xref: /dragonfly/sys/vfs/devfs/devfs_rules.c (revision ffe53622) 
1 /*
2  * Copyright (c) 2009 The DragonFly Project.  All rights reserved.
3  *
4  * This code is derived from software contributed to The DragonFly Project
5  * by Alex Hornung <ahornung@gmail.com>
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  *
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in
15  *    the documentation and/or other materials provided with the
16  *    distribution.
17  * 3. Neither the name of The DragonFly Project nor the names of its
18  *    contributors may be used to endorse or promote products derived
19  *    from this software without specific, prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
34 #include <sys/param.h>
35 #include <sys/systm.h>
36 #include <sys/kernel.h>
37 #include <sys/types.h>
38 #include <sys/lock.h>
39 #include <sys/spinlock2.h>
40 #include <sys/fcntl.h>
41 #include <sys/device.h>
42 #include <sys/mount.h>
43 #include <sys/devfs.h>
44 #include <sys/devfs_rules.h>
45 
46 MALLOC_DECLARE(M_DEVFS);
47 
48 static d_open_t      devfs_dev_open;
49 static d_close_t     devfs_dev_close;
50 static d_ioctl_t     devfs_dev_ioctl;
51 
52 static struct devfs_rule *devfs_rule_alloc(struct devfs_rule_ioctl *);
53 static void devfs_rule_free(struct devfs_rule *);
54 static int devfs_rule_insert(struct devfs_rule_ioctl *);
55 static void devfs_rule_remove(struct devfs_rule *);
56 static int devfs_rule_clear(struct devfs_rule_ioctl *);
57 static void devfs_rule_create_link(struct devfs_node *, struct devfs_rule *);
58 static int devfs_rule_checkname(struct devfs_rule *, struct devfs_node *);
59 
60 static struct objcache	*devfs_rule_cache;
61 static struct lock	devfs_rule_lock;
62 
63 static struct objcache_malloc_args devfs_rule_malloc_args = {
64 	sizeof(struct devfs_rule), M_DEVFS };
65 
66 static cdev_t devfs_dev;
67 static struct devfs_rule_head devfs_rule_list =
68 		TAILQ_HEAD_INITIALIZER(devfs_rule_list);
69 
70 static struct dev_ops devfs_dev_ops = {
71 	{ "devfs", 0, D_MPSAFE },
72 	.d_open = devfs_dev_open,
73 	.d_close = devfs_dev_close,
74 	.d_ioctl = devfs_dev_ioctl
75 };
76 
77 
78 static struct devfs_rule *
79 devfs_rule_alloc(struct devfs_rule_ioctl *templ)
80 {
81 	struct devfs_rule *rule;
82 	size_t len;
83 
84 	rule = objcache_get(devfs_rule_cache, M_WAITOK);
85 	memset(rule, 0, sizeof(struct devfs_rule));
86 
87 	if (templ->mntpoint == NULL)
88 		goto error_out;
89 		/* NOTREACHED */
90 
91 	len = strlen(templ->mntpoint);
92 	if (len == 0)
93 		goto error_out;
94 		/* NOTREACHED */
95 
96 	rule->mntpoint = kstrdup(templ->mntpoint, M_DEVFS);
97 	rule->mntpointlen = len;
98 
99 	if (templ->rule_type & DEVFS_RULE_NAME) {
100 		if (templ->name == NULL)
101 			goto error_out;
102 			/* NOTREACHED */
103 
104 		len = strlen(templ->name);
105 		if (len == 0)
106 			goto error_out;
107 			/* NOTREACHED */
108 
109 		rule->name = kstrdup(templ->name, M_DEVFS);
110 		rule->namlen = len;
111 	}
112 
113 	if (templ->rule_cmd & DEVFS_RULE_LINK) {
114 		if (templ->linkname == NULL)
115 			goto error_out;
116 			/* NOTREACHED */
117 
118 		len = strlen(templ->linkname);
119 		if (len == 0)
120 			goto error_out;
121 			/* NOTREACHED */
122 
123 		rule->linkname = kstrdup(templ->linkname, M_DEVFS);
124 		rule->linknamlen = len;
125 	}
126 
127 	rule->rule_type = templ->rule_type;
128 	rule->rule_cmd = templ->rule_cmd;
129 	rule->dev_type = templ->dev_type;
130 	rule->mode = templ->mode;
131 	rule->uid = templ->uid;
132 	rule->gid = templ->gid;
133 
134 	return rule;
135 
136 error_out:
137 	devfs_rule_free(rule);
138 	return NULL;
139 }
140 
141 
142 static void
143 devfs_rule_free(struct devfs_rule *rule)
144 {
145 	if (rule->mntpoint != NULL) {
146 		kfree(rule->mntpoint, M_DEVFS);
147 	}
148 
149 	if (rule->name != NULL) {
150 		kfree(rule->name, M_DEVFS);
151 	}
152 
153 	if (rule->linkname != NULL) {
154 		kfree(rule->linkname, M_DEVFS);
155 	}
156 	objcache_put(devfs_rule_cache, rule);
157 }
158 
159 
160 static int
161 devfs_rule_insert(struct devfs_rule_ioctl *templ)
162 {
163 	struct devfs_rule *rule;
164 
165 	rule = devfs_rule_alloc(templ);
166 	if (rule == NULL)
167 		return EINVAL;
168 
169 	lockmgr(&devfs_rule_lock, LK_EXCLUSIVE);
170 	TAILQ_INSERT_TAIL(&devfs_rule_list, rule, link);
171 	lockmgr(&devfs_rule_lock, LK_RELEASE);
172 
173 	return 0;
174 }
175 
176 
177 static void
178 devfs_rule_remove(struct devfs_rule *rule)
179 {
180 	TAILQ_REMOVE(&devfs_rule_list, rule, link);
181 	devfs_rule_free(rule);
182 }
183 
184 
185 static int
186 devfs_rule_clear(struct devfs_rule_ioctl *templ)
187 {
188 	struct devfs_rule *rule1, *rule2;
189 	size_t mntpointlen;
190 
191 	if (templ->mntpoint == NULL)
192 		return EINVAL;
193 
194 	mntpointlen = strlen(templ->mntpoint);
195 	if (mntpointlen == 0)
196 		return EINVAL;
197 
198 	lockmgr(&devfs_rule_lock, LK_EXCLUSIVE);
199 	TAILQ_FOREACH_MUTABLE(rule1, &devfs_rule_list, link, rule2) {
200 		if ((templ->mntpoint[0] == '*') ||
201 			( (mntpointlen == rule1->mntpointlen) &&
202 			  (!memcmp(templ->mntpoint, rule1->mntpoint, mntpointlen)) )) {
203 			devfs_rule_remove(rule1);
204 		}
205 	}
206 	lockmgr(&devfs_rule_lock, LK_RELEASE);
207 
208 	return 0;
209 }
210 
211 
212 void *
213 devfs_rule_reset_node(struct devfs_node *node, void *unused)
214 {
215 	/*
216 	 * Don't blindly unhide all devices, some, like unix98 pty masters,
217 	 * haven't been hidden by a rule.
218 	 */
219 	if (node->flags & DEVFS_RULE_HIDDEN)
220 		node->flags &= ~(DEVFS_HIDDEN | DEVFS_RULE_HIDDEN);
221 
222 	if ((node->node_type == Nlink) && (node->flags & DEVFS_RULE_CREATED)) {
223 		KKASSERT(node->link_target);
224 		node->flags &= ~DEVFS_RULE_CREATED;
225 		--node->link_target->nlinks;
226 		devfs_gc(node);
227 	} else if ((node->node_type == Ndev) && (node->d_dev)) {
228 		node->uid = node->d_dev->si_uid;
229 		node->gid = node->d_dev->si_gid;
230 		node->mode = node->d_dev->si_perms;
231 	}
232 
233 	return NULL;
234 }
235 
236 static void
237 devfs_rule_create_link(struct devfs_node *node, struct devfs_rule *rule)
238 {
239 	size_t len = 0;
240 	char *path = NULL;
241 	char *name, name_buf[PATH_MAX], buf[PATH_MAX];
242 
243 	if (rule->name[rule->namlen-1] == '*') {
244 		devfs_resolve_name_path(rule->name, name_buf, &path, &name);
245 		len = strlen(name);
246 		--len;
247 		ksnprintf(buf, sizeof(buf), "%s%s",
248 		    rule->linkname, node->d_dir.d_name+len);
249 		devfs_alias_create(buf, node, 1);
250 	} else {
251 		devfs_alias_create(rule->linkname, node, 1);
252 	}
253 }
254 
255 void *
256 devfs_rule_check_apply(struct devfs_node *node, void *unused)
257 {
258 	struct devfs_rule *rule;
259 	struct mount *mp = node->mp;
260 	int locked = 0;
261 
262 	/* Check if it is locked already. if not, we acquire the devfs lock */
263 	if ((lockstatus(&devfs_rule_lock, curthread)) != LK_EXCLUSIVE) {
264 		lockmgr(&devfs_rule_lock, LK_EXCLUSIVE);
265 		locked = 1;
266 	}
267 
268 	TAILQ_FOREACH(rule, &devfs_rule_list, link) {
269 		/*
270 		 * Skip this rule if it is only intended for jailed mount points
271 		 * and the current mount point isn't jailed
272 		 */
273 		if ((rule->rule_type & DEVFS_RULE_JAIL) &&
274 			(!(DEVFS_MNTDATA(mp)->jailed)) )
275 			continue;
276 
277 		/*
278 		 * Skip this rule if it is not intended for jailed mount points
279 		 * and the current mount point is jailed.
280 		 */
281 		if (!(rule->rule_type & DEVFS_RULE_JAIL) &&
282 			(DEVFS_MNTDATA(mp)->jailed))
283 		    continue;
284 
285 		/*
286 		 * Skip this rule if the mount point specified in the rule doesn't
287 		 * match the mount point of the node
288 		 */
289 		if ((rule->mntpoint[0] != '*') &&
290 			(strcmp(rule->mntpoint, mp->mnt_stat.f_mntonname)))
291 			continue;
292 
293 		/*
294 		 * Skip this rule if this is a by-type rule and the device flags
295 		 * don't match the specified device type in the rule
296 		 */
297 		if ((rule->rule_type & DEVFS_RULE_TYPE) &&
298 			( (rule->dev_type == 0) || (!dev_is_good(node->d_dev)) ||
299 			  (!(dev_dflags(node->d_dev) & rule->dev_type))) )
300 			continue;
301 
302 		/*
303 		 * Skip this rule if this is a by-name rule and the node name
304 		 * doesn't match the wildcard string in the rule
305 		 */
306 		if ((rule->rule_type & DEVFS_RULE_NAME) &&
307 			(!devfs_rule_checkname(rule, node)) )
308 			continue;
309 
310 		if (rule->rule_cmd & DEVFS_RULE_HIDE) {
311 			/*
312 			 * If we should hide the device, we just apply the relevant
313 			 * hide flag to the node and let devfs do the rest in the
314 			 * vnops
315 			 */
316 			if ((node->d_dir.d_namlen == 5) &&
317 				(!memcmp(node->d_dir.d_name, "devfs", 5))) {
318 				/*
319 				 * Magically avoid /dev/devfs from being hidden, so that one
320 				 * can still use the rule system even after a "* hide".
321 				 */
322 				 continue;
323 			}
324 			node->flags |= (DEVFS_HIDDEN | DEVFS_RULE_HIDDEN);
325 		} else if (rule->rule_cmd & DEVFS_RULE_SHOW) {
326 			/*
327 			 * Show rule just means that the node should not be hidden, so
328 			 * what we do is clear the hide flag from the node.
329 			 */
330 			node->flags &= ~DEVFS_HIDDEN;
331 		} else if (rule->rule_cmd & DEVFS_RULE_LINK) {
332 			/*
333 			 * This is a LINK rule, so we tell devfs to create
334 			 * a link with the correct name to this node.
335 			 */
336 			devfs_rule_create_link(node, rule);
337 #if 0
338 			devfs_alias_create(rule->linkname, node, 1);
339 #endif
340 		} else if (rule->rule_cmd & DEVFS_RULE_PERM) {
341 			/*
342 			 * This is a normal ownership/permission rule. We
343 			 * just apply the permissions and ownership and
344 			 * we are done.
345 			 */
346 			node->mode = rule->mode;
347 			node->uid = rule->uid;
348 			node->gid = rule->gid;
349 		}
350 	}
351 
352 	/* If we acquired the lock, we also get rid of it */
353 	if (locked)
354 		lockmgr(&devfs_rule_lock, LK_RELEASE);
355 
356 	return NULL;
357 }
358 
359 
360 static int
361 devfs_rule_checkname(struct devfs_rule *rule, struct devfs_node *node)
362 {
363 	struct devfs_node *parent = DEVFS_MNTDATA(node->mp)->root_node;
364 	char *path = NULL;
365 	char *name, name_buf[PATH_MAX];
366 	int no_match = 0;
367 
368 	devfs_resolve_name_path(rule->name, name_buf, &path, &name);
369 	parent = devfs_resolve_or_create_path(parent, path, 0);
370 
371 	if (parent == NULL)
372 		return 0; /* no match */
373 
374 	/* Check if node is a child of the parent we found */
375 	if (node->parent != parent)
376 		return 0; /* no match */
377 
378 #if 0
379 	if (rule->rule_type & DEVFS_RULE_LINK)
380 		no_match = memcmp(name, node->d_dir.d_name, strlen(name));
381 	else
382 #endif
383 	no_match = devfs_WildCaseCmp(name, node->d_dir.d_name);
384 
385 	return !no_match;
386 }
387 
388 
389 static int
390 devfs_dev_open(struct dev_open_args *ap)
391 {
392 	/*
393 	 * Only allow read-write access.
394 	 */
395 	if (((ap->a_oflags & FWRITE) == 0) || ((ap->a_oflags & FREAD) == 0))
396 		return(EPERM);
397 
398 	/*
399 	 * We don't allow nonblocking access.
400 	 */
401 	if ((ap->a_oflags & O_NONBLOCK) != 0) {
402 		devfs_debug(DEVFS_DEBUG_SHOW,
403 			    "devfs_dev: can't do nonblocking access\n");
404 		return(ENODEV);
405 	}
406 
407 	return 0;
408 }
409 
410 
411 static int
412 devfs_dev_close(struct dev_close_args *ap)
413 {
414 	return 0;
415 }
416 
417 
418 static int
419 devfs_dev_ioctl(struct dev_ioctl_args *ap)
420 {
421 	int error;
422 	struct devfs_rule_ioctl *rule;
423 
424 	error = 0;
425 	rule = (struct devfs_rule_ioctl *)ap->a_data;
426 
427 	switch(ap->a_cmd) {
428 	case DEVFS_RULE_ADD:
429 		error = devfs_rule_insert(rule);
430 		break;
431 
432 	case DEVFS_RULE_APPLY:
433 		if (rule->mntpoint == NULL)
434 			error = EINVAL;
435 		else
436 			devfs_apply_rules(rule->mntpoint);
437 		break;
438 
439 	case DEVFS_RULE_CLEAR:
440 		error = devfs_rule_clear(rule);
441 		break;
442 
443 	case DEVFS_RULE_RESET:
444 		if (rule->mntpoint == NULL)
445 			error = EINVAL;
446 		else
447 			devfs_reset_rules(rule->mntpoint);
448 		break;
449 
450 	default:
451 		error = ENOTTY; /* Inappropriate ioctl for device */
452 		break;
453 	}
454 
455 	return(error);
456 }
457 
458 
459 static void
460 devfs_dev_init(void *unused)
461 {
462 	lockinit(&devfs_rule_lock, "devfs_rule lock", 0, 0);
463 
464     devfs_rule_cache = objcache_create("devfs-rule-cache", 0, 0,
465 			NULL, NULL, NULL,
466 			objcache_malloc_alloc,
467 			objcache_malloc_free,
468 			&devfs_rule_malloc_args );
469 
470     devfs_dev = make_dev(&devfs_dev_ops,
471             0,
472             UID_ROOT,
473             GID_WHEEL,
474             0600,
475             "devfs");
476 }
477 
478 
479 static void
480 devfs_dev_uninit(void *unused)
481 {
482 	/* XXX: destroy all rules first */
483     destroy_dev(devfs_dev);
484 	objcache_destroy(devfs_rule_cache);
485 }
486 
487 
488 SYSINIT(devfsdev,SI_SUB_DRIVERS,SI_ORDER_FIRST,devfs_dev_init,NULL);
489 SYSUNINIT(devfsdev, SI_SUB_DRIVERS,SI_ORDER_FIRST,devfs_dev_uninit, NULL);
490 
491