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/kobject.txt 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 
57 /*
58  * populate_dir - populate directory with attributes.
59  * @kobj: object we're working on.
60  *
61  * Most subsystems have a set of default attributes that are associated
62  * with an object that registers with them.  This is a helper called during
63  * object registration that loops through the default attributes of the
64  * subsystem and creates attributes files for them in sysfs.
65  */
populate_dir(struct kobject * kobj)66 static int populate_dir(struct kobject *kobj)
67 {
68 	struct kobj_type *t = get_ktype(kobj);
69 	struct attribute *attr;
70 	int error = 0;
71 	int i;
72 
73 	if (t && t->default_attrs) {
74 		for (i = 0; (attr = t->default_attrs[i]) != NULL; i++) {
75 			error = sysfs_create_file(kobj, attr);
76 			if (error)
77 				break;
78 		}
79 	}
80 	return error;
81 }
82 
create_dir(struct kobject * kobj)83 static int create_dir(struct kobject *kobj)
84 {
85 	const struct kobj_ns_type_operations *ops;
86 	int error;
87 
88 	error = sysfs_create_dir_ns(kobj, kobject_namespace(kobj));
89 	if (error)
90 		return error;
91 
92 	error = populate_dir(kobj);
93 	if (error) {
94 		sysfs_remove_dir(kobj);
95 		return error;
96 	}
97 
98 	/*
99 	 * @kobj->sd may be deleted by an ancestor going away.  Hold an
100 	 * extra reference so that it stays until @kobj is gone.
101 	 */
102 	sysfs_get(kobj->sd);
103 
104 	/*
105 	 * If @kobj has ns_ops, its children need to be filtered based on
106 	 * their namespace tags.  Enable namespace support on @kobj->sd.
107 	 */
108 	ops = kobj_child_ns_ops(kobj);
109 	if (ops) {
110 		BUG_ON(ops->type <= KOBJ_NS_TYPE_NONE);
111 		BUG_ON(ops->type >= KOBJ_NS_TYPES);
112 		BUG_ON(!kobj_ns_type_registered(ops->type));
113 
114 		sysfs_enable_ns(kobj->sd);
115 	}
116 
117 	return 0;
118 }
119 
get_kobj_path_length(struct kobject * kobj)120 static int get_kobj_path_length(struct kobject *kobj)
121 {
122 	int length = 1;
123 	struct kobject *parent = kobj;
124 
125 	/* walk up the ancestors until we hit the one pointing to the
126 	 * root.
127 	 * Add 1 to strlen for leading '/' of each level.
128 	 */
129 	do {
130 		if (kobject_name(parent) == NULL)
131 			return 0;
132 		length += strlen(kobject_name(parent)) + 1;
133 		parent = parent->parent;
134 	} while (parent);
135 	return length;
136 }
137 
fill_kobj_path(struct kobject * kobj,char * path,int length)138 static void fill_kobj_path(struct kobject *kobj, char *path, int length)
139 {
140 	struct kobject *parent;
141 
142 	--length;
143 	for (parent = kobj; parent; parent = parent->parent) {
144 		int cur = strlen(kobject_name(parent));
145 		/* back up enough to print this name with '/' */
146 		length -= cur;
147 		memcpy(path + length, kobject_name(parent), cur);
148 		*(path + --length) = '/';
149 	}
150 
151 	pr_debug("kobject: '%s' (%p): %s: path = '%s'\n", kobject_name(kobj),
152 		 kobj, __func__, path);
153 }
154 
155 /**
156  * kobject_get_path - generate and return the path associated with a given kobj and kset pair.
157  *
158  * @kobj:	kobject in question, with which to build the path
159  * @gfp_mask:	the allocation type used to allocate the path
160  *
161  * The result must be freed by the caller with kfree().
162  */
kobject_get_path(struct kobject * kobj,gfp_t gfp_mask)163 char *kobject_get_path(struct kobject *kobj, gfp_t gfp_mask)
164 {
165 	char *path;
166 	int len;
167 
168 	len = get_kobj_path_length(kobj);
169 	if (len == 0)
170 		return NULL;
171 	path = kzalloc(len, gfp_mask);
172 	if (!path)
173 		return NULL;
174 	fill_kobj_path(kobj, path, len);
175 
176 	return path;
177 }
178 EXPORT_SYMBOL_GPL(kobject_get_path);
179 
180 /* add the kobject to its kset's list */
kobj_kset_join(struct kobject * kobj)181 static void kobj_kset_join(struct kobject *kobj)
182 {
183 	if (!kobj->kset)
184 		return;
185 
186 	kset_get(kobj->kset);
187 	spin_lock(&kobj->kset->list_lock);
188 	list_add_tail(&kobj->entry, &kobj->kset->list);
189 	spin_unlock(&kobj->kset->list_lock);
190 }
191 
192 /* remove the kobject from its kset's list */
kobj_kset_leave(struct kobject * kobj)193 static void kobj_kset_leave(struct kobject *kobj)
194 {
195 	if (!kobj->kset)
196 		return;
197 
198 	spin_lock(&kobj->kset->list_lock);
199 	list_del_init(&kobj->entry);
200 	spin_unlock(&kobj->kset->list_lock);
201 	kset_put(kobj->kset);
202 }
203 
kobject_init_internal(struct kobject * kobj)204 static void kobject_init_internal(struct kobject *kobj)
205 {
206 	if (!kobj)
207 		return;
208 	kref_init(&kobj->kref);
209 	INIT_LIST_HEAD(&kobj->entry);
210 	kobj->state_in_sysfs = 0;
211 	kobj->state_add_uevent_sent = 0;
212 	kobj->state_remove_uevent_sent = 0;
213 	kobj->state_initialized = 1;
214 }
215 
216 
kobject_add_internal(struct kobject * kobj)217 static int kobject_add_internal(struct kobject *kobj)
218 {
219 	int error = 0;
220 	struct kobject *parent;
221 
222 	if (!kobj)
223 		return -ENOENT;
224 
225 	if (!kobj->name || !kobj->name[0]) {
226 		WARN(1,
227 		     "kobject: (%p): attempted to be registered with empty name!\n",
228 		     kobj);
229 		return -EINVAL;
230 	}
231 
232 	parent = kobject_get(kobj->parent);
233 
234 	/* join kset if set, use it as parent if we do not already have one */
235 	if (kobj->kset) {
236 		if (!parent)
237 			parent = kobject_get(&kobj->kset->kobj);
238 		kobj_kset_join(kobj);
239 		kobj->parent = parent;
240 	}
241 
242 	pr_debug("kobject: '%s' (%p): %s: parent: '%s', set: '%s'\n",
243 		 kobject_name(kobj), kobj, __func__,
244 		 parent ? kobject_name(parent) : "<NULL>",
245 		 kobj->kset ? kobject_name(&kobj->kset->kobj) : "<NULL>");
246 
247 	error = create_dir(kobj);
248 	if (error) {
249 		kobj_kset_leave(kobj);
250 		kobject_put(parent);
251 		kobj->parent = NULL;
252 
253 		/* be noisy on error issues */
254 		if (error == -EEXIST)
255 			pr_err("%s failed for %s with -EEXIST, don't try to register things with the same name in the same directory.\n",
256 			       __func__, kobject_name(kobj));
257 		else
258 			pr_err("%s failed for %s (error: %d parent: %s)\n",
259 			       __func__, kobject_name(kobj), error,
260 			       parent ? kobject_name(parent) : "'none'");
261 	} else
262 		kobj->state_in_sysfs = 1;
263 
264 	return error;
265 }
266 
267 /**
268  * kobject_set_name_vargs - Set the name of an kobject
269  * @kobj: struct kobject to set the name of
270  * @fmt: format string used to build the name
271  * @vargs: vargs to format the string.
272  */
kobject_set_name_vargs(struct kobject * kobj,const char * fmt,va_list vargs)273 int kobject_set_name_vargs(struct kobject *kobj, const char *fmt,
274 				  va_list vargs)
275 {
276 	const char *s;
277 
278 	if (kobj->name && !fmt)
279 		return 0;
280 
281 	s = kvasprintf_const(GFP_KERNEL, fmt, vargs);
282 	if (!s)
283 		return -ENOMEM;
284 
285 	/*
286 	 * ewww... some of these buggers have '/' in the name ... If
287 	 * that's the case, we need to make sure we have an actual
288 	 * allocated copy to modify, since kvasprintf_const may have
289 	 * returned something from .rodata.
290 	 */
291 	if (strchr(s, '/')) {
292 		char *t;
293 
294 		t = kstrdup(s, GFP_KERNEL);
295 		kfree_const(s);
296 		if (!t)
297 			return -ENOMEM;
298 		strreplace(t, '/', '!');
299 		s = t;
300 	}
301 	kfree_const(kobj->name);
302 	kobj->name = s;
303 
304 	return 0;
305 }
306 
307 /**
308  * kobject_set_name - Set the name of a kobject
309  * @kobj: struct kobject to set the name of
310  * @fmt: format string used to build the name
311  *
312  * This sets the name of the kobject.  If you have already added the
313  * kobject to the system, you must call kobject_rename() in order to
314  * change the name of the kobject.
315  */
kobject_set_name(struct kobject * kobj,const char * fmt,...)316 int kobject_set_name(struct kobject *kobj, const char *fmt, ...)
317 {
318 	va_list vargs;
319 	int retval;
320 
321 	va_start(vargs, fmt);
322 	retval = kobject_set_name_vargs(kobj, fmt, vargs);
323 	va_end(vargs);
324 
325 	return retval;
326 }
327 EXPORT_SYMBOL(kobject_set_name);
328 
329 /**
330  * kobject_init - initialize a kobject structure
331  * @kobj: pointer to the kobject to initialize
332  * @ktype: pointer to the ktype for this kobject.
333  *
334  * This function will properly initialize a kobject such that it can then
335  * be passed to the kobject_add() call.
336  *
337  * After this function is called, the kobject MUST be cleaned up by a call
338  * to kobject_put(), not by a call to kfree directly to ensure that all of
339  * the memory is cleaned up properly.
340  */
kobject_init(struct kobject * kobj,struct kobj_type * ktype)341 void kobject_init(struct kobject *kobj, struct kobj_type *ktype)
342 {
343 	char *err_str;
344 
345 	if (!kobj) {
346 		err_str = "invalid kobject pointer!";
347 		goto error;
348 	}
349 	if (!ktype) {
350 		err_str = "must have a ktype to be initialized properly!\n";
351 		goto error;
352 	}
353 	if (kobj->state_initialized) {
354 		/* do not error out as sometimes we can recover */
355 		pr_err("kobject (%p): tried to init an initialized object, something is seriously wrong.\n",
356 		       kobj);
357 		dump_stack();
358 	}
359 
360 	kobject_init_internal(kobj);
361 	kobj->ktype = ktype;
362 	return;
363 
364 error:
365 	pr_err("kobject (%p): %s\n", kobj, err_str);
366 	dump_stack();
367 }
368 EXPORT_SYMBOL(kobject_init);
369 
kobject_add_varg(struct kobject * kobj,struct kobject * parent,const char * fmt,va_list vargs)370 static __printf(3, 0) int kobject_add_varg(struct kobject *kobj,
371 					   struct kobject *parent,
372 					   const char *fmt, va_list vargs)
373 {
374 	int retval;
375 
376 	retval = kobject_set_name_vargs(kobj, fmt, vargs);
377 	if (retval) {
378 		pr_err("kobject: can not set name properly!\n");
379 		return retval;
380 	}
381 	kobj->parent = parent;
382 	return kobject_add_internal(kobj);
383 }
384 
385 /**
386  * kobject_add - the main kobject add function
387  * @kobj: the kobject to add
388  * @parent: pointer to the parent of the kobject.
389  * @fmt: format to name the kobject with.
390  *
391  * The kobject name is set and added to the kobject hierarchy in this
392  * function.
393  *
394  * If @parent is set, then the parent of the @kobj will be set to it.
395  * If @parent is NULL, then the parent of the @kobj will be set to the
396  * kobject associated with the kset assigned to this kobject.  If no kset
397  * is assigned to the kobject, then the kobject will be located in the
398  * root of the sysfs tree.
399  *
400  * If this function returns an error, kobject_put() must be called to
401  * properly clean up the memory associated with the object.
402  * Under no instance should the kobject that is passed to this function
403  * be directly freed with a call to kfree(), that can leak memory.
404  *
405  * Note, no "add" uevent will be created with this call, the caller should set
406  * up all of the necessary sysfs files for the object and then call
407  * kobject_uevent() with the UEVENT_ADD parameter to ensure that
408  * userspace is properly notified of this kobject's creation.
409  */
kobject_add(struct kobject * kobj,struct kobject * parent,const char * fmt,...)410 int kobject_add(struct kobject *kobj, struct kobject *parent,
411 		const char *fmt, ...)
412 {
413 	va_list args;
414 	int retval;
415 
416 	if (!kobj)
417 		return -EINVAL;
418 
419 	if (!kobj->state_initialized) {
420 		pr_err("kobject '%s' (%p): tried to add an uninitialized object, something is seriously wrong.\n",
421 		       kobject_name(kobj), kobj);
422 		dump_stack();
423 		return -EINVAL;
424 	}
425 	va_start(args, fmt);
426 	retval = kobject_add_varg(kobj, parent, fmt, args);
427 	va_end(args);
428 
429 	return retval;
430 }
431 EXPORT_SYMBOL(kobject_add);
432 
433 /**
434  * kobject_init_and_add - initialize a kobject structure and add it to the kobject hierarchy
435  * @kobj: pointer to the kobject to initialize
436  * @ktype: pointer to the ktype for this kobject.
437  * @parent: pointer to the parent of this kobject.
438  * @fmt: the name of the kobject.
439  *
440  * This function combines the call to kobject_init() and
441  * kobject_add().  The same type of error handling after a call to
442  * kobject_add() and kobject lifetime rules are the same here.
443  */
kobject_init_and_add(struct kobject * kobj,struct kobj_type * ktype,struct kobject * parent,const char * fmt,...)444 int kobject_init_and_add(struct kobject *kobj, struct kobj_type *ktype,
445 			 struct kobject *parent, const char *fmt, ...)
446 {
447 	va_list args;
448 	int retval;
449 
450 	kobject_init(kobj, ktype);
451 
452 	va_start(args, fmt);
453 	retval = kobject_add_varg(kobj, parent, fmt, args);
454 	va_end(args);
455 
456 	return retval;
457 }
458 EXPORT_SYMBOL_GPL(kobject_init_and_add);
459 
460 /**
461  * kobject_rename - change the name of an object
462  * @kobj: object in question.
463  * @new_name: object's new name
464  *
465  * It is the responsibility of the caller to provide mutual
466  * exclusion between two different calls of kobject_rename
467  * on the same kobject and to ensure that new_name is valid and
468  * won't conflict with other kobjects.
469  */
kobject_rename(struct kobject * kobj,const char * new_name)470 int kobject_rename(struct kobject *kobj, const char *new_name)
471 {
472 	int error = 0;
473 	const char *devpath = NULL;
474 	const char *dup_name = NULL, *name;
475 	char *devpath_string = NULL;
476 	char *envp[2];
477 
478 	kobj = kobject_get(kobj);
479 	if (!kobj)
480 		return -EINVAL;
481 	if (!kobj->parent)
482 		return -EINVAL;
483 
484 	devpath = kobject_get_path(kobj, GFP_KERNEL);
485 	if (!devpath) {
486 		error = -ENOMEM;
487 		goto out;
488 	}
489 	devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
490 	if (!devpath_string) {
491 		error = -ENOMEM;
492 		goto out;
493 	}
494 	sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
495 	envp[0] = devpath_string;
496 	envp[1] = NULL;
497 
498 	name = dup_name = kstrdup_const(new_name, GFP_KERNEL);
499 	if (!name) {
500 		error = -ENOMEM;
501 		goto out;
502 	}
503 
504 	error = sysfs_rename_dir_ns(kobj, new_name, kobject_namespace(kobj));
505 	if (error)
506 		goto out;
507 
508 	/* Install the new kobject name */
509 	dup_name = kobj->name;
510 	kobj->name = name;
511 
512 	/* This function is mostly/only used for network interface.
513 	 * Some hotplug package track interfaces by their name and
514 	 * therefore want to know when the name is changed by the user. */
515 	kobject_uevent_env(kobj, KOBJ_MOVE, envp);
516 
517 out:
518 	kfree_const(dup_name);
519 	kfree(devpath_string);
520 	kfree(devpath);
521 	kobject_put(kobj);
522 
523 	return error;
524 }
525 EXPORT_SYMBOL_GPL(kobject_rename);
526 
527 /**
528  * kobject_move - move object to another parent
529  * @kobj: object in question.
530  * @new_parent: object's new parent (can be NULL)
531  */
kobject_move(struct kobject * kobj,struct kobject * new_parent)532 int kobject_move(struct kobject *kobj, struct kobject *new_parent)
533 {
534 	int error;
535 	struct kobject *old_parent;
536 	const char *devpath = NULL;
537 	char *devpath_string = NULL;
538 	char *envp[2];
539 
540 	kobj = kobject_get(kobj);
541 	if (!kobj)
542 		return -EINVAL;
543 	new_parent = kobject_get(new_parent);
544 	if (!new_parent) {
545 		if (kobj->kset)
546 			new_parent = kobject_get(&kobj->kset->kobj);
547 	}
548 
549 	/* old object path */
550 	devpath = kobject_get_path(kobj, GFP_KERNEL);
551 	if (!devpath) {
552 		error = -ENOMEM;
553 		goto out;
554 	}
555 	devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
556 	if (!devpath_string) {
557 		error = -ENOMEM;
558 		goto out;
559 	}
560 	sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
561 	envp[0] = devpath_string;
562 	envp[1] = NULL;
563 	error = sysfs_move_dir_ns(kobj, new_parent, kobject_namespace(kobj));
564 	if (error)
565 		goto out;
566 	old_parent = kobj->parent;
567 	kobj->parent = new_parent;
568 	new_parent = NULL;
569 	kobject_put(old_parent);
570 	kobject_uevent_env(kobj, KOBJ_MOVE, envp);
571 out:
572 	kobject_put(new_parent);
573 	kobject_put(kobj);
574 	kfree(devpath_string);
575 	kfree(devpath);
576 	return error;
577 }
578 EXPORT_SYMBOL_GPL(kobject_move);
579 
580 /**
581  * kobject_del - unlink kobject from hierarchy.
582  * @kobj: object.
583  */
kobject_del(struct kobject * kobj)584 void kobject_del(struct kobject *kobj)
585 {
586 	struct kernfs_node *sd;
587 
588 	if (!kobj)
589 		return;
590 
591 	sd = kobj->sd;
592 	sysfs_remove_dir(kobj);
593 	sysfs_put(sd);
594 
595 	kobj->state_in_sysfs = 0;
596 	kobj_kset_leave(kobj);
597 	kobject_put(kobj->parent);
598 	kobj->parent = NULL;
599 }
600 EXPORT_SYMBOL(kobject_del);
601 
602 /**
603  * kobject_get - increment refcount for object.
604  * @kobj: object.
605  */
kobject_get(struct kobject * kobj)606 struct kobject *kobject_get(struct kobject *kobj)
607 {
608 	if (kobj) {
609 		if (!kobj->state_initialized)
610 			WARN(1, KERN_WARNING
611 				"kobject: '%s' (%p): is not initialized, yet kobject_get() is being called.\n",
612 			     kobject_name(kobj), kobj);
613 		kref_get(&kobj->kref);
614 	}
615 	return kobj;
616 }
617 EXPORT_SYMBOL(kobject_get);
618 
kobject_get_unless_zero(struct kobject * kobj)619 struct kobject * __must_check kobject_get_unless_zero(struct kobject *kobj)
620 {
621 	if (!kobj)
622 		return NULL;
623 	if (!kref_get_unless_zero(&kobj->kref))
624 		kobj = NULL;
625 	return kobj;
626 }
627 EXPORT_SYMBOL(kobject_get_unless_zero);
628 
629 /*
630  * kobject_cleanup - free kobject resources.
631  * @kobj: object to cleanup
632  */
kobject_cleanup(struct kobject * kobj)633 static void kobject_cleanup(struct kobject *kobj)
634 {
635 	struct kobj_type *t = get_ktype(kobj);
636 	const char *name = kobj->name;
637 
638 	pr_debug("kobject: '%s' (%p): %s, parent %p\n",
639 		 kobject_name(kobj), kobj, __func__, kobj->parent);
640 
641 	if (t && !t->release)
642 		pr_debug("kobject: '%s' (%p): does not have a release() function, it is broken and must be fixed.\n",
643 			 kobject_name(kobj), kobj);
644 
645 	/* send "remove" if the caller did not do it but sent "add" */
646 	if (kobj->state_add_uevent_sent && !kobj->state_remove_uevent_sent) {
647 		pr_debug("kobject: '%s' (%p): auto cleanup 'remove' event\n",
648 			 kobject_name(kobj), kobj);
649 		kobject_uevent(kobj, KOBJ_REMOVE);
650 	}
651 
652 	/* remove from sysfs if the caller did not do it */
653 	if (kobj->state_in_sysfs) {
654 		pr_debug("kobject: '%s' (%p): auto cleanup kobject_del\n",
655 			 kobject_name(kobj), kobj);
656 		kobject_del(kobj);
657 	}
658 
659 	if (t && t->release) {
660 		pr_debug("kobject: '%s' (%p): calling ktype release\n",
661 			 kobject_name(kobj), kobj);
662 		t->release(kobj);
663 	}
664 
665 	/* free name if we allocated it */
666 	if (name) {
667 		pr_debug("kobject: '%s': free name\n", name);
668 		kfree_const(name);
669 	}
670 }
671 
672 #ifdef CONFIG_DEBUG_KOBJECT_RELEASE
kobject_delayed_cleanup(struct work_struct * work)673 static void kobject_delayed_cleanup(struct work_struct *work)
674 {
675 	kobject_cleanup(container_of(to_delayed_work(work),
676 				     struct kobject, release));
677 }
678 #endif
679 
kobject_release(struct kref * kref)680 static void kobject_release(struct kref *kref)
681 {
682 	struct kobject *kobj = container_of(kref, struct kobject, kref);
683 #ifdef CONFIG_DEBUG_KOBJECT_RELEASE
684 	unsigned long delay = HZ + HZ * (get_random_int() & 0x3);
685 	pr_info("kobject: '%s' (%p): %s, parent %p (delayed %ld)\n",
686 		 kobject_name(kobj), kobj, __func__, kobj->parent, delay);
687 	INIT_DELAYED_WORK(&kobj->release, kobject_delayed_cleanup);
688 
689 	schedule_delayed_work(&kobj->release, delay);
690 #else
691 	kobject_cleanup(kobj);
692 #endif
693 }
694 
695 /**
696  * kobject_put - decrement refcount for object.
697  * @kobj: object.
698  *
699  * Decrement the refcount, and if 0, call kobject_cleanup().
700  */
kobject_put(struct kobject * kobj)701 void kobject_put(struct kobject *kobj)
702 {
703 	if (kobj) {
704 		if (!kobj->state_initialized)
705 			WARN(1, KERN_WARNING
706 				"kobject: '%s' (%p): is not initialized, yet kobject_put() is being called.\n",
707 			     kobject_name(kobj), kobj);
708 		kref_put(&kobj->kref, kobject_release);
709 	}
710 }
711 EXPORT_SYMBOL(kobject_put);
712 
dynamic_kobj_release(struct kobject * kobj)713 static void dynamic_kobj_release(struct kobject *kobj)
714 {
715 	pr_debug("kobject: (%p): %s\n", kobj, __func__);
716 	kfree(kobj);
717 }
718 
719 static struct kobj_type dynamic_kobj_ktype = {
720 	.release	= dynamic_kobj_release,
721 	.sysfs_ops	= &kobj_sysfs_ops,
722 };
723 
724 /**
725  * kobject_create - create a struct kobject dynamically
726  *
727  * This function creates a kobject structure dynamically and sets it up
728  * to be a "dynamic" kobject with a default release function set up.
729  *
730  * If the kobject was not able to be created, NULL will be returned.
731  * The kobject structure returned from here must be cleaned up with a
732  * call to kobject_put() and not kfree(), as kobject_init() has
733  * already been called on this structure.
734  */
kobject_create(void)735 struct kobject *kobject_create(void)
736 {
737 	struct kobject *kobj;
738 
739 	kobj = kzalloc(sizeof(*kobj), GFP_KERNEL);
740 	if (!kobj)
741 		return NULL;
742 
743 	kobject_init(kobj, &dynamic_kobj_ktype);
744 	return kobj;
745 }
746 
747 /**
748  * kobject_create_and_add - create a struct kobject dynamically and register it with sysfs
749  *
750  * @name: the name for the kobject
751  * @parent: the parent kobject of this kobject, if any.
752  *
753  * This function creates a kobject structure dynamically and registers it
754  * with sysfs.  When you are finished with this structure, call
755  * kobject_put() and the structure will be dynamically freed when
756  * it is no longer being used.
757  *
758  * If the kobject was not able to be created, NULL will be returned.
759  */
kobject_create_and_add(const char * name,struct kobject * parent)760 struct kobject *kobject_create_and_add(const char *name, struct kobject *parent)
761 {
762 	struct kobject *kobj;
763 	int retval;
764 
765 	kobj = kobject_create();
766 	if (!kobj)
767 		return NULL;
768 
769 	retval = kobject_add(kobj, parent, "%s", name);
770 	if (retval) {
771 		pr_warn("%s: kobject_add error: %d\n", __func__, retval);
772 		kobject_put(kobj);
773 		kobj = NULL;
774 	}
775 	return kobj;
776 }
777 EXPORT_SYMBOL_GPL(kobject_create_and_add);
778 
779 /**
780  * kset_init - initialize a kset for use
781  * @k: kset
782  */
kset_init(struct kset * k)783 void kset_init(struct kset *k)
784 {
785 	kobject_init_internal(&k->kobj);
786 	INIT_LIST_HEAD(&k->list);
787 	spin_lock_init(&k->list_lock);
788 }
789 
790 /* default kobject attribute operations */
kobj_attr_show(struct kobject * kobj,struct attribute * attr,char * buf)791 static ssize_t kobj_attr_show(struct kobject *kobj, struct attribute *attr,
792 			      char *buf)
793 {
794 	struct kobj_attribute *kattr;
795 	ssize_t ret = -EIO;
796 
797 	kattr = container_of(attr, struct kobj_attribute, attr);
798 	if (kattr->show)
799 		ret = kattr->show(kobj, kattr, buf);
800 	return ret;
801 }
802 
kobj_attr_store(struct kobject * kobj,struct attribute * attr,const char * buf,size_t count)803 static ssize_t kobj_attr_store(struct kobject *kobj, struct attribute *attr,
804 			       const char *buf, size_t count)
805 {
806 	struct kobj_attribute *kattr;
807 	ssize_t ret = -EIO;
808 
809 	kattr = container_of(attr, struct kobj_attribute, attr);
810 	if (kattr->store)
811 		ret = kattr->store(kobj, kattr, buf, count);
812 	return ret;
813 }
814 
815 const struct sysfs_ops kobj_sysfs_ops = {
816 	.show	= kobj_attr_show,
817 	.store	= kobj_attr_store,
818 };
819 EXPORT_SYMBOL_GPL(kobj_sysfs_ops);
820 
821 /**
822  * kset_register - initialize and add a kset.
823  * @k: kset.
824  */
kset_register(struct kset * k)825 int kset_register(struct kset *k)
826 {
827 	int err;
828 
829 	if (!k)
830 		return -EINVAL;
831 
832 	if (!k->kobj.ktype) {
833 		pr_err("must have a ktype to be initialized properly!\n");
834 		return -EINVAL;
835 	}
836 
837 	kset_init(k);
838 	err = kobject_add_internal(&k->kobj);
839 	if (err)
840 		return err;
841 	kobject_uevent(&k->kobj, KOBJ_ADD);
842 	return 0;
843 }
844 EXPORT_SYMBOL(kset_register);
845 
846 /**
847  * kset_unregister - remove a kset.
848  * @k: kset.
849  */
kset_unregister(struct kset * k)850 void kset_unregister(struct kset *k)
851 {
852 	if (!k)
853 		return;
854 	kobject_del(&k->kobj);
855 	kobject_put(&k->kobj);
856 }
857 EXPORT_SYMBOL(kset_unregister);
858 
859 /**
860  * kset_find_obj - search for object in kset.
861  * @kset: kset we're looking in.
862  * @name: object's name.
863  *
864  * Lock kset via @kset->subsys, and iterate over @kset->list,
865  * looking for a matching kobject. If matching object is found
866  * take a reference and return the object.
867  */
kset_find_obj(struct kset * kset,const char * name)868 struct kobject *kset_find_obj(struct kset *kset, const char *name)
869 {
870 	struct kobject *k;
871 	struct kobject *ret = NULL;
872 
873 	spin_lock(&kset->list_lock);
874 
875 	list_for_each_entry(k, &kset->list, entry) {
876 		if (kobject_name(k) && !strcmp(kobject_name(k), name)) {
877 			ret = kobject_get_unless_zero(k);
878 			break;
879 		}
880 	}
881 
882 	spin_unlock(&kset->list_lock);
883 	return ret;
884 }
885 EXPORT_SYMBOL_GPL(kset_find_obj);
886 
kset_release(struct kobject * kobj)887 static void kset_release(struct kobject *kobj)
888 {
889 	struct kset *kset = container_of(kobj, struct kset, kobj);
890 	pr_debug("kobject: '%s' (%p): %s\n",
891 		 kobject_name(kobj), kobj, __func__);
892 	kfree(kset);
893 }
894 
kset_get_ownership(struct kobject * kobj,kuid_t * uid,kgid_t * gid)895 void kset_get_ownership(struct kobject *kobj, kuid_t *uid, kgid_t *gid)
896 {
897 	if (kobj->parent)
898 		kobject_get_ownership(kobj->parent, uid, gid);
899 }
900 
901 static struct kobj_type kset_ktype = {
902 	.sysfs_ops	= &kobj_sysfs_ops,
903 	.release	= kset_release,
904 	.get_ownership	= kset_get_ownership,
905 };
906 
907 /**
908  * kset_create - create a struct kset dynamically
909  *
910  * @name: the name for the kset
911  * @uevent_ops: a struct kset_uevent_ops for the kset
912  * @parent_kobj: the parent kobject of this kset, if any.
913  *
914  * This function creates a kset structure dynamically.  This structure can
915  * then be registered with the system and show up in sysfs with a call to
916  * kset_register().  When you are finished with this structure, if
917  * kset_register() has been called, call kset_unregister() and the
918  * structure will be dynamically freed when it is no longer being used.
919  *
920  * If the kset was not able to be created, NULL will be returned.
921  */
kset_create(const char * name,const struct kset_uevent_ops * uevent_ops,struct kobject * parent_kobj)922 static struct kset *kset_create(const char *name,
923 				const struct kset_uevent_ops *uevent_ops,
924 				struct kobject *parent_kobj)
925 {
926 	struct kset *kset;
927 	int retval;
928 
929 	kset = kzalloc(sizeof(*kset), GFP_KERNEL);
930 	if (!kset)
931 		return NULL;
932 	retval = kobject_set_name(&kset->kobj, "%s", name);
933 	if (retval) {
934 		kfree(kset);
935 		return NULL;
936 	}
937 	kset->uevent_ops = uevent_ops;
938 	kset->kobj.parent = parent_kobj;
939 
940 	/*
941 	 * The kobject of this kset will have a type of kset_ktype and belong to
942 	 * no kset itself.  That way we can properly free it when it is
943 	 * finished being used.
944 	 */
945 	kset->kobj.ktype = &kset_ktype;
946 	kset->kobj.kset = NULL;
947 
948 	return kset;
949 }
950 
951 /**
952  * kset_create_and_add - create a struct kset dynamically and add it to sysfs
953  *
954  * @name: the name for the kset
955  * @uevent_ops: a struct kset_uevent_ops for the kset
956  * @parent_kobj: the parent kobject of this kset, if any.
957  *
958  * This function creates a kset structure dynamically and registers it
959  * with sysfs.  When you are finished with this structure, call
960  * kset_unregister() and the structure will be dynamically freed when it
961  * is no longer being used.
962  *
963  * If the kset was not able to be created, NULL will be returned.
964  */
kset_create_and_add(const char * name,const struct kset_uevent_ops * uevent_ops,struct kobject * parent_kobj)965 struct kset *kset_create_and_add(const char *name,
966 				 const struct kset_uevent_ops *uevent_ops,
967 				 struct kobject *parent_kobj)
968 {
969 	struct kset *kset;
970 	int error;
971 
972 	kset = kset_create(name, uevent_ops, parent_kobj);
973 	if (!kset)
974 		return NULL;
975 	error = kset_register(kset);
976 	if (error) {
977 		kfree(kset);
978 		return NULL;
979 	}
980 	return kset;
981 }
982 EXPORT_SYMBOL_GPL(kset_create_and_add);
983 
984 
985 static DEFINE_SPINLOCK(kobj_ns_type_lock);
986 static const struct kobj_ns_type_operations *kobj_ns_ops_tbl[KOBJ_NS_TYPES];
987 
kobj_ns_type_register(const struct kobj_ns_type_operations * ops)988 int kobj_ns_type_register(const struct kobj_ns_type_operations *ops)
989 {
990 	enum kobj_ns_type type = ops->type;
991 	int error;
992 
993 	spin_lock(&kobj_ns_type_lock);
994 
995 	error = -EINVAL;
996 	if (type >= KOBJ_NS_TYPES)
997 		goto out;
998 
999 	error = -EINVAL;
1000 	if (type <= KOBJ_NS_TYPE_NONE)
1001 		goto out;
1002 
1003 	error = -EBUSY;
1004 	if (kobj_ns_ops_tbl[type])
1005 		goto out;
1006 
1007 	error = 0;
1008 	kobj_ns_ops_tbl[type] = ops;
1009 
1010 out:
1011 	spin_unlock(&kobj_ns_type_lock);
1012 	return error;
1013 }
1014 
kobj_ns_type_registered(enum kobj_ns_type type)1015 int kobj_ns_type_registered(enum kobj_ns_type type)
1016 {
1017 	int registered = 0;
1018 
1019 	spin_lock(&kobj_ns_type_lock);
1020 	if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES))
1021 		registered = kobj_ns_ops_tbl[type] != NULL;
1022 	spin_unlock(&kobj_ns_type_lock);
1023 
1024 	return registered;
1025 }
1026 
kobj_child_ns_ops(struct kobject * parent)1027 const struct kobj_ns_type_operations *kobj_child_ns_ops(struct kobject *parent)
1028 {
1029 	const struct kobj_ns_type_operations *ops = NULL;
1030 
1031 	if (parent && parent->ktype && parent->ktype->child_ns_type)
1032 		ops = parent->ktype->child_ns_type(parent);
1033 
1034 	return ops;
1035 }
1036 
kobj_ns_ops(struct kobject * kobj)1037 const struct kobj_ns_type_operations *kobj_ns_ops(struct kobject *kobj)
1038 {
1039 	return kobj_child_ns_ops(kobj->parent);
1040 }
1041 
kobj_ns_current_may_mount(enum kobj_ns_type type)1042 bool kobj_ns_current_may_mount(enum kobj_ns_type type)
1043 {
1044 	bool may_mount = true;
1045 
1046 	spin_lock(&kobj_ns_type_lock);
1047 	if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1048 	    kobj_ns_ops_tbl[type])
1049 		may_mount = kobj_ns_ops_tbl[type]->current_may_mount();
1050 	spin_unlock(&kobj_ns_type_lock);
1051 
1052 	return may_mount;
1053 }
1054 
kobj_ns_grab_current(enum kobj_ns_type type)1055 void *kobj_ns_grab_current(enum kobj_ns_type type)
1056 {
1057 	void *ns = NULL;
1058 
1059 	spin_lock(&kobj_ns_type_lock);
1060 	if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1061 	    kobj_ns_ops_tbl[type])
1062 		ns = kobj_ns_ops_tbl[type]->grab_current_ns();
1063 	spin_unlock(&kobj_ns_type_lock);
1064 
1065 	return ns;
1066 }
1067 EXPORT_SYMBOL_GPL(kobj_ns_grab_current);
1068 
kobj_ns_netlink(enum kobj_ns_type type,struct sock * sk)1069 const void *kobj_ns_netlink(enum kobj_ns_type type, struct sock *sk)
1070 {
1071 	const void *ns = NULL;
1072 
1073 	spin_lock(&kobj_ns_type_lock);
1074 	if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1075 	    kobj_ns_ops_tbl[type])
1076 		ns = kobj_ns_ops_tbl[type]->netlink_ns(sk);
1077 	spin_unlock(&kobj_ns_type_lock);
1078 
1079 	return ns;
1080 }
1081 
kobj_ns_initial(enum kobj_ns_type type)1082 const void *kobj_ns_initial(enum kobj_ns_type type)
1083 {
1084 	const void *ns = NULL;
1085 
1086 	spin_lock(&kobj_ns_type_lock);
1087 	if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1088 	    kobj_ns_ops_tbl[type])
1089 		ns = kobj_ns_ops_tbl[type]->initial_ns();
1090 	spin_unlock(&kobj_ns_type_lock);
1091 
1092 	return ns;
1093 }
1094 
kobj_ns_drop(enum kobj_ns_type type,void * ns)1095 void kobj_ns_drop(enum kobj_ns_type type, void *ns)
1096 {
1097 	spin_lock(&kobj_ns_type_lock);
1098 	if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1099 	    kobj_ns_ops_tbl[type] && kobj_ns_ops_tbl[type]->drop_ns)
1100 		kobj_ns_ops_tbl[type]->drop_ns(ns);
1101 	spin_unlock(&kobj_ns_type_lock);
1102 }
1103 EXPORT_SYMBOL_GPL(kobj_ns_drop);
1104