizeof (ud)); 475 if (error) 476 return (error); 477 if (ud == NOUDEV) 478 return(EINVAL); 479 dev = makedev(umajor(ud), uminor(ud)); 480 if (dev->si_name[0] == '\0') 481 error = ENOENT; 482 else 483 error = SYSCTL_OUT(req, dev->si_name, strlen(dev->si_name) + 1); 484 freedev(dev); 485 return (error); 486} 487 488SYSCTL_PROC(_kern, OID_AUTO, devname, CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_ANYBODY, 489 NULL, 0, sysctl_devname, "", "devname(3) handler"); 490 491/* 492 * Set ready_for_devs; prior to this point, device creation is not allowed. 493 */ 494static void 495dev_set_ready(void *junk) 496{ 497 ready_for_devs = 1; 498} 499 500SYSINIT(dev_ready, SI_SUB_DEVFS, SI_ORDER_FIRST, dev_set_ready, NULL); 501