Loading...
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 */
28const 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 */
48void 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 */
66static 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
83static 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
129static 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
147static 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 */
171char *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}
186EXPORT_SYMBOL_GPL(kobject_get_path);
187
188/* add the kobject to its kset's list */
189static 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 */
201static 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
212static 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
225static 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 */
281int 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 */
324int 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}
335EXPORT_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 */
349void 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
372error:
373 pr_err("kobject (%p): %s\n", kobj, err_str);
374 dump_stack();
375}
376EXPORT_SYMBOL(kobject_init);
377
378static __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 */
426int 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}
447EXPORT_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 */
464int 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}
478EXPORT_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 */
490int 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
539out:
540 kfree_const(dup_name);
541 kfree(devpath_string);
542 kfree(devpath);
543 kobject_put(kobj);
544
545 return error;
546}
547EXPORT_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 */
554int 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);
593out:
594 kobject_put(new_parent);
595 kobject_put(kobj);
596 kfree(devpath_string);
597 kfree(devpath);
598 return error;
599}
600EXPORT_SYMBOL_GPL(kobject_move);
601
602static 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 */
635void 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}
646EXPORT_SYMBOL(kobject_del);
647
648/**
649 * kobject_get() - Increment refcount for object.
650 * @kobj: object.
651 */
652struct 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}
663EXPORT_SYMBOL(kobject_get);
664
665struct 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}
673EXPORT_SYMBOL(kobject_get_unless_zero);
674
675/*
676 * kobject_cleanup - free kobject resources.
677 * @kobj: object to cleanup
678 */
679static 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
718static 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
725static 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 */
746void 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}
756EXPORT_SYMBOL(kobject_put);
757
758static void dynamic_kobj_release(struct kobject *kobj)
759{
760 pr_debug("kobject: (%p): %s\n", kobj, __func__);
761 kfree(kobj);
762}
763
764static 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 */
780struct 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 */
805struct 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}
822EXPORT_SYMBOL_GPL(kobject_create_and_add);
823
824/**
825 * kset_init() - Initialize a kset for use.
826 * @k: kset
827 */
828void 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 */
836static 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
848static 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
860const struct sysfs_ops kobj_sysfs_ops = {
861 .show = kobj_attr_show,
862 .store = kobj_attr_store,
863};
864EXPORT_SYMBOL_GPL(kobj_sysfs_ops);
865
866/**
867 * kset_register() - Initialize and add a kset.
868 * @k: kset.
869 */
870int 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}
884EXPORT_SYMBOL(kset_register);
885
886/**
887 * kset_unregister() - Remove a kset.
888 * @k: kset.
889 */
890void kset_unregister(struct kset *k)
891{
892 if (!k)
893 return;
894 kobject_del(&k->kobj);
895 kobject_put(&k->kobj);
896}
897EXPORT_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 */
908struct 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}
925EXPORT_SYMBOL_GPL(kset_find_obj);
926
927static 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
935static 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
941static 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 */
962static 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 */
1005struct 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}
1022EXPORT_SYMBOL_GPL(kset_create_and_add);
1023
1024
1025static DEFINE_SPINLOCK(kobj_ns_type_lock);
1026static const struct kobj_ns_type_operations *kobj_ns_ops_tbl[KOBJ_NS_TYPES];
1027
1028int 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
1050out:
1051 spin_unlock(&kobj_ns_type_lock);
1052 return error;
1053}
1054
1055int 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
1067const 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
1077const struct kobj_ns_type_operations *kobj_ns_ops(struct kobject *kobj)
1078{
1079 return kobj_child_ns_ops(kobj->parent);
1080}
1081
1082bool 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
1095void *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}
1107EXPORT_SYMBOL_GPL(kobj_ns_grab_current);
1108
1109const 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
1122const 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
1135void 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}
1143EXPORT_SYMBOL_GPL(kobj_ns_drop);
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 */
30const 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 */
50void 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
59static 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
67static 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
106static 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
124static 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 */
152char *kobject_get_path(const struct kobject *kobj, gfp_t gfp_mask)
153{
154 char *path;
155 int len;
156
157retry:
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}
171EXPORT_SYMBOL_GPL(kobject_get_path);
172
173/* add the kobject to its kset's list */
174static 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 */
186static 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
197static 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
210static 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 */
266int 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 */
308int 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}
319EXPORT_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 */
333void 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
356error:
357 pr_err("kobject (%p): %s\n", kobj, err_str);
358 dump_stack_lvl(KERN_ERR);
359}
360EXPORT_SYMBOL(kobject_init);
361
362static __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 */
410int 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}
431EXPORT_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 */
448int 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}
462EXPORT_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 */
474int 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
523out:
524 kfree_const(dup_name);
525 kfree(devpath_string);
526 kfree(devpath);
527 kobject_put(kobj);
528
529 return error;
530}
531EXPORT_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 */
538int 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);
577out:
578 kobject_put(new_parent);
579 kobject_put(kobj);
580 kfree(devpath_string);
581 kfree(devpath);
582 return error;
583}
584EXPORT_SYMBOL_GPL(kobject_move);
585
586static 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 */
619void 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}
630EXPORT_SYMBOL(kobject_del);
631
632/**
633 * kobject_get() - Increment refcount for object.
634 * @kobj: object.
635 */
636struct 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}
647EXPORT_SYMBOL(kobject_get);
648
649struct 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}
657EXPORT_SYMBOL(kobject_get_unless_zero);
658
659/*
660 * kobject_cleanup - free kobject resources.
661 * @kobj: object to cleanup
662 */
663static 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
702static 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
709static 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 */
730void 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}
740EXPORT_SYMBOL(kobject_put);
741
742static void dynamic_kobj_release(struct kobject *kobj)
743{
744 pr_debug("(%p): %s\n", kobj, __func__);
745 kfree(kobj);
746}
747
748static 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 */
764static 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 */
789struct 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}
806EXPORT_SYMBOL_GPL(kobject_create_and_add);
807
808/**
809 * kset_init() - Initialize a kset for use.
810 * @k: kset
811 */
812void 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 */
820static 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
832static 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
844const struct sysfs_ops kobj_sysfs_ops = {
845 .show = kobj_attr_show,
846 .store = kobj_attr_store,
847};
848EXPORT_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 */
857int 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}
880EXPORT_SYMBOL(kset_register);
881
882/**
883 * kset_unregister() - Remove a kset.
884 * @k: kset.
885 */
886void kset_unregister(struct kset *k)
887{
888 if (!k)
889 return;
890 kobject_del(&k->kobj);
891 kobject_put(&k->kobj);
892}
893EXPORT_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 */
904struct 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}
921EXPORT_SYMBOL_GPL(kset_find_obj);
922
923static 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
931static 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
937static 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 */
958static 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 */
1001struct 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}
1018EXPORT_SYMBOL_GPL(kset_create_and_add);
1019
1020
1021static DEFINE_SPINLOCK(kobj_ns_type_lock);
1022static const struct kobj_ns_type_operations *kobj_ns_ops_tbl[KOBJ_NS_TYPES];
1023
1024int 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
1042out:
1043 spin_unlock(&kobj_ns_type_lock);
1044 return error;
1045}
1046
1047int 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
1059const 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
1069const struct kobj_ns_type_operations *kobj_ns_ops(const struct kobject *kobj)
1070{
1071 return kobj_child_ns_ops(kobj->parent);
1072}
1073
1074bool 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
1086void *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}
1097EXPORT_SYMBOL_GPL(kobj_ns_grab_current);
1098
1099const 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
1111const 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
1123void 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}
1131EXPORT_SYMBOL_GPL(kobj_ns_drop);