kern_conf.c revision 111760
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 111760 2003-03-02 19:46:45Z 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_open == NULL) devsw->d_open = noopen; 281 if (devsw->d_close == NULL) devsw->d_close = noclose; 282 if (devsw->d_read == NULL) devsw->d_read = noread; 283 if (devsw->d_write == NULL) devsw->d_write = nowrite; 284 if (devsw->d_ioctl == NULL) devsw->d_ioctl = noioctl; 285 if (devsw->d_poll == NULL) devsw->d_poll = nopoll; 286 if (devsw->d_mmap == NULL) devsw->d_mmap = nommap; 287 if (devsw->d_strategy == NULL) devsw->d_strategy = nostrategy; 288 if (devsw->d_dump == NULL) devsw->d_dump = nodump; 289 if (devsw->d_kqfilter == NULL) devsw->d_kqfilter = nokqfilter; 290 291 if (devsw->d_maj == MAJOR_AUTO) { 292 for (i = NUMCDEVSW - 1; i > 0; i--) 293 if (reserved_majors[i] != i) 294 break; 295 KASSERT(i > 0, ("Out of major numbers (%s)", devsw->d_name)); 296 printf("Allocating major#%d to \"%s\"\n", i, devsw->d_name); 297 devsw->d_maj = i; 298 reserved_majors[i] = i; 299 } else { 300 KASSERT(devsw->d_maj >= 0 && devsw->d_maj < 256, 301 ("Invalid major (%d) in make_dev", devsw->d_maj)); 302 if (reserved_majors[devsw->d_maj] != devsw->d_maj) { 303 printf("WARNING: driver \"%s\" used %s %d\n", 304 devsw->d_name, "unreserved major device number", 305 devsw->d_maj); 306 reserved_majors[devsw->d_maj] = devsw->d_maj; 307 } 308 } 309 310 if (!ready_for_devs) { 311 printf("WARNING: Driver mistake: make_dev(%s) called before SI_SUB_DRIVERS\n", 312 fmt); 313 /* XXX panic here once drivers are cleaned up */ 314 } 315 316 dev = makedev(devsw->d_maj, minor); 317 if (dev->si_flags & SI_NAMED) { 318 printf( "WARNING: Driver mistake: repeat make_dev(\"%s\")\n", 319 dev->si_name); 320 panic("don't do that"); 321 return (dev); 322 } 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 dev->si_devsw = devsw; 331 dev->si_uid = uid; 332 dev->si_gid = gid; 333 dev->si_mode = perms; 334 dev->si_flags |= SI_NAMED; 335 336 devfs_create(dev); 337 return (dev); 338} 339 340int 341dev_named(dev_t pdev, const char *name) 342{ 343 dev_t cdev; 344 345 if (strcmp(devtoname(pdev), name) == 0) 346 return (1); 347 LIST_FOREACH(cdev, &pdev->si_children, si_siblings) 348 if (strcmp(devtoname(cdev), name) == 0) 349 return (1); 350 return (0); 351} 352 353void 354dev_depends(dev_t pdev, dev_t cdev) 355{ 356 357 cdev->si_parent = pdev; 358 cdev->si_flags |= SI_CHILD; 359 LIST_INSERT_HEAD(&pdev->si_children, cdev, si_siblings); 360} 361 362dev_t 363make_dev_alias(dev_t pdev, const char *fmt, ...) 364{ 365 dev_t dev; 366 va_list ap; 367 int i; 368 369 dev = allocdev(); 370 dev->si_flags |= SI_ALIAS; 371 dev->si_flags |= SI_NAMED; 372 dev_depends(pdev, dev); 373 va_start(ap, fmt); 374 i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap); 375 if (i > (sizeof dev->__si_namebuf - 1)) { 376 printf("WARNING: Device name truncated! (%s)", 377 dev->__si_namebuf); 378 } 379 va_end(ap); 380 381 devfs_create(dev); 382 return (dev); 383} 384 385void 386revoke_and_destroy_dev(dev_t dev) 387{ 388 struct vnode *vp; 389 390 GIANT_REQUIRED; 391 392 vp = SLIST_FIRST(&dev->si_hlist); 393 if (vp != NULL) 394 VOP_REVOKE(vp, REVOKEALL); 395 destroy_dev(dev); 396} 397 398void 399destroy_dev(dev_t dev) 400{ 401 402 if (!(dev->si_flags & SI_NAMED)) { 403 printf( "WARNING: Driver mistake: destroy_dev on %d/%d\n", 404 major(dev), minor(dev)); 405 panic("don't do that"); 406 return; 407 } 408 409 devfs_destroy(dev); 410 if (dev->si_flags & SI_CHILD) { 411 LIST_REMOVE(dev, si_siblings); 412 dev->si_flags &= ~SI_CHILD; 413 } 414 while (!LIST_EMPTY(&dev->si_children)) 415 destroy_dev(LIST_FIRST(&dev->si_children)); 416 dev->si_drv1 = 0; 417 dev->si_drv2 = 0; 418 dev->si_devsw = 0; 419 bzero(&dev->__si_u, sizeof(dev->__si_u)); 420 dev->si_flags &= ~SI_NAMED; 421 dev->si_flags &= ~SI_ALIAS; 422 freedev(dev); 423} 424 425const char * 426devtoname(dev_t dev) 427{ 428 char *p; 429 int mynor; 430 431 if (dev->si_name[0] == '#' || dev->si_name[0] == '\0') { 432 p = dev->si_name; 433 if (devsw(dev)) 434 sprintf(p, "#%s/", devsw(dev)->d_name); 435 else 436 sprintf(p, "#%d/", major(dev)); 437 p += strlen(p); 438 mynor = minor(dev); 439 if (mynor < 0 || mynor > 255) 440 sprintf(p, "%#x", (u_int)mynor); 441 else 442 sprintf(p, "%d", mynor); 443 } 444 return (dev->si_name); 445} 446 447int 448dev_stdclone(char *name, char **namep, const char *stem, int *unit) 449{ 450 int u, i; 451 452 i = strlen(stem); 453 if (bcmp(stem, name, i) != 0) 454 return (0); 455 if (!isdigit(name[i])) 456 return (0); 457 u = 0; 458 if (name[i] == '0' && isdigit(name[i+1])) 459 return (0); 460 while (isdigit(name[i])) { 461 u *= 10; 462 u += name[i++] - '0'; 463 } 464 if (u > 0xffffff) 465 return (0); 466 *unit = u; 467 if (namep) 468 *namep = &name[i]; 469 if (name[i]) 470 return (2); 471 return (1); 472} 473 474/* 475 * Helper sysctl for devname(3). We're given a {u}dev_t and return 476 * the name, if any, registered by the device driver. 477 */ 478static int 479sysctl_devname(SYSCTL_HANDLER_ARGS) 480{ 481 int error; 482 udev_t ud; 483 dev_t dev; 484 485 error = SYSCTL_IN(req, &ud, sizeof (ud)); 486 if (error) 487 return (error); 488 if (ud == NOUDEV) 489 return(EINVAL); 490 dev = makedev(umajor(ud), uminor(ud)); 491 if (dev->si_name[0] == '\0') 492 error = ENOENT; 493 else 494 error = SYSCTL_OUT(req, dev->si_name, strlen(dev->si_name) + 1); 495 freedev(dev); 496 return (error); 497} 498 499SYSCTL_PROC(_kern, OID_AUTO, devname, CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_ANYBODY, 500 NULL, 0, sysctl_devname, "", "devname(3) handler"); 501 502/* 503 * Set ready_for_devs; prior to this point, device creation is not allowed. 504 */ 505static void 506dev_set_ready(void *junk) 507{ 508 ready_for_devs = 1; 509} 510 511SYSINIT(dev_ready, SI_SUB_DEVFS, SI_ORDER_FIRST, dev_set_ready, NULL); 512