projects/linux·blob v6.1 · refs

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