projects/linux·blob v6.12-rc2 · 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#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);