Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/fs/devfs/devfs_devs.c
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1 /*- 2 * Copyright (c) 2000,2004 3 * Poul-Henning Kamp. 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. Neither the name of the University nor the names of its contributors 11 * may be used to endorse or promote products derived from this software 12 * without specific prior written permission. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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 * From: FreeBSD: src/sys/miscfs/kernfs/kernfs_vfsops.c 1.36 27 * 28 * $FreeBSD$ 29 */ 30 31 #include "opt_devfs.h" 32 #include "opt_mac.h" 33 34 #include <sys/param.h> 35 #include <sys/systm.h> 36 #include <sys/conf.h> 37 #include <sys/dirent.h> 38 #include <sys/kernel.h> 39 #include <sys/limits.h> 40 #include <sys/lock.h> 41 #include <sys/mac.h> 42 #include <sys/malloc.h> 43 #include <sys/proc.h> 44 #include <sys/sx.h> 45 #include <sys/sysctl.h> 46 #include <sys/vnode.h> 47 48 #include <sys/kdb.h> 49 50 #include <fs/devfs/devfs.h> 51 #include <fs/devfs/devfs_int.h> 52 53 /* 54 * The one true (but secret) list of active devices in the system. 55 * Locked by dev_lock()/devmtx 56 */ 57 struct cdev_priv_list cdevp_list = TAILQ_HEAD_INITIALIZER(cdevp_list); 58 59 struct unrhdr *devfs_inos; 60 61 62 static MALLOC_DEFINE(M_DEVFS2, "DEVFS2", "DEVFS data 2"); 63 static MALLOC_DEFINE(M_DEVFS3, "DEVFS3", "DEVFS data 3"); 64 static MALLOC_DEFINE(M_CDEVP, "DEVFS1", "DEVFS cdev_priv storage"); 65 66 static SYSCTL_NODE(_vfs, OID_AUTO, devfs, CTLFLAG_RW, 0, "DEVFS filesystem"); 67 68 static unsigned devfs_generation; 69 SYSCTL_UINT(_vfs_devfs, OID_AUTO, generation, CTLFLAG_RD, 70 &devfs_generation, 0, "DEVFS generation number"); 71 72 unsigned devfs_rule_depth = 1; 73 SYSCTL_UINT(_vfs_devfs, OID_AUTO, rule_depth, CTLFLAG_RW, 74 &devfs_rule_depth, 0, "Max depth of ruleset include"); 75 76 /* 77 * Helper sysctl for devname(3). We're given a struct cdev * and return 78 * the name, if any, registered by the device driver. 79 */ 80 static int 81 sysctl_devname(SYSCTL_HANDLER_ARGS) 82 { 83 int error; 84 dev_t ud; 85 struct cdev_priv *cdp; 86 87 error = SYSCTL_IN(req, &ud, sizeof (ud)); 88 if (error) 89 return (error); 90 if (ud == NODEV) 91 return(EINVAL); 92 /* 93 ud ^ devfs_random(); 94 */ 95 dev_lock(); 96 TAILQ_FOREACH(cdp, &cdevp_list, cdp_list) 97 if (cdp->cdp_inode == ud) 98 break; 99 dev_unlock(); 100 if (cdp == NULL) 101 return(ENOENT); 102 return(SYSCTL_OUT(req, cdp->cdp_c.si_name, strlen(cdp->cdp_c.si_name) + 1)); 103 return (error); 104 } 105 106 SYSCTL_PROC(_kern, OID_AUTO, devname, CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_ANYBODY, 107 NULL, 0, sysctl_devname, "", "devname(3) handler"); 108 109 SYSCTL_INT(_debug_sizeof, OID_AUTO, cdev, CTLFLAG_RD, 110 0, sizeof(struct cdev), "sizeof(struct cdev)"); 111 112 SYSCTL_INT(_debug_sizeof, OID_AUTO, cdev_priv, CTLFLAG_RD, 113 0, sizeof(struct cdev_priv), "sizeof(struct cdev_priv)"); 114 115 struct cdev * 116 devfs_alloc(void) 117 { 118 struct cdev_priv *cdp; 119 struct cdev *cdev; 120 121 cdp = malloc(sizeof *cdp, M_CDEVP, M_USE_RESERVE | M_ZERO | M_WAITOK); 122 123 cdp->cdp_dirents = &cdp->cdp_dirent0; 124 cdp->cdp_dirent0 = NULL; 125 cdp->cdp_maxdirent = 0; 126 127 cdev = &cdp->cdp_c; 128 cdev->si_priv = cdp; 129 130 cdev->si_name = cdev->__si_namebuf; 131 LIST_INIT(&cdev->si_children); 132 return (cdev); 133 } 134 135 void 136 devfs_free(struct cdev *cdev) 137 { 138 struct cdev_priv *cdp; 139 140 cdp = cdev->si_priv; 141 if (cdev->si_cred != NULL) 142 crfree(cdev->si_cred); 143 if (cdp->cdp_inode > 0) 144 free_unr(devfs_inos, cdp->cdp_inode); 145 if (cdp->cdp_maxdirent > 0) 146 free(cdp->cdp_dirents, M_DEVFS2); 147 free(cdp, M_CDEVP); 148 } 149 150 struct devfs_dirent * 151 devfs_find(struct devfs_dirent *dd, const char *name, int namelen) 152 { 153 struct devfs_dirent *de; 154 155 TAILQ_FOREACH(de, &dd->de_dlist, de_list) { 156 if (namelen != de->de_dirent->d_namlen) 157 continue; 158 if (bcmp(name, de->de_dirent->d_name, namelen) != 0) 159 continue; 160 break; 161 } 162 return (de); 163 } 164 165 struct devfs_dirent * 166 devfs_newdirent(char *name, int namelen) 167 { 168 int i; 169 struct devfs_dirent *de; 170 struct dirent d; 171 172 d.d_namlen = namelen; 173 i = sizeof (*de) + GENERIC_DIRSIZ(&d); 174 de = malloc(i, M_DEVFS3, M_WAITOK | M_ZERO); 175 de->de_dirent = (struct dirent *)(de + 1); 176 de->de_dirent->d_namlen = namelen; 177 de->de_dirent->d_reclen = GENERIC_DIRSIZ(&d); 178 bcopy(name, de->de_dirent->d_name, namelen); 179 de->de_dirent->d_name[namelen] = '\0'; 180 vfs_timestamp(&de->de_ctime); 181 de->de_mtime = de->de_atime = de->de_ctime; 182 de->de_links = 1; 183 de->de_holdcnt = 1; 184 #ifdef MAC 185 mac_init_devfsdirent(de); 186 #endif 187 return (de); 188 } 189 190 struct devfs_dirent * 191 devfs_vmkdir(struct devfs_mount *dmp, char *name, int namelen, struct devfs_dirent *dotdot, u_int inode) 192 { 193 struct devfs_dirent *dd; 194 struct devfs_dirent *de; 195 196 /* Create the new directory */ 197 dd = devfs_newdirent(name, namelen); 198 TAILQ_INIT(&dd->de_dlist); 199 dd->de_dirent->d_type = DT_DIR; 200 dd->de_mode = 0555; 201 dd->de_links = 2; 202 dd->de_dir = dd; 203 if (inode != 0) 204 dd->de_inode = inode; 205 else 206 dd->de_inode = alloc_unr(devfs_inos); 207 208 /* Create the "." entry in the new directory */ 209 de = devfs_newdirent(".", 1); 210 de->de_dirent->d_type = DT_DIR; 211 de->de_flags |= DE_DOT; 212 TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list); 213 de->de_dir = dd; 214 215 /* Create the ".." entry in the new directory */ 216 de = devfs_newdirent("..", 2); 217 de->de_dirent->d_type = DT_DIR; 218 de->de_flags |= DE_DOTDOT; 219 TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list); 220 if (dotdot == NULL) { 221 de->de_dir = dd; 222 } else { 223 de->de_dir = dotdot; 224 TAILQ_INSERT_TAIL(&dotdot->de_dlist, dd, de_list); 225 dotdot->de_links++; 226 } 227 228 #ifdef MAC 229 mac_create_devfs_directory(dmp->dm_mount, name, namelen, dd); 230 #endif 231 return (dd); 232 } 233 234 void 235 devfs_dirent_free(struct devfs_dirent *de) 236 { 237 free(de, M_DEVFS3); 238 } 239 240 /* 241 * The caller needs to hold the dm for the duration of the call since 242 * dm->dm_lock may be temporary dropped. 243 */ 244 void 245 devfs_delete(struct devfs_mount *dm, struct devfs_dirent *de, int vp_locked) 246 { 247 struct vnode *vp; 248 struct thread *td; 249 250 KASSERT((de->de_flags & DE_DOOMED) == 0, 251 ("devfs_delete doomed dirent")); 252 td = curthread; 253 de->de_flags |= DE_DOOMED; 254 mtx_lock(&devfs_de_interlock); 255 vp = de->de_vnode; 256 if (vp != NULL) { 257 VI_LOCK(vp); 258 mtx_unlock(&devfs_de_interlock); 259 vholdl(vp); 260 sx_unlock(&dm->dm_lock); 261 if (!vp_locked) 262 vn_lock(vp, LK_EXCLUSIVE | LK_INTERLOCK | LK_RETRY, td); 263 else 264 VI_UNLOCK(vp); 265 vgone(vp); 266 if (!vp_locked) 267 VOP_UNLOCK(vp, 0, td); 268 vdrop(vp); 269 sx_xlock(&dm->dm_lock); 270 } else 271 mtx_unlock(&devfs_de_interlock); 272 if (de->de_symlink) { 273 free(de->de_symlink, M_DEVFS); 274 de->de_symlink = NULL; 275 } 276 #ifdef MAC 277 mac_destroy_devfsdirent(de); 278 #endif 279 if (de->de_inode > DEVFS_ROOTINO) { 280 free_unr(devfs_inos, de->de_inode); 281 de->de_inode = 0; 282 } 283 if (DEVFS_DE_DROP(de)) 284 devfs_dirent_free(de); 285 } 286 287 /* 288 * Called on unmount. 289 * Recursively removes the entire tree. 290 * The caller needs to hold the dm for the duration of the call. 291 */ 292 293 static void 294 devfs_purge(struct devfs_mount *dm, struct devfs_dirent *dd) 295 { 296 struct devfs_dirent *de; 297 298 sx_assert(&dm->dm_lock, SX_XLOCKED); 299 for (;;) { 300 de = TAILQ_FIRST(&dd->de_dlist); 301 if (de == NULL) 302 break; 303 TAILQ_REMOVE(&dd->de_dlist, de, de_list); 304 if (de->de_flags & (DE_DOT|DE_DOTDOT)) 305 devfs_delete(dm, de, 0); 306 else if (de->de_dirent->d_type == DT_DIR) 307 devfs_purge(dm, de); 308 else 309 devfs_delete(dm, de, 0); 310 } 311 devfs_delete(dm, dd, 0); 312 } 313 314 /* 315 * Each cdev_priv has an array of pointers to devfs_dirent which is indexed 316 * by the mount points dm_idx. 317 * This function extends the array when necessary, taking into account that 318 * the default array is 1 element and not malloc'ed. 319 */ 320 static void 321 devfs_metoo(struct cdev_priv *cdp, struct devfs_mount *dm) 322 { 323 struct devfs_dirent **dep; 324 int siz; 325 326 siz = (dm->dm_idx + 1) * sizeof *dep; 327 dep = malloc(siz, M_DEVFS2, M_WAITOK | M_ZERO); 328 dev_lock(); 329 if (dm->dm_idx <= cdp->cdp_maxdirent) { 330 /* We got raced */ 331 dev_unlock(); 332 free(dep, M_DEVFS2); 333 return; 334 } 335 memcpy(dep, cdp->cdp_dirents, (cdp->cdp_maxdirent + 1) * sizeof *dep); 336 if (cdp->cdp_maxdirent > 0) 337 free(cdp->cdp_dirents, M_DEVFS2); 338 cdp->cdp_dirents = dep; 339 /* 340 * XXX: if malloc told us how much we actually got this could 341 * XXX: be optimized. 342 */ 343 cdp->cdp_maxdirent = dm->dm_idx; 344 dev_unlock(); 345 } 346 347 /* 348 * The caller needs to hold the dm for the duration of the call. 349 */ 350 static int 351 devfs_populate_loop(struct devfs_mount *dm, int cleanup) 352 { 353 struct cdev_priv *cdp; 354 struct devfs_dirent *de; 355 struct devfs_dirent *dd; 356 struct cdev *pdev; 357 int j; 358 char *q, *s; 359 360 sx_assert(&dm->dm_lock, SX_XLOCKED); 361 dev_lock(); 362 TAILQ_FOREACH(cdp, &cdevp_list, cdp_list) { 363 364 KASSERT(cdp->cdp_dirents != NULL, ("NULL cdp_dirents")); 365 366 /* 367 * If we are unmounting, or the device has been destroyed, 368 * clean up our dirent. 369 */ 370 if ((cleanup || !(cdp->cdp_flags & CDP_ACTIVE)) && 371 dm->dm_idx <= cdp->cdp_maxdirent && 372 cdp->cdp_dirents[dm->dm_idx] != NULL) { 373 de = cdp->cdp_dirents[dm->dm_idx]; 374 cdp->cdp_dirents[dm->dm_idx] = NULL; 375 KASSERT(cdp == de->de_cdp, 376 ("%s %d %s %p %p", __func__, __LINE__, 377 cdp->cdp_c.si_name, cdp, de->de_cdp)); 378 KASSERT(de->de_dir != NULL, ("Null de->de_dir")); 379 dev_unlock(); 380 381 TAILQ_REMOVE(&de->de_dir->de_dlist, de, de_list); 382 de->de_cdp = NULL; 383 de->de_inode = 0; 384 devfs_delete(dm, de, 0); 385 dev_lock(); 386 cdp->cdp_inuse--; 387 dev_unlock(); 388 return (1); 389 } 390 /* 391 * GC any lingering devices 392 */ 393 if (!(cdp->cdp_flags & CDP_ACTIVE)) { 394 if (cdp->cdp_inuse > 0) 395 continue; 396 TAILQ_REMOVE(&cdevp_list, cdp, cdp_list); 397 dev_unlock(); 398 dev_rel(&cdp->cdp_c); 399 return (1); 400 } 401 /* 402 * Don't create any new dirents if we are unmounting 403 */ 404 if (cleanup) 405 continue; 406 KASSERT((cdp->cdp_flags & CDP_ACTIVE), ("Bogons, I tell ya'!")); 407 408 if (dm->dm_idx <= cdp->cdp_maxdirent && 409 cdp->cdp_dirents[dm->dm_idx] != NULL) { 410 de = cdp->cdp_dirents[dm->dm_idx]; 411 KASSERT(cdp == de->de_cdp, ("inconsistent cdp")); 412 continue; 413 } 414 415 416 cdp->cdp_inuse++; 417 dev_unlock(); 418 419 if (dm->dm_idx > cdp->cdp_maxdirent) 420 devfs_metoo(cdp, dm); 421 422 dd = dm->dm_rootdir; 423 s = cdp->cdp_c.si_name; 424 for (;;) { 425 for (q = s; *q != '/' && *q != '\0'; q++) 426 continue; 427 if (*q != '/') 428 break; 429 de = devfs_find(dd, s, q - s); 430 if (de == NULL) 431 de = devfs_vmkdir(dm, s, q - s, dd, 0); 432 s = q + 1; 433 dd = de; 434 } 435 436 de = devfs_newdirent(s, q - s); 437 if (cdp->cdp_c.si_flags & SI_ALIAS) { 438 de->de_uid = 0; 439 de->de_gid = 0; 440 de->de_mode = 0755; 441 de->de_dirent->d_type = DT_LNK; 442 pdev = cdp->cdp_c.si_parent; 443 j = strlen(pdev->si_name) + 1; 444 de->de_symlink = malloc(j, M_DEVFS, M_WAITOK); 445 bcopy(pdev->si_name, de->de_symlink, j); 446 } else { 447 de->de_uid = cdp->cdp_c.si_uid; 448 de->de_gid = cdp->cdp_c.si_gid; 449 de->de_mode = cdp->cdp_c.si_mode; 450 de->de_dirent->d_type = DT_CHR; 451 } 452 de->de_inode = cdp->cdp_inode; 453 de->de_cdp = cdp; 454 #ifdef MAC 455 mac_create_devfs_device(cdp->cdp_c.si_cred, dm->dm_mount, 456 &cdp->cdp_c, de); 457 #endif 458 de->de_dir = dd; 459 TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list); 460 devfs_rules_apply(dm, de); 461 dev_lock(); 462 /* XXX: could check that cdp is still active here */ 463 KASSERT(cdp->cdp_dirents[dm->dm_idx] == NULL, 464 ("%s %d\n", __func__, __LINE__)); 465 cdp->cdp_dirents[dm->dm_idx] = de; 466 KASSERT(de->de_cdp != (void *)0xdeadc0de, 467 ("%s %d\n", __func__, __LINE__)); 468 dev_unlock(); 469 return (1); 470 } 471 dev_unlock(); 472 return (0); 473 } 474 475 /* 476 * The caller needs to hold the dm for the duration of the call. 477 */ 478 void 479 devfs_populate(struct devfs_mount *dm) 480 { 481 482 sx_assert(&dm->dm_lock, SX_XLOCKED); 483 if (dm->dm_generation == devfs_generation) 484 return; 485 while (devfs_populate_loop(dm, 0)) 486 continue; 487 dm->dm_generation = devfs_generation; 488 } 489 490 /* 491 * The caller needs to hold the dm for the duration of the call. 492 */ 493 void 494 devfs_cleanup(struct devfs_mount *dm) 495 { 496 497 sx_assert(&dm->dm_lock, SX_XLOCKED); 498 while (devfs_populate_loop(dm, 1)) 499 continue; 500 devfs_purge(dm, dm->dm_rootdir); 501 } 502 503 /* 504 * devfs_create() and devfs_destroy() are called from kern_conf.c and 505 * in both cases the devlock() mutex is held, so no further locking 506 * is necesary and no sleeping allowed. 507 */ 508 509 void 510 devfs_create(struct cdev *dev) 511 { 512 struct cdev_priv *cdp; 513 514 mtx_assert(&devmtx, MA_OWNED); 515 cdp = dev->si_priv; 516 cdp->cdp_flags |= CDP_ACTIVE; 517 cdp->cdp_inode = alloc_unrl(devfs_inos); 518 dev_refl(dev); 519 TAILQ_INSERT_TAIL(&cdevp_list, cdp, cdp_list); 520 devfs_generation++; 521 } 522 523 void 524 devfs_destroy(struct cdev *dev) 525 { 526 struct cdev_priv *cdp; 527 528 mtx_assert(&devmtx, MA_OWNED); 529 cdp = dev->si_priv; 530 cdp->cdp_flags &= ~CDP_ACTIVE; 531 devfs_generation++; 532 } 533 534 static void 535 devfs_devs_init(void *junk __unused) 536 { 537 538 devfs_inos = new_unrhdr(DEVFS_ROOTINO + 1, INT_MAX, &devmtx); 539 } 540 541 SYSINIT(devfs_devs, SI_SUB_DEVFS, SI_ORDER_FIRST, devfs_devs_init, NULL);
Cache object: 2d200dd279e7b3d19325919c0ea86cb2
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