xref: /openbmc/linux/lib/kobject.c (revision 7f414d30)
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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
14 
15 #include <linux/kobject.h>
16 #include <linux/string.h>
17 #include <linux/export.h>
18 #include <linux/stat.h>
19 #include <linux/slab.h>
20 #include <linux/random.h>
21 
22 /**
23  * kobject_namespace() - Return @kobj's namespace tag.
24  * @kobj: kobject in question
25  *
26  * Returns namespace tag of @kobj if its parent has namespace ops enabled
27  * and thus @kobj should have a namespace tag associated with it.  Returns
28  * %NULL otherwise.
29  */
kobject_namespace(const struct kobject * kobj)30 const void *kobject_namespace(const struct kobject *kobj)
31 {
32 	const struct kobj_ns_type_operations *ns_ops = kobj_ns_ops(kobj);
33 
34 	if (!ns_ops || ns_ops->type == KOBJ_NS_TYPE_NONE)
35 		return NULL;
36 
37 	return kobj->ktype->namespace(kobj);
38 }
39 
40 /**
41  * kobject_get_ownership() - Get sysfs ownership data for @kobj.
42  * @kobj: kobject in question
43  * @uid: kernel user ID for sysfs objects
44  * @gid: kernel group ID for sysfs objects
45  *
46  * Returns initial uid/gid pair that should be used when creating sysfs
47  * representation of given kobject. Normally used to adjust ownership of
48  * objects in a container.
49  */
kobject_get_ownership(const struct kobject * kobj,kuid_t * uid,kgid_t * gid)50 void kobject_get_ownership(const struct kobject *kobj, kuid_t *uid, kgid_t *gid)
51 {
52 	*uid = GLOBAL_ROOT_UID;
53 	*gid = GLOBAL_ROOT_GID;
54 
55 	if (kobj->ktype->get_ownership)
56 		kobj->ktype->get_ownership(kobj, uid, gid);
57 }
58 
kobj_ns_type_is_valid(enum kobj_ns_type type)59 static bool kobj_ns_type_is_valid(enum kobj_ns_type type)
60 {
61 	if ((type <= KOBJ_NS_TYPE_NONE) || (type >= KOBJ_NS_TYPES))
62 		return false;
63 
64 	return true;
65 }
66 
create_dir(struct kobject * kobj)67 static int create_dir(struct kobject *kobj)
68 {
69 	const struct kobj_type *ktype = get_ktype(kobj);
70 	const struct kobj_ns_type_operations *ops;
71 	int error;
72 
73 	error = sysfs_create_dir_ns(kobj, kobject_namespace(kobj));
74 	if (error)
75 		return error;
76 
77 	if (ktype) {
78 		error = sysfs_create_groups(kobj, ktype->default_groups);
79 		if (error) {
80 			sysfs_remove_dir(kobj);
81 			return error;
82 		}
83 	}
84 
85 	/*
86 	 * @kobj->sd may be deleted by an ancestor going away.  Hold an
87 	 * extra reference so that it stays until @kobj is gone.
88 	 */
89 	sysfs_get(kobj->sd);
90 
91 	/*
92 	 * If @kobj has ns_ops, its children need to be filtered based on
93 	 * their namespace tags.  Enable namespace support on @kobj->sd.
94 	 */
95 	ops = kobj_child_ns_ops(kobj);
96 	if (ops) {
97 		BUG_ON(!kobj_ns_type_is_valid(ops->type));
98 		BUG_ON(!kobj_ns_type_registered(ops->type));
99 
100 		sysfs_enable_ns(kobj->sd);
101 	}
102 
103 	return 0;
104 }
105 
get_kobj_path_length(const struct kobject * kobj)106 static int get_kobj_path_length(const struct kobject *kobj)
107 {
108 	int length = 1;
109 	const struct kobject *parent = kobj;
110 
111 	/* walk up the ancestors until we hit the one pointing to the
112 	 * root.
113 	 * Add 1 to strlen for leading '/' of each level.
114 	 */
115 	do {
116 		if (kobject_name(parent) == NULL)
117 			return 0;
118 		length += strlen(kobject_name(parent)) + 1;
119 		parent = parent->parent;
120 	} while (parent);
121 	return length;
122 }
123 
fill_kobj_path(const struct kobject * kobj,char * path,int length)124 static int fill_kobj_path(const struct kobject *kobj, char *path, int length)
125 {
126 	const struct kobject *parent;
127 
128 	--length;
129 	for (parent = kobj; parent; parent = parent->parent) {
130 		int cur = strlen(kobject_name(parent));
131 		/* back up enough to print this name with '/' */
132 		length -= cur;
133 		if (length <= 0)
134 			return -EINVAL;
135 		memcpy(path + length, kobject_name(parent), cur);
136 		*(path + --length) = '/';
137 	}
138 
139 	pr_debug("'%s' (%p): %s: path = '%s'\n", kobject_name(kobj),
140 		 kobj, __func__, path);
141 
142 	return 0;
143 }
144 
145 /**
146  * kobject_get_path() - Allocate memory and fill in the path for @kobj.
147  * @kobj:	kobject in question, with which to build the path
148  * @gfp_mask:	the allocation type used to allocate the path
149  *
150  * Return: The newly allocated memory, caller must free with kfree().
151  */
kobject_get_path(const struct kobject * kobj,gfp_t gfp_mask)152 char *kobject_get_path(const struct kobject *kobj, gfp_t gfp_mask)
153 {
154 	char *path;
155 	int len;
156 
157 retry:
158 	len = get_kobj_path_length(kobj);
159 	if (len == 0)
160 		return NULL;
161 	path = kzalloc(len, gfp_mask);
162 	if (!path)
163 		return NULL;
164 	if (fill_kobj_path(kobj, path, len)) {
165 		kfree(path);
166 		goto retry;
167 	}
168 
169 	return path;
170 }
171 EXPORT_SYMBOL_GPL(kobject_get_path);
172 
173 /* add the kobject to its kset's list */
kobj_kset_join(struct kobject * kobj)174 static void kobj_kset_join(struct kobject *kobj)
175 {
176 	if (!kobj->kset)
177 		return;
178 
179 	kset_get(kobj->kset);
180 	spin_lock(&kobj->kset->list_lock);
181 	list_add_tail(&kobj->entry, &kobj->kset->list);
182 	spin_unlock(&kobj->kset->list_lock);
183 }
184 
185 /* remove the kobject from its kset's list */
kobj_kset_leave(struct kobject * kobj)186 static void kobj_kset_leave(struct kobject *kobj)
187 {
188 	if (!kobj->kset)
189 		return;
190 
191 	spin_lock(&kobj->kset->list_lock);
192 	list_del_init(&kobj->entry);
193 	spin_unlock(&kobj->kset->list_lock);
194 	kset_put(kobj->kset);
195 }
196 
kobject_init_internal(struct kobject * kobj)197 static void kobject_init_internal(struct kobject *kobj)
198 {
199 	if (!kobj)
200 		return;
201 	kref_init(&kobj->kref);
202 	INIT_LIST_HEAD(&kobj->entry);
203 	kobj->state_in_sysfs = 0;
204 	kobj->state_add_uevent_sent = 0;
205 	kobj->state_remove_uevent_sent = 0;
206 	kobj->state_initialized = 1;
207 }
208 
209 
kobject_add_internal(struct kobject * kobj)210 static int kobject_add_internal(struct kobject *kobj)
211 {
212 	int error = 0;
213 	struct kobject *parent;
214 
215 	if (!kobj)
216 		return -ENOENT;
217 
218 	if (!kobj->name || !kobj->name[0]) {
219 		WARN(1,
220 		     "kobject: (%p): attempted to be registered with empty name!\n",
221 		     kobj);
222 		return -EINVAL;
223 	}
224 
225 	parent = kobject_get(kobj->parent);
226 
227 	/* join kset if set, use it as parent if we do not already have one */
228 	if (kobj->kset) {
229 		if (!parent)
230 			parent = kobject_get(&kobj->kset->kobj);
231 		kobj_kset_join(kobj);
232 		kobj->parent = parent;
233 	}
234 
235 	pr_debug("'%s' (%p): %s: parent: '%s', set: '%s'\n",
236 		 kobject_name(kobj), kobj, __func__,
237 		 parent ? kobject_name(parent) : "<NULL>",
238 		 kobj->kset ? kobject_name(&kobj->kset->kobj) : "<NULL>");
239 
240 	error = create_dir(kobj);
241 	if (error) {
242 		kobj_kset_leave(kobj);
243 		kobject_put(parent);
244 		kobj->parent = NULL;
245 
246 		/* be noisy on error issues */
247 		if (error == -EEXIST)
248 			pr_err("%s failed for %s with -EEXIST, don't try to register things with the same name in the same directory.\n",
249 			       __func__, kobject_name(kobj));
250 		else
251 			pr_err("%s failed for %s (error: %d parent: %s)\n",
252 			       __func__, kobject_name(kobj), error,
253 			       parent ? kobject_name(parent) : "'none'");
254 	} else
255 		kobj->state_in_sysfs = 1;
256 
257 	return error;
258 }
259 
260 /**
261  * kobject_set_name_vargs() - Set the name of a kobject.
262  * @kobj: struct kobject to set the name of
263  * @fmt: format string used to build the name
264  * @vargs: vargs to format the string.
265  */
kobject_set_name_vargs(struct kobject * kobj,const char * fmt,va_list vargs)266 int kobject_set_name_vargs(struct kobject *kobj, const char *fmt,
267 				  va_list vargs)
268 {
269 	const char *s;
270 
271 	if (kobj->name && !fmt)
272 		return 0;
273 
274 	s = kvasprintf_const(GFP_KERNEL, fmt, vargs);
275 	if (!s)
276 		return -ENOMEM;
277 
278 	/*
279 	 * ewww... some of these buggers have '/' in the name ... If
280 	 * that's the case, we need to make sure we have an actual
281 	 * allocated copy to modify, since kvasprintf_const may have
282 	 * returned something from .rodata.
283 	 */
284 	if (strchr(s, '/')) {
285 		char *t;
286 
287 		t = kstrdup(s, GFP_KERNEL);
288 		kfree_const(s);
289 		if (!t)
290 			return -ENOMEM;
291 		s = strreplace(t, '/', '!');
292 	}
293 	kfree_const(kobj->name);
294 	kobj->name = s;
295 
296 	return 0;
297 }
298 
299 /**
300  * kobject_set_name() - Set the name of a kobject.
301  * @kobj: struct kobject to set the name of
302  * @fmt: format string used to build the name
303  *
304  * This sets the name of the kobject.  If you have already added the
305  * kobject to the system, you must call kobject_rename() in order to
306  * change the name of the kobject.
307  */
kobject_set_name(struct kobject * kobj,const char * fmt,...)308 int kobject_set_name(struct kobject *kobj, const char *fmt, ...)
309 {
310 	va_list vargs;
311 	int retval;
312 
313 	va_start(vargs, fmt);
314 	retval = kobject_set_name_vargs(kobj, fmt, vargs);
315 	va_end(vargs);
316 
317 	return retval;
318 }
319 EXPORT_SYMBOL(kobject_set_name);
320 
321 /**
322  * kobject_init() - Initialize a kobject structure.
323  * @kobj: pointer to the kobject to initialize
324  * @ktype: pointer to the ktype for this kobject.
325  *
326  * This function will properly initialize a kobject such that it can then
327  * be passed to the kobject_add() call.
328  *
329  * After this function is called, the kobject MUST be cleaned up by a call
330  * to kobject_put(), not by a call to kfree directly to ensure that all of
331  * the memory is cleaned up properly.
332  */
kobject_init(struct kobject * kobj,const struct kobj_type * ktype)333 void kobject_init(struct kobject *kobj, const struct kobj_type *ktype)
334 {
335 	char *err_str;
336 
337 	if (!kobj) {
338 		err_str = "invalid kobject pointer!";
339 		goto error;
340 	}
341 	if (!ktype) {
342 		err_str = "must have a ktype to be initialized properly!\n";
343 		goto error;
344 	}
345 	if (kobj->state_initialized) {
346 		/* do not error out as sometimes we can recover */
347 		pr_err("kobject (%p): tried to init an initialized object, something is seriously wrong.\n",
348 		       kobj);
349 		dump_stack_lvl(KERN_ERR);
350 	}
351 
352 	kobject_init_internal(kobj);
353 	kobj->ktype = ktype;
354 	return;
355 
356 error:
357 	pr_err("kobject (%p): %s\n", kobj, err_str);
358 	dump_stack_lvl(KERN_ERR);
359 }
360 EXPORT_SYMBOL(kobject_init);
361 
kobject_add_varg(struct kobject * kobj,struct kobject * parent,const char * fmt,va_list vargs)362 static __printf(3, 0) int kobject_add_varg(struct kobject *kobj,
363 					   struct kobject *parent,
364 					   const char *fmt, va_list vargs)
365 {
366 	int retval;
367 
368 	retval = kobject_set_name_vargs(kobj, fmt, vargs);
369 	if (retval) {
370 		pr_err("can not set name properly!\n");
371 		return retval;
372 	}
373 	kobj->parent = parent;
374 	return kobject_add_internal(kobj);
375 }
376 
377 /**
378  * kobject_add() - The main kobject add function.
379  * @kobj: the kobject to add
380  * @parent: pointer to the parent of the kobject.
381  * @fmt: format to name the kobject with.
382  *
383  * The kobject name is set and added to the kobject hierarchy in this
384  * function.
385  *
386  * If @parent is set, then the parent of the @kobj will be set to it.
387  * If @parent is NULL, then the parent of the @kobj will be set to the
388  * kobject associated with the kset assigned to this kobject.  If no kset
389  * is assigned to the kobject, then the kobject will be located in the
390  * root of the sysfs tree.
391  *
392  * Note, no "add" uevent will be created with this call, the caller should set
393  * up all of the necessary sysfs files for the object and then call
394  * kobject_uevent() with the UEVENT_ADD parameter to ensure that
395  * userspace is properly notified of this kobject's creation.
396  *
397  * Return: If this function returns an error, kobject_put() must be
398  *         called to properly clean up the memory associated with the
399  *         object.  Under no instance should the kobject that is passed
400  *         to this function be directly freed with a call to kfree(),
401  *         that can leak memory.
402  *
403  *         If this function returns success, kobject_put() must also be called
404  *         in order to properly clean up the memory associated with the object.
405  *
406  *         In short, once this function is called, kobject_put() MUST be called
407  *         when the use of the object is finished in order to properly free
408  *         everything.
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_lvl(KERN_ERR);
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
435  *                          the kobject hierarchy.
436  * @kobj: pointer to the kobject to initialize
437  * @ktype: pointer to the ktype for this kobject.
438  * @parent: pointer to the parent of this kobject.
439  * @fmt: the name of the kobject.
440  *
441  * This function combines the call to kobject_init() and kobject_add().
442  *
443  * If this function returns an error, kobject_put() must be called to
444  * properly clean up the memory associated with the object.  This is the
445  * same type of error handling after a call to kobject_add() and kobject
446  * lifetime rules are the same here.
447  */
kobject_init_and_add(struct kobject * kobj,const struct kobj_type * ktype,struct kobject * parent,const char * fmt,...)448 int kobject_init_and_add(struct kobject *kobj, const struct kobj_type *ktype,
449 			 struct kobject *parent, const char *fmt, ...)
450 {
451 	va_list args;
452 	int retval;
453 
454 	kobject_init(kobj, ktype);
455 
456 	va_start(args, fmt);
457 	retval = kobject_add_varg(kobj, parent, fmt, args);
458 	va_end(args);
459 
460 	return retval;
461 }
462 EXPORT_SYMBOL_GPL(kobject_init_and_add);
463 
464 /**
465  * kobject_rename() - Change the name of an object.
466  * @kobj: object in question.
467  * @new_name: object's new name
468  *
469  * It is the responsibility of the caller to provide mutual
470  * exclusion between two different calls of kobject_rename
471  * on the same kobject and to ensure that new_name is valid and
472  * won't conflict with other kobjects.
473  */
kobject_rename(struct kobject * kobj,const char * new_name)474 int kobject_rename(struct kobject *kobj, const char *new_name)
475 {
476 	int error = 0;
477 	const char *devpath = NULL;
478 	const char *dup_name = NULL, *name;
479 	char *devpath_string = NULL;
480 	char *envp[2];
481 
482 	kobj = kobject_get(kobj);
483 	if (!kobj)
484 		return -EINVAL;
485 	if (!kobj->parent) {
486 		kobject_put(kobj);
487 		return -EINVAL;
488 	}
489 
490 	devpath = kobject_get_path(kobj, GFP_KERNEL);
491 	if (!devpath) {
492 		error = -ENOMEM;
493 		goto out;
494 	}
495 	devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
496 	if (!devpath_string) {
497 		error = -ENOMEM;
498 		goto out;
499 	}
500 	sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
501 	envp[0] = devpath_string;
502 	envp[1] = NULL;
503 
504 	name = dup_name = kstrdup_const(new_name, GFP_KERNEL);
505 	if (!name) {
506 		error = -ENOMEM;
507 		goto out;
508 	}
509 
510 	error = sysfs_rename_dir_ns(kobj, new_name, kobject_namespace(kobj));
511 	if (error)
512 		goto out;
513 
514 	/* Install the new kobject name */
515 	dup_name = kobj->name;
516 	kobj->name = name;
517 
518 	/* This function is mostly/only used for network interface.
519 	 * Some hotplug package track interfaces by their name and
520 	 * therefore want to know when the name is changed by the user. */
521 	kobject_uevent_env(kobj, KOBJ_MOVE, envp);
522 
523 out:
524 	kfree_const(dup_name);
525 	kfree(devpath_string);
526 	kfree(devpath);
527 	kobject_put(kobj);
528 
529 	return error;
530 }
531 EXPORT_SYMBOL_GPL(kobject_rename);
532 
533 /**
534  * kobject_move() - Move object to another parent.
535  * @kobj: object in question.
536  * @new_parent: object's new parent (can be NULL)
537  */
kobject_move(struct kobject * kobj,struct kobject * new_parent)538 int kobject_move(struct kobject *kobj, struct kobject *new_parent)
539 {
540 	int error;
541 	struct kobject *old_parent;
542 	const char *devpath = NULL;
543 	char *devpath_string = NULL;
544 	char *envp[2];
545 
546 	kobj = kobject_get(kobj);
547 	if (!kobj)
548 		return -EINVAL;
549 	new_parent = kobject_get(new_parent);
550 	if (!new_parent) {
551 		if (kobj->kset)
552 			new_parent = kobject_get(&kobj->kset->kobj);
553 	}
554 
555 	/* old object path */
556 	devpath = kobject_get_path(kobj, GFP_KERNEL);
557 	if (!devpath) {
558 		error = -ENOMEM;
559 		goto out;
560 	}
561 	devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
562 	if (!devpath_string) {
563 		error = -ENOMEM;
564 		goto out;
565 	}
566 	sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
567 	envp[0] = devpath_string;
568 	envp[1] = NULL;
569 	error = sysfs_move_dir_ns(kobj, new_parent, kobject_namespace(kobj));
570 	if (error)
571 		goto out;
572 	old_parent = kobj->parent;
573 	kobj->parent = new_parent;
574 	new_parent = NULL;
575 	kobject_put(old_parent);
576 	kobject_uevent_env(kobj, KOBJ_MOVE, envp);
577 out:
578 	kobject_put(new_parent);
579 	kobject_put(kobj);
580 	kfree(devpath_string);
581 	kfree(devpath);
582 	return error;
583 }
584 EXPORT_SYMBOL_GPL(kobject_move);
585 
__kobject_del(struct kobject * kobj)586 static void __kobject_del(struct kobject *kobj)
587 {
588 	struct kernfs_node *sd;
589 	const struct kobj_type *ktype;
590 
591 	sd = kobj->sd;
592 	ktype = get_ktype(kobj);
593 
594 	if (ktype)
595 		sysfs_remove_groups(kobj, ktype->default_groups);
596 
597 	/* send "remove" if the caller did not do it but sent "add" */
598 	if (kobj->state_add_uevent_sent && !kobj->state_remove_uevent_sent) {
599 		pr_debug("'%s' (%p): auto cleanup 'remove' event\n",
600 			 kobject_name(kobj), kobj);
601 		kobject_uevent(kobj, KOBJ_REMOVE);
602 	}
603 
604 	sysfs_remove_dir(kobj);
605 	sysfs_put(sd);
606 
607 	kobj->state_in_sysfs = 0;
608 	kobj_kset_leave(kobj);
609 	kobj->parent = NULL;
610 }
611 
612 /**
613  * kobject_del() - Unlink kobject from hierarchy.
614  * @kobj: object.
615  *
616  * This is the function that should be called to delete an object
617  * successfully added via kobject_add().
618  */
kobject_del(struct kobject * kobj)619 void kobject_del(struct kobject *kobj)
620 {
621 	struct kobject *parent;
622 
623 	if (!kobj)
624 		return;
625 
626 	parent = kobj->parent;
627 	__kobject_del(kobj);
628 	kobject_put(parent);
629 }
630 EXPORT_SYMBOL(kobject_del);
631 
632 /**
633  * kobject_get() - Increment refcount for object.
634  * @kobj: object.
635  */
kobject_get(struct kobject * kobj)636 struct kobject *kobject_get(struct kobject *kobj)
637 {
638 	if (kobj) {
639 		if (!kobj->state_initialized)
640 			WARN(1, KERN_WARNING
641 				"kobject: '%s' (%p): is not initialized, yet kobject_get() is being called.\n",
642 			     kobject_name(kobj), kobj);
643 		kref_get(&kobj->kref);
644 	}
645 	return kobj;
646 }
647 EXPORT_SYMBOL(kobject_get);
648 
kobject_get_unless_zero(struct kobject * kobj)649 struct kobject * __must_check kobject_get_unless_zero(struct kobject *kobj)
650 {
651 	if (!kobj)
652 		return NULL;
653 	if (!kref_get_unless_zero(&kobj->kref))
654 		kobj = NULL;
655 	return kobj;
656 }
657 EXPORT_SYMBOL(kobject_get_unless_zero);
658 
659 /*
660  * kobject_cleanup - free kobject resources.
661  * @kobj: object to cleanup
662  */
kobject_cleanup(struct kobject * kobj)663 static void kobject_cleanup(struct kobject *kobj)
664 {
665 	struct kobject *parent = kobj->parent;
666 	const struct kobj_type *t = get_ktype(kobj);
667 	const char *name = kobj->name;
668 
669 	pr_debug("'%s' (%p): %s, parent %p\n",
670 		 kobject_name(kobj), kobj, __func__, kobj->parent);
671 
672 	if (t && !t->release)
673 		pr_debug("'%s' (%p): does not have a release() function, it is broken and must be fixed. See Documentation/core-api/kobject.rst.\n",
674 			 kobject_name(kobj), kobj);
675 
676 	/* remove from sysfs if the caller did not do it */
677 	if (kobj->state_in_sysfs) {
678 		pr_debug("'%s' (%p): auto cleanup kobject_del\n",
679 			 kobject_name(kobj), kobj);
680 		__kobject_del(kobj);
681 	} else {
682 		/* avoid dropping the parent reference unnecessarily */
683 		parent = NULL;
684 	}
685 
686 	if (t && t->release) {
687 		pr_debug("'%s' (%p): calling ktype release\n",
688 			 kobject_name(kobj), kobj);
689 		t->release(kobj);
690 	}
691 
692 	/* free name if we allocated it */
693 	if (name) {
694 		pr_debug("'%s': free name\n", name);
695 		kfree_const(name);
696 	}
697 
698 	kobject_put(parent);
699 }
700 
701 #ifdef CONFIG_DEBUG_KOBJECT_RELEASE
kobject_delayed_cleanup(struct work_struct * work)702 static void kobject_delayed_cleanup(struct work_struct *work)
703 {
704 	kobject_cleanup(container_of(to_delayed_work(work),
705 				     struct kobject, release));
706 }
707 #endif
708 
kobject_release(struct kref * kref)709 static void kobject_release(struct kref *kref)
710 {
711 	struct kobject *kobj = container_of(kref, struct kobject, kref);
712 #ifdef CONFIG_DEBUG_KOBJECT_RELEASE
713 	unsigned long delay = HZ + HZ * get_random_u32_below(4);
714 	pr_info("'%s' (%p): %s, parent %p (delayed %ld)\n",
715 		kobject_name(kobj), kobj, __func__, kobj->parent, delay);
716 	INIT_DELAYED_WORK(&kobj->release, kobject_delayed_cleanup);
717 
718 	schedule_delayed_work(&kobj->release, delay);
719 #else
720 	kobject_cleanup(kobj);
721 #endif
722 }
723 
724 /**
725  * kobject_put() - Decrement refcount for object.
726  * @kobj: object.
727  *
728  * Decrement the refcount, and if 0, call kobject_cleanup().
729  */
kobject_put(struct kobject * kobj)730 void kobject_put(struct kobject *kobj)
731 {
732 	if (kobj) {
733 		if (!kobj->state_initialized)
734 			WARN(1, KERN_WARNING
735 				"kobject: '%s' (%p): is not initialized, yet kobject_put() is being called.\n",
736 			     kobject_name(kobj), kobj);
737 		kref_put(&kobj->kref, kobject_release);
738 	}
739 }
740 EXPORT_SYMBOL(kobject_put);
741 
dynamic_kobj_release(struct kobject * kobj)742 static void dynamic_kobj_release(struct kobject *kobj)
743 {
744 	pr_debug("(%p): %s\n", kobj, __func__);
745 	kfree(kobj);
746 }
747 
748 static const struct kobj_type dynamic_kobj_ktype = {
749 	.release	= dynamic_kobj_release,
750 	.sysfs_ops	= &kobj_sysfs_ops,
751 };
752 
753 /**
754  * kobject_create() - Create a struct kobject dynamically.
755  *
756  * This function creates a kobject structure dynamically and sets it up
757  * to be a "dynamic" kobject with a default release function set up.
758  *
759  * If the kobject was not able to be created, NULL will be returned.
760  * The kobject structure returned from here must be cleaned up with a
761  * call to kobject_put() and not kfree(), as kobject_init() has
762  * already been called on this structure.
763  */
kobject_create(void)764 static struct kobject *kobject_create(void)
765 {
766 	struct kobject *kobj;
767 
768 	kobj = kzalloc(sizeof(*kobj), GFP_KERNEL);
769 	if (!kobj)
770 		return NULL;
771 
772 	kobject_init(kobj, &dynamic_kobj_ktype);
773 	return kobj;
774 }
775 
776 /**
777  * kobject_create_and_add() - Create a struct kobject dynamically and
778  *                            register it with sysfs.
779  * @name: the name for the kobject
780  * @parent: the parent kobject of this kobject, if any.
781  *
782  * This function creates a kobject structure dynamically and registers it
783  * with sysfs.  When you are finished with this structure, call
784  * kobject_put() and the structure will be dynamically freed when
785  * it is no longer being used.
786  *
787  * If the kobject was not able to be created, NULL will be returned.
788  */
kobject_create_and_add(const char * name,struct kobject * parent)789 struct kobject *kobject_create_and_add(const char *name, struct kobject *parent)
790 {
791 	struct kobject *kobj;
792 	int retval;
793 
794 	kobj = kobject_create();
795 	if (!kobj)
796 		return NULL;
797 
798 	retval = kobject_add(kobj, parent, "%s", name);
799 	if (retval) {
800 		pr_warn("%s: kobject_add error: %d\n", __func__, retval);
801 		kobject_put(kobj);
802 		kobj = NULL;
803 	}
804 	return kobj;
805 }
806 EXPORT_SYMBOL_GPL(kobject_create_and_add);
807 
808 /**
809  * kset_init() - Initialize a kset for use.
810  * @k: kset
811  */
kset_init(struct kset * k)812 void kset_init(struct kset *k)
813 {
814 	kobject_init_internal(&k->kobj);
815 	INIT_LIST_HEAD(&k->list);
816 	spin_lock_init(&k->list_lock);
817 }
818 
819 /* default kobject attribute operations */
kobj_attr_show(struct kobject * kobj,struct attribute * attr,char * buf)820 static ssize_t kobj_attr_show(struct kobject *kobj, struct attribute *attr,
821 			      char *buf)
822 {
823 	struct kobj_attribute *kattr;
824 	ssize_t ret = -EIO;
825 
826 	kattr = container_of(attr, struct kobj_attribute, attr);
827 	if (kattr->show)
828 		ret = kattr->show(kobj, kattr, buf);
829 	return ret;
830 }
831 
kobj_attr_store(struct kobject * kobj,struct attribute * attr,const char * buf,size_t count)832 static ssize_t kobj_attr_store(struct kobject *kobj, struct attribute *attr,
833 			       const char *buf, size_t count)
834 {
835 	struct kobj_attribute *kattr;
836 	ssize_t ret = -EIO;
837 
838 	kattr = container_of(attr, struct kobj_attribute, attr);
839 	if (kattr->store)
840 		ret = kattr->store(kobj, kattr, buf, count);
841 	return ret;
842 }
843 
844 const struct sysfs_ops kobj_sysfs_ops = {
845 	.show	= kobj_attr_show,
846 	.store	= kobj_attr_store,
847 };
848 EXPORT_SYMBOL_GPL(kobj_sysfs_ops);
849 
850 /**
851  * kset_register() - Initialize and add a kset.
852  * @k: kset.
853  *
854  * NOTE: On error, the kset.kobj.name allocated by() kobj_set_name()
855  * is freed, it can not be used any more.
856  */
kset_register(struct kset * k)857 int kset_register(struct kset *k)
858 {
859 	int err;
860 
861 	if (!k)
862 		return -EINVAL;
863 
864 	if (!k->kobj.ktype) {
865 		pr_err("must have a ktype to be initialized properly!\n");
866 		return -EINVAL;
867 	}
868 
869 	kset_init(k);
870 	err = kobject_add_internal(&k->kobj);
871 	if (err) {
872 		kfree_const(k->kobj.name);
873 		/* Set it to NULL to avoid accessing bad pointer in callers. */
874 		k->kobj.name = NULL;
875 		return err;
876 	}
877 	kobject_uevent(&k->kobj, KOBJ_ADD);
878 	return 0;
879 }
880 EXPORT_SYMBOL(kset_register);
881 
882 /**
883  * kset_unregister() - Remove a kset.
884  * @k: kset.
885  */
kset_unregister(struct kset * k)886 void kset_unregister(struct kset *k)
887 {
888 	if (!k)
889 		return;
890 	kobject_del(&k->kobj);
891 	kobject_put(&k->kobj);
892 }
893 EXPORT_SYMBOL(kset_unregister);
894 
895 /**
896  * kset_find_obj() - Search for object in kset.
897  * @kset: kset we're looking in.
898  * @name: object's name.
899  *
900  * Lock kset via @kset->subsys, and iterate over @kset->list,
901  * looking for a matching kobject. If matching object is found
902  * take a reference and return the object.
903  */
kset_find_obj(struct kset * kset,const char * name)904 struct kobject *kset_find_obj(struct kset *kset, const char *name)
905 {
906 	struct kobject *k;
907 	struct kobject *ret = NULL;
908 
909 	spin_lock(&kset->list_lock);
910 
911 	list_for_each_entry(k, &kset->list, entry) {
912 		if (kobject_name(k) && !strcmp(kobject_name(k), name)) {
913 			ret = kobject_get_unless_zero(k);
914 			break;
915 		}
916 	}
917 
918 	spin_unlock(&kset->list_lock);
919 	return ret;
920 }
921 EXPORT_SYMBOL_GPL(kset_find_obj);
922 
kset_release(struct kobject * kobj)923 static void kset_release(struct kobject *kobj)
924 {
925 	struct kset *kset = container_of(kobj, struct kset, kobj);
926 	pr_debug("'%s' (%p): %s\n",
927 		 kobject_name(kobj), kobj, __func__);
928 	kfree(kset);
929 }
930 
kset_get_ownership(const struct kobject * kobj,kuid_t * uid,kgid_t * gid)931 static void kset_get_ownership(const struct kobject *kobj, kuid_t *uid, kgid_t *gid)
932 {
933 	if (kobj->parent)
934 		kobject_get_ownership(kobj->parent, uid, gid);
935 }
936 
937 static const struct kobj_type kset_ktype = {
938 	.sysfs_ops	= &kobj_sysfs_ops,
939 	.release	= kset_release,
940 	.get_ownership	= kset_get_ownership,
941 };
942 
943 /**
944  * kset_create() - Create a struct kset dynamically.
945  *
946  * @name: the name for the kset
947  * @uevent_ops: a struct kset_uevent_ops for the kset
948  * @parent_kobj: the parent kobject of this kset, if any.
949  *
950  * This function creates a kset structure dynamically.  This structure can
951  * then be registered with the system and show up in sysfs with a call to
952  * kset_register().  When you are finished with this structure, if
953  * kset_register() has been called, call kset_unregister() and the
954  * structure will be dynamically freed when it is no longer being used.
955  *
956  * If the kset was not able to be created, NULL will be returned.
957  */
kset_create(const char * name,const struct kset_uevent_ops * uevent_ops,struct kobject * parent_kobj)958 static struct kset *kset_create(const char *name,
959 				const struct kset_uevent_ops *uevent_ops,
960 				struct kobject *parent_kobj)
961 {
962 	struct kset *kset;
963 	int retval;
964 
965 	kset = kzalloc(sizeof(*kset), GFP_KERNEL);
966 	if (!kset)
967 		return NULL;
968 	retval = kobject_set_name(&kset->kobj, "%s", name);
969 	if (retval) {
970 		kfree(kset);
971 		return NULL;
972 	}
973 	kset->uevent_ops = uevent_ops;
974 	kset->kobj.parent = parent_kobj;
975 
976 	/*
977 	 * The kobject of this kset will have a type of kset_ktype and belong to
978 	 * no kset itself.  That way we can properly free it when it is
979 	 * finished being used.
980 	 */
981 	kset->kobj.ktype = &kset_ktype;
982 	kset->kobj.kset = NULL;
983 
984 	return kset;
985 }
986 
987 /**
988  * kset_create_and_add() - Create a struct kset dynamically and add it to sysfs.
989  *
990  * @name: the name for the kset
991  * @uevent_ops: a struct kset_uevent_ops for the kset
992  * @parent_kobj: the parent kobject of this kset, if any.
993  *
994  * This function creates a kset structure dynamically and registers it
995  * with sysfs.  When you are finished with this structure, call
996  * kset_unregister() and the structure will be dynamically freed when it
997  * is no longer being used.
998  *
999  * If the kset was not able to be created, NULL will be returned.
1000  */
kset_create_and_add(const char * name,const struct kset_uevent_ops * uevent_ops,struct kobject * parent_kobj)1001 struct kset *kset_create_and_add(const char *name,
1002 				 const struct kset_uevent_ops *uevent_ops,
1003 				 struct kobject *parent_kobj)
1004 {
1005 	struct kset *kset;
1006 	int error;
1007 
1008 	kset = kset_create(name, uevent_ops, parent_kobj);
1009 	if (!kset)
1010 		return NULL;
1011 	error = kset_register(kset);
1012 	if (error) {
1013 		kfree(kset);
1014 		return NULL;
1015 	}
1016 	return kset;
1017 }
1018 EXPORT_SYMBOL_GPL(kset_create_and_add);
1019 
1020 
1021 static DEFINE_SPINLOCK(kobj_ns_type_lock);
1022 static const struct kobj_ns_type_operations *kobj_ns_ops_tbl[KOBJ_NS_TYPES];
1023 
kobj_ns_type_register(const struct kobj_ns_type_operations * ops)1024 int kobj_ns_type_register(const struct kobj_ns_type_operations *ops)
1025 {
1026 	enum kobj_ns_type type = ops->type;
1027 	int error;
1028 
1029 	spin_lock(&kobj_ns_type_lock);
1030 
1031 	error = -EINVAL;
1032 	if (!kobj_ns_type_is_valid(type))
1033 		goto out;
1034 
1035 	error = -EBUSY;
1036 	if (kobj_ns_ops_tbl[type])
1037 		goto out;
1038 
1039 	error = 0;
1040 	kobj_ns_ops_tbl[type] = ops;
1041 
1042 out:
1043 	spin_unlock(&kobj_ns_type_lock);
1044 	return error;
1045 }
1046 
kobj_ns_type_registered(enum kobj_ns_type type)1047 int kobj_ns_type_registered(enum kobj_ns_type type)
1048 {
1049 	int registered = 0;
1050 
1051 	spin_lock(&kobj_ns_type_lock);
1052 	if (kobj_ns_type_is_valid(type))
1053 		registered = kobj_ns_ops_tbl[type] != NULL;
1054 	spin_unlock(&kobj_ns_type_lock);
1055 
1056 	return registered;
1057 }
1058 
kobj_child_ns_ops(const struct kobject * parent)1059 const struct kobj_ns_type_operations *kobj_child_ns_ops(const struct kobject *parent)
1060 {
1061 	const struct kobj_ns_type_operations *ops = NULL;
1062 
1063 	if (parent && parent->ktype && parent->ktype->child_ns_type)
1064 		ops = parent->ktype->child_ns_type(parent);
1065 
1066 	return ops;
1067 }
1068 
kobj_ns_ops(const struct kobject * kobj)1069 const struct kobj_ns_type_operations *kobj_ns_ops(const struct kobject *kobj)
1070 {
1071 	return kobj_child_ns_ops(kobj->parent);
1072 }
1073 
kobj_ns_current_may_mount(enum kobj_ns_type type)1074 bool kobj_ns_current_may_mount(enum kobj_ns_type type)
1075 {
1076 	bool may_mount = true;
1077 
1078 	spin_lock(&kobj_ns_type_lock);
1079 	if (kobj_ns_type_is_valid(type) && kobj_ns_ops_tbl[type])
1080 		may_mount = kobj_ns_ops_tbl[type]->current_may_mount();
1081 	spin_unlock(&kobj_ns_type_lock);
1082 
1083 	return may_mount;
1084 }
1085 
kobj_ns_grab_current(enum kobj_ns_type type)1086 void *kobj_ns_grab_current(enum kobj_ns_type type)
1087 {
1088 	void *ns = NULL;
1089 
1090 	spin_lock(&kobj_ns_type_lock);
1091 	if (kobj_ns_type_is_valid(type) && kobj_ns_ops_tbl[type])
1092 		ns = kobj_ns_ops_tbl[type]->grab_current_ns();
1093 	spin_unlock(&kobj_ns_type_lock);
1094 
1095 	return ns;
1096 }
1097 EXPORT_SYMBOL_GPL(kobj_ns_grab_current);
1098 
kobj_ns_netlink(enum kobj_ns_type type,struct sock * sk)1099 const void *kobj_ns_netlink(enum kobj_ns_type type, struct sock *sk)
1100 {
1101 	const void *ns = NULL;
1102 
1103 	spin_lock(&kobj_ns_type_lock);
1104 	if (kobj_ns_type_is_valid(type) && kobj_ns_ops_tbl[type])
1105 		ns = kobj_ns_ops_tbl[type]->netlink_ns(sk);
1106 	spin_unlock(&kobj_ns_type_lock);
1107 
1108 	return ns;
1109 }
1110 
kobj_ns_initial(enum kobj_ns_type type)1111 const void *kobj_ns_initial(enum kobj_ns_type type)
1112 {
1113 	const void *ns = NULL;
1114 
1115 	spin_lock(&kobj_ns_type_lock);
1116 	if (kobj_ns_type_is_valid(type) && kobj_ns_ops_tbl[type])
1117 		ns = kobj_ns_ops_tbl[type]->initial_ns();
1118 	spin_unlock(&kobj_ns_type_lock);
1119 
1120 	return ns;
1121 }
1122 
kobj_ns_drop(enum kobj_ns_type type,void * ns)1123 void kobj_ns_drop(enum kobj_ns_type type, void *ns)
1124 {
1125 	spin_lock(&kobj_ns_type_lock);
1126 	if (kobj_ns_type_is_valid(type) &&
1127 	    kobj_ns_ops_tbl[type] && kobj_ns_ops_tbl[type]->drop_ns)
1128 		kobj_ns_ops_tbl[type]->drop_ns(ns);
1129 	spin_unlock(&kobj_ns_type_lock);
1130 }
1131 EXPORT_SYMBOL_GPL(kobj_ns_drop);
1132