1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * kobject.c - library routines for handling generic kernel objects
4  *
5  * Copyright (c) 2002-2003 Patrick Mochel <mochel@osdl.org>
6  * Copyright (c) 2006-2007 Greg Kroah-Hartman <greg@kroah.com>
7  * Copyright (c) 2006-2007 Novell Inc.
8  *
9  * Please see the file Documentation/core-api/kobject.rst for critical information
10  * about using the kobject interface.
11  */
12 
13 #include <linux/kobject.h>
14 #include <linux/string.h>
15 #include <linux/export.h>
16 #include <linux/stat.h>
17 #include <linux/slab.h>
18 #include <linux/random.h>
19 
20 /**
21  * kobject_namespace() - Return @kobj's namespace tag.
22  * @kobj: kobject in question
23  *
24  * Returns namespace tag of @kobj if its parent has namespace ops enabled
25  * and thus @kobj should have a namespace tag associated with it.  Returns
26  * %NULL otherwise.
27  */
kobject_namespace(struct kobject * kobj)28 const void *kobject_namespace(struct kobject *kobj)
29 {
30 	const struct kobj_ns_type_operations *ns_ops = kobj_ns_ops(kobj);
31 
32 	if (!ns_ops || ns_ops->type == KOBJ_NS_TYPE_NONE)
33 		return NULL;
34 
35 	return kobj->ktype->namespace(kobj);
36 }
37 
38 /**
39  * kobject_get_ownership() - Get sysfs ownership data for @kobj.
40  * @kobj: kobject in question
41  * @uid: kernel user ID for sysfs objects
42  * @gid: kernel group ID for sysfs objects
43  *
44  * Returns initial uid/gid pair that should be used when creating sysfs
45  * representation of given kobject. Normally used to adjust ownership of
46  * objects in a container.
47  */
kobject_get_ownership(struct kobject * kobj,kuid_t * uid,kgid_t * gid)48 void kobject_get_ownership(struct kobject *kobj, kuid_t *uid, kgid_t *gid)
49 {
50 	*uid = GLOBAL_ROOT_UID;
51 	*gid = GLOBAL_ROOT_GID;
52 
53 	if (kobj->ktype->get_ownership)
54 		kobj->ktype->get_ownership(kobj, uid, gid);
55 }
56 
create_dir(struct kobject * kobj)57 static int create_dir(struct kobject *kobj)
58 {
59 	const struct kobj_type *ktype = get_ktype(kobj);
60 	const struct kobj_ns_type_operations *ops;
61 	int error;
62 
63 	error = sysfs_create_dir_ns(kobj, kobject_namespace(kobj));
64 	if (error)
65 		return error;
66 
67 	if (ktype) {
68 		error = sysfs_create_groups(kobj, ktype->default_groups);
69 		if (error) {
70 			sysfs_remove_dir(kobj);
71 			return error;
72 		}
73 	}
74 
75 	/*
76 	 * @kobj->sd may be deleted by an ancestor going away.  Hold an
77 	 * extra reference so that it stays until @kobj is gone.
78 	 */
79 	sysfs_get(kobj->sd);
80 
81 	/*
82 	 * If @kobj has ns_ops, its children need to be filtered based on
83 	 * their namespace tags.  Enable namespace support on @kobj->sd.
84 	 */
85 	ops = kobj_child_ns_ops(kobj);
86 	if (ops) {
87 		BUG_ON(ops->type <= KOBJ_NS_TYPE_NONE);
88 		BUG_ON(ops->type >= KOBJ_NS_TYPES);
89 		BUG_ON(!kobj_ns_type_registered(ops->type));
90 
91 		sysfs_enable_ns(kobj->sd);
92 	}
93 
94 	return 0;
95 }
96 
get_kobj_path_length(struct kobject * kobj)97 static int get_kobj_path_length(struct kobject *kobj)
98 {
99 	int length = 1;
100 	struct kobject *parent = kobj;
101 
102 	/* walk up the ancestors until we hit the one pointing to the
103 	 * root.
104 	 * Add 1 to strlen for leading '/' of each level.
105 	 */
106 	do {
107 		if (kobject_name(parent) == NULL)
108 			return 0;
109 		length += strlen(kobject_name(parent)) + 1;
110 		parent = parent->parent;
111 	} while (parent);
112 	return length;
113 }
114 
fill_kobj_path(struct kobject * kobj,char * path,int length)115 static void fill_kobj_path(struct kobject *kobj, char *path, int length)
116 {
117 	struct kobject *parent;
118 
119 	--length;
120 	for (parent = kobj; parent; parent = parent->parent) {
121 		int cur = strlen(kobject_name(parent));
122 		/* back up enough to print this name with '/' */
123 		length -= cur;
124 		memcpy(path + length, kobject_name(parent), cur);
125 		*(path + --length) = '/';
126 	}
127 
128 	pr_debug("kobject: '%s' (%p): %s: path = '%s'\n", kobject_name(kobj),
129 		 kobj, __func__, path);
130 }
131 
132 /**
133  * kobject_get_path() - Allocate memory and fill in the path for @kobj.
134  * @kobj:	kobject in question, with which to build the path
135  * @gfp_mask:	the allocation type used to allocate the path
136  *
137  * Return: The newly allocated memory, caller must free with kfree().
138  */
kobject_get_path(struct kobject * kobj,gfp_t gfp_mask)139 char *kobject_get_path(struct kobject *kobj, gfp_t gfp_mask)
140 {
141 	char *path;
142 	int len;
143 
144 	len = get_kobj_path_length(kobj);
145 	if (len == 0)
146 		return NULL;
147 	path = kzalloc(len, gfp_mask);
148 	if (!path)
149 		return NULL;
150 	fill_kobj_path(kobj, path, len);
151 
152 	return path;
153 }
154 EXPORT_SYMBOL_GPL(kobject_get_path);
155 
156 /* add the kobject to its kset's list */
kobj_kset_join(struct kobject * kobj)157 static void kobj_kset_join(struct kobject *kobj)
158 {
159 	if (!kobj->kset)
160 		return;
161 
162 	kset_get(kobj->kset);
163 	spin_lock(&kobj->kset->list_lock);
164 	list_add_tail(&kobj->entry, &kobj->kset->list);
165 	spin_unlock(&kobj->kset->list_lock);
166 }
167 
168 /* remove the kobject from its kset's list */
kobj_kset_leave(struct kobject * kobj)169 static void kobj_kset_leave(struct kobject *kobj)
170 {
171 	if (!kobj->kset)
172 		return;
173 
174 	spin_lock(&kobj->kset->list_lock);
175 	list_del_init(&kobj->entry);
176 	spin_unlock(&kobj->kset->list_lock);
177 	kset_put(kobj->kset);
178 }
179 
kobject_init_internal(struct kobject * kobj)180 static void kobject_init_internal(struct kobject *kobj)
181 {
182 	if (!kobj)
183 		return;
184 	kref_init(&kobj->kref);
185 	INIT_LIST_HEAD(&kobj->entry);
186 	kobj->state_in_sysfs = 0;
187 	kobj->state_add_uevent_sent = 0;
188 	kobj->state_remove_uevent_sent = 0;
189 	kobj->state_initialized = 1;
190 }
191 
192 
kobject_add_internal(struct kobject * kobj)193 static int kobject_add_internal(struct kobject *kobj)
194 {
195 	int error = 0;
196 	struct kobject *parent;
197 
198 	if (!kobj)
199 		return -ENOENT;
200 
201 	if (!kobj->name || !kobj->name[0]) {
202 		WARN(1,
203 		     "kobject: (%p): attempted to be registered with empty name!\n",
204 		     kobj);
205 		return -EINVAL;
206 	}
207 
208 	parent = kobject_get(kobj->parent);
209 
210 	/* join kset if set, use it as parent if we do not already have one */
211 	if (kobj->kset) {
212 		if (!parent)
213 			parent = kobject_get(&kobj->kset->kobj);
214 		kobj_kset_join(kobj);
215 		kobj->parent = parent;
216 	}
217 
218 	pr_debug("kobject: '%s' (%p): %s: parent: '%s', set: '%s'\n",
219 		 kobject_name(kobj), kobj, __func__,
220 		 parent ? kobject_name(parent) : "<NULL>",
221 		 kobj->kset ? kobject_name(&kobj->kset->kobj) : "<NULL>");
222 
223 	error = create_dir(kobj);
224 	if (error) {
225 		kobj_kset_leave(kobj);
226 		kobject_put(parent);
227 		kobj->parent = NULL;
228 
229 		/* be noisy on error issues */
230 		if (error == -EEXIST)
231 			pr_err("%s failed for %s with -EEXIST, don't try to register things with the same name in the same directory.\n",
232 			       __func__, kobject_name(kobj));
233 		else
234 			pr_err("%s failed for %s (error: %d parent: %s)\n",
235 			       __func__, kobject_name(kobj), error,
236 			       parent ? kobject_name(parent) : "'none'");
237 	} else
238 		kobj->state_in_sysfs = 1;
239 
240 	return error;
241 }
242 
243 /**
244  * kobject_set_name_vargs() - Set the name of a kobject.
245  * @kobj: struct kobject to set the name of
246  * @fmt: format string used to build the name
247  * @vargs: vargs to format the string.
248  */
kobject_set_name_vargs(struct kobject * kobj,const char * fmt,va_list vargs)249 int kobject_set_name_vargs(struct kobject *kobj, const char *fmt,
250 				  va_list vargs)
251 {
252 	const char *s;
253 
254 	if (kobj->name && !fmt)
255 		return 0;
256 
257 	s = kvasprintf_const(GFP_KERNEL, fmt, vargs);
258 	if (!s)
259 		return -ENOMEM;
260 
261 	/*
262 	 * ewww... some of these buggers have '/' in the name ... If
263 	 * that's the case, we need to make sure we have an actual
264 	 * allocated copy to modify, since kvasprintf_const may have
265 	 * returned something from .rodata.
266 	 */
267 	if (strchr(s, '/')) {
268 		char *t;
269 
270 		t = kstrdup(s, GFP_KERNEL);
271 		kfree_const(s);
272 		if (!t)
273 			return -ENOMEM;
274 		strreplace(t, '/', '!');
275 		s = t;
276 	}
277 	kfree_const(kobj->name);
278 	kobj->name = s;
279 
280 	return 0;
281 }
282 
283 /**
284  * kobject_set_name() - Set the name of a kobject.
285  * @kobj: struct kobject to set the name of
286  * @fmt: format string used to build the name
287  *
288  * This sets the name of the kobject.  If you have already added the
289  * kobject to the system, you must call kobject_rename() in order to
290  * change the name of the kobject.
291  */
kobject_set_name(struct kobject * kobj,const char * fmt,...)292 int kobject_set_name(struct kobject *kobj, const char *fmt, ...)
293 {
294 	va_list vargs;
295 	int retval;
296 
297 	va_start(vargs, fmt);
298 	retval = kobject_set_name_vargs(kobj, fmt, vargs);
299 	va_end(vargs);
300 
301 	return retval;
302 }
303 EXPORT_SYMBOL(kobject_set_name);
304 
305 /**
306  * kobject_init() - Initialize a kobject structure.
307  * @kobj: pointer to the kobject to initialize
308  * @ktype: pointer to the ktype for this kobject.
309  *
310  * This function will properly initialize a kobject such that it can then
311  * be passed to the kobject_add() call.
312  *
313  * After this function is called, the kobject MUST be cleaned up by a call
314  * to kobject_put(), not by a call to kfree directly to ensure that all of
315  * the memory is cleaned up properly.
316  */
kobject_init(struct kobject * kobj,const struct kobj_type * ktype)317 void kobject_init(struct kobject *kobj, const struct kobj_type *ktype)
318 {
319 	char *err_str;
320 
321 	if (!kobj) {
322 		err_str = "invalid kobject pointer!";
323 		goto error;
324 	}
325 	if (!ktype) {
326 		err_str = "must have a ktype to be initialized properly!\n";
327 		goto error;
328 	}
329 	if (kobj->state_initialized) {
330 		/* do not error out as sometimes we can recover */
331 		pr_err("kobject (%p): tried to init an initialized object, something is seriously wrong.\n",
332 		       kobj);
333 		dump_stack();
334 	}
335 
336 	kobject_init_internal(kobj);
337 	kobj->ktype = ktype;
338 	return;
339 
340 error:
341 	pr_err("kobject (%p): %s\n", kobj, err_str);
342 	dump_stack();
343 }
344 EXPORT_SYMBOL(kobject_init);
345 
kobject_add_varg(struct kobject * kobj,struct kobject * parent,const char * fmt,va_list vargs)346 static __printf(3, 0) int kobject_add_varg(struct kobject *kobj,
347 					   struct kobject *parent,
348 					   const char *fmt, va_list vargs)
349 {
350 	int retval;
351 
352 	retval = kobject_set_name_vargs(kobj, fmt, vargs);
353 	if (retval) {
354 		pr_err("kobject: can not set name properly!\n");
355 		return retval;
356 	}
357 	kobj->parent = parent;
358 	return kobject_add_internal(kobj);
359 }
360 
361 /**
362  * kobject_add() - The main kobject add function.
363  * @kobj: the kobject to add
364  * @parent: pointer to the parent of the kobject.
365  * @fmt: format to name the kobject with.
366  *
367  * The kobject name is set and added to the kobject hierarchy in this
368  * function.
369  *
370  * If @parent is set, then the parent of the @kobj will be set to it.
371  * If @parent is NULL, then the parent of the @kobj will be set to the
372  * kobject associated with the kset assigned to this kobject.  If no kset
373  * is assigned to the kobject, then the kobject will be located in the
374  * root of the sysfs tree.
375  *
376  * Note, no "add" uevent will be created with this call, the caller should set
377  * up all of the necessary sysfs files for the object and then call
378  * kobject_uevent() with the UEVENT_ADD parameter to ensure that
379  * userspace is properly notified of this kobject's creation.
380  *
381  * Return: If this function returns an error, kobject_put() must be
382  *         called to properly clean up the memory associated with the
383  *         object.  Under no instance should the kobject that is passed
384  *         to this function be directly freed with a call to kfree(),
385  *         that can leak memory.
386  *
387  *         If this function returns success, kobject_put() must also be called
388  *         in order to properly clean up the memory associated with the object.
389  *
390  *         In short, once this function is called, kobject_put() MUST be called
391  *         when the use of the object is finished in order to properly free
392  *         everything.
393  */
kobject_add(struct kobject * kobj,struct kobject * parent,const char * fmt,...)394 int kobject_add(struct kobject *kobj, struct kobject *parent,
395 		const char *fmt, ...)
396 {
397 	va_list args;
398 	int retval;
399 
400 	if (!kobj)
401 		return -EINVAL;
402 
403 	if (!kobj->state_initialized) {
404 		pr_err("kobject '%s' (%p): tried to add an uninitialized object, something is seriously wrong.\n",
405 		       kobject_name(kobj), kobj);
406 		dump_stack();
407 		return -EINVAL;
408 	}
409 	va_start(args, fmt);
410 	retval = kobject_add_varg(kobj, parent, fmt, args);
411 	va_end(args);
412 
413 	return retval;
414 }
415 EXPORT_SYMBOL(kobject_add);
416 
417 /**
418  * kobject_init_and_add() - Initialize a kobject structure and add it to
419  *                          the kobject hierarchy.
420  * @kobj: pointer to the kobject to initialize
421  * @ktype: pointer to the ktype for this kobject.
422  * @parent: pointer to the parent of this kobject.
423  * @fmt: the name of the kobject.
424  *
425  * This function combines the call to kobject_init() and kobject_add().
426  *
427  * If this function returns an error, kobject_put() must be called to
428  * properly clean up the memory associated with the object.  This is the
429  * same type of error handling after a call to kobject_add() and kobject
430  * lifetime rules are the same here.
431  */
kobject_init_and_add(struct kobject * kobj,const struct kobj_type * ktype,struct kobject * parent,const char * fmt,...)432 int kobject_init_and_add(struct kobject *kobj, const struct kobj_type *ktype,
433 			 struct kobject *parent, const char *fmt, ...)
434 {
435 	va_list args;
436 	int retval;
437 
438 	kobject_init(kobj, ktype);
439 
440 	va_start(args, fmt);
441 	retval = kobject_add_varg(kobj, parent, fmt, args);
442 	va_end(args);
443 
444 	return retval;
445 }
446 EXPORT_SYMBOL_GPL(kobject_init_and_add);
447 
448 /**
449  * kobject_rename() - Change the name of an object.
450  * @kobj: object in question.
451  * @new_name: object's new name
452  *
453  * It is the responsibility of the caller to provide mutual
454  * exclusion between two different calls of kobject_rename
455  * on the same kobject and to ensure that new_name is valid and
456  * won't conflict with other kobjects.
457  */
kobject_rename(struct kobject * kobj,const char * new_name)458 int kobject_rename(struct kobject *kobj, const char *new_name)
459 {
460 	int error = 0;
461 	const char *devpath = NULL;
462 	const char *dup_name = NULL, *name;
463 	char *devpath_string = NULL;
464 	char *envp[2];
465 
466 	kobj = kobject_get(kobj);
467 	if (!kobj)
468 		return -EINVAL;
469 	if (!kobj->parent) {
470 		kobject_put(kobj);
471 		return -EINVAL;
472 	}
473 
474 	devpath = kobject_get_path(kobj, GFP_KERNEL);
475 	if (!devpath) {
476 		error = -ENOMEM;
477 		goto out;
478 	}
479 	devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
480 	if (!devpath_string) {
481 		error = -ENOMEM;
482 		goto out;
483 	}
484 	sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
485 	envp[0] = devpath_string;
486 	envp[1] = NULL;
487 
488 	name = dup_name = kstrdup_const(new_name, GFP_KERNEL);
489 	if (!name) {
490 		error = -ENOMEM;
491 		goto out;
492 	}
493 
494 	error = sysfs_rename_dir_ns(kobj, new_name, kobject_namespace(kobj));
495 	if (error)
496 		goto out;
497 
498 	/* Install the new kobject name */
499 	dup_name = kobj->name;
500 	kobj->name = name;
501 
502 	/* This function is mostly/only used for network interface.
503 	 * Some hotplug package track interfaces by their name and
504 	 * therefore want to know when the name is changed by the user. */
505 	kobject_uevent_env(kobj, KOBJ_MOVE, envp);
506 
507 out:
508 	kfree_const(dup_name);
509 	kfree(devpath_string);
510 	kfree(devpath);
511 	kobject_put(kobj);
512 
513 	return error;
514 }
515 EXPORT_SYMBOL_GPL(kobject_rename);
516 
517 /**
518  * kobject_move() - Move object to another parent.
519  * @kobj: object in question.
520  * @new_parent: object's new parent (can be NULL)
521  */
kobject_move(struct kobject * kobj,struct kobject * new_parent)522 int kobject_move(struct kobject *kobj, struct kobject *new_parent)
523 {
524 	int error;
525 	struct kobject *old_parent;
526 	const char *devpath = NULL;
527 	char *devpath_string = NULL;
528 	char *envp[2];
529 
530 	kobj = kobject_get(kobj);
531 	if (!kobj)
532 		return -EINVAL;
533 	new_parent = kobject_get(new_parent);
534 	if (!new_parent) {
535 		if (kobj->kset)
536 			new_parent = kobject_get(&kobj->kset->kobj);
537 	}
538 
539 	/* old object path */
540 	devpath = kobject_get_path(kobj, GFP_KERNEL);
541 	if (!devpath) {
542 		error = -ENOMEM;
543 		goto out;
544 	}
545 	devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
546 	if (!devpath_string) {
547 		error = -ENOMEM;
548 		goto out;
549 	}
550 	sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
551 	envp[0] = devpath_string;
552 	envp[1] = NULL;
553 	error = sysfs_move_dir_ns(kobj, new_parent, kobject_namespace(kobj));
554 	if (error)
555 		goto out;
556 	old_parent = kobj->parent;
557 	kobj->parent = new_parent;
558 	new_parent = NULL;
559 	kobject_put(old_parent);
560 	kobject_uevent_env(kobj, KOBJ_MOVE, envp);
561 out:
562 	kobject_put(new_parent);
563 	kobject_put(kobj);
564 	kfree(devpath_string);
565 	kfree(devpath);
566 	return error;
567 }
568 EXPORT_SYMBOL_GPL(kobject_move);
569 
__kobject_del(struct kobject * kobj)570 static void __kobject_del(struct kobject *kobj)
571 {
572 	struct kernfs_node *sd;
573 	const struct kobj_type *ktype;
574 
575 	sd = kobj->sd;
576 	ktype = get_ktype(kobj);
577 
578 	if (ktype)
579 		sysfs_remove_groups(kobj, ktype->default_groups);
580 
581 	/* send "remove" if the caller did not do it but sent "add" */
582 	if (kobj->state_add_uevent_sent && !kobj->state_remove_uevent_sent) {
583 		pr_debug("kobject: '%s' (%p): auto cleanup 'remove' event\n",
584 			 kobject_name(kobj), kobj);
585 		kobject_uevent(kobj, KOBJ_REMOVE);
586 	}
587 
588 	sysfs_remove_dir(kobj);
589 	sysfs_put(sd);
590 
591 	kobj->state_in_sysfs = 0;
592 	kobj_kset_leave(kobj);
593 	kobj->parent = NULL;
594 }
595 
596 /**
597  * kobject_del() - Unlink kobject from hierarchy.
598  * @kobj: object.
599  *
600  * This is the function that should be called to delete an object
601  * successfully added via kobject_add().
602  */
kobject_del(struct kobject * kobj)603 void kobject_del(struct kobject *kobj)
604 {
605 	struct kobject *parent;
606 
607 	if (!kobj)
608 		return;
609 
610 	parent = kobj->parent;
611 	__kobject_del(kobj);
612 	kobject_put(parent);
613 }
614 EXPORT_SYMBOL(kobject_del);
615 
616 /**
617  * kobject_get() - Increment refcount for object.
618  * @kobj: object.
619  */
kobject_get(struct kobject * kobj)620 struct kobject *kobject_get(struct kobject *kobj)
621 {
622 	if (kobj) {
623 		if (!kobj->state_initialized)
624 			WARN(1, KERN_WARNING
625 				"kobject: '%s' (%p): is not initialized, yet kobject_get() is being called.\n",
626 			     kobject_name(kobj), kobj);
627 		kref_get(&kobj->kref);
628 	}
629 	return kobj;
630 }
631 EXPORT_SYMBOL(kobject_get);
632 
kobject_get_unless_zero(struct kobject * kobj)633 struct kobject * __must_check kobject_get_unless_zero(struct kobject *kobj)
634 {
635 	if (!kobj)
636 		return NULL;
637 	if (!kref_get_unless_zero(&kobj->kref))
638 		kobj = NULL;
639 	return kobj;
640 }
641 EXPORT_SYMBOL(kobject_get_unless_zero);
642 
643 /*
644  * kobject_cleanup - free kobject resources.
645  * @kobj: object to cleanup
646  */
kobject_cleanup(struct kobject * kobj)647 static void kobject_cleanup(struct kobject *kobj)
648 {
649 	struct kobject *parent = kobj->parent;
650 	const struct kobj_type *t = get_ktype(kobj);
651 	const char *name = kobj->name;
652 
653 	pr_debug("kobject: '%s' (%p): %s, parent %p\n",
654 		 kobject_name(kobj), kobj, __func__, kobj->parent);
655 
656 	if (t && !t->release)
657 		pr_debug("kobject: '%s' (%p): does not have a release() function, it is broken and must be fixed. See Documentation/core-api/kobject.rst.\n",
658 			 kobject_name(kobj), kobj);
659 
660 	/* remove from sysfs if the caller did not do it */
661 	if (kobj->state_in_sysfs) {
662 		pr_debug("kobject: '%s' (%p): auto cleanup kobject_del\n",
663 			 kobject_name(kobj), kobj);
664 		__kobject_del(kobj);
665 	} else {
666 		/* avoid dropping the parent reference unnecessarily */
667 		parent = NULL;
668 	}
669 
670 	if (t && t->release) {
671 		pr_debug("kobject: '%s' (%p): calling ktype release\n",
672 			 kobject_name(kobj), kobj);
673 		t->release(kobj);
674 	}
675 
676 	/* free name if we allocated it */
677 	if (name) {
678 		pr_debug("kobject: '%s': free name\n", name);
679 		kfree_const(name);
680 	}
681 
682 	kobject_put(parent);
683 }
684 
685 #ifdef CONFIG_DEBUG_KOBJECT_RELEASE
kobject_delayed_cleanup(struct work_struct * work)686 static void kobject_delayed_cleanup(struct work_struct *work)
687 {
688 	kobject_cleanup(container_of(to_delayed_work(work),
689 				     struct kobject, release));
690 }
691 #endif
692 
kobject_release(struct kref * kref)693 static void kobject_release(struct kref *kref)
694 {
695 	struct kobject *kobj = container_of(kref, struct kobject, kref);
696 #ifdef CONFIG_DEBUG_KOBJECT_RELEASE
697 	unsigned long delay = HZ + HZ * prandom_u32_max(4);
698 	pr_info("kobject: '%s' (%p): %s, parent %p (delayed %ld)\n",
699 		 kobject_name(kobj), kobj, __func__, kobj->parent, delay);
700 	INIT_DELAYED_WORK(&kobj->release, kobject_delayed_cleanup);
701 
702 	schedule_delayed_work(&kobj->release, delay);
703 #else
704 	kobject_cleanup(kobj);
705 #endif
706 }
707 
708 /**
709  * kobject_put() - Decrement refcount for object.
710  * @kobj: object.
711  *
712  * Decrement the refcount, and if 0, call kobject_cleanup().
713  */
kobject_put(struct kobject * kobj)714 void kobject_put(struct kobject *kobj)
715 {
716 	if (kobj) {
717 		if (!kobj->state_initialized)
718 			WARN(1, KERN_WARNING
719 				"kobject: '%s' (%p): is not initialized, yet kobject_put() is being called.\n",
720 			     kobject_name(kobj), kobj);
721 		kref_put(&kobj->kref, kobject_release);
722 	}
723 }
724 EXPORT_SYMBOL(kobject_put);
725 
dynamic_kobj_release(struct kobject * kobj)726 static void dynamic_kobj_release(struct kobject *kobj)
727 {
728 	pr_debug("kobject: (%p): %s\n", kobj, __func__);
729 	kfree(kobj);
730 }
731 
732 static struct kobj_type dynamic_kobj_ktype = {
733 	.release	= dynamic_kobj_release,
734 	.sysfs_ops	= &kobj_sysfs_ops,
735 };
736 
737 /**
738  * kobject_create() - Create a struct kobject dynamically.
739  *
740  * This function creates a kobject structure dynamically and sets it up
741  * to be a "dynamic" kobject with a default release function set up.
742  *
743  * If the kobject was not able to be created, NULL will be returned.
744  * The kobject structure returned from here must be cleaned up with a
745  * call to kobject_put() and not kfree(), as kobject_init() has
746  * already been called on this structure.
747  */
kobject_create(void)748 static struct kobject *kobject_create(void)
749 {
750 	struct kobject *kobj;
751 
752 	kobj = kzalloc(sizeof(*kobj), GFP_KERNEL);
753 	if (!kobj)
754 		return NULL;
755 
756 	kobject_init(kobj, &dynamic_kobj_ktype);
757 	return kobj;
758 }
759 
760 /**
761  * kobject_create_and_add() - Create a struct kobject dynamically and
762  *                            register it with sysfs.
763  * @name: the name for the kobject
764  * @parent: the parent kobject of this kobject, if any.
765  *
766  * This function creates a kobject structure dynamically and registers it
767  * with sysfs.  When you are finished with this structure, call
768  * kobject_put() and the structure will be dynamically freed when
769  * it is no longer being used.
770  *
771  * If the kobject was not able to be created, NULL will be returned.
772  */
kobject_create_and_add(const char * name,struct kobject * parent)773 struct kobject *kobject_create_and_add(const char *name, struct kobject *parent)
774 {
775 	struct kobject *kobj;
776 	int retval;
777 
778 	kobj = kobject_create();
779 	if (!kobj)
780 		return NULL;
781 
782 	retval = kobject_add(kobj, parent, "%s", name);
783 	if (retval) {
784 		pr_warn("%s: kobject_add error: %d\n", __func__, retval);
785 		kobject_put(kobj);
786 		kobj = NULL;
787 	}
788 	return kobj;
789 }
790 EXPORT_SYMBOL_GPL(kobject_create_and_add);
791 
792 /**
793  * kset_init() - Initialize a kset for use.
794  * @k: kset
795  */
kset_init(struct kset * k)796 void kset_init(struct kset *k)
797 {
798 	kobject_init_internal(&k->kobj);
799 	INIT_LIST_HEAD(&k->list);
800 	spin_lock_init(&k->list_lock);
801 }
802 
803 /* default kobject attribute operations */
kobj_attr_show(struct kobject * kobj,struct attribute * attr,char * buf)804 static ssize_t kobj_attr_show(struct kobject *kobj, struct attribute *attr,
805 			      char *buf)
806 {
807 	struct kobj_attribute *kattr;
808 	ssize_t ret = -EIO;
809 
810 	kattr = container_of(attr, struct kobj_attribute, attr);
811 	if (kattr->show)
812 		ret = kattr->show(kobj, kattr, buf);
813 	return ret;
814 }
815 
kobj_attr_store(struct kobject * kobj,struct attribute * attr,const char * buf,size_t count)816 static ssize_t kobj_attr_store(struct kobject *kobj, struct attribute *attr,
817 			       const char *buf, size_t count)
818 {
819 	struct kobj_attribute *kattr;
820 	ssize_t ret = -EIO;
821 
822 	kattr = container_of(attr, struct kobj_attribute, attr);
823 	if (kattr->store)
824 		ret = kattr->store(kobj, kattr, buf, count);
825 	return ret;
826 }
827 
828 const struct sysfs_ops kobj_sysfs_ops = {
829 	.show	= kobj_attr_show,
830 	.store	= kobj_attr_store,
831 };
832 EXPORT_SYMBOL_GPL(kobj_sysfs_ops);
833 
834 /**
835  * kset_register() - Initialize and add a kset.
836  * @k: kset.
837  */
kset_register(struct kset * k)838 int kset_register(struct kset *k)
839 {
840 	int err;
841 
842 	if (!k)
843 		return -EINVAL;
844 
845 	kset_init(k);
846 	err = kobject_add_internal(&k->kobj);
847 	if (err)
848 		return err;
849 	kobject_uevent(&k->kobj, KOBJ_ADD);
850 	return 0;
851 }
852 EXPORT_SYMBOL(kset_register);
853 
854 /**
855  * kset_unregister() - Remove a kset.
856  * @k: kset.
857  */
kset_unregister(struct kset * k)858 void kset_unregister(struct kset *k)
859 {
860 	if (!k)
861 		return;
862 	kobject_del(&k->kobj);
863 	kobject_put(&k->kobj);
864 }
865 EXPORT_SYMBOL(kset_unregister);
866 
867 /**
868  * kset_find_obj() - Search for object in kset.
869  * @kset: kset we're looking in.
870  * @name: object's name.
871  *
872  * Lock kset via @kset->subsys, and iterate over @kset->list,
873  * looking for a matching kobject. If matching object is found
874  * take a reference and return the object.
875  */
kset_find_obj(struct kset * kset,const char * name)876 struct kobject *kset_find_obj(struct kset *kset, const char *name)
877 {
878 	struct kobject *k;
879 	struct kobject *ret = NULL;
880 
881 	spin_lock(&kset->list_lock);
882 
883 	list_for_each_entry(k, &kset->list, entry) {
884 		if (kobject_name(k) && !strcmp(kobject_name(k), name)) {
885 			ret = kobject_get_unless_zero(k);
886 			break;
887 		}
888 	}
889 
890 	spin_unlock(&kset->list_lock);
891 	return ret;
892 }
893 EXPORT_SYMBOL_GPL(kset_find_obj);
894 
kset_release(struct kobject * kobj)895 static void kset_release(struct kobject *kobj)
896 {
897 	struct kset *kset = container_of(kobj, struct kset, kobj);
898 	pr_debug("kobject: '%s' (%p): %s\n",
899 		 kobject_name(kobj), kobj, __func__);
900 	kfree(kset);
901 }
902 
kset_get_ownership(struct kobject * kobj,kuid_t * uid,kgid_t * gid)903 static void kset_get_ownership(struct kobject *kobj, kuid_t *uid, kgid_t *gid)
904 {
905 	if (kobj->parent)
906 		kobject_get_ownership(kobj->parent, uid, gid);
907 }
908 
909 static struct kobj_type kset_ktype = {
910 	.sysfs_ops	= &kobj_sysfs_ops,
911 	.release	= kset_release,
912 	.get_ownership	= kset_get_ownership,
913 };
914 
915 /**
916  * kset_create() - Create a struct kset dynamically.
917  *
918  * @name: the name for the kset
919  * @uevent_ops: a struct kset_uevent_ops for the kset
920  * @parent_kobj: the parent kobject of this kset, if any.
921  *
922  * This function creates a kset structure dynamically.  This structure can
923  * then be registered with the system and show up in sysfs with a call to
924  * kset_register().  When you are finished with this structure, if
925  * kset_register() has been called, call kset_unregister() and the
926  * structure will be dynamically freed when it is no longer being used.
927  *
928  * If the kset was not able to be created, NULL will be returned.
929  */
kset_create(const char * name,const struct kset_uevent_ops * uevent_ops,struct kobject * parent_kobj)930 static struct kset *kset_create(const char *name,
931 				const struct kset_uevent_ops *uevent_ops,
932 				struct kobject *parent_kobj)
933 {
934 	struct kset *kset;
935 	int retval;
936 
937 	kset = kzalloc(sizeof(*kset), GFP_KERNEL);
938 	if (!kset)
939 		return NULL;
940 	retval = kobject_set_name(&kset->kobj, "%s", name);
941 	if (retval) {
942 		kfree(kset);
943 		return NULL;
944 	}
945 	kset->uevent_ops = uevent_ops;
946 	kset->kobj.parent = parent_kobj;
947 
948 	/*
949 	 * The kobject of this kset will have a type of kset_ktype and belong to
950 	 * no kset itself.  That way we can properly free it when it is
951 	 * finished being used.
952 	 */
953 	kset->kobj.ktype = &kset_ktype;
954 	kset->kobj.kset = NULL;
955 
956 	return kset;
957 }
958 
959 /**
960  * kset_create_and_add() - Create a struct kset dynamically and add it to sysfs.
961  *
962  * @name: the name for the kset
963  * @uevent_ops: a struct kset_uevent_ops for the kset
964  * @parent_kobj: the parent kobject of this kset, if any.
965  *
966  * This function creates a kset structure dynamically and registers it
967  * with sysfs.  When you are finished with this structure, call
968  * kset_unregister() and the structure will be dynamically freed when it
969  * is no longer being used.
970  *
971  * If the kset was not able to be created, NULL will be returned.
972  */
kset_create_and_add(const char * name,const struct kset_uevent_ops * uevent_ops,struct kobject * parent_kobj)973 struct kset *kset_create_and_add(const char *name,
974 				 const struct kset_uevent_ops *uevent_ops,
975 				 struct kobject *parent_kobj)
976 {
977 	struct kset *kset;
978 	int error;
979 
980 	kset = kset_create(name, uevent_ops, parent_kobj);
981 	if (!kset)
982 		return NULL;
983 	error = kset_register(kset);
984 	if (error) {
985 		kfree(kset);
986 		return NULL;
987 	}
988 	return kset;
989 }
990 EXPORT_SYMBOL_GPL(kset_create_and_add);
991 
992 
993 static DEFINE_SPINLOCK(kobj_ns_type_lock);
994 static const struct kobj_ns_type_operations *kobj_ns_ops_tbl[KOBJ_NS_TYPES];
995 
kobj_ns_type_register(const struct kobj_ns_type_operations * ops)996 int kobj_ns_type_register(const struct kobj_ns_type_operations *ops)
997 {
998 	enum kobj_ns_type type = ops->type;
999 	int error;
1000 
1001 	spin_lock(&kobj_ns_type_lock);
1002 
1003 	error = -EINVAL;
1004 	if (type >= KOBJ_NS_TYPES)
1005 		goto out;
1006 
1007 	error = -EINVAL;
1008 	if (type <= KOBJ_NS_TYPE_NONE)
1009 		goto out;
1010 
1011 	error = -EBUSY;
1012 	if (kobj_ns_ops_tbl[type])
1013 		goto out;
1014 
1015 	error = 0;
1016 	kobj_ns_ops_tbl[type] = ops;
1017 
1018 out:
1019 	spin_unlock(&kobj_ns_type_lock);
1020 	return error;
1021 }
1022 
kobj_ns_type_registered(enum kobj_ns_type type)1023 int kobj_ns_type_registered(enum kobj_ns_type type)
1024 {
1025 	int registered = 0;
1026 
1027 	spin_lock(&kobj_ns_type_lock);
1028 	if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES))
1029 		registered = kobj_ns_ops_tbl[type] != NULL;
1030 	spin_unlock(&kobj_ns_type_lock);
1031 
1032 	return registered;
1033 }
1034 
kobj_child_ns_ops(struct kobject * parent)1035 const struct kobj_ns_type_operations *kobj_child_ns_ops(struct kobject *parent)
1036 {
1037 	const struct kobj_ns_type_operations *ops = NULL;
1038 
1039 	if (parent && parent->ktype && parent->ktype->child_ns_type)
1040 		ops = parent->ktype->child_ns_type(parent);
1041 
1042 	return ops;
1043 }
1044 
kobj_ns_ops(struct kobject * kobj)1045 const struct kobj_ns_type_operations *kobj_ns_ops(struct kobject *kobj)
1046 {
1047 	return kobj_child_ns_ops(kobj->parent);
1048 }
1049 
kobj_ns_current_may_mount(enum kobj_ns_type type)1050 bool kobj_ns_current_may_mount(enum kobj_ns_type type)
1051 {
1052 	bool may_mount = true;
1053 
1054 	spin_lock(&kobj_ns_type_lock);
1055 	if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1056 	    kobj_ns_ops_tbl[type])
1057 		may_mount = kobj_ns_ops_tbl[type]->current_may_mount();
1058 	spin_unlock(&kobj_ns_type_lock);
1059 
1060 	return may_mount;
1061 }
1062 
kobj_ns_grab_current(enum kobj_ns_type type)1063 void *kobj_ns_grab_current(enum kobj_ns_type type)
1064 {
1065 	void *ns = NULL;
1066 
1067 	spin_lock(&kobj_ns_type_lock);
1068 	if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1069 	    kobj_ns_ops_tbl[type])
1070 		ns = kobj_ns_ops_tbl[type]->grab_current_ns();
1071 	spin_unlock(&kobj_ns_type_lock);
1072 
1073 	return ns;
1074 }
1075 EXPORT_SYMBOL_GPL(kobj_ns_grab_current);
1076 
kobj_ns_netlink(enum kobj_ns_type type,struct sock * sk)1077 const void *kobj_ns_netlink(enum kobj_ns_type type, struct sock *sk)
1078 {
1079 	const void *ns = NULL;
1080 
1081 	spin_lock(&kobj_ns_type_lock);
1082 	if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1083 	    kobj_ns_ops_tbl[type])
1084 		ns = kobj_ns_ops_tbl[type]->netlink_ns(sk);
1085 	spin_unlock(&kobj_ns_type_lock);
1086 
1087 	return ns;
1088 }
1089 
kobj_ns_initial(enum kobj_ns_type type)1090 const void *kobj_ns_initial(enum kobj_ns_type type)
1091 {
1092 	const void *ns = NULL;
1093 
1094 	spin_lock(&kobj_ns_type_lock);
1095 	if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1096 	    kobj_ns_ops_tbl[type])
1097 		ns = kobj_ns_ops_tbl[type]->initial_ns();
1098 	spin_unlock(&kobj_ns_type_lock);
1099 
1100 	return ns;
1101 }
1102 
kobj_ns_drop(enum kobj_ns_type type,void * ns)1103 void kobj_ns_drop(enum kobj_ns_type type, void *ns)
1104 {
1105 	spin_lock(&kobj_ns_type_lock);
1106 	if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1107 	    kobj_ns_ops_tbl[type] && kobj_ns_ops_tbl[type]->drop_ns)
1108 		kobj_ns_ops_tbl[type]->drop_ns(ns);
1109 	spin_unlock(&kobj_ns_type_lock);
1110 }
1111 EXPORT_SYMBOL_GPL(kobj_ns_drop);
1112