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: releng/6.0/sys/fs/devfs/devfs_devs.c 150569 2005-09-26 14:36:54Z phk $
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 static TAILQ_HEAD(,cdev_priv) 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 #ifdef MAC
184 mac_init_devfsdirent(de);
185 #endif
186 return (de);
187 }
188
189 struct devfs_dirent *
190 devfs_vmkdir(struct devfs_mount *dmp, char *name, int namelen, struct devfs_dirent *dotdot, u_int inode)
191 {
192 struct devfs_dirent *dd;
193 struct devfs_dirent *de;
194
195 /* Create the new directory */
196 dd = devfs_newdirent(name, namelen);
197 TAILQ_INIT(&dd->de_dlist);
198 dd->de_dirent->d_type = DT_DIR;
199 dd->de_mode = 0555;
200 dd->de_links = 2;
201 dd->de_dir = dd;
202 if (inode != 0)
203 dd->de_inode = inode;
204 else
205 dd->de_inode = alloc_unr(devfs_inos);
206
207 /* Create the "." entry in the new directory */
208 de = devfs_newdirent(".", 1);
209 de->de_dirent->d_type = DT_DIR;
210 de->de_flags |= DE_DOT;
211 TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list);
212 de->de_dir = dd;
213
214 /* Create the ".." entry in the new directory */
215 de = devfs_newdirent("..", 2);
216 de->de_dirent->d_type = DT_DIR;
217 de->de_flags |= DE_DOTDOT;
218 TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list);
219 if (dotdot == NULL) {
220 de->de_dir = dd;
221 } else {
222 de->de_dir = dotdot;
223 TAILQ_INSERT_TAIL(&dotdot->de_dlist, dd, de_list);
224 dotdot->de_links++;
225 }
226
227 #ifdef MAC
228 mac_create_devfs_directory(dmp->dm_mount, name, namelen, dd);
229 #endif
230 return (dd);
231 }
232
233 void
234 devfs_delete(struct devfs_mount *dm, struct devfs_dirent *de)
235 {
236
237 if (de->de_symlink) {
238 free(de->de_symlink, M_DEVFS);
239 de->de_symlink = NULL;
240 }
241 if (de->de_vnode != NULL) {
242 de->de_vnode->v_data = NULL;
243 vgone(de->de_vnode);
244 de->de_vnode = NULL;
245 }
246 #ifdef MAC
247 mac_destroy_devfsdirent(de);
248 #endif
249 if (de->de_inode > DEVFS_ROOTINO) {
250 free_unr(devfs_inos, de->de_inode);
251 de->de_inode = 0;
252 }
253 free(de, M_DEVFS3);
254 }
255
256 /*
257 * Called on unmount.
258 * Recursively removes the entire tree
259 */
260
261 static void
262 devfs_purge(struct devfs_mount *dm, struct devfs_dirent *dd)
263 {
264 struct devfs_dirent *de;
265
266 sx_assert(&dm->dm_lock, SX_XLOCKED);
267 for (;;) {
268 de = TAILQ_FIRST(&dd->de_dlist);
269 if (de == NULL)
270 break;
271 TAILQ_REMOVE(&dd->de_dlist, de, de_list);
272 if (de->de_flags & (DE_DOT|DE_DOTDOT))
273 devfs_delete(dm, de);
274 else if (de->de_dirent->d_type == DT_DIR)
275 devfs_purge(dm, de);
276 else
277 devfs_delete(dm, de);
278 }
279 devfs_delete(dm, dd);
280 }
281
282 /*
283 * Each cdev_priv has an array of pointers to devfs_dirent which is indexed
284 * by the mount points dm_idx.
285 * This function extends the array when necessary, taking into account that
286 * the default array is 1 element and not malloc'ed.
287 */
288 static void
289 devfs_metoo(struct cdev_priv *cdp, struct devfs_mount *dm)
290 {
291 struct devfs_dirent **dep;
292 int siz;
293
294 siz = (dm->dm_idx + 1) * sizeof *dep;
295 dep = malloc(siz, M_DEVFS2, M_WAITOK | M_ZERO);
296 dev_lock();
297 if (dm->dm_idx <= cdp->cdp_maxdirent) {
298 /* We got raced */
299 dev_unlock();
300 free(dep, M_DEVFS2);
301 return;
302 }
303 memcpy(dep, cdp->cdp_dirents, (cdp->cdp_maxdirent + 1) * sizeof *dep);
304 if (cdp->cdp_maxdirent > 0)
305 free(cdp->cdp_dirents, M_DEVFS2);
306 cdp->cdp_dirents = dep;
307 /*
308 * XXX: if malloc told us how much we actually got this could
309 * XXX: be optimized.
310 */
311 cdp->cdp_maxdirent = dm->dm_idx;
312 dev_unlock();
313 }
314
315 static int
316 devfs_populate_loop(struct devfs_mount *dm, int cleanup)
317 {
318 struct cdev_priv *cdp;
319 struct devfs_dirent *de;
320 struct devfs_dirent *dd;
321 struct cdev *pdev;
322 int j;
323 char *q, *s;
324
325 sx_assert(&dm->dm_lock, SX_XLOCKED);
326 dev_lock();
327 TAILQ_FOREACH(cdp, &cdevp_list, cdp_list) {
328
329 KASSERT(cdp->cdp_dirents != NULL, ("NULL cdp_dirents"));
330
331 /*
332 * If we are unmounting, or the device has been destroyed,
333 * clean up our dirent.
334 */
335 if ((cleanup || !(cdp->cdp_flags & CDP_ACTIVE)) &&
336 dm->dm_idx <= cdp->cdp_maxdirent &&
337 cdp->cdp_dirents[dm->dm_idx] != NULL) {
338 de = cdp->cdp_dirents[dm->dm_idx];
339 cdp->cdp_dirents[dm->dm_idx] = NULL;
340 cdp->cdp_inuse--;
341 KASSERT(cdp == de->de_cdp,
342 ("%s %d %s %p %p", __func__, __LINE__,
343 cdp->cdp_c.si_name, cdp, de->de_cdp));
344 KASSERT(de->de_dir != NULL, ("Null de->de_dir"));
345 dev_unlock();
346
347 TAILQ_REMOVE(&de->de_dir->de_dlist, de, de_list);
348 de->de_cdp = NULL;
349 de->de_inode = 0;
350 devfs_delete(dm, de);
351 return (1);
352 }
353 /*
354 * GC any lingering devices
355 */
356 if (!(cdp->cdp_flags & CDP_ACTIVE)) {
357 if (cdp->cdp_inuse > 0)
358 continue;
359 TAILQ_REMOVE(&cdevp_list, cdp, cdp_list);
360 dev_unlock();
361 dev_rel(&cdp->cdp_c);
362 return (1);
363 }
364 /*
365 * Don't create any new dirents if we are unmounting
366 */
367 if (cleanup)
368 continue;
369 KASSERT((cdp->cdp_flags & CDP_ACTIVE), ("Bogons, I tell ya'!"));
370
371 if (dm->dm_idx <= cdp->cdp_maxdirent &&
372 cdp->cdp_dirents[dm->dm_idx] != NULL) {
373 de = cdp->cdp_dirents[dm->dm_idx];
374 KASSERT(cdp == de->de_cdp, ("inconsistent cdp"));
375 continue;
376 }
377
378
379 cdp->cdp_inuse++;
380 dev_unlock();
381
382 if (dm->dm_idx > cdp->cdp_maxdirent)
383 devfs_metoo(cdp, dm);
384
385 dd = dm->dm_rootdir;
386 s = cdp->cdp_c.si_name;
387 for (;;) {
388 for (q = s; *q != '/' && *q != '\0'; q++)
389 continue;
390 if (*q != '/')
391 break;
392 de = devfs_find(dd, s, q - s);
393 if (de == NULL)
394 de = devfs_vmkdir(dm, s, q - s, dd, 0);
395 s = q + 1;
396 dd = de;
397 }
398
399 de = devfs_newdirent(s, q - s);
400 if (cdp->cdp_c.si_flags & SI_ALIAS) {
401 de->de_uid = 0;
402 de->de_gid = 0;
403 de->de_mode = 0755;
404 de->de_dirent->d_type = DT_LNK;
405 pdev = cdp->cdp_c.si_parent;
406 j = strlen(pdev->si_name) + 1;
407 de->de_symlink = malloc(j, M_DEVFS, M_WAITOK);
408 bcopy(pdev->si_name, de->de_symlink, j);
409 } else {
410 de->de_uid = cdp->cdp_c.si_uid;
411 de->de_gid = cdp->cdp_c.si_gid;
412 de->de_mode = cdp->cdp_c.si_mode;
413 de->de_dirent->d_type = DT_CHR;
414 }
415 de->de_inode = cdp->cdp_inode;
416 de->de_cdp = cdp;
417 #ifdef MAC
418 mac_create_devfs_device(cdp->cdp_c.si_cred, dm->dm_mount,
419 &cdp->cdp_c, de);
420 #endif
421 de->de_dir = dd;
422 TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list);
423 devfs_rules_apply(dm, de);
424 dev_lock();
425 /* XXX: could check that cdp is still active here */
426 KASSERT(cdp->cdp_dirents[dm->dm_idx] == NULL,
427 ("%s %d\n", __func__, __LINE__));
428 cdp->cdp_dirents[dm->dm_idx] = de;
429 KASSERT(de->de_cdp != (void *)0xdeadc0de,
430 ("%s %d\n", __func__, __LINE__));
431 dev_unlock();
432 return (1);
433 }
434 dev_unlock();
435 return (0);
436 }
437
438 void
439 devfs_populate(struct devfs_mount *dm)
440 {
441
442 sx_assert(&dm->dm_lock, SX_XLOCKED);
443 if (dm->dm_generation == devfs_generation)
444 return;
445 while (devfs_populate_loop(dm, 0))
446 continue;
447 dm->dm_generation = devfs_generation;
448 }
449
450 void
451 devfs_cleanup(struct devfs_mount *dm)
452 {
453
454 sx_assert(&dm->dm_lock, SX_XLOCKED);
455 while (devfs_populate_loop(dm, 1))
456 continue;
457 devfs_purge(dm, dm->dm_rootdir);
458 }
459
460 /*
461 * devfs_create() and devfs_destroy() are called from kern_conf.c and
462 * in both cases the devlock() mutex is held, so no further locking
463 * is necesary and no sleeping allowed.
464 */
465
466 void
467 devfs_create(struct cdev *dev)
468 {
469 struct cdev_priv *cdp;
470
471 mtx_assert(&devmtx, MA_OWNED);
472 cdp = dev->si_priv;
473 cdp->cdp_flags |= CDP_ACTIVE;
474 cdp->cdp_inode = alloc_unrl(devfs_inos);
475 dev_refl(dev);
476 TAILQ_INSERT_TAIL(&cdevp_list, cdp, cdp_list);
477 devfs_generation++;
478 }
479
480 void
481 devfs_destroy(struct cdev *dev)
482 {
483 struct cdev_priv *cdp;
484
485 mtx_assert(&devmtx, MA_OWNED);
486 cdp = dev->si_priv;
487 cdp->cdp_flags &= ~CDP_ACTIVE;
488 devfs_generation++;
489 }
490
491 static void
492 devfs_devs_init(void *junk __unused)
493 {
494
495 devfs_inos = new_unrhdr(DEVFS_ROOTINO + 1, INT_MAX, &devmtx);
496 }
497
498 SYSINIT(devfs_devs, SI_SUB_DEVFS, SI_ORDER_FIRST, devfs_devs_init, NULL);
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