xref: /freebsd/sys/fs/devfs/devfs_devs.c (revision 109c1de8bad542e1ce21e866a36b2b86dbe8d49d)
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 void
146 devfs_free(struct cdev *cdev)
147 {
148 	struct cdev_priv *cdp;
149 
150 	cdp = cdev2priv(cdev);
151 	if (cdev->si_cred != NULL)
152 		crfree(cdev->si_cred);
153 	if (cdp->cdp_inode > 0)
154 		free_unr(devfs_inos, cdp->cdp_inode);
155 	if (cdp->cdp_maxdirent > 0)
156 		free(cdp->cdp_dirents, M_DEVFS2);
157 	free(cdp, M_CDEVP);
158 }
159 
160 struct devfs_dirent *
161 devfs_find(struct devfs_dirent *dd, const char *name, int namelen, int type)
162 {
163 	struct devfs_dirent *de;
164 
165 	TAILQ_FOREACH(de, &dd->de_dlist, de_list) {
166 		if (namelen != de->de_dirent->d_namlen)
167 			continue;
168 		if (type != 0 && type != de->de_dirent->d_type)
169 			continue;
170 		if (bcmp(name, de->de_dirent->d_name, namelen) != 0)
171 			continue;
172 		break;
173 	}
174 	KASSERT(de == NULL || (de->de_flags & DE_DOOMED) == 0,
175 	    ("devfs_find: returning a doomed entry"));
176 	return (de);
177 }
178 
179 struct devfs_dirent *
180 devfs_newdirent(char *name, int namelen)
181 {
182 	int i;
183 	struct devfs_dirent *de;
184 	struct dirent d;
185 
186 	d.d_namlen = namelen;
187 	i = sizeof (*de) + GENERIC_DIRSIZ(&d);
188 	de = malloc(i, M_DEVFS3, M_WAITOK | M_ZERO);
189 	de->de_dirent = (struct dirent *)(de + 1);
190 	de->de_dirent->d_namlen = namelen;
191 	de->de_dirent->d_reclen = GENERIC_DIRSIZ(&d);
192 	bcopy(name, de->de_dirent->d_name, namelen);
193 	de->de_dirent->d_name[namelen] = '\0';
194 	vfs_timestamp(&de->de_ctime);
195 	de->de_mtime = de->de_atime = de->de_ctime;
196 	de->de_links = 1;
197 	de->de_holdcnt = 1;
198 #ifdef MAC
199 	mac_devfs_init(de);
200 #endif
201 	return (de);
202 }
203 
204 struct devfs_dirent *
205 devfs_parent_dirent(struct devfs_dirent *de)
206 {
207 
208 	if (de->de_dirent->d_type != DT_DIR)
209 		return (de->de_dir);
210 
211 	if (de->de_flags & (DE_DOT | DE_DOTDOT))
212 		return (NULL);
213 
214 	de = TAILQ_FIRST(&de->de_dlist);	/* "." */
215 	if (de == NULL)
216 		return (NULL);
217 	de = TAILQ_NEXT(de, de_list);		/* ".." */
218 	if (de == NULL)
219 		return (NULL);
220 
221 	return (de->de_dir);
222 }
223 
224 struct devfs_dirent *
225 devfs_vmkdir(struct devfs_mount *dmp, char *name, int namelen, struct devfs_dirent *dotdot, u_int inode)
226 {
227 	struct devfs_dirent *dd;
228 	struct devfs_dirent *de;
229 
230 	/* Create the new directory */
231 	dd = devfs_newdirent(name, namelen);
232 	TAILQ_INIT(&dd->de_dlist);
233 	dd->de_dirent->d_type = DT_DIR;
234 	dd->de_mode = 0555;
235 	dd->de_links = 2;
236 	dd->de_dir = dd;
237 	if (inode != 0)
238 		dd->de_inode = inode;
239 	else
240 		dd->de_inode = alloc_unr(devfs_inos);
241 
242 	/*
243 	 * "." and ".." are always the two first entries in the
244 	 * de_dlist list.
245 	 *
246 	 * Create the "." entry in the new directory.
247 	 */
248 	de = devfs_newdirent(".", 1);
249 	de->de_dirent->d_type = DT_DIR;
250 	de->de_flags |= DE_DOT;
251 	TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list);
252 	de->de_dir = dd;
253 
254 	/* Create the ".." entry in the new directory. */
255 	de = devfs_newdirent("..", 2);
256 	de->de_dirent->d_type = DT_DIR;
257 	de->de_flags |= DE_DOTDOT;
258 	TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list);
259 	if (dotdot == NULL) {
260 		de->de_dir = dd;
261 	} else {
262 		de->de_dir = dotdot;
263 		TAILQ_INSERT_TAIL(&dotdot->de_dlist, dd, de_list);
264 		dotdot->de_links++;
265 	}
266 
267 #ifdef MAC
268 	mac_devfs_create_directory(dmp->dm_mount, name, namelen, dd);
269 #endif
270 	return (dd);
271 }
272 
273 void
274 devfs_dirent_free(struct devfs_dirent *de)
275 {
276 	free(de, M_DEVFS3);
277 }
278 
279 /*
280  * Removes a directory if it is empty. Also empty parent directories are
281  * removed recursively.
282  */
283 static void
284 devfs_rmdir_empty(struct devfs_mount *dm, struct devfs_dirent *de)
285 {
286 	struct devfs_dirent *dd, *de_dot, *de_dotdot;
287 
288 	sx_assert(&dm->dm_lock, SX_XLOCKED);
289 
290 	for (;;) {
291 		KASSERT(de->de_dirent->d_type == DT_DIR,
292 		    ("devfs_rmdir_empty: de is not a directory"));
293 
294 		if ((de->de_flags & DE_DOOMED) != 0 || de == dm->dm_rootdir)
295 			return;
296 
297 		de_dot = TAILQ_FIRST(&de->de_dlist);
298 		KASSERT(de_dot != NULL, ("devfs_rmdir_empty: . missing"));
299 		de_dotdot = TAILQ_NEXT(de_dot, de_list);
300 		KASSERT(de_dotdot != NULL, ("devfs_rmdir_empty: .. missing"));
301 		/* Return if the directory is not empty. */
302 		if (TAILQ_NEXT(de_dotdot, de_list) != NULL)
303 			return;
304 
305 		dd = devfs_parent_dirent(de);
306 		KASSERT(dd != NULL, ("devfs_rmdir_empty: NULL dd"));
307 		TAILQ_REMOVE(&de->de_dlist, de_dot, de_list);
308 		TAILQ_REMOVE(&de->de_dlist, de_dotdot, de_list);
309 		TAILQ_REMOVE(&dd->de_dlist, de, de_list);
310 		DEVFS_DE_HOLD(dd);
311 		devfs_delete(dm, de, DEVFS_DEL_NORECURSE);
312 		devfs_delete(dm, de_dot, DEVFS_DEL_NORECURSE);
313 		devfs_delete(dm, de_dotdot, DEVFS_DEL_NORECURSE);
314 		if (DEVFS_DE_DROP(dd)) {
315 			devfs_dirent_free(dd);
316 			return;
317 		}
318 
319 		de = dd;
320 	}
321 }
322 
323 /*
324  * The caller needs to hold the dm for the duration of the call since
325  * dm->dm_lock may be temporary dropped.
326  */
327 void
328 devfs_delete(struct devfs_mount *dm, struct devfs_dirent *de, int flags)
329 {
330 	struct devfs_dirent *dd;
331 	struct vnode *vp;
332 
333 	KASSERT((de->de_flags & DE_DOOMED) == 0,
334 		("devfs_delete doomed dirent"));
335 	de->de_flags |= DE_DOOMED;
336 
337 	if ((flags & DEVFS_DEL_NORECURSE) == 0) {
338 		dd = devfs_parent_dirent(de);
339 		if (dd != NULL)
340 			DEVFS_DE_HOLD(dd);
341 	} else
342 		dd = NULL;
343 
344 	mtx_lock(&devfs_de_interlock);
345 	vp = de->de_vnode;
346 	if (vp != NULL) {
347 		VI_LOCK(vp);
348 		mtx_unlock(&devfs_de_interlock);
349 		vholdl(vp);
350 		sx_unlock(&dm->dm_lock);
351 		if ((flags & DEVFS_DEL_VNLOCKED) == 0)
352 			vn_lock(vp, LK_EXCLUSIVE | LK_INTERLOCK | LK_RETRY);
353 		else
354 			VI_UNLOCK(vp);
355 		vgone(vp);
356 		if ((flags & DEVFS_DEL_VNLOCKED) == 0)
357 			VOP_UNLOCK(vp, 0);
358 		vdrop(vp);
359 		sx_xlock(&dm->dm_lock);
360 	} else
361 		mtx_unlock(&devfs_de_interlock);
362 	if (de->de_symlink) {
363 		free(de->de_symlink, M_DEVFS);
364 		de->de_symlink = NULL;
365 	}
366 #ifdef MAC
367 	mac_devfs_destroy(de);
368 #endif
369 	if (de->de_inode > DEVFS_ROOTINO) {
370 		free_unr(devfs_inos, de->de_inode);
371 		de->de_inode = 0;
372 	}
373 	if (DEVFS_DE_DROP(de))
374 		devfs_dirent_free(de);
375 
376 	if (dd != NULL) {
377 		if (DEVFS_DE_DROP(dd))
378 			devfs_dirent_free(dd);
379 		else
380 			devfs_rmdir_empty(dm, dd);
381 	}
382 }
383 
384 /*
385  * Called on unmount.
386  * Recursively removes the entire tree.
387  * The caller needs to hold the dm for the duration of the call.
388  */
389 
390 static void
391 devfs_purge(struct devfs_mount *dm, struct devfs_dirent *dd)
392 {
393 	struct devfs_dirent *de;
394 
395 	sx_assert(&dm->dm_lock, SX_XLOCKED);
396 
397 	DEVFS_DE_HOLD(dd);
398 	for (;;) {
399 		de = TAILQ_FIRST(&dd->de_dlist);
400 		if (de == NULL)
401 			break;
402 		TAILQ_REMOVE(&dd->de_dlist, de, de_list);
403 		if (de->de_flags & (DE_DOT | DE_DOTDOT))
404 			devfs_delete(dm, de, DEVFS_DEL_NORECURSE);
405 		else if (de->de_dirent->d_type == DT_DIR)
406 			devfs_purge(dm, de);
407 		else
408 			devfs_delete(dm, de, DEVFS_DEL_NORECURSE);
409 	}
410 	if (DEVFS_DE_DROP(dd))
411 		devfs_dirent_free(dd);
412 	else if ((dd->de_flags & DE_DOOMED) == 0)
413 		devfs_delete(dm, dd, DEVFS_DEL_NORECURSE);
414 }
415 
416 /*
417  * Each cdev_priv has an array of pointers to devfs_dirent which is indexed
418  * by the mount points dm_idx.
419  * This function extends the array when necessary, taking into account that
420  * the default array is 1 element and not malloc'ed.
421  */
422 static void
423 devfs_metoo(struct cdev_priv *cdp, struct devfs_mount *dm)
424 {
425 	struct devfs_dirent **dep;
426 	int siz;
427 
428 	siz = (dm->dm_idx + 1) * sizeof *dep;
429 	dep = malloc(siz, M_DEVFS2, M_WAITOK | M_ZERO);
430 	dev_lock();
431 	if (dm->dm_idx <= cdp->cdp_maxdirent) {
432 		/* We got raced */
433 		dev_unlock();
434 		free(dep, M_DEVFS2);
435 		return;
436 	}
437 	memcpy(dep, cdp->cdp_dirents, (cdp->cdp_maxdirent + 1) * sizeof *dep);
438 	if (cdp->cdp_maxdirent > 0)
439 		free(cdp->cdp_dirents, M_DEVFS2);
440 	cdp->cdp_dirents = dep;
441 	/*
442 	 * XXX: if malloc told us how much we actually got this could
443 	 * XXX: be optimized.
444 	 */
445 	cdp->cdp_maxdirent = dm->dm_idx;
446 	dev_unlock();
447 }
448 
449 /*
450  * The caller needs to hold the dm for the duration of the call.
451  */
452 static int
453 devfs_populate_loop(struct devfs_mount *dm, int cleanup)
454 {
455 	struct cdev_priv *cdp;
456 	struct devfs_dirent *de;
457 	struct devfs_dirent *dd;
458 	struct cdev *pdev;
459 	int de_flags, j;
460 	char *q, *s;
461 
462 	sx_assert(&dm->dm_lock, SX_XLOCKED);
463 	dev_lock();
464 	TAILQ_FOREACH(cdp, &cdevp_list, cdp_list) {
465 
466 		KASSERT(cdp->cdp_dirents != NULL, ("NULL cdp_dirents"));
467 
468 		/*
469 		 * If we are unmounting, or the device has been destroyed,
470 		 * clean up our dirent.
471 		 */
472 		if ((cleanup || !(cdp->cdp_flags & CDP_ACTIVE)) &&
473 		    dm->dm_idx <= cdp->cdp_maxdirent &&
474 		    cdp->cdp_dirents[dm->dm_idx] != NULL) {
475 			de = cdp->cdp_dirents[dm->dm_idx];
476 			cdp->cdp_dirents[dm->dm_idx] = NULL;
477 			KASSERT(cdp == de->de_cdp,
478 			    ("%s %d %s %p %p", __func__, __LINE__,
479 			    cdp->cdp_c.si_name, cdp, de->de_cdp));
480 			KASSERT(de->de_dir != NULL, ("Null de->de_dir"));
481 			dev_unlock();
482 
483 			TAILQ_REMOVE(&de->de_dir->de_dlist, de, de_list);
484 			de->de_cdp = NULL;
485 			de->de_inode = 0;
486 			devfs_delete(dm, de, 0);
487 			dev_lock();
488 			cdp->cdp_inuse--;
489 			dev_unlock();
490 			return (1);
491 		}
492 		/*
493 	 	 * GC any lingering devices
494 		 */
495 		if (!(cdp->cdp_flags & CDP_ACTIVE)) {
496 			if (cdp->cdp_inuse > 0)
497 				continue;
498 			TAILQ_REMOVE(&cdevp_list, cdp, cdp_list);
499 			dev_unlock();
500 			dev_rel(&cdp->cdp_c);
501 			return (1);
502 		}
503 		/*
504 		 * Don't create any new dirents if we are unmounting
505 		 */
506 		if (cleanup)
507 			continue;
508 		KASSERT((cdp->cdp_flags & CDP_ACTIVE), ("Bogons, I tell ya'!"));
509 
510 		if (dm->dm_idx <= cdp->cdp_maxdirent &&
511 		    cdp->cdp_dirents[dm->dm_idx] != NULL) {
512 			de = cdp->cdp_dirents[dm->dm_idx];
513 			KASSERT(cdp == de->de_cdp, ("inconsistent cdp"));
514 			continue;
515 		}
516 
517 
518 		cdp->cdp_inuse++;
519 		dev_unlock();
520 
521 		if (dm->dm_idx > cdp->cdp_maxdirent)
522 		        devfs_metoo(cdp, dm);
523 
524 		dd = dm->dm_rootdir;
525 		s = cdp->cdp_c.si_name;
526 		for (;;) {
527 			for (q = s; *q != '/' && *q != '\0'; q++)
528 				continue;
529 			if (*q != '/')
530 				break;
531 			de = devfs_find(dd, s, q - s, 0);
532 			if (de == NULL)
533 				de = devfs_vmkdir(dm, s, q - s, dd, 0);
534 			else if (de->de_dirent->d_type == DT_LNK) {
535 				de = devfs_find(dd, s, q - s, DT_DIR);
536 				if (de == NULL)
537 					de = devfs_vmkdir(dm, s, q - s, dd, 0);
538 				de->de_flags |= DE_COVERED;
539 			}
540 			s = q + 1;
541 			dd = de;
542 			KASSERT(dd->de_dirent->d_type == DT_DIR &&
543 			    (dd->de_flags & (DE_DOT | DE_DOTDOT)) == 0,
544 			    ("%s: invalid directory (si_name=%s)",
545 			    __func__, cdp->cdp_c.si_name));
546 
547 		}
548 		de_flags = 0;
549 		de = devfs_find(dd, s, q - s, DT_LNK);
550 		if (de != NULL)
551 			de_flags |= DE_COVERED;
552 
553 		de = devfs_newdirent(s, q - s);
554 		if (cdp->cdp_c.si_flags & SI_ALIAS) {
555 			de->de_uid = 0;
556 			de->de_gid = 0;
557 			de->de_mode = 0755;
558 			de->de_dirent->d_type = DT_LNK;
559 			pdev = cdp->cdp_c.si_parent;
560 			j = strlen(pdev->si_name) + 1;
561 			de->de_symlink = malloc(j, M_DEVFS, M_WAITOK);
562 			bcopy(pdev->si_name, de->de_symlink, j);
563 		} else {
564 			de->de_uid = cdp->cdp_c.si_uid;
565 			de->de_gid = cdp->cdp_c.si_gid;
566 			de->de_mode = cdp->cdp_c.si_mode;
567 			de->de_dirent->d_type = DT_CHR;
568 		}
569 		de->de_flags |= de_flags;
570 		de->de_inode = cdp->cdp_inode;
571 		de->de_cdp = cdp;
572 #ifdef MAC
573 		mac_devfs_create_device(cdp->cdp_c.si_cred, dm->dm_mount,
574 		    &cdp->cdp_c, de);
575 #endif
576 		de->de_dir = dd;
577 		TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list);
578 		devfs_rules_apply(dm, de);
579 		dev_lock();
580 		/* XXX: could check that cdp is still active here */
581 		KASSERT(cdp->cdp_dirents[dm->dm_idx] == NULL,
582 		    ("%s %d\n", __func__, __LINE__));
583 		cdp->cdp_dirents[dm->dm_idx] = de;
584 		KASSERT(de->de_cdp != (void *)0xdeadc0de,
585 		    ("%s %d\n", __func__, __LINE__));
586 		dev_unlock();
587 		return (1);
588 	}
589 	dev_unlock();
590 	return (0);
591 }
592 
593 /*
594  * The caller needs to hold the dm for the duration of the call.
595  */
596 void
597 devfs_populate(struct devfs_mount *dm)
598 {
599 
600 	sx_assert(&dm->dm_lock, SX_XLOCKED);
601 	if (dm->dm_generation == devfs_generation)
602 		return;
603 	while (devfs_populate_loop(dm, 0))
604 		continue;
605 	dm->dm_generation = devfs_generation;
606 }
607 
608 /*
609  * The caller needs to hold the dm for the duration of the call.
610  */
611 void
612 devfs_cleanup(struct devfs_mount *dm)
613 {
614 
615 	sx_assert(&dm->dm_lock, SX_XLOCKED);
616 	while (devfs_populate_loop(dm, 1))
617 		continue;
618 	devfs_purge(dm, dm->dm_rootdir);
619 }
620 
621 /*
622  * devfs_create() and devfs_destroy() are called from kern_conf.c and
623  * in both cases the devlock() mutex is held, so no further locking
624  * is necesary and no sleeping allowed.
625  */
626 
627 void
628 devfs_create(struct cdev *dev)
629 {
630 	struct cdev_priv *cdp;
631 
632 	mtx_assert(&devmtx, MA_OWNED);
633 	cdp = cdev2priv(dev);
634 	cdp->cdp_flags |= CDP_ACTIVE;
635 	cdp->cdp_inode = alloc_unrl(devfs_inos);
636 	dev_refl(dev);
637 	TAILQ_INSERT_TAIL(&cdevp_list, cdp, cdp_list);
638 	devfs_generation++;
639 }
640 
641 void
642 devfs_destroy(struct cdev *dev)
643 {
644 	struct cdev_priv *cdp;
645 
646 	mtx_assert(&devmtx, MA_OWNED);
647 	cdp = cdev2priv(dev);
648 	cdp->cdp_flags &= ~CDP_ACTIVE;
649 	devfs_generation++;
650 }
651 
652 static void
653 devfs_devs_init(void *junk __unused)
654 {
655 
656 	devfs_inos = new_unrhdr(DEVFS_ROOTINO + 1, INT_MAX, &devmtx);
657 }
658 
659 SYSINIT(devfs_devs, SI_SUB_DEVFS, SI_ORDER_FIRST, devfs_devs_init, NULL);
660