1 /*-
2 * Copyright (c) 2002 Dima Dorfman.
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: releng/6.0/sys/fs/devfs/devfs_rule.c 150569 2005-09-26 14:36:54Z phk $
27 */
28
29 /*
30 * DEVFS ruleset implementation.
31 *
32 * A note on terminology: To "run" a rule on a dirent is to take the
33 * prescribed action; to "apply" a rule is to check whether it matches
34 * a dirent and run if if it does.
35 *
36 * A note on locking: Only foreign entry points (non-static functions)
37 * should deal with locking. Everything else assumes we already hold
38 * the required kind of lock.
39 *
40 * A note on namespace: devfs_rules_* are the non-static functions for
41 * the entire "ruleset" subsystem, devfs_rule_* are the static
42 * functions that operate on rules, and devfs_ruleset_* are the static
43 * functions that operate on rulesets. The line between the last two
44 * isn't always clear, but the guideline is still useful.
45 *
46 * A note on "special" identifiers: Ruleset 0 is the NULL, or empty,
47 * ruleset; it cannot be deleted or changed in any way. This may be
48 * assumed inside the code; e.g., a ruleset of 0 may be interpeted to
49 * mean "no ruleset". The interpretation of rule 0 is
50 * command-dependent, but in no case is there a real rule with number
51 * 0.
52 *
53 * A note on errno codes: To make it easier for the userland to tell
54 * what went wrong, we sometimes use errno codes that are not entirely
55 * appropriate for the error but that would be less ambiguous than the
56 * appropriate "generic" code. For example, when we can't find a
57 * ruleset, we return ESRCH instead of ENOENT (except in
58 * DEVFSIO_{R,S}GETNEXT, where a nonexistent ruleset means "end of
59 * list", and the userland expects ENOENT to be this indicator); this
60 * way, when an operation fails, it's clear that what couldn't be
61 * found is a ruleset and not a rule (well, it's clear to those who
62 * know the convention).
63 */
64
65 #include "opt_devfs.h"
66
67 #include <sys/param.h>
68 #include <sys/systm.h>
69 #include <sys/conf.h>
70 #include <sys/kernel.h>
71 #include <sys/malloc.h>
72 #include <sys/dirent.h>
73 #include <sys/ioccom.h>
74 #include <sys/lock.h>
75 #include <sys/sx.h>
76
77 #include <fs/devfs/devfs.h>
78 #include <fs/devfs/devfs_int.h>
79
80 /*
81 * Kernel version of devfs_rule.
82 */
83 struct devfs_krule {
84 TAILQ_ENTRY(devfs_krule) dk_list;
85 struct devfs_ruleset *dk_ruleset;
86 struct devfs_rule dk_rule;
87 };
88
89 TAILQ_HEAD(rulehead, devfs_krule);
90 static MALLOC_DEFINE(M_DEVFSRULE, "DEVFS_RULE", "DEVFS rule storage");
91
92 /*
93 * Structure to describe a ruleset.
94 */
95 struct devfs_ruleset {
96 TAILQ_ENTRY(devfs_ruleset) ds_list;
97 struct rulehead ds_rules;
98 devfs_rsnum ds_number;
99 int ds_refcount;
100 };
101
102 static devfs_rid devfs_rid_input(devfs_rid rid, struct devfs_mount *dm);
103
104 static void devfs_rule_applyde_recursive(struct devfs_krule *dk,
105 struct devfs_dirent *de);
106 static void devfs_rule_applydm(struct devfs_krule *dk, struct devfs_mount *dm);
107 static int devfs_rule_autonumber(struct devfs_ruleset *ds, devfs_rnum *rnp);
108 static struct devfs_krule *devfs_rule_byid(devfs_rid rid);
109 static int devfs_rule_delete(struct devfs_krule *dkp);
110 static struct cdev *devfs_rule_getdev(struct devfs_dirent *de);
111 static int devfs_rule_input(struct devfs_rule *dr, struct devfs_mount *dm);
112 static int devfs_rule_insert(struct devfs_rule *dr);
113 static int devfs_rule_match(struct devfs_krule *dk, struct devfs_dirent *de);
114 static int devfs_rule_matchpath(struct devfs_krule *dk,
115 struct devfs_dirent *de);
116 static void devfs_rule_run(struct devfs_krule *dk, struct devfs_dirent *de, unsigned depth);
117
118 static void devfs_ruleset_applyde(struct devfs_ruleset *ds,
119 struct devfs_dirent *de, unsigned depth);
120 static void devfs_ruleset_applydm(struct devfs_ruleset *ds,
121 struct devfs_mount *dm);
122 static struct devfs_ruleset *devfs_ruleset_bynum(devfs_rsnum rsnum);
123 static struct devfs_ruleset *devfs_ruleset_create(devfs_rsnum rsnum);
124 static void devfs_ruleset_reap(struct devfs_ruleset *dsp);
125 static int devfs_ruleset_use(devfs_rsnum rsnum, struct devfs_mount *dm);
126
127 static struct sx sx_rules;
128 SX_SYSINIT(sx_rules, &sx_rules, "DEVFS ruleset lock");
129
130 static TAILQ_HEAD(, devfs_ruleset) devfs_rulesets =
131 TAILQ_HEAD_INITIALIZER(devfs_rulesets);
132
133 /*
134 * Called to apply the proper rules for 'de' before it can be
135 * exposed to the userland. This should be called with an exclusive
136 * lock on dm in case we need to run anything.
137 */
138 void
139 devfs_rules_apply(struct devfs_mount *dm, struct devfs_dirent *de)
140 {
141 struct devfs_ruleset *ds;
142
143 if (dm->dm_ruleset == 0)
144 return;
145 sx_slock(&sx_rules);
146 ds = devfs_ruleset_bynum(dm->dm_ruleset);
147 KASSERT(ds != NULL, ("mount-point has NULL ruleset"));
148 devfs_ruleset_applyde(ds, de, devfs_rule_depth);
149 sx_sunlock(&sx_rules);
150 }
151
152 /*
153 * Rule subsystem ioctl hook.
154 */
155 int
156 devfs_rules_ioctl(struct devfs_mount *dm, u_long cmd, caddr_t data, struct thread *td)
157 {
158 struct devfs_ruleset *ds;
159 struct devfs_krule *dk;
160 struct devfs_rule *dr;
161 devfs_rsnum rsnum;
162 devfs_rnum rnum;
163 devfs_rid rid;
164 int error;
165
166 sx_assert(&dm->dm_lock, SX_XLOCKED);
167
168 /*
169 * XXX: This returns an error regardless of whether we
170 * actually support the cmd or not.
171 */
172 error = suser(td);
173 if (error != 0)
174 return (error);
175
176 sx_xlock(&sx_rules);
177
178 switch (cmd) {
179 case DEVFSIO_RADD:
180 dr = (struct devfs_rule *)data;
181 error = devfs_rule_input(dr, dm);
182 if (error != 0)
183 break;
184 dk = devfs_rule_byid(dr->dr_id);
185 if (dk != NULL) {
186 error = EEXIST;
187 break;
188 }
189 if (rid2rsn(dr->dr_id) == 0)
190 return (EIO);
191 error = devfs_rule_insert(dr);
192 break;
193 case DEVFSIO_RAPPLY:
194 dr = (struct devfs_rule *)data;
195 error = devfs_rule_input(dr, dm);
196 if (error != 0)
197 break;
198
199 /*
200 * This is one of many possible hackish
201 * implementations. The primary contender is an
202 * implementation where the rule we read in is
203 * temporarily inserted into some ruleset, perhaps
204 * with a hypothetical DRO_NOAUTO flag so that it
205 * doesn't get used where it isn't intended, and
206 * applied in the normal way. This can be done in the
207 * userland (DEVFSIO_ADD, DEVFSIO_APPLYID,
208 * DEVFSIO_DEL) or in the kernel; either way it breaks
209 * some corner case assumptions in other parts of the
210 * code (not that this implementation doesn't do
211 * that).
212 */
213 if (dr->dr_iacts & DRA_INCSET &&
214 devfs_ruleset_bynum(dr->dr_incset) == NULL) {
215 error = ESRCH;
216 break;
217 }
218 dk = malloc(sizeof(*dk), M_TEMP, M_WAITOK | M_ZERO);
219 memcpy(&dk->dk_rule, dr, sizeof(*dr));
220 devfs_rule_applydm(dk, dm);
221 free(dk, M_TEMP);
222 break;
223 case DEVFSIO_RAPPLYID:
224 rid = *(devfs_rid *)data;
225 rid = devfs_rid_input(rid, dm);
226 dk = devfs_rule_byid(rid);
227 if (dk == NULL) {
228 error = ENOENT;
229 break;
230 }
231 devfs_rule_applydm(dk, dm);
232 break;
233 case DEVFSIO_RDEL:
234 rid = *(devfs_rid *)data;
235 rid = devfs_rid_input(rid, dm);
236 dk = devfs_rule_byid(rid);
237 if (dk == NULL) {
238 error = ENOENT;
239 break;
240 }
241 ds = dk->dk_ruleset;
242 error = devfs_rule_delete(dk);
243 break;
244 case DEVFSIO_RGETNEXT:
245 dr = (struct devfs_rule *)data;
246 error = devfs_rule_input(dr, dm);
247 if (error != 0)
248 break;
249 /*
250 * We can't use devfs_rule_byid() here since that
251 * requires the rule specified to exist, but we want
252 * getnext(N) to work whether there is a rule N or not
253 * (specifically, getnext(0) must work, but we should
254 * never have a rule 0 since the add command
255 * interprets 0 to mean "auto-number").
256 */
257 ds = devfs_ruleset_bynum(rid2rsn(dr->dr_id));
258 if (ds == NULL) {
259 error = ENOENT;
260 break;
261 }
262 rnum = rid2rn(dr->dr_id);
263 TAILQ_FOREACH(dk, &ds->ds_rules, dk_list) {
264 if (rid2rn(dk->dk_rule.dr_id) > rnum)
265 break;
266 }
267 if (dk == NULL) {
268 error = ENOENT;
269 break;
270 }
271 memcpy(dr, &dk->dk_rule, sizeof(*dr));
272 break;
273 case DEVFSIO_SUSE:
274 rsnum = *(devfs_rsnum *)data;
275 error = devfs_ruleset_use(rsnum, dm);
276 break;
277 case DEVFSIO_SAPPLY:
278 rsnum = *(devfs_rsnum *)data;
279 rsnum = rid2rsn(devfs_rid_input(mkrid(rsnum, 0), dm));
280 ds = devfs_ruleset_bynum(rsnum);
281 if (ds == NULL) {
282 error = ESRCH;
283 break;
284 }
285 devfs_ruleset_applydm(ds, dm);
286 break;
287 case DEVFSIO_SGETNEXT:
288 rsnum = *(devfs_rsnum *)data;
289 TAILQ_FOREACH(ds, &devfs_rulesets, ds_list) {
290 if (ds->ds_number > rsnum)
291 break;
292 }
293 if (ds == NULL) {
294 error = ENOENT;
295 break;
296 }
297 *(devfs_rsnum *)data = ds->ds_number;
298 break;
299 default:
300 error = ENOIOCTL;
301 break;
302 }
303
304 sx_xunlock(&sx_rules);
305 return (error);
306 }
307
308 /*
309 * Adjust the rule identifier to use the ruleset of dm if one isn't
310 * explicitly specified.
311 *
312 * Note that after this operation, rid2rsn(rid) might still be 0, and
313 * that's okay; ruleset 0 is a valid ruleset, but when it's read in
314 * from the userland, it means "current ruleset for this mount-point".
315 */
316 static devfs_rid
317 devfs_rid_input(devfs_rid rid, struct devfs_mount *dm)
318 {
319
320 if (rid2rsn(rid) == 0)
321 return (mkrid(dm->dm_ruleset, rid2rn(rid)));
322 else
323 return (rid);
324 }
325
326 /*
327 * Apply dk to de and everything under de.
328 *
329 * XXX: This method needs a function call for every nested
330 * subdirectory in a devfs mount. If we plan to have many of these,
331 * we might eventually run out of kernel stack space.
332 * XXX: a linear search could be done through the cdev list instead.
333 */
334 static void
335 devfs_rule_applyde_recursive(struct devfs_krule *dk, struct devfs_dirent *de)
336 {
337 struct devfs_dirent *de2;
338
339 TAILQ_FOREACH(de2, &de->de_dlist, de_list)
340 devfs_rule_applyde_recursive(dk, de2);
341 devfs_rule_run(dk, de, devfs_rule_depth);
342 }
343
344 /*
345 * Apply dk to all entires in dm.
346 */
347 static void
348 devfs_rule_applydm(struct devfs_krule *dk, struct devfs_mount *dm)
349 {
350
351 devfs_rule_applyde_recursive(dk, dm->dm_rootdir);
352 }
353
354 /*
355 * Automatically select a number for a new rule in ds, and write the
356 * result into rnump.
357 */
358 static int
359 devfs_rule_autonumber(struct devfs_ruleset *ds, devfs_rnum *rnump)
360 {
361 struct devfs_krule *dk;
362
363 /* Find the last rule. */
364 dk = TAILQ_LAST(&ds->ds_rules, rulehead);
365 if (dk == NULL)
366 *rnump = 100;
367 else {
368 *rnump = rid2rn(dk->dk_rule.dr_id) + 100;
369 /* Detect overflow. */
370 if (*rnump < rid2rn(dk->dk_rule.dr_id))
371 return (ERANGE);
372 }
373 KASSERT(devfs_rule_byid(mkrid(ds->ds_number, *rnump)) == NULL,
374 ("autonumbering resulted in an already existing rule"));
375 return (0);
376 }
377
378 /*
379 * Find a krule by id.
380 */
381 static struct devfs_krule *
382 devfs_rule_byid(devfs_rid rid)
383 {
384 struct devfs_ruleset *ds;
385 struct devfs_krule *dk;
386 devfs_rnum rn;
387
388 rn = rid2rn(rid);
389 ds = devfs_ruleset_bynum(rid2rsn(rid));
390 if (ds == NULL)
391 return (NULL);
392 TAILQ_FOREACH(dk, &ds->ds_rules, dk_list) {
393 if (rid2rn(dk->dk_rule.dr_id) == rn)
394 return (dk);
395 else if (rid2rn(dk->dk_rule.dr_id) > rn)
396 break;
397 }
398 return (NULL);
399 }
400
401 /*
402 * Remove dkp from any lists it may be on and remove memory associated
403 * with it.
404 */
405 static int
406 devfs_rule_delete(struct devfs_krule *dk)
407 {
408 struct devfs_ruleset *ds;
409
410 if (dk->dk_rule.dr_iacts & DRA_INCSET) {
411 ds = devfs_ruleset_bynum(dk->dk_rule.dr_incset);
412 KASSERT(ds != NULL, ("DRA_INCSET but bad dr_incset"));
413 --ds->ds_refcount;
414 devfs_ruleset_reap(ds);
415 }
416 ds = dk->dk_ruleset;
417 TAILQ_REMOVE(&ds->ds_rules, dk, dk_list);
418 devfs_ruleset_reap(ds);
419 free(dk, M_DEVFSRULE);
420 return (0);
421 }
422
423 /*
424 * Get a struct cdev *corresponding to de so we can try to match rules based
425 * on it. If this routine returns NULL, there is no struct cdev *associated
426 * with the dirent (symlinks and directories don't have dev_ts), and
427 * the caller should assume that any critera dependent on a dev_t
428 * don't match.
429 */
430 static struct cdev *
431 devfs_rule_getdev(struct devfs_dirent *de)
432 {
433
434 if (de->de_cdp == NULL)
435 return (NULL);
436 if (de->de_cdp->cdp_flags & CDP_ACTIVE)
437 return (&de->de_cdp->cdp_c);
438 else
439 return (NULL);
440 }
441
442 /*
443 * Do what we need to do to a rule that we just loaded from the
444 * userland. In particular, we need to check the magic, and adjust
445 * the ruleset appropriate if desired.
446 */
447 static int
448 devfs_rule_input(struct devfs_rule *dr, struct devfs_mount *dm)
449 {
450
451 if (dr->dr_magic != DEVFS_MAGIC)
452 return (ERPCMISMATCH);
453 dr->dr_id = devfs_rid_input(dr->dr_id, dm);
454 return (0);
455 }
456
457 /*
458 * Import dr into the appropriate place in the kernel (i.e., make a
459 * krule). The value of dr is copied, so the pointer may be destroyed
460 * after this call completes.
461 */
462 static int
463 devfs_rule_insert(struct devfs_rule *dr)
464 {
465 struct devfs_ruleset *ds, *dsi;
466 struct devfs_krule *k1;
467 struct devfs_krule *dk;
468 devfs_rsnum rsnum;
469 devfs_rnum dkrn;
470 int error;
471
472 /*
473 * This stuff seems out of place here, but we want to do it as
474 * soon as possible so that if it fails, we don't have to roll
475 * back any changes we already made (e.g., ruleset creation).
476 */
477 if (dr->dr_iacts & DRA_INCSET) {
478 dsi = devfs_ruleset_bynum(dr->dr_incset);
479 if (dsi == NULL)
480 return (ESRCH);
481 } else
482 dsi = NULL;
483
484 rsnum = rid2rsn(dr->dr_id);
485 KASSERT(rsnum != 0, ("Inserting into ruleset zero"));
486
487 ds = devfs_ruleset_bynum(rsnum);
488 if (ds == NULL)
489 ds = devfs_ruleset_create(rsnum);
490 dkrn = rid2rn(dr->dr_id);
491 if (dkrn == 0) {
492 error = devfs_rule_autonumber(ds, &dkrn);
493 if (error != 0) {
494 devfs_ruleset_reap(ds);
495 return (error);
496 }
497 }
498
499 dk = malloc(sizeof(*dk), M_DEVFSRULE, M_WAITOK | M_ZERO);
500 dk->dk_ruleset = ds;
501 if (dsi != NULL)
502 ++dsi->ds_refcount;
503 /* XXX: Inspect dr? */
504 memcpy(&dk->dk_rule, dr, sizeof(*dr));
505 dk->dk_rule.dr_id = mkrid(rid2rsn(dk->dk_rule.dr_id), dkrn);
506
507 TAILQ_FOREACH(k1, &ds->ds_rules, dk_list) {
508 if (rid2rn(k1->dk_rule.dr_id) > dkrn) {
509 TAILQ_INSERT_BEFORE(k1, dk, dk_list);
510 break;
511 }
512 }
513 if (k1 == NULL)
514 TAILQ_INSERT_TAIL(&ds->ds_rules, dk, dk_list);
515 return (0);
516 }
517
518 /*
519 * Determine whether dk matches de. Returns 1 if dk should be run on
520 * de; 0, otherwise.
521 */
522 static int
523 devfs_rule_match(struct devfs_krule *dk, struct devfs_dirent *de)
524 {
525 struct devfs_rule *dr = &dk->dk_rule;
526 struct cdev *dev;
527
528 dev = devfs_rule_getdev(de);
529 /*
530 * At this point, if dev is NULL, we should assume that any
531 * criteria that depend on it don't match. We should *not*
532 * just ignore them (i.e., act like they weren't specified),
533 * since that makes a rule that only has criteria dependent on
534 * the struct cdev *match all symlinks and directories.
535 *
536 * Note also that the following tests are somewhat reversed:
537 * They're actually testing to see whether the condition does
538 * *not* match, since the default is to assume the rule should
539 * be run (such as if there are no conditions).
540 *
541 * XXX: lacks threadref on dev
542 */
543 if (dr->dr_icond & DRC_DSWFLAGS)
544 if (dev == NULL ||
545 (dev->si_devsw->d_flags & dr->dr_dswflags) == 0)
546 return (0);
547 if (dr->dr_icond & DRC_PATHPTRN)
548 if (!devfs_rule_matchpath(dk, de))
549 return (0);
550
551 return (1);
552 }
553
554 /*
555 * Determine whether dk matches de on account of dr_pathptrn.
556 */
557 static int
558 devfs_rule_matchpath(struct devfs_krule *dk, struct devfs_dirent *de)
559 {
560 struct devfs_rule *dr = &dk->dk_rule;
561 char *pname;
562 struct cdev *dev;
563
564 dev = devfs_rule_getdev(de);
565 if (dev != NULL)
566 pname = dev->si_name;
567 else if (de->de_dirent->d_type == DT_LNK ||
568 de->de_dirent->d_type == DT_DIR)
569 pname = de->de_dirent->d_name;
570 else
571 return (0);
572 KASSERT(pname != NULL, ("devfs_rule_matchpath: NULL pname"));
573
574 return (fnmatch(dr->dr_pathptrn, pname, 0) == 0);
575 }
576
577 /*
578 * Run dk on de.
579 */
580 static void
581 devfs_rule_run(struct devfs_krule *dk, struct devfs_dirent *de, unsigned depth)
582 {
583 struct devfs_rule *dr = &dk->dk_rule;
584 struct devfs_ruleset *ds;
585
586 if (!devfs_rule_match(dk, de))
587 return;
588 if (dr->dr_iacts & DRA_BACTS) {
589 if (dr->dr_bacts & DRB_HIDE)
590 de->de_flags |= DE_WHITEOUT;
591 if (dr->dr_bacts & DRB_UNHIDE)
592 de->de_flags &= ~DE_WHITEOUT;
593 }
594 if (dr->dr_iacts & DRA_UID)
595 de->de_uid = dr->dr_uid;
596 if (dr->dr_iacts & DRA_GID)
597 de->de_gid = dr->dr_gid;
598 if (dr->dr_iacts & DRA_MODE)
599 de->de_mode = dr->dr_mode;
600 if (dr->dr_iacts & DRA_INCSET) {
601 /*
602 * XXX: we should tell the user if the depth is exceeded here
603 * XXX: but it is not obvious how to. A return value will
604 * XXX: not work as this is called when devices are created
605 * XXX: long time after the rules were instantiated.
606 * XXX: a printf() would probably give too much noise, or
607 * XXX: DoS the machine. I guess a a rate-limited message
608 * XXX: might work.
609 */
610 if (depth > 0) {
611 ds = devfs_ruleset_bynum(dk->dk_rule.dr_incset);
612 KASSERT(ds != NULL, ("DRA_INCSET but bad dr_incset"));
613 devfs_ruleset_applyde(ds, de, depth - 1);
614 }
615 }
616 }
617
618 /*
619 * Apply all the rules in ds to de.
620 */
621 static void
622 devfs_ruleset_applyde(struct devfs_ruleset *ds, struct devfs_dirent *de, unsigned depth)
623 {
624 struct devfs_krule *dk;
625
626 TAILQ_FOREACH(dk, &ds->ds_rules, dk_list)
627 devfs_rule_run(dk, de, depth);
628 }
629
630 /*
631 * Apply all the rules in ds to all the entires in dm.
632 */
633 static void
634 devfs_ruleset_applydm(struct devfs_ruleset *ds, struct devfs_mount *dm)
635 {
636 struct devfs_krule *dk;
637
638 /*
639 * XXX: Does it matter whether we do
640 *
641 * foreach(dk in ds)
642 * foreach(de in dm)
643 * apply(dk to de)
644 *
645 * as opposed to
646 *
647 * foreach(de in dm)
648 * foreach(dk in ds)
649 * apply(dk to de)
650 *
651 * The end result is obviously the same, but does the order
652 * matter?
653 */
654 TAILQ_FOREACH(dk, &ds->ds_rules, dk_list)
655 devfs_rule_applydm(dk, dm);
656 }
657
658 /*
659 * Find a ruleset by number.
660 */
661 static struct devfs_ruleset *
662 devfs_ruleset_bynum(devfs_rsnum rsnum)
663 {
664 struct devfs_ruleset *ds;
665
666 TAILQ_FOREACH(ds, &devfs_rulesets, ds_list) {
667 if (ds->ds_number == rsnum)
668 return (ds);
669 }
670 return (NULL);
671 }
672
673 /*
674 * Create a new ruleset.
675 */
676 static struct devfs_ruleset *
677 devfs_ruleset_create(devfs_rsnum rsnum)
678 {
679 struct devfs_ruleset *s1;
680 struct devfs_ruleset *ds;
681
682 KASSERT(rsnum != 0, ("creating ruleset zero"));
683
684 KASSERT(devfs_ruleset_bynum(rsnum) == NULL,
685 ("creating already existent ruleset %d", rsnum));
686
687 ds = malloc(sizeof(*ds), M_DEVFSRULE, M_WAITOK | M_ZERO);
688 ds->ds_number = rsnum;
689 TAILQ_INIT(&ds->ds_rules);
690
691 TAILQ_FOREACH(s1, &devfs_rulesets, ds_list) {
692 if (s1->ds_number > rsnum) {
693 TAILQ_INSERT_BEFORE(s1, ds, ds_list);
694 break;
695 }
696 }
697 if (s1 == NULL)
698 TAILQ_INSERT_TAIL(&devfs_rulesets, ds, ds_list);
699 return (ds);
700 }
701
702 /*
703 * Remove a ruleset from the system if it's empty and not used
704 * anywhere. This should be called after every time a rule is deleted
705 * from this ruleset or the reference count is decremented.
706 */
707 static void
708 devfs_ruleset_reap(struct devfs_ruleset *ds)
709 {
710
711 KASSERT(ds->ds_number != 0, ("reaping ruleset zero "));
712
713 if (!TAILQ_EMPTY(&ds->ds_rules) || ds->ds_refcount != 0)
714 return;
715
716 TAILQ_REMOVE(&devfs_rulesets, ds, ds_list);
717 free(ds, M_DEVFSRULE);
718 }
719
720 /*
721 * Make rsnum the active ruleset for dm.
722 */
723 static int
724 devfs_ruleset_use(devfs_rsnum rsnum, struct devfs_mount *dm)
725 {
726 struct devfs_ruleset *cds, *ds;
727
728 ds = devfs_ruleset_bynum(rsnum);
729 if (ds == NULL)
730 ds = devfs_ruleset_create(rsnum);
731 if (dm->dm_ruleset != 0) {
732 cds = devfs_ruleset_bynum(dm->dm_ruleset);
733 --cds->ds_refcount;
734 devfs_ruleset_reap(cds);
735 }
736
737 /* These should probably be made atomic somehow. */
738 ++ds->ds_refcount;
739 dm->dm_ruleset = rsnum;
740
741 return (0);
742 }
743
744 void
745 devfs_rules_cleanup(struct devfs_mount *dm)
746 {
747 struct devfs_ruleset *ds;
748
749 sx_assert(&dm->dm_lock, SX_XLOCKED);
750 if (dm->dm_ruleset != 0) {
751 ds = devfs_ruleset_bynum(dm->dm_ruleset);
752 --ds->ds_refcount;
753 devfs_ruleset_reap(ds);
754 }
755 }
Cache object: 1c0e8a7647fa54f504fe534407e55401
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