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 
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_type *ktype = get_ktype(kobj);
86 	const struct kobj_ns_type_operations *ops;
87 	int error;
88 
89 	error = sysfs_create_dir_ns(kobj, kobject_namespace(kobj));
90 	if (error)
91 		return error;
92 
93 	error = populate_dir(kobj);
94 	if (error) {
95 		sysfs_remove_dir(kobj);
96 		return error;
97 	}
98 
99 	if (ktype) {
100 		error = sysfs_create_groups(kobj, ktype->default_groups);
101 		if (error) {
102 			sysfs_remove_dir(kobj);
103 			return error;
104 		}
105 	}
106 
107 	/*
108 	 * @kobj->sd may be deleted by an ancestor going away.  Hold an
109 	 * extra reference so that it stays until @kobj is gone.
110 	 */
111 	sysfs_get(kobj->sd);
112 
113 	/*
114 	 * If @kobj has ns_ops, its children need to be filtered based on
115 	 * their namespace tags.  Enable namespace support on @kobj->sd.
116 	 */
117 	ops = kobj_child_ns_ops(kobj);
118 	if (ops) {
119 		BUG_ON(ops->type <= KOBJ_NS_TYPE_NONE);
120 		BUG_ON(ops->type >= KOBJ_NS_TYPES);
121 		BUG_ON(!kobj_ns_type_registered(ops->type));
122 
123 		sysfs_enable_ns(kobj->sd);
124 	}
125 
126 	return 0;
127 }
128 
get_kobj_path_length(struct kobject * kobj)129 static int get_kobj_path_length(struct kobject *kobj)
130 {
131 	int length = 1;
132 	struct kobject *parent = kobj;
133 
134 	/* walk up the ancestors until we hit the one pointing to the
135 	 * root.
136 	 * Add 1 to strlen for leading '/' of each level.
137 	 */
138 	do {
139 		if (kobject_name(parent) == NULL)
140 			return 0;
141 		length += strlen(kobject_name(parent)) + 1;
142 		parent = parent->parent;
143 	} while (parent);
144 	return length;
145 }
146 
fill_kobj_path(struct kobject * kobj,char * path,int length)147 static void fill_kobj_path(struct kobject *kobj, char *path, int length)
148 {
149 	struct kobject *parent;
150 
151 	--length;
152 	for (parent = kobj; parent; parent = parent->parent) {
153 		int cur = strlen(kobject_name(parent));
154 		/* back up enough to print this name with '/' */
155 		length -= cur;
156 		memcpy(path + length, kobject_name(parent), cur);
157 		*(path + --length) = '/';
158 	}
159 
160 	pr_debug("kobject: '%s' (%p): %s: path = '%s'\n", kobject_name(kobj),
161 		 kobj, __func__, path);
162 }
163 
164 /**
165  * kobject_get_path() - Allocate memory and fill in the path for @kobj.
166  * @kobj:	kobject in question, with which to build the path
167  * @gfp_mask:	the allocation type used to allocate the path
168  *
169  * Return: The newly allocated memory, caller must free with kfree().
170  */
kobject_get_path(struct kobject * kobj,gfp_t gfp_mask)171 char *kobject_get_path(struct kobject *kobj, gfp_t gfp_mask)
172 {
173 	char *path;
174 	int len;
175 
176 	len = get_kobj_path_length(kobj);
177 	if (len == 0)
178 		return NULL;
179 	path = kzalloc(len, gfp_mask);
180 	if (!path)
181 		return NULL;
182 	fill_kobj_path(kobj, path, len);
183 
184 	return path;
185 }
186 EXPORT_SYMBOL_GPL(kobject_get_path);
187 
188 /* add the kobject to its kset's list */
kobj_kset_join(struct kobject * kobj)189 static void kobj_kset_join(struct kobject *kobj)
190 {
191 	if (!kobj->kset)
192 		return;
193 
194 	kset_get(kobj->kset);
195 	spin_lock(&kobj->kset->list_lock);
196 	list_add_tail(&kobj->entry, &kobj->kset->list);
197 	spin_unlock(&kobj->kset->list_lock);
198 }
199 
200 /* remove the kobject from its kset's list */
kobj_kset_leave(struct kobject * kobj)201 static void kobj_kset_leave(struct kobject *kobj)
202 {
203 	if (!kobj->kset)
204 		return;
205 
206 	spin_lock(&kobj->kset->list_lock);
207 	list_del_init(&kobj->entry);
208 	spin_unlock(&kobj->kset->list_lock);
209 	kset_put(kobj->kset);
210 }
211 
kobject_init_internal(struct kobject * kobj)212 static void kobject_init_internal(struct kobject *kobj)
213 {
214 	if (!kobj)
215 		return;
216 	kref_init(&kobj->kref);
217 	INIT_LIST_HEAD(&kobj->entry);
218 	kobj->state_in_sysfs = 0;
219 	kobj->state_add_uevent_sent = 0;
220 	kobj->state_remove_uevent_sent = 0;
221 	kobj->state_initialized = 1;
222 }
223 
224 
kobject_add_internal(struct kobject * kobj)225 static int kobject_add_internal(struct kobject *kobj)
226 {
227 	int error = 0;
228 	struct kobject *parent;
229 
230 	if (!kobj)
231 		return -ENOENT;
232 
233 	if (!kobj->name || !kobj->name[0]) {
234 		WARN(1,
235 		     "kobject: (%p): attempted to be registered with empty name!\n",
236 		     kobj);
237 		return -EINVAL;
238 	}
239 
240 	parent = kobject_get(kobj->parent);
241 
242 	/* join kset if set, use it as parent if we do not already have one */
243 	if (kobj->kset) {
244 		if (!parent)
245 			parent = kobject_get(&kobj->kset->kobj);
246 		kobj_kset_join(kobj);
247 		kobj->parent = parent;
248 	}
249 
250 	pr_debug("kobject: '%s' (%p): %s: parent: '%s', set: '%s'\n",
251 		 kobject_name(kobj), kobj, __func__,
252 		 parent ? kobject_name(parent) : "<NULL>",
253 		 kobj->kset ? kobject_name(&kobj->kset->kobj) : "<NULL>");
254 
255 	error = create_dir(kobj);
256 	if (error) {
257 		kobj_kset_leave(kobj);
258 		kobject_put(parent);
259 		kobj->parent = NULL;
260 
261 		/* be noisy on error issues */
262 		if (error == -EEXIST)
263 			pr_err("%s failed for %s with -EEXIST, don't try to register things with the same name in the same directory.\n",
264 			       __func__, kobject_name(kobj));
265 		else
266 			pr_err("%s failed for %s (error: %d parent: %s)\n",
267 			       __func__, kobject_name(kobj), error,
268 			       parent ? kobject_name(parent) : "'none'");
269 	} else
270 		kobj->state_in_sysfs = 1;
271 
272 	return error;
273 }
274 
275 /**
276  * kobject_set_name_vargs() - Set the name of a kobject.
277  * @kobj: struct kobject to set the name of
278  * @fmt: format string used to build the name
279  * @vargs: vargs to format the string.
280  */
kobject_set_name_vargs(struct kobject * kobj,const char * fmt,va_list vargs)281 int kobject_set_name_vargs(struct kobject *kobj, const char *fmt,
282 				  va_list vargs)
283 {
284 	const char *s;
285 
286 	if (kobj->name && !fmt)
287 		return 0;
288 
289 	s = kvasprintf_const(GFP_KERNEL, fmt, vargs);
290 	if (!s)
291 		return -ENOMEM;
292 
293 	/*
294 	 * ewww... some of these buggers have '/' in the name ... If
295 	 * that's the case, we need to make sure we have an actual
296 	 * allocated copy to modify, since kvasprintf_const may have
297 	 * returned something from .rodata.
298 	 */
299 	if (strchr(s, '/')) {
300 		char *t;
301 
302 		t = kstrdup(s, GFP_KERNEL);
303 		kfree_const(s);
304 		if (!t)
305 			return -ENOMEM;
306 		strreplace(t, '/', '!');
307 		s = t;
308 	}
309 	kfree_const(kobj->name);
310 	kobj->name = s;
311 
312 	return 0;
313 }
314 
315 /**
316  * kobject_set_name() - Set the name of a kobject.
317  * @kobj: struct kobject to set the name of
318  * @fmt: format string used to build the name
319  *
320  * This sets the name of the kobject.  If you have already added the
321  * kobject to the system, you must call kobject_rename() in order to
322  * change the name of the kobject.
323  */
kobject_set_name(struct kobject * kobj,const char * fmt,...)324 int kobject_set_name(struct kobject *kobj, const char *fmt, ...)
325 {
326 	va_list vargs;
327 	int retval;
328 
329 	va_start(vargs, fmt);
330 	retval = kobject_set_name_vargs(kobj, fmt, vargs);
331 	va_end(vargs);
332 
333 	return retval;
334 }
335 EXPORT_SYMBOL(kobject_set_name);
336 
337 /**
338  * kobject_init() - Initialize a kobject structure.
339  * @kobj: pointer to the kobject to initialize
340  * @ktype: pointer to the ktype for this kobject.
341  *
342  * This function will properly initialize a kobject such that it can then
343  * be passed to the kobject_add() call.
344  *
345  * After this function is called, the kobject MUST be cleaned up by a call
346  * to kobject_put(), not by a call to kfree directly to ensure that all of
347  * the memory is cleaned up properly.
348  */
kobject_init(struct kobject * kobj,struct kobj_type * ktype)349 void kobject_init(struct kobject *kobj, struct kobj_type *ktype)
350 {
351 	char *err_str;
352 
353 	if (!kobj) {
354 		err_str = "invalid kobject pointer!";
355 		goto error;
356 	}
357 	if (!ktype) {
358 		err_str = "must have a ktype to be initialized properly!\n";
359 		goto error;
360 	}
361 	if (kobj->state_initialized) {
362 		/* do not error out as sometimes we can recover */
363 		pr_err("kobject (%p): tried to init an initialized object, something is seriously wrong.\n",
364 		       kobj);
365 		dump_stack();
366 	}
367 
368 	kobject_init_internal(kobj);
369 	kobj->ktype = ktype;
370 	return;
371 
372 error:
373 	pr_err("kobject (%p): %s\n", kobj, err_str);
374 	dump_stack();
375 }
376 EXPORT_SYMBOL(kobject_init);
377 
kobject_add_varg(struct kobject * kobj,struct kobject * parent,const char * fmt,va_list vargs)378 static __printf(3, 0) int kobject_add_varg(struct kobject *kobj,
379 					   struct kobject *parent,
380 					   const char *fmt, va_list vargs)
381 {
382 	int retval;
383 
384 	retval = kobject_set_name_vargs(kobj, fmt, vargs);
385 	if (retval) {
386 		pr_err("kobject: can not set name properly!\n");
387 		return retval;
388 	}
389 	kobj->parent = parent;
390 	return kobject_add_internal(kobj);
391 }
392 
393 /**
394  * kobject_add() - The main kobject add function.
395  * @kobj: the kobject to add
396  * @parent: pointer to the parent of the kobject.
397  * @fmt: format to name the kobject with.
398  *
399  * The kobject name is set and added to the kobject hierarchy in this
400  * function.
401  *
402  * If @parent is set, then the parent of the @kobj will be set to it.
403  * If @parent is NULL, then the parent of the @kobj will be set to the
404  * kobject associated with the kset assigned to this kobject.  If no kset
405  * is assigned to the kobject, then the kobject will be located in the
406  * root of the sysfs tree.
407  *
408  * Note, no "add" uevent will be created with this call, the caller should set
409  * up all of the necessary sysfs files for the object and then call
410  * kobject_uevent() with the UEVENT_ADD parameter to ensure that
411  * userspace is properly notified of this kobject's creation.
412  *
413  * Return: If this function returns an error, kobject_put() must be
414  *         called to properly clean up the memory associated with the
415  *         object.  Under no instance should the kobject that is passed
416  *         to this function be directly freed with a call to kfree(),
417  *         that can leak memory.
418  *
419  *         If this function returns success, kobject_put() must also be called
420  *         in order to properly clean up the memory associated with the object.
421  *
422  *         In short, once this function is called, kobject_put() MUST be called
423  *         when the use of the object is finished in order to properly free
424  *         everything.
425  */
kobject_add(struct kobject * kobj,struct kobject * parent,const char * fmt,...)426 int kobject_add(struct kobject *kobj, struct kobject *parent,
427 		const char *fmt, ...)
428 {
429 	va_list args;
430 	int retval;
431 
432 	if (!kobj)
433 		return -EINVAL;
434 
435 	if (!kobj->state_initialized) {
436 		pr_err("kobject '%s' (%p): tried to add an uninitialized object, something is seriously wrong.\n",
437 		       kobject_name(kobj), kobj);
438 		dump_stack();
439 		return -EINVAL;
440 	}
441 	va_start(args, fmt);
442 	retval = kobject_add_varg(kobj, parent, fmt, args);
443 	va_end(args);
444 
445 	return retval;
446 }
447 EXPORT_SYMBOL(kobject_add);
448 
449 /**
450  * kobject_init_and_add() - Initialize a kobject structure and add it to
451  *                          the kobject hierarchy.
452  * @kobj: pointer to the kobject to initialize
453  * @ktype: pointer to the ktype for this kobject.
454  * @parent: pointer to the parent of this kobject.
455  * @fmt: the name of the kobject.
456  *
457  * This function combines the call to kobject_init() and kobject_add().
458  *
459  * If this function returns an error, kobject_put() must be called to
460  * properly clean up the memory associated with the object.  This is the
461  * same type of error handling after a call to kobject_add() and kobject
462  * lifetime rules are the same here.
463  */
kobject_init_and_add(struct kobject * kobj,struct kobj_type * ktype,struct kobject * parent,const char * fmt,...)464 int kobject_init_and_add(struct kobject *kobj, struct kobj_type *ktype,
465 			 struct kobject *parent, const char *fmt, ...)
466 {
467 	va_list args;
468 	int retval;
469 
470 	kobject_init(kobj, ktype);
471 
472 	va_start(args, fmt);
473 	retval = kobject_add_varg(kobj, parent, fmt, args);
474 	va_end(args);
475 
476 	return retval;
477 }
478 EXPORT_SYMBOL_GPL(kobject_init_and_add);
479 
480 /**
481  * kobject_rename() - Change the name of an object.
482  * @kobj: object in question.
483  * @new_name: object's new name
484  *
485  * It is the responsibility of the caller to provide mutual
486  * exclusion between two different calls of kobject_rename
487  * on the same kobject and to ensure that new_name is valid and
488  * won't conflict with other kobjects.
489  */
kobject_rename(struct kobject * kobj,const char * new_name)490 int kobject_rename(struct kobject *kobj, const char *new_name)
491 {
492 	int error = 0;
493 	const char *devpath = NULL;
494 	const char *dup_name = NULL, *name;
495 	char *devpath_string = NULL;
496 	char *envp[2];
497 
498 	kobj = kobject_get(kobj);
499 	if (!kobj)
500 		return -EINVAL;
501 	if (!kobj->parent) {
502 		kobject_put(kobj);
503 		return -EINVAL;
504 	}
505 
506 	devpath = kobject_get_path(kobj, GFP_KERNEL);
507 	if (!devpath) {
508 		error = -ENOMEM;
509 		goto out;
510 	}
511 	devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
512 	if (!devpath_string) {
513 		error = -ENOMEM;
514 		goto out;
515 	}
516 	sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
517 	envp[0] = devpath_string;
518 	envp[1] = NULL;
519 
520 	name = dup_name = kstrdup_const(new_name, GFP_KERNEL);
521 	if (!name) {
522 		error = -ENOMEM;
523 		goto out;
524 	}
525 
526 	error = sysfs_rename_dir_ns(kobj, new_name, kobject_namespace(kobj));
527 	if (error)
528 		goto out;
529 
530 	/* Install the new kobject name */
531 	dup_name = kobj->name;
532 	kobj->name = name;
533 
534 	/* This function is mostly/only used for network interface.
535 	 * Some hotplug package track interfaces by their name and
536 	 * therefore want to know when the name is changed by the user. */
537 	kobject_uevent_env(kobj, KOBJ_MOVE, envp);
538 
539 out:
540 	kfree_const(dup_name);
541 	kfree(devpath_string);
542 	kfree(devpath);
543 	kobject_put(kobj);
544 
545 	return error;
546 }
547 EXPORT_SYMBOL_GPL(kobject_rename);
548 
549 /**
550  * kobject_move() - Move object to another parent.
551  * @kobj: object in question.
552  * @new_parent: object's new parent (can be NULL)
553  */
kobject_move(struct kobject * kobj,struct kobject * new_parent)554 int kobject_move(struct kobject *kobj, struct kobject *new_parent)
555 {
556 	int error;
557 	struct kobject *old_parent;
558 	const char *devpath = NULL;
559 	char *devpath_string = NULL;
560 	char *envp[2];
561 
562 	kobj = kobject_get(kobj);
563 	if (!kobj)
564 		return -EINVAL;
565 	new_parent = kobject_get(new_parent);
566 	if (!new_parent) {
567 		if (kobj->kset)
568 			new_parent = kobject_get(&kobj->kset->kobj);
569 	}
570 
571 	/* old object path */
572 	devpath = kobject_get_path(kobj, GFP_KERNEL);
573 	if (!devpath) {
574 		error = -ENOMEM;
575 		goto out;
576 	}
577 	devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
578 	if (!devpath_string) {
579 		error = -ENOMEM;
580 		goto out;
581 	}
582 	sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
583 	envp[0] = devpath_string;
584 	envp[1] = NULL;
585 	error = sysfs_move_dir_ns(kobj, new_parent, kobject_namespace(kobj));
586 	if (error)
587 		goto out;
588 	old_parent = kobj->parent;
589 	kobj->parent = new_parent;
590 	new_parent = NULL;
591 	kobject_put(old_parent);
592 	kobject_uevent_env(kobj, KOBJ_MOVE, envp);
593 out:
594 	kobject_put(new_parent);
595 	kobject_put(kobj);
596 	kfree(devpath_string);
597 	kfree(devpath);
598 	return error;
599 }
600 EXPORT_SYMBOL_GPL(kobject_move);
601 
__kobject_del(struct kobject * kobj)602 static void __kobject_del(struct kobject *kobj)
603 {
604 	struct kernfs_node *sd;
605 	const struct kobj_type *ktype;
606 
607 	sd = kobj->sd;
608 	ktype = get_ktype(kobj);
609 
610 	if (ktype)
611 		sysfs_remove_groups(kobj, ktype->default_groups);
612 
613 	/* send "remove" if the caller did not do it but sent "add" */
614 	if (kobj->state_add_uevent_sent && !kobj->state_remove_uevent_sent) {
615 		pr_debug("kobject: '%s' (%p): auto cleanup 'remove' event\n",
616 			 kobject_name(kobj), kobj);
617 		kobject_uevent(kobj, KOBJ_REMOVE);
618 	}
619 
620 	sysfs_remove_dir(kobj);
621 	sysfs_put(sd);
622 
623 	kobj->state_in_sysfs = 0;
624 	kobj_kset_leave(kobj);
625 	kobj->parent = NULL;
626 }
627 
628 /**
629  * kobject_del() - Unlink kobject from hierarchy.
630  * @kobj: object.
631  *
632  * This is the function that should be called to delete an object
633  * successfully added via kobject_add().
634  */
kobject_del(struct kobject * kobj)635 void kobject_del(struct kobject *kobj)
636 {
637 	struct kobject *parent;
638 
639 	if (!kobj)
640 		return;
641 
642 	parent = kobj->parent;
643 	__kobject_del(kobj);
644 	kobject_put(parent);
645 }
646 EXPORT_SYMBOL(kobject_del);
647 
648 /**
649  * kobject_get() - Increment refcount for object.
650  * @kobj: object.
651  */
kobject_get(struct kobject * kobj)652 struct kobject *kobject_get(struct kobject *kobj)
653 {
654 	if (kobj) {
655 		if (!kobj->state_initialized)
656 			WARN(1, KERN_WARNING
657 				"kobject: '%s' (%p): is not initialized, yet kobject_get() is being called.\n",
658 			     kobject_name(kobj), kobj);
659 		kref_get(&kobj->kref);
660 	}
661 	return kobj;
662 }
663 EXPORT_SYMBOL(kobject_get);
664 
kobject_get_unless_zero(struct kobject * kobj)665 struct kobject * __must_check kobject_get_unless_zero(struct kobject *kobj)
666 {
667 	if (!kobj)
668 		return NULL;
669 	if (!kref_get_unless_zero(&kobj->kref))
670 		kobj = NULL;
671 	return kobj;
672 }
673 EXPORT_SYMBOL(kobject_get_unless_zero);
674 
675 /*
676  * kobject_cleanup - free kobject resources.
677  * @kobj: object to cleanup
678  */
kobject_cleanup(struct kobject * kobj)679 static void kobject_cleanup(struct kobject *kobj)
680 {
681 	struct kobject *parent = kobj->parent;
682 	struct kobj_type *t = get_ktype(kobj);
683 	const char *name = kobj->name;
684 
685 	pr_debug("kobject: '%s' (%p): %s, parent %p\n",
686 		 kobject_name(kobj), kobj, __func__, kobj->parent);
687 
688 	if (t && !t->release)
689 		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",
690 			 kobject_name(kobj), kobj);
691 
692 	/* remove from sysfs if the caller did not do it */
693 	if (kobj->state_in_sysfs) {
694 		pr_debug("kobject: '%s' (%p): auto cleanup kobject_del\n",
695 			 kobject_name(kobj), kobj);
696 		__kobject_del(kobj);
697 	} else {
698 		/* avoid dropping the parent reference unnecessarily */
699 		parent = NULL;
700 	}
701 
702 	if (t && t->release) {
703 		pr_debug("kobject: '%s' (%p): calling ktype release\n",
704 			 kobject_name(kobj), kobj);
705 		t->release(kobj);
706 	}
707 
708 	/* free name if we allocated it */
709 	if (name) {
710 		pr_debug("kobject: '%s': free name\n", name);
711 		kfree_const(name);
712 	}
713 
714 	kobject_put(parent);
715 }
716 
717 #ifdef CONFIG_DEBUG_KOBJECT_RELEASE
kobject_delayed_cleanup(struct work_struct * work)718 static void kobject_delayed_cleanup(struct work_struct *work)
719 {
720 	kobject_cleanup(container_of(to_delayed_work(work),
721 				     struct kobject, release));
722 }
723 #endif
724 
kobject_release(struct kref * kref)725 static void kobject_release(struct kref *kref)
726 {
727 	struct kobject *kobj = container_of(kref, struct kobject, kref);
728 #ifdef CONFIG_DEBUG_KOBJECT_RELEASE
729 	unsigned long delay = HZ + HZ * (get_random_int() & 0x3);
730 	pr_info("kobject: '%s' (%p): %s, parent %p (delayed %ld)\n",
731 		 kobject_name(kobj), kobj, __func__, kobj->parent, delay);
732 	INIT_DELAYED_WORK(&kobj->release, kobject_delayed_cleanup);
733 
734 	schedule_delayed_work(&kobj->release, delay);
735 #else
736 	kobject_cleanup(kobj);
737 #endif
738 }
739 
740 /**
741  * kobject_put() - Decrement refcount for object.
742  * @kobj: object.
743  *
744  * Decrement the refcount, and if 0, call kobject_cleanup().
745  */
kobject_put(struct kobject * kobj)746 void kobject_put(struct kobject *kobj)
747 {
748 	if (kobj) {
749 		if (!kobj->state_initialized)
750 			WARN(1, KERN_WARNING
751 				"kobject: '%s' (%p): is not initialized, yet kobject_put() is being called.\n",
752 			     kobject_name(kobj), kobj);
753 		kref_put(&kobj->kref, kobject_release);
754 	}
755 }
756 EXPORT_SYMBOL(kobject_put);
757 
dynamic_kobj_release(struct kobject * kobj)758 static void dynamic_kobj_release(struct kobject *kobj)
759 {
760 	pr_debug("kobject: (%p): %s\n", kobj, __func__);
761 	kfree(kobj);
762 }
763 
764 static struct kobj_type dynamic_kobj_ktype = {
765 	.release	= dynamic_kobj_release,
766 	.sysfs_ops	= &kobj_sysfs_ops,
767 };
768 
769 /**
770  * kobject_create() - Create a struct kobject dynamically.
771  *
772  * This function creates a kobject structure dynamically and sets it up
773  * to be a "dynamic" kobject with a default release function set up.
774  *
775  * If the kobject was not able to be created, NULL will be returned.
776  * The kobject structure returned from here must be cleaned up with a
777  * call to kobject_put() and not kfree(), as kobject_init() has
778  * already been called on this structure.
779  */
kobject_create(void)780 static struct kobject *kobject_create(void)
781 {
782 	struct kobject *kobj;
783 
784 	kobj = kzalloc(sizeof(*kobj), GFP_KERNEL);
785 	if (!kobj)
786 		return NULL;
787 
788 	kobject_init(kobj, &dynamic_kobj_ktype);
789 	return kobj;
790 }
791 
792 /**
793  * kobject_create_and_add() - Create a struct kobject dynamically and
794  *                            register it with sysfs.
795  * @name: the name for the kobject
796  * @parent: the parent kobject of this kobject, if any.
797  *
798  * This function creates a kobject structure dynamically and registers it
799  * with sysfs.  When you are finished with this structure, call
800  * kobject_put() and the structure will be dynamically freed when
801  * it is no longer being used.
802  *
803  * If the kobject was not able to be created, NULL will be returned.
804  */
kobject_create_and_add(const char * name,struct kobject * parent)805 struct kobject *kobject_create_and_add(const char *name, struct kobject *parent)
806 {
807 	struct kobject *kobj;
808 	int retval;
809 
810 	kobj = kobject_create();
811 	if (!kobj)
812 		return NULL;
813 
814 	retval = kobject_add(kobj, parent, "%s", name);
815 	if (retval) {
816 		pr_warn("%s: kobject_add error: %d\n", __func__, retval);
817 		kobject_put(kobj);
818 		kobj = NULL;
819 	}
820 	return kobj;
821 }
822 EXPORT_SYMBOL_GPL(kobject_create_and_add);
823 
824 /**
825  * kset_init() - Initialize a kset for use.
826  * @k: kset
827  */
kset_init(struct kset * k)828 void kset_init(struct kset *k)
829 {
830 	kobject_init_internal(&k->kobj);
831 	INIT_LIST_HEAD(&k->list);
832 	spin_lock_init(&k->list_lock);
833 }
834 
835 /* default kobject attribute operations */
kobj_attr_show(struct kobject * kobj,struct attribute * attr,char * buf)836 static ssize_t kobj_attr_show(struct kobject *kobj, struct attribute *attr,
837 			      char *buf)
838 {
839 	struct kobj_attribute *kattr;
840 	ssize_t ret = -EIO;
841 
842 	kattr = container_of(attr, struct kobj_attribute, attr);
843 	if (kattr->show)
844 		ret = kattr->show(kobj, kattr, buf);
845 	return ret;
846 }
847 
kobj_attr_store(struct kobject * kobj,struct attribute * attr,const char * buf,size_t count)848 static ssize_t kobj_attr_store(struct kobject *kobj, struct attribute *attr,
849 			       const char *buf, size_t count)
850 {
851 	struct kobj_attribute *kattr;
852 	ssize_t ret = -EIO;
853 
854 	kattr = container_of(attr, struct kobj_attribute, attr);
855 	if (kattr->store)
856 		ret = kattr->store(kobj, kattr, buf, count);
857 	return ret;
858 }
859 
860 const struct sysfs_ops kobj_sysfs_ops = {
861 	.show	= kobj_attr_show,
862 	.store	= kobj_attr_store,
863 };
864 EXPORT_SYMBOL_GPL(kobj_sysfs_ops);
865 
866 /**
867  * kset_register() - Initialize and add a kset.
868  * @k: kset.
869  */
kset_register(struct kset * k)870 int kset_register(struct kset *k)
871 {
872 	int err;
873 
874 	if (!k)
875 		return -EINVAL;
876 
877 	kset_init(k);
878 	err = kobject_add_internal(&k->kobj);
879 	if (err)
880 		return err;
881 	kobject_uevent(&k->kobj, KOBJ_ADD);
882 	return 0;
883 }
884 EXPORT_SYMBOL(kset_register);
885 
886 /**
887  * kset_unregister() - Remove a kset.
888  * @k: kset.
889  */
kset_unregister(struct kset * k)890 void kset_unregister(struct kset *k)
891 {
892 	if (!k)
893 		return;
894 	kobject_del(&k->kobj);
895 	kobject_put(&k->kobj);
896 }
897 EXPORT_SYMBOL(kset_unregister);
898 
899 /**
900  * kset_find_obj() - Search for object in kset.
901  * @kset: kset we're looking in.
902  * @name: object's name.
903  *
904  * Lock kset via @kset->subsys, and iterate over @kset->list,
905  * looking for a matching kobject. If matching object is found
906  * take a reference and return the object.
907  */
kset_find_obj(struct kset * kset,const char * name)908 struct kobject *kset_find_obj(struct kset *kset, const char *name)
909 {
910 	struct kobject *k;
911 	struct kobject *ret = NULL;
912 
913 	spin_lock(&kset->list_lock);
914 
915 	list_for_each_entry(k, &kset->list, entry) {
916 		if (kobject_name(k) && !strcmp(kobject_name(k), name)) {
917 			ret = kobject_get_unless_zero(k);
918 			break;
919 		}
920 	}
921 
922 	spin_unlock(&kset->list_lock);
923 	return ret;
924 }
925 EXPORT_SYMBOL_GPL(kset_find_obj);
926 
kset_release(struct kobject * kobj)927 static void kset_release(struct kobject *kobj)
928 {
929 	struct kset *kset = container_of(kobj, struct kset, kobj);
930 	pr_debug("kobject: '%s' (%p): %s\n",
931 		 kobject_name(kobj), kobj, __func__);
932 	kfree(kset);
933 }
934 
kset_get_ownership(struct kobject * kobj,kuid_t * uid,kgid_t * gid)935 static void kset_get_ownership(struct kobject *kobj, kuid_t *uid, kgid_t *gid)
936 {
937 	if (kobj->parent)
938 		kobject_get_ownership(kobj->parent, uid, gid);
939 }
940 
941 static struct kobj_type kset_ktype = {
942 	.sysfs_ops	= &kobj_sysfs_ops,
943 	.release	= kset_release,
944 	.get_ownership	= kset_get_ownership,
945 };
946 
947 /**
948  * kset_create() - Create a struct kset dynamically.
949  *
950  * @name: the name for the kset
951  * @uevent_ops: a struct kset_uevent_ops for the kset
952  * @parent_kobj: the parent kobject of this kset, if any.
953  *
954  * This function creates a kset structure dynamically.  This structure can
955  * then be registered with the system and show up in sysfs with a call to
956  * kset_register().  When you are finished with this structure, if
957  * kset_register() has been called, call kset_unregister() and the
958  * structure will be dynamically freed when it is no longer being used.
959  *
960  * If the kset was not able to be created, NULL will be returned.
961  */
kset_create(const char * name,const struct kset_uevent_ops * uevent_ops,struct kobject * parent_kobj)962 static struct kset *kset_create(const char *name,
963 				const struct kset_uevent_ops *uevent_ops,
964 				struct kobject *parent_kobj)
965 {
966 	struct kset *kset;
967 	int retval;
968 
969 	kset = kzalloc(sizeof(*kset), GFP_KERNEL);
970 	if (!kset)
971 		return NULL;
972 	retval = kobject_set_name(&kset->kobj, "%s", name);
973 	if (retval) {
974 		kfree(kset);
975 		return NULL;
976 	}
977 	kset->uevent_ops = uevent_ops;
978 	kset->kobj.parent = parent_kobj;
979 
980 	/*
981 	 * The kobject of this kset will have a type of kset_ktype and belong to
982 	 * no kset itself.  That way we can properly free it when it is
983 	 * finished being used.
984 	 */
985 	kset->kobj.ktype = &kset_ktype;
986 	kset->kobj.kset = NULL;
987 
988 	return kset;
989 }
990 
991 /**
992  * kset_create_and_add() - Create a struct kset dynamically and add it to sysfs.
993  *
994  * @name: the name for the kset
995  * @uevent_ops: a struct kset_uevent_ops for the kset
996  * @parent_kobj: the parent kobject of this kset, if any.
997  *
998  * This function creates a kset structure dynamically and registers it
999  * with sysfs.  When you are finished with this structure, call
1000  * kset_unregister() and the structure will be dynamically freed when it
1001  * is no longer being used.
1002  *
1003  * If the kset was not able to be created, NULL will be returned.
1004  */
kset_create_and_add(const char * name,const struct kset_uevent_ops * uevent_ops,struct kobject * parent_kobj)1005 struct kset *kset_create_and_add(const char *name,
1006 				 const struct kset_uevent_ops *uevent_ops,
1007 				 struct kobject *parent_kobj)
1008 {
1009 	struct kset *kset;
1010 	int error;
1011 
1012 	kset = kset_create(name, uevent_ops, parent_kobj);
1013 	if (!kset)
1014 		return NULL;
1015 	error = kset_register(kset);
1016 	if (error) {
1017 		kfree(kset);
1018 		return NULL;
1019 	}
1020 	return kset;
1021 }
1022 EXPORT_SYMBOL_GPL(kset_create_and_add);
1023 
1024 
1025 static DEFINE_SPINLOCK(kobj_ns_type_lock);
1026 static const struct kobj_ns_type_operations *kobj_ns_ops_tbl[KOBJ_NS_TYPES];
1027 
kobj_ns_type_register(const struct kobj_ns_type_operations * ops)1028 int kobj_ns_type_register(const struct kobj_ns_type_operations *ops)
1029 {
1030 	enum kobj_ns_type type = ops->type;
1031 	int error;
1032 
1033 	spin_lock(&kobj_ns_type_lock);
1034 
1035 	error = -EINVAL;
1036 	if (type >= KOBJ_NS_TYPES)
1037 		goto out;
1038 
1039 	error = -EINVAL;
1040 	if (type <= KOBJ_NS_TYPE_NONE)
1041 		goto out;
1042 
1043 	error = -EBUSY;
1044 	if (kobj_ns_ops_tbl[type])
1045 		goto out;
1046 
1047 	error = 0;
1048 	kobj_ns_ops_tbl[type] = ops;
1049 
1050 out:
1051 	spin_unlock(&kobj_ns_type_lock);
1052 	return error;
1053 }
1054 
kobj_ns_type_registered(enum kobj_ns_type type)1055 int kobj_ns_type_registered(enum kobj_ns_type type)
1056 {
1057 	int registered = 0;
1058 
1059 	spin_lock(&kobj_ns_type_lock);
1060 	if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES))
1061 		registered = kobj_ns_ops_tbl[type] != NULL;
1062 	spin_unlock(&kobj_ns_type_lock);
1063 
1064 	return registered;
1065 }
1066 
kobj_child_ns_ops(struct kobject * parent)1067 const struct kobj_ns_type_operations *kobj_child_ns_ops(struct kobject *parent)
1068 {
1069 	const struct kobj_ns_type_operations *ops = NULL;
1070 
1071 	if (parent && parent->ktype && parent->ktype->child_ns_type)
1072 		ops = parent->ktype->child_ns_type(parent);
1073 
1074 	return ops;
1075 }
1076 
kobj_ns_ops(struct kobject * kobj)1077 const struct kobj_ns_type_operations *kobj_ns_ops(struct kobject *kobj)
1078 {
1079 	return kobj_child_ns_ops(kobj->parent);
1080 }
1081 
kobj_ns_current_may_mount(enum kobj_ns_type type)1082 bool kobj_ns_current_may_mount(enum kobj_ns_type type)
1083 {
1084 	bool may_mount = true;
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 		may_mount = kobj_ns_ops_tbl[type]->current_may_mount();
1090 	spin_unlock(&kobj_ns_type_lock);
1091 
1092 	return may_mount;
1093 }
1094 
kobj_ns_grab_current(enum kobj_ns_type type)1095 void *kobj_ns_grab_current(enum kobj_ns_type type)
1096 {
1097 	void *ns = NULL;
1098 
1099 	spin_lock(&kobj_ns_type_lock);
1100 	if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1101 	    kobj_ns_ops_tbl[type])
1102 		ns = kobj_ns_ops_tbl[type]->grab_current_ns();
1103 	spin_unlock(&kobj_ns_type_lock);
1104 
1105 	return ns;
1106 }
1107 EXPORT_SYMBOL_GPL(kobj_ns_grab_current);
1108 
kobj_ns_netlink(enum kobj_ns_type type,struct sock * sk)1109 const void *kobj_ns_netlink(enum kobj_ns_type type, struct sock *sk)
1110 {
1111 	const void *ns = NULL;
1112 
1113 	spin_lock(&kobj_ns_type_lock);
1114 	if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1115 	    kobj_ns_ops_tbl[type])
1116 		ns = kobj_ns_ops_tbl[type]->netlink_ns(sk);
1117 	spin_unlock(&kobj_ns_type_lock);
1118 
1119 	return ns;
1120 }
1121 
kobj_ns_initial(enum kobj_ns_type type)1122 const void *kobj_ns_initial(enum kobj_ns_type type)
1123 {
1124 	const void *ns = NULL;
1125 
1126 	spin_lock(&kobj_ns_type_lock);
1127 	if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1128 	    kobj_ns_ops_tbl[type])
1129 		ns = kobj_ns_ops_tbl[type]->initial_ns();
1130 	spin_unlock(&kobj_ns_type_lock);
1131 
1132 	return ns;
1133 }
1134 
kobj_ns_drop(enum kobj_ns_type type,void * ns)1135 void kobj_ns_drop(enum kobj_ns_type type, void *ns)
1136 {
1137 	spin_lock(&kobj_ns_type_lock);
1138 	if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1139 	    kobj_ns_ops_tbl[type] && kobj_ns_ops_tbl[type]->drop_ns)
1140 		kobj_ns_ops_tbl[type]->drop_ns(ns);
1141 	spin_unlock(&kobj_ns_type_lock);
1142 }
1143 EXPORT_SYMBOL_GPL(kobj_ns_drop);
1144