xref: /freebsd/sys/fs/devfs/devfs_devs.c (revision 6b129086dcee14496517fae085b448e3edc69bc7)
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     SYSCTL_NULL_INT_PTR, sizeof(struct cdev), "sizeof(struct cdev)");
113 
114 SYSCTL_INT(_debug_sizeof, OID_AUTO, cdev_priv, CTLFLAG_RD,
115     SYSCTL_NULL_INT_PTR, 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_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 	LIST_INIT(&cdev->si_children);
137 	vfs_timestamp(&ts);
138 	cdev->si_atime = cdev->si_mtime = cdev->si_ctime = ts;
139 	cdev->si_cred = NULL;
140 
141 	return (cdev);
142 }
143 
144 int
145 devfs_dev_exists(const char *name)
146 {
147 	struct cdev_priv *cdp;
148 
149 	mtx_assert(&devmtx, MA_OWNED);
150 
151 	TAILQ_FOREACH(cdp, &cdevp_list, cdp_list) {
152 		if ((cdp->cdp_flags & CDP_ACTIVE) == 0)
153 			continue;
154 		if (devfs_pathpath(cdp->cdp_c.si_name, name) != 0)
155 			return (1);
156 		if (devfs_pathpath(name, cdp->cdp_c.si_name) != 0)
157 			return (1);
158 	}
159 	if (devfs_dir_find(name) != 0)
160 		return (1);
161 
162 	return (0);
163 }
164 
165 void
166 devfs_free(struct cdev *cdev)
167 {
168 	struct cdev_priv *cdp;
169 
170 	cdp = cdev2priv(cdev);
171 	if (cdev->si_cred != NULL)
172 		crfree(cdev->si_cred);
173 	devfs_free_cdp_inode(cdp->cdp_inode);
174 	if (cdp->cdp_maxdirent > 0)
175 		free(cdp->cdp_dirents, M_DEVFS2);
176 	free(cdp, M_CDEVP);
177 }
178 
179 struct devfs_dirent *
180 devfs_find(struct devfs_dirent *dd, const char *name, int namelen, int type)
181 {
182 	struct devfs_dirent *de;
183 
184 	TAILQ_FOREACH(de, &dd->de_dlist, de_list) {
185 		if (namelen != de->de_dirent->d_namlen)
186 			continue;
187 		if (type != 0 && type != de->de_dirent->d_type)
188 			continue;
189 		if (bcmp(name, de->de_dirent->d_name, namelen) != 0)
190 			continue;
191 		break;
192 	}
193 	KASSERT(de == NULL || (de->de_flags & DE_DOOMED) == 0,
194 	    ("devfs_find: returning a doomed entry"));
195 	return (de);
196 }
197 
198 struct devfs_dirent *
199 devfs_newdirent(char *name, int namelen)
200 {
201 	int i;
202 	struct devfs_dirent *de;
203 	struct dirent d;
204 
205 	d.d_namlen = namelen;
206 	i = sizeof (*de) + GENERIC_DIRSIZ(&d);
207 	de = malloc(i, M_DEVFS3, M_WAITOK | M_ZERO);
208 	de->de_dirent = (struct dirent *)(de + 1);
209 	de->de_dirent->d_namlen = namelen;
210 	de->de_dirent->d_reclen = GENERIC_DIRSIZ(&d);
211 	bcopy(name, de->de_dirent->d_name, namelen);
212 	de->de_dirent->d_name[namelen] = '\0';
213 	vfs_timestamp(&de->de_ctime);
214 	de->de_mtime = de->de_atime = de->de_ctime;
215 	de->de_links = 1;
216 	de->de_holdcnt = 1;
217 #ifdef MAC
218 	mac_devfs_init(de);
219 #endif
220 	return (de);
221 }
222 
223 struct devfs_dirent *
224 devfs_parent_dirent(struct devfs_dirent *de)
225 {
226 
227 	if (de->de_dirent->d_type != DT_DIR)
228 		return (de->de_dir);
229 
230 	if (de->de_flags & (DE_DOT | DE_DOTDOT))
231 		return (NULL);
232 
233 	de = TAILQ_FIRST(&de->de_dlist);	/* "." */
234 	if (de == NULL)
235 		return (NULL);
236 	de = TAILQ_NEXT(de, de_list);		/* ".." */
237 	if (de == NULL)
238 		return (NULL);
239 
240 	return (de->de_dir);
241 }
242 
243 struct devfs_dirent *
244 devfs_vmkdir(struct devfs_mount *dmp, char *name, int namelen, struct devfs_dirent *dotdot, u_int inode)
245 {
246 	struct devfs_dirent *dd;
247 	struct devfs_dirent *de;
248 
249 	/* Create the new directory */
250 	dd = devfs_newdirent(name, namelen);
251 	TAILQ_INIT(&dd->de_dlist);
252 	dd->de_dirent->d_type = DT_DIR;
253 	dd->de_mode = 0555;
254 	dd->de_links = 2;
255 	dd->de_dir = dd;
256 	if (inode != 0)
257 		dd->de_inode = inode;
258 	else
259 		dd->de_inode = alloc_unr(devfs_inos);
260 
261 	/*
262 	 * "." and ".." are always the two first entries in the
263 	 * de_dlist list.
264 	 *
265 	 * Create the "." entry in the new directory.
266 	 */
267 	de = devfs_newdirent(".", 1);
268 	de->de_dirent->d_type = DT_DIR;
269 	de->de_flags |= DE_DOT;
270 	TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list);
271 	de->de_dir = dd;
272 
273 	/* Create the ".." entry in the new directory. */
274 	de = devfs_newdirent("..", 2);
275 	de->de_dirent->d_type = DT_DIR;
276 	de->de_flags |= DE_DOTDOT;
277 	TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list);
278 	if (dotdot == NULL) {
279 		de->de_dir = dd;
280 	} else {
281 		de->de_dir = dotdot;
282 		sx_assert(&dmp->dm_lock, SX_XLOCKED);
283 		TAILQ_INSERT_TAIL(&dotdot->de_dlist, dd, de_list);
284 		dotdot->de_links++;
285 		devfs_rules_apply(dmp, dd);
286 	}
287 
288 #ifdef MAC
289 	mac_devfs_create_directory(dmp->dm_mount, name, namelen, dd);
290 #endif
291 	return (dd);
292 }
293 
294 void
295 devfs_dirent_free(struct devfs_dirent *de)
296 {
297 	free(de, M_DEVFS3);
298 }
299 
300 /*
301  * Removes a directory if it is empty. Also empty parent directories are
302  * removed recursively.
303  */
304 static void
305 devfs_rmdir_empty(struct devfs_mount *dm, struct devfs_dirent *de)
306 {
307 	struct devfs_dirent *dd, *de_dot, *de_dotdot;
308 
309 	sx_assert(&dm->dm_lock, SX_XLOCKED);
310 
311 	for (;;) {
312 		KASSERT(de->de_dirent->d_type == DT_DIR,
313 		    ("devfs_rmdir_empty: de is not a directory"));
314 
315 		if ((de->de_flags & DE_DOOMED) != 0 || de == dm->dm_rootdir)
316 			return;
317 
318 		de_dot = TAILQ_FIRST(&de->de_dlist);
319 		KASSERT(de_dot != NULL, ("devfs_rmdir_empty: . missing"));
320 		de_dotdot = TAILQ_NEXT(de_dot, de_list);
321 		KASSERT(de_dotdot != NULL, ("devfs_rmdir_empty: .. missing"));
322 		/* Return if the directory is not empty. */
323 		if (TAILQ_NEXT(de_dotdot, de_list) != NULL)
324 			return;
325 
326 		dd = devfs_parent_dirent(de);
327 		KASSERT(dd != NULL, ("devfs_rmdir_empty: NULL dd"));
328 		TAILQ_REMOVE(&de->de_dlist, de_dot, de_list);
329 		TAILQ_REMOVE(&de->de_dlist, de_dotdot, de_list);
330 		TAILQ_REMOVE(&dd->de_dlist, de, de_list);
331 		DEVFS_DE_HOLD(dd);
332 		devfs_delete(dm, de, DEVFS_DEL_NORECURSE);
333 		devfs_delete(dm, de_dot, DEVFS_DEL_NORECURSE);
334 		devfs_delete(dm, de_dotdot, DEVFS_DEL_NORECURSE);
335 		if (DEVFS_DE_DROP(dd)) {
336 			devfs_dirent_free(dd);
337 			return;
338 		}
339 
340 		de = dd;
341 	}
342 }
343 
344 /*
345  * The caller needs to hold the dm for the duration of the call since
346  * dm->dm_lock may be temporary dropped.
347  */
348 void
349 devfs_delete(struct devfs_mount *dm, struct devfs_dirent *de, int flags)
350 {
351 	struct devfs_dirent *dd;
352 	struct vnode *vp;
353 
354 	KASSERT((de->de_flags & DE_DOOMED) == 0,
355 		("devfs_delete doomed dirent"));
356 	de->de_flags |= DE_DOOMED;
357 
358 	if ((flags & DEVFS_DEL_NORECURSE) == 0) {
359 		dd = devfs_parent_dirent(de);
360 		if (dd != NULL)
361 			DEVFS_DE_HOLD(dd);
362 		if (de->de_flags & DE_USER) {
363 			KASSERT(dd != NULL, ("devfs_delete: NULL dd"));
364 			devfs_dir_unref_de(dm, dd);
365 		}
366 	} else
367 		dd = NULL;
368 
369 	mtx_lock(&devfs_de_interlock);
370 	vp = de->de_vnode;
371 	if (vp != NULL) {
372 		VI_LOCK(vp);
373 		mtx_unlock(&devfs_de_interlock);
374 		vholdl(vp);
375 		sx_unlock(&dm->dm_lock);
376 		if ((flags & DEVFS_DEL_VNLOCKED) == 0)
377 			vn_lock(vp, LK_EXCLUSIVE | LK_INTERLOCK | LK_RETRY);
378 		else
379 			VI_UNLOCK(vp);
380 		vgone(vp);
381 		if ((flags & DEVFS_DEL_VNLOCKED) == 0)
382 			VOP_UNLOCK(vp, 0);
383 		vdrop(vp);
384 		sx_xlock(&dm->dm_lock);
385 	} else
386 		mtx_unlock(&devfs_de_interlock);
387 	if (de->de_symlink) {
388 		free(de->de_symlink, M_DEVFS);
389 		de->de_symlink = NULL;
390 	}
391 #ifdef MAC
392 	mac_devfs_destroy(de);
393 #endif
394 	if (de->de_inode > DEVFS_ROOTINO) {
395 		devfs_free_cdp_inode(de->de_inode);
396 		de->de_inode = 0;
397 	}
398 	if (DEVFS_DE_DROP(de))
399 		devfs_dirent_free(de);
400 
401 	if (dd != NULL) {
402 		if (DEVFS_DE_DROP(dd))
403 			devfs_dirent_free(dd);
404 		else
405 			devfs_rmdir_empty(dm, dd);
406 	}
407 }
408 
409 /*
410  * Called on unmount.
411  * Recursively removes the entire tree.
412  * The caller needs to hold the dm for the duration of the call.
413  */
414 
415 static void
416 devfs_purge(struct devfs_mount *dm, struct devfs_dirent *dd)
417 {
418 	struct devfs_dirent *de;
419 
420 	sx_assert(&dm->dm_lock, SX_XLOCKED);
421 
422 	DEVFS_DE_HOLD(dd);
423 	for (;;) {
424 		/*
425 		 * Use TAILQ_LAST() to remove "." and ".." last.
426 		 * We might need ".." to resolve a path in
427 		 * devfs_dir_unref_de().
428 		 */
429 		de = TAILQ_LAST(&dd->de_dlist, devfs_dlist_head);
430 		if (de == NULL)
431 			break;
432 		TAILQ_REMOVE(&dd->de_dlist, de, de_list);
433 		if (de->de_flags & DE_USER)
434 			devfs_dir_unref_de(dm, dd);
435 		if (de->de_flags & (DE_DOT | DE_DOTDOT))
436 			devfs_delete(dm, de, DEVFS_DEL_NORECURSE);
437 		else if (de->de_dirent->d_type == DT_DIR)
438 			devfs_purge(dm, de);
439 		else
440 			devfs_delete(dm, de, DEVFS_DEL_NORECURSE);
441 	}
442 	if (DEVFS_DE_DROP(dd))
443 		devfs_dirent_free(dd);
444 	else if ((dd->de_flags & DE_DOOMED) == 0)
445 		devfs_delete(dm, dd, DEVFS_DEL_NORECURSE);
446 }
447 
448 /*
449  * Each cdev_priv has an array of pointers to devfs_dirent which is indexed
450  * by the mount points dm_idx.
451  * This function extends the array when necessary, taking into account that
452  * the default array is 1 element and not malloc'ed.
453  */
454 static void
455 devfs_metoo(struct cdev_priv *cdp, struct devfs_mount *dm)
456 {
457 	struct devfs_dirent **dep;
458 	int siz;
459 
460 	siz = (dm->dm_idx + 1) * sizeof *dep;
461 	dep = malloc(siz, M_DEVFS2, M_WAITOK | M_ZERO);
462 	dev_lock();
463 	if (dm->dm_idx <= cdp->cdp_maxdirent) {
464 		/* We got raced */
465 		dev_unlock();
466 		free(dep, M_DEVFS2);
467 		return;
468 	}
469 	memcpy(dep, cdp->cdp_dirents, (cdp->cdp_maxdirent + 1) * sizeof *dep);
470 	if (cdp->cdp_maxdirent > 0)
471 		free(cdp->cdp_dirents, M_DEVFS2);
472 	cdp->cdp_dirents = dep;
473 	/*
474 	 * XXX: if malloc told us how much we actually got this could
475 	 * XXX: be optimized.
476 	 */
477 	cdp->cdp_maxdirent = dm->dm_idx;
478 	dev_unlock();
479 }
480 
481 /*
482  * The caller needs to hold the dm for the duration of the call.
483  */
484 static int
485 devfs_populate_loop(struct devfs_mount *dm, int cleanup)
486 {
487 	struct cdev_priv *cdp;
488 	struct devfs_dirent *de;
489 	struct devfs_dirent *dd, *dt;
490 	struct cdev *pdev;
491 	int de_flags, depth, j;
492 	char *q, *s;
493 
494 	sx_assert(&dm->dm_lock, SX_XLOCKED);
495 	dev_lock();
496 	TAILQ_FOREACH(cdp, &cdevp_list, cdp_list) {
497 
498 		KASSERT(cdp->cdp_dirents != NULL, ("NULL cdp_dirents"));
499 
500 		/*
501 		 * If we are unmounting, or the device has been destroyed,
502 		 * clean up our dirent.
503 		 */
504 		if ((cleanup || !(cdp->cdp_flags & CDP_ACTIVE)) &&
505 		    dm->dm_idx <= cdp->cdp_maxdirent &&
506 		    cdp->cdp_dirents[dm->dm_idx] != NULL) {
507 			de = cdp->cdp_dirents[dm->dm_idx];
508 			cdp->cdp_dirents[dm->dm_idx] = NULL;
509 			KASSERT(cdp == de->de_cdp,
510 			    ("%s %d %s %p %p", __func__, __LINE__,
511 			    cdp->cdp_c.si_name, cdp, de->de_cdp));
512 			KASSERT(de->de_dir != NULL, ("Null de->de_dir"));
513 			dev_unlock();
514 
515 			TAILQ_REMOVE(&de->de_dir->de_dlist, de, de_list);
516 			de->de_cdp = NULL;
517 			de->de_inode = 0;
518 			devfs_delete(dm, de, 0);
519 			dev_lock();
520 			cdp->cdp_inuse--;
521 			dev_unlock();
522 			return (1);
523 		}
524 		/*
525 	 	 * GC any lingering devices
526 		 */
527 		if (!(cdp->cdp_flags & CDP_ACTIVE)) {
528 			if (cdp->cdp_inuse > 0)
529 				continue;
530 			TAILQ_REMOVE(&cdevp_list, cdp, cdp_list);
531 			dev_unlock();
532 			dev_rel(&cdp->cdp_c);
533 			return (1);
534 		}
535 		/*
536 		 * Don't create any new dirents if we are unmounting
537 		 */
538 		if (cleanup)
539 			continue;
540 		KASSERT((cdp->cdp_flags & CDP_ACTIVE), ("Bogons, I tell ya'!"));
541 
542 		if (dm->dm_idx <= cdp->cdp_maxdirent &&
543 		    cdp->cdp_dirents[dm->dm_idx] != NULL) {
544 			de = cdp->cdp_dirents[dm->dm_idx];
545 			KASSERT(cdp == de->de_cdp, ("inconsistent cdp"));
546 			continue;
547 		}
548 
549 
550 		cdp->cdp_inuse++;
551 		dev_unlock();
552 
553 		if (dm->dm_idx > cdp->cdp_maxdirent)
554 		        devfs_metoo(cdp, dm);
555 
556 		dd = dm->dm_rootdir;
557 		s = cdp->cdp_c.si_name;
558 		for (;;) {
559 			for (q = s; *q != '/' && *q != '\0'; q++)
560 				continue;
561 			if (*q != '/')
562 				break;
563 			de = devfs_find(dd, s, q - s, 0);
564 			if (de == NULL)
565 				de = devfs_vmkdir(dm, s, q - s, dd, 0);
566 			else if (de->de_dirent->d_type == DT_LNK) {
567 				de = devfs_find(dd, s, q - s, DT_DIR);
568 				if (de == NULL)
569 					de = devfs_vmkdir(dm, s, q - s, dd, 0);
570 				de->de_flags |= DE_COVERED;
571 			}
572 			s = q + 1;
573 			dd = de;
574 			KASSERT(dd->de_dirent->d_type == DT_DIR &&
575 			    (dd->de_flags & (DE_DOT | DE_DOTDOT)) == 0,
576 			    ("%s: invalid directory (si_name=%s)",
577 			    __func__, cdp->cdp_c.si_name));
578 
579 		}
580 		de_flags = 0;
581 		de = devfs_find(dd, s, q - s, DT_LNK);
582 		if (de != NULL)
583 			de_flags |= DE_COVERED;
584 
585 		de = devfs_newdirent(s, q - s);
586 		if (cdp->cdp_c.si_flags & SI_ALIAS) {
587 			de->de_uid = 0;
588 			de->de_gid = 0;
589 			de->de_mode = 0755;
590 			de->de_dirent->d_type = DT_LNK;
591 			pdev = cdp->cdp_c.si_parent;
592 			dt = dd;
593 			depth = 0;
594 			while (dt != dm->dm_rootdir &&
595 			    (dt = devfs_parent_dirent(dt)) != NULL)
596 				depth++;
597 			j = depth * 3 + strlen(pdev->si_name) + 1;
598 			de->de_symlink = malloc(j, M_DEVFS, M_WAITOK);
599 			de->de_symlink[0] = 0;
600 			while (depth-- > 0)
601 				strcat(de->de_symlink, "../");
602 			strcat(de->de_symlink, pdev->si_name);
603 		} else {
604 			de->de_uid = cdp->cdp_c.si_uid;
605 			de->de_gid = cdp->cdp_c.si_gid;
606 			de->de_mode = cdp->cdp_c.si_mode;
607 			de->de_dirent->d_type = DT_CHR;
608 		}
609 		de->de_flags |= de_flags;
610 		de->de_inode = cdp->cdp_inode;
611 		de->de_cdp = cdp;
612 #ifdef MAC
613 		mac_devfs_create_device(cdp->cdp_c.si_cred, dm->dm_mount,
614 		    &cdp->cdp_c, de);
615 #endif
616 		de->de_dir = dd;
617 		TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list);
618 		devfs_rules_apply(dm, de);
619 		dev_lock();
620 		/* XXX: could check that cdp is still active here */
621 		KASSERT(cdp->cdp_dirents[dm->dm_idx] == NULL,
622 		    ("%s %d\n", __func__, __LINE__));
623 		cdp->cdp_dirents[dm->dm_idx] = de;
624 		KASSERT(de->de_cdp != (void *)0xdeadc0de,
625 		    ("%s %d\n", __func__, __LINE__));
626 		dev_unlock();
627 		return (1);
628 	}
629 	dev_unlock();
630 	return (0);
631 }
632 
633 /*
634  * The caller needs to hold the dm for the duration of the call.
635  */
636 void
637 devfs_populate(struct devfs_mount *dm)
638 {
639 	unsigned gen;
640 
641 	sx_assert(&dm->dm_lock, SX_XLOCKED);
642 	gen = devfs_generation;
643 	if (dm->dm_generation == gen)
644 		return;
645 	while (devfs_populate_loop(dm, 0))
646 		continue;
647 	dm->dm_generation = gen;
648 }
649 
650 /*
651  * The caller needs to hold the dm for the duration of the call.
652  */
653 void
654 devfs_cleanup(struct devfs_mount *dm)
655 {
656 
657 	sx_assert(&dm->dm_lock, SX_XLOCKED);
658 	while (devfs_populate_loop(dm, 1))
659 		continue;
660 	devfs_purge(dm, dm->dm_rootdir);
661 }
662 
663 /*
664  * devfs_create() and devfs_destroy() are called from kern_conf.c and
665  * in both cases the devlock() mutex is held, so no further locking
666  * is necessary and no sleeping allowed.
667  */
668 
669 void
670 devfs_create(struct cdev *dev)
671 {
672 	struct cdev_priv *cdp;
673 
674 	mtx_assert(&devmtx, MA_OWNED);
675 	cdp = cdev2priv(dev);
676 	cdp->cdp_flags |= CDP_ACTIVE;
677 	cdp->cdp_inode = alloc_unrl(devfs_inos);
678 	dev_refl(dev);
679 	TAILQ_INSERT_TAIL(&cdevp_list, cdp, cdp_list);
680 	devfs_generation++;
681 }
682 
683 void
684 devfs_destroy(struct cdev *dev)
685 {
686 	struct cdev_priv *cdp;
687 
688 	mtx_assert(&devmtx, MA_OWNED);
689 	cdp = cdev2priv(dev);
690 	cdp->cdp_flags &= ~CDP_ACTIVE;
691 	devfs_generation++;
692 }
693 
694 ino_t
695 devfs_alloc_cdp_inode(void)
696 {
697 
698 	return (alloc_unr(devfs_inos));
699 }
700 
701 void
702 devfs_free_cdp_inode(ino_t ino)
703 {
704 
705 	if (ino > 0)
706 		free_unr(devfs_inos, ino);
707 }
708 
709 static void
710 devfs_devs_init(void *junk __unused)
711 {
712 
713 	devfs_inos = new_unrhdr(DEVFS_ROOTINO + 1, INT_MAX, &devmtx);
714 }
715 
716 SYSINIT(devfs_devs, SI_SUB_DEVFS, SI_ORDER_FIRST, devfs_devs_init, NULL);
717