xref: /freebsd/sys/fs/devfs/devfs_devs.c (revision 884a2a699669ec61e2366e3e358342dbc94be24a)
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 <sys/param.h>
32 #include <sys/systm.h>
33 #include <sys/conf.h>
34 #include <sys/dirent.h>
35 #include <sys/kernel.h>
36 #include <sys/limits.h>
37 #include <sys/lock.h>
38 #include <sys/malloc.h>
39 #include <sys/proc.h>
40 #include <sys/sx.h>
41 #include <sys/sysctl.h>
42 #include <sys/vnode.h>
43 
44 #include <sys/kdb.h>
45 
46 #include <fs/devfs/devfs.h>
47 #include <fs/devfs/devfs_int.h>
48 
49 #include <security/mac/mac_framework.h>
50 
51 /*
52  * The one true (but secret) list of active devices in the system.
53  * Locked by dev_lock()/devmtx
54  */
55 struct cdev_priv_list cdevp_list = TAILQ_HEAD_INITIALIZER(cdevp_list);
56 
57 struct unrhdr *devfs_inos;
58 
59 
60 static MALLOC_DEFINE(M_DEVFS2, "DEVFS2", "DEVFS data 2");
61 static MALLOC_DEFINE(M_DEVFS3, "DEVFS3", "DEVFS data 3");
62 static MALLOC_DEFINE(M_CDEVP, "DEVFS1", "DEVFS cdev_priv storage");
63 
64 static SYSCTL_NODE(_vfs, OID_AUTO, devfs, CTLFLAG_RW, 0, "DEVFS filesystem");
65 
66 static unsigned devfs_generation;
67 SYSCTL_UINT(_vfs_devfs, OID_AUTO, generation, CTLFLAG_RD,
68 	&devfs_generation, 0, "DEVFS generation number");
69 
70 unsigned devfs_rule_depth = 1;
71 SYSCTL_UINT(_vfs_devfs, OID_AUTO, rule_depth, CTLFLAG_RW,
72 	&devfs_rule_depth, 0, "Max depth of ruleset include");
73 
74 /*
75  * Helper sysctl for devname(3).  We're given a dev_t and return the
76  * name, if any, registered by the device driver.
77  */
78 static int
79 sysctl_devname(SYSCTL_HANDLER_ARGS)
80 {
81 	int error;
82 	dev_t ud;
83 	struct cdev_priv *cdp;
84 	struct cdev *dev;
85 
86 	error = SYSCTL_IN(req, &ud, sizeof (ud));
87 	if (error)
88 		return (error);
89 	if (ud == NODEV)
90 		return (EINVAL);
91 	dev = NULL;
92 	dev_lock();
93 	TAILQ_FOREACH(cdp, &cdevp_list, cdp_list)
94 		if (cdp->cdp_inode == ud) {
95 			dev = &cdp->cdp_c;
96 			dev_refl(dev);
97 			break;
98 		}
99 	dev_unlock();
100 	if (dev == NULL)
101 		return (ENOENT);
102 	error = SYSCTL_OUT(req, dev->si_name, strlen(dev->si_name) + 1);
103 	dev_rel(dev);
104 	return (error);
105 }
106 
107 SYSCTL_PROC(_kern, OID_AUTO, devname,
108     CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_ANYBODY|CTLFLAG_MPSAFE,
109     NULL, 0, sysctl_devname, "", "devname(3) handler");
110 
111 SYSCTL_INT(_debug_sizeof, OID_AUTO, cdev, CTLFLAG_RD,
112     0, sizeof(struct cdev), "sizeof(struct cdev)");
113 
114 SYSCTL_INT(_debug_sizeof, OID_AUTO, cdev_priv, CTLFLAG_RD,
115     0, sizeof(struct cdev_priv), "sizeof(struct cdev_priv)");
116 
117 struct cdev *
118 devfs_alloc(int flags)
119 {
120 	struct cdev_priv *cdp;
121 	struct cdev *cdev;
122 	struct timespec ts;
123 
124 	cdp = malloc(sizeof *cdp, M_CDEVP, M_USE_RESERVE | M_ZERO |
125 	    ((flags & MAKEDEV_NOWAIT) ? M_NOWAIT : M_WAITOK));
126 	if (cdp == NULL)
127 		return (NULL);
128 
129 	cdp->cdp_dirents = &cdp->cdp_dirent0;
130 	cdp->cdp_dirent0 = NULL;
131 	cdp->cdp_maxdirent = 0;
132 	cdp->cdp_inode = 0;
133 
134 	cdev = &cdp->cdp_c;
135 
136 	cdev->si_name = cdev->__si_namebuf;
137 	LIST_INIT(&cdev->si_children);
138 	vfs_timestamp(&ts);
139 	cdev->si_atime = cdev->si_mtime = cdev->si_ctime = ts;
140 	cdev->si_cred = NULL;
141 
142 	return (cdev);
143 }
144 
145 int
146 devfs_dev_exists(const char *name)
147 {
148 	struct cdev_priv *cdp;
149 
150 	mtx_assert(&devmtx, MA_OWNED);
151 
152 	TAILQ_FOREACH(cdp, &cdevp_list, cdp_list) {
153 		if ((cdp->cdp_flags & CDP_ACTIVE) == 0)
154 			continue;
155 		if (devfs_pathpath(cdp->cdp_c.si_name, name) != 0)
156 			return (1);
157 		if (devfs_pathpath(name, cdp->cdp_c.si_name) != 0)
158 			return (1);
159 	}
160 	if (devfs_dir_find(name) != 0)
161 		return (1);
162 
163 	return (0);
164 }
165 
166 void
167 devfs_free(struct cdev *cdev)
168 {
169 	struct cdev_priv *cdp;
170 
171 	cdp = cdev2priv(cdev);
172 	if (cdev->si_cred != NULL)
173 		crfree(cdev->si_cred);
174 	if (cdp->cdp_inode > 0)
175 		free_unr(devfs_inos, cdp->cdp_inode);
176 	if (cdp->cdp_maxdirent > 0)
177 		free(cdp->cdp_dirents, M_DEVFS2);
178 	free(cdp, M_CDEVP);
179 }
180 
181 struct devfs_dirent *
182 devfs_find(struct devfs_dirent *dd, const char *name, int namelen, int type)
183 {
184 	struct devfs_dirent *de;
185 
186 	TAILQ_FOREACH(de, &dd->de_dlist, de_list) {
187 		if (namelen != de->de_dirent->d_namlen)
188 			continue;
189 		if (type != 0 && type != de->de_dirent->d_type)
190 			continue;
191 		if (bcmp(name, de->de_dirent->d_name, namelen) != 0)
192 			continue;
193 		break;
194 	}
195 	KASSERT(de == NULL || (de->de_flags & DE_DOOMED) == 0,
196 	    ("devfs_find: returning a doomed entry"));
197 	return (de);
198 }
199 
200 struct devfs_dirent *
201 devfs_newdirent(char *name, int namelen)
202 {
203 	int i;
204 	struct devfs_dirent *de;
205 	struct dirent d;
206 
207 	d.d_namlen = namelen;
208 	i = sizeof (*de) + GENERIC_DIRSIZ(&d);
209 	de = malloc(i, M_DEVFS3, M_WAITOK | M_ZERO);
210 	de->de_dirent = (struct dirent *)(de + 1);
211 	de->de_dirent->d_namlen = namelen;
212 	de->de_dirent->d_reclen = GENERIC_DIRSIZ(&d);
213 	bcopy(name, de->de_dirent->d_name, namelen);
214 	de->de_dirent->d_name[namelen] = '\0';
215 	vfs_timestamp(&de->de_ctime);
216 	de->de_mtime = de->de_atime = de->de_ctime;
217 	de->de_links = 1;
218 	de->de_holdcnt = 1;
219 #ifdef MAC
220 	mac_devfs_init(de);
221 #endif
222 	return (de);
223 }
224 
225 struct devfs_dirent *
226 devfs_parent_dirent(struct devfs_dirent *de)
227 {
228 
229 	if (de->de_dirent->d_type != DT_DIR)
230 		return (de->de_dir);
231 
232 	if (de->de_flags & (DE_DOT | DE_DOTDOT))
233 		return (NULL);
234 
235 	de = TAILQ_FIRST(&de->de_dlist);	/* "." */
236 	if (de == NULL)
237 		return (NULL);
238 	de = TAILQ_NEXT(de, de_list);		/* ".." */
239 	if (de == NULL)
240 		return (NULL);
241 
242 	return (de->de_dir);
243 }
244 
245 struct devfs_dirent *
246 devfs_vmkdir(struct devfs_mount *dmp, char *name, int namelen, struct devfs_dirent *dotdot, u_int inode)
247 {
248 	struct devfs_dirent *dd;
249 	struct devfs_dirent *de;
250 
251 	/* Create the new directory */
252 	dd = devfs_newdirent(name, namelen);
253 	TAILQ_INIT(&dd->de_dlist);
254 	dd->de_dirent->d_type = DT_DIR;
255 	dd->de_mode = 0555;
256 	dd->de_links = 2;
257 	dd->de_dir = dd;
258 	if (inode != 0)
259 		dd->de_inode = inode;
260 	else
261 		dd->de_inode = alloc_unr(devfs_inos);
262 
263 	/*
264 	 * "." and ".." are always the two first entries in the
265 	 * de_dlist list.
266 	 *
267 	 * Create the "." entry in the new directory.
268 	 */
269 	de = devfs_newdirent(".", 1);
270 	de->de_dirent->d_type = DT_DIR;
271 	de->de_flags |= DE_DOT;
272 	TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list);
273 	de->de_dir = dd;
274 
275 	/* Create the ".." entry in the new directory. */
276 	de = devfs_newdirent("..", 2);
277 	de->de_dirent->d_type = DT_DIR;
278 	de->de_flags |= DE_DOTDOT;
279 	TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list);
280 	if (dotdot == NULL) {
281 		de->de_dir = dd;
282 	} else {
283 		de->de_dir = dotdot;
284 		sx_assert(&dmp->dm_lock, SX_XLOCKED);
285 		TAILQ_INSERT_TAIL(&dotdot->de_dlist, dd, de_list);
286 		dotdot->de_links++;
287 		devfs_rules_apply(dmp, dd);
288 	}
289 
290 #ifdef MAC
291 	mac_devfs_create_directory(dmp->dm_mount, name, namelen, dd);
292 #endif
293 	return (dd);
294 }
295 
296 void
297 devfs_dirent_free(struct devfs_dirent *de)
298 {
299 	free(de, M_DEVFS3);
300 }
301 
302 /*
303  * Removes a directory if it is empty. Also empty parent directories are
304  * removed recursively.
305  */
306 static void
307 devfs_rmdir_empty(struct devfs_mount *dm, struct devfs_dirent *de)
308 {
309 	struct devfs_dirent *dd, *de_dot, *de_dotdot;
310 
311 	sx_assert(&dm->dm_lock, SX_XLOCKED);
312 
313 	for (;;) {
314 		KASSERT(de->de_dirent->d_type == DT_DIR,
315 		    ("devfs_rmdir_empty: de is not a directory"));
316 
317 		if ((de->de_flags & DE_DOOMED) != 0 || de == dm->dm_rootdir)
318 			return;
319 
320 		de_dot = TAILQ_FIRST(&de->de_dlist);
321 		KASSERT(de_dot != NULL, ("devfs_rmdir_empty: . missing"));
322 		de_dotdot = TAILQ_NEXT(de_dot, de_list);
323 		KASSERT(de_dotdot != NULL, ("devfs_rmdir_empty: .. missing"));
324 		/* Return if the directory is not empty. */
325 		if (TAILQ_NEXT(de_dotdot, de_list) != NULL)
326 			return;
327 
328 		dd = devfs_parent_dirent(de);
329 		KASSERT(dd != NULL, ("devfs_rmdir_empty: NULL dd"));
330 		TAILQ_REMOVE(&de->de_dlist, de_dot, de_list);
331 		TAILQ_REMOVE(&de->de_dlist, de_dotdot, de_list);
332 		TAILQ_REMOVE(&dd->de_dlist, de, de_list);
333 		DEVFS_DE_HOLD(dd);
334 		devfs_delete(dm, de, DEVFS_DEL_NORECURSE);
335 		devfs_delete(dm, de_dot, DEVFS_DEL_NORECURSE);
336 		devfs_delete(dm, de_dotdot, DEVFS_DEL_NORECURSE);
337 		if (DEVFS_DE_DROP(dd)) {
338 			devfs_dirent_free(dd);
339 			return;
340 		}
341 
342 		de = dd;
343 	}
344 }
345 
346 /*
347  * The caller needs to hold the dm for the duration of the call since
348  * dm->dm_lock may be temporary dropped.
349  */
350 void
351 devfs_delete(struct devfs_mount *dm, struct devfs_dirent *de, int flags)
352 {
353 	struct devfs_dirent *dd;
354 	struct vnode *vp;
355 
356 	KASSERT((de->de_flags & DE_DOOMED) == 0,
357 		("devfs_delete doomed dirent"));
358 	de->de_flags |= DE_DOOMED;
359 
360 	if ((flags & DEVFS_DEL_NORECURSE) == 0) {
361 		dd = devfs_parent_dirent(de);
362 		if (dd != NULL)
363 			DEVFS_DE_HOLD(dd);
364 		if (de->de_flags & DE_USER) {
365 			KASSERT(dd != NULL, ("devfs_delete: NULL dd"));
366 			devfs_dir_unref_de(dm, dd);
367 		}
368 	} else
369 		dd = NULL;
370 
371 	mtx_lock(&devfs_de_interlock);
372 	vp = de->de_vnode;
373 	if (vp != NULL) {
374 		VI_LOCK(vp);
375 		mtx_unlock(&devfs_de_interlock);
376 		vholdl(vp);
377 		sx_unlock(&dm->dm_lock);
378 		if ((flags & DEVFS_DEL_VNLOCKED) == 0)
379 			vn_lock(vp, LK_EXCLUSIVE | LK_INTERLOCK | LK_RETRY);
380 		else
381 			VI_UNLOCK(vp);
382 		vgone(vp);
383 		if ((flags & DEVFS_DEL_VNLOCKED) == 0)
384 			VOP_UNLOCK(vp, 0);
385 		vdrop(vp);
386 		sx_xlock(&dm->dm_lock);
387 	} else
388 		mtx_unlock(&devfs_de_interlock);
389 	if (de->de_symlink) {
390 		free(de->de_symlink, M_DEVFS);
391 		de->de_symlink = NULL;
392 	}
393 #ifdef MAC
394 	mac_devfs_destroy(de);
395 #endif
396 	if (de->de_inode > DEVFS_ROOTINO) {
397 		free_unr(devfs_inos, de->de_inode);
398 		de->de_inode = 0;
399 	}
400 	if (DEVFS_DE_DROP(de))
401 		devfs_dirent_free(de);
402 
403 	if (dd != NULL) {
404 		if (DEVFS_DE_DROP(dd))
405 			devfs_dirent_free(dd);
406 		else
407 			devfs_rmdir_empty(dm, dd);
408 	}
409 }
410 
411 /*
412  * Called on unmount.
413  * Recursively removes the entire tree.
414  * The caller needs to hold the dm for the duration of the call.
415  */
416 
417 static void
418 devfs_purge(struct devfs_mount *dm, struct devfs_dirent *dd)
419 {
420 	struct devfs_dirent *de;
421 
422 	sx_assert(&dm->dm_lock, SX_XLOCKED);
423 
424 	DEVFS_DE_HOLD(dd);
425 	for (;;) {
426 		/*
427 		 * Use TAILQ_LAST() to remove "." and ".." last.
428 		 * We might need ".." to resolve a path in
429 		 * devfs_dir_unref_de().
430 		 */
431 		de = TAILQ_LAST(&dd->de_dlist, devfs_dlist_head);
432 		if (de == NULL)
433 			break;
434 		TAILQ_REMOVE(&dd->de_dlist, de, de_list);
435 		if (de->de_flags & DE_USER)
436 			devfs_dir_unref_de(dm, dd);
437 		if (de->de_flags & (DE_DOT | DE_DOTDOT))
438 			devfs_delete(dm, de, DEVFS_DEL_NORECURSE);
439 		else if (de->de_dirent->d_type == DT_DIR)
440 			devfs_purge(dm, de);
441 		else
442 			devfs_delete(dm, de, DEVFS_DEL_NORECURSE);
443 	}
444 	if (DEVFS_DE_DROP(dd))
445 		devfs_dirent_free(dd);
446 	else if ((dd->de_flags & DE_DOOMED) == 0)
447 		devfs_delete(dm, dd, DEVFS_DEL_NORECURSE);
448 }
449 
450 /*
451  * Each cdev_priv has an array of pointers to devfs_dirent which is indexed
452  * by the mount points dm_idx.
453  * This function extends the array when necessary, taking into account that
454  * the default array is 1 element and not malloc'ed.
455  */
456 static void
457 devfs_metoo(struct cdev_priv *cdp, struct devfs_mount *dm)
458 {
459 	struct devfs_dirent **dep;
460 	int siz;
461 
462 	siz = (dm->dm_idx + 1) * sizeof *dep;
463 	dep = malloc(siz, M_DEVFS2, M_WAITOK | M_ZERO);
464 	dev_lock();
465 	if (dm->dm_idx <= cdp->cdp_maxdirent) {
466 		/* We got raced */
467 		dev_unlock();
468 		free(dep, M_DEVFS2);
469 		return;
470 	}
471 	memcpy(dep, cdp->cdp_dirents, (cdp->cdp_maxdirent + 1) * sizeof *dep);
472 	if (cdp->cdp_maxdirent > 0)
473 		free(cdp->cdp_dirents, M_DEVFS2);
474 	cdp->cdp_dirents = dep;
475 	/*
476 	 * XXX: if malloc told us how much we actually got this could
477 	 * XXX: be optimized.
478 	 */
479 	cdp->cdp_maxdirent = dm->dm_idx;
480 	dev_unlock();
481 }
482 
483 /*
484  * The caller needs to hold the dm for the duration of the call.
485  */
486 static int
487 devfs_populate_loop(struct devfs_mount *dm, int cleanup)
488 {
489 	struct cdev_priv *cdp;
490 	struct devfs_dirent *de;
491 	struct devfs_dirent *dd;
492 	struct cdev *pdev;
493 	int de_flags, j;
494 	char *q, *s;
495 
496 	sx_assert(&dm->dm_lock, SX_XLOCKED);
497 	dev_lock();
498 	TAILQ_FOREACH(cdp, &cdevp_list, cdp_list) {
499 
500 		KASSERT(cdp->cdp_dirents != NULL, ("NULL cdp_dirents"));
501 
502 		/*
503 		 * If we are unmounting, or the device has been destroyed,
504 		 * clean up our dirent.
505 		 */
506 		if ((cleanup || !(cdp->cdp_flags & CDP_ACTIVE)) &&
507 		    dm->dm_idx <= cdp->cdp_maxdirent &&
508 		    cdp->cdp_dirents[dm->dm_idx] != NULL) {
509 			de = cdp->cdp_dirents[dm->dm_idx];
510 			cdp->cdp_dirents[dm->dm_idx] = NULL;
511 			KASSERT(cdp == de->de_cdp,
512 			    ("%s %d %s %p %p", __func__, __LINE__,
513 			    cdp->cdp_c.si_name, cdp, de->de_cdp));
514 			KASSERT(de->de_dir != NULL, ("Null de->de_dir"));
515 			dev_unlock();
516 
517 			TAILQ_REMOVE(&de->de_dir->de_dlist, de, de_list);
518 			de->de_cdp = NULL;
519 			de->de_inode = 0;
520 			devfs_delete(dm, de, 0);
521 			dev_lock();
522 			cdp->cdp_inuse--;
523 			dev_unlock();
524 			return (1);
525 		}
526 		/*
527 	 	 * GC any lingering devices
528 		 */
529 		if (!(cdp->cdp_flags & CDP_ACTIVE)) {
530 			if (cdp->cdp_inuse > 0)
531 				continue;
532 			TAILQ_REMOVE(&cdevp_list, cdp, cdp_list);
533 			dev_unlock();
534 			dev_rel(&cdp->cdp_c);
535 			return (1);
536 		}
537 		/*
538 		 * Don't create any new dirents if we are unmounting
539 		 */
540 		if (cleanup)
541 			continue;
542 		KASSERT((cdp->cdp_flags & CDP_ACTIVE), ("Bogons, I tell ya'!"));
543 
544 		if (dm->dm_idx <= cdp->cdp_maxdirent &&
545 		    cdp->cdp_dirents[dm->dm_idx] != NULL) {
546 			de = cdp->cdp_dirents[dm->dm_idx];
547 			KASSERT(cdp == de->de_cdp, ("inconsistent cdp"));
548 			continue;
549 		}
550 
551 
552 		cdp->cdp_inuse++;
553 		dev_unlock();
554 
555 		if (dm->dm_idx > cdp->cdp_maxdirent)
556 		        devfs_metoo(cdp, dm);
557 
558 		dd = dm->dm_rootdir;
559 		s = cdp->cdp_c.si_name;
560 		for (;;) {
561 			for (q = s; *q != '/' && *q != '\0'; q++)
562 				continue;
563 			if (*q != '/')
564 				break;
565 			de = devfs_find(dd, s, q - s, 0);
566 			if (de == NULL)
567 				de = devfs_vmkdir(dm, s, q - s, dd, 0);
568 			else if (de->de_dirent->d_type == DT_LNK) {
569 				de = devfs_find(dd, s, q - s, DT_DIR);
570 				if (de == NULL)
571 					de = devfs_vmkdir(dm, s, q - s, dd, 0);
572 				de->de_flags |= DE_COVERED;
573 			}
574 			s = q + 1;
575 			dd = de;
576 			KASSERT(dd->de_dirent->d_type == DT_DIR &&
577 			    (dd->de_flags & (DE_DOT | DE_DOTDOT)) == 0,
578 			    ("%s: invalid directory (si_name=%s)",
579 			    __func__, cdp->cdp_c.si_name));
580 
581 		}
582 		de_flags = 0;
583 		de = devfs_find(dd, s, q - s, DT_LNK);
584 		if (de != NULL)
585 			de_flags |= DE_COVERED;
586 
587 		de = devfs_newdirent(s, q - s);
588 		if (cdp->cdp_c.si_flags & SI_ALIAS) {
589 			de->de_uid = 0;
590 			de->de_gid = 0;
591 			de->de_mode = 0755;
592 			de->de_dirent->d_type = DT_LNK;
593 			pdev = cdp->cdp_c.si_parent;
594 			j = strlen(pdev->si_name) + 1;
595 			de->de_symlink = malloc(j, M_DEVFS, M_WAITOK);
596 			bcopy(pdev->si_name, de->de_symlink, j);
597 		} else {
598 			de->de_uid = cdp->cdp_c.si_uid;
599 			de->de_gid = cdp->cdp_c.si_gid;
600 			de->de_mode = cdp->cdp_c.si_mode;
601 			de->de_dirent->d_type = DT_CHR;
602 		}
603 		de->de_flags |= de_flags;
604 		de->de_inode = cdp->cdp_inode;
605 		de->de_cdp = cdp;
606 #ifdef MAC
607 		mac_devfs_create_device(cdp->cdp_c.si_cred, dm->dm_mount,
608 		    &cdp->cdp_c, de);
609 #endif
610 		de->de_dir = dd;
611 		TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list);
612 		devfs_rules_apply(dm, de);
613 		dev_lock();
614 		/* XXX: could check that cdp is still active here */
615 		KASSERT(cdp->cdp_dirents[dm->dm_idx] == NULL,
616 		    ("%s %d\n", __func__, __LINE__));
617 		cdp->cdp_dirents[dm->dm_idx] = de;
618 		KASSERT(de->de_cdp != (void *)0xdeadc0de,
619 		    ("%s %d\n", __func__, __LINE__));
620 		dev_unlock();
621 		return (1);
622 	}
623 	dev_unlock();
624 	return (0);
625 }
626 
627 /*
628  * The caller needs to hold the dm for the duration of the call.
629  */
630 void
631 devfs_populate(struct devfs_mount *dm)
632 {
633 
634 	sx_assert(&dm->dm_lock, SX_XLOCKED);
635 	if (dm->dm_generation == devfs_generation)
636 		return;
637 	while (devfs_populate_loop(dm, 0))
638 		continue;
639 	dm->dm_generation = devfs_generation;
640 }
641 
642 /*
643  * The caller needs to hold the dm for the duration of the call.
644  */
645 void
646 devfs_cleanup(struct devfs_mount *dm)
647 {
648 
649 	sx_assert(&dm->dm_lock, SX_XLOCKED);
650 	while (devfs_populate_loop(dm, 1))
651 		continue;
652 	devfs_purge(dm, dm->dm_rootdir);
653 }
654 
655 /*
656  * devfs_create() and devfs_destroy() are called from kern_conf.c and
657  * in both cases the devlock() mutex is held, so no further locking
658  * is necesary and no sleeping allowed.
659  */
660 
661 void
662 devfs_create(struct cdev *dev)
663 {
664 	struct cdev_priv *cdp;
665 
666 	mtx_assert(&devmtx, MA_OWNED);
667 	cdp = cdev2priv(dev);
668 	cdp->cdp_flags |= CDP_ACTIVE;
669 	cdp->cdp_inode = alloc_unrl(devfs_inos);
670 	dev_refl(dev);
671 	TAILQ_INSERT_TAIL(&cdevp_list, cdp, cdp_list);
672 	devfs_generation++;
673 }
674 
675 void
676 devfs_destroy(struct cdev *dev)
677 {
678 	struct cdev_priv *cdp;
679 
680 	mtx_assert(&devmtx, MA_OWNED);
681 	cdp = cdev2priv(dev);
682 	cdp->cdp_flags &= ~CDP_ACTIVE;
683 	devfs_generation++;
684 }
685 
686 static void
687 devfs_devs_init(void *junk __unused)
688 {
689 
690 	devfs_inos = new_unrhdr(DEVFS_ROOTINO + 1, INT_MAX, &devmtx);
691 }
692 
693 SYSINIT(devfs_devs, SI_SUB_DEVFS, SI_ORDER_FIRST, devfs_devs_init, NULL);
694