projects/linux·blob v4.16-rc4 · refs

1076 lines · 26.2 KiB

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/kobject.txt 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 * populate_dir - populate directory with attributes.
40 * @kobj: object we're working on.
41 *
42 * Most subsystems have a set of default attributes that are associated
43 * with an object that registers with them. This is a helper called during
44 * object registration that loops through the default attributes of the
45 * subsystem and creates attributes files for them in sysfs.
46 */
47static int populate_dir(struct kobject *kobj)
48{
49 struct kobj_type *t = get_ktype(kobj);
50 struct attribute *attr;
51 int error = 0;
52 int i;
53
54 if (t && t->default_attrs) {
55 for (i = 0; (attr = t->default_attrs[i]) != NULL; i++) {
56 error = sysfs_create_file(kobj, attr);
57 if (error)
58 break;
59 }
60 }
61 return error;
62}
63
64static int create_dir(struct kobject *kobj)
65{
66 const struct kobj_ns_type_operations *ops;
67 int error;
68
69 error = sysfs_create_dir_ns(kobj, kobject_namespace(kobj));
70 if (error)
71 return error;
72
73 error = populate_dir(kobj);
74 if (error) {
75 sysfs_remove_dir(kobj);
76 return error;
77 }
78
79 /*
80 * @kobj->sd may be deleted by an ancestor going away. Hold an
81 * extra reference so that it stays until @kobj is gone.
82 */
83 sysfs_get(kobj->sd);
84
85 /*
86 * If @kobj has ns_ops, its children need to be filtered based on
87 * their namespace tags. Enable namespace support on @kobj->sd.
88 */
89 ops = kobj_child_ns_ops(kobj);
90 if (ops) {
91 BUG_ON(ops->type <= KOBJ_NS_TYPE_NONE);
92 BUG_ON(ops->type >= KOBJ_NS_TYPES);
93 BUG_ON(!kobj_ns_type_registered(ops->type));
94
95 sysfs_enable_ns(kobj->sd);
96 }
97
98 return 0;
99}
100
101static int get_kobj_path_length(struct kobject *kobj)
102{
103 int length = 1;
104 struct kobject *parent = kobj;
105
106 /* walk up the ancestors until we hit the one pointing to the
107 * root.
108 * Add 1 to strlen for leading '/' of each level.
109 */
110 do {
111 if (kobject_name(parent) == NULL)
112 return 0;
113 length += strlen(kobject_name(parent)) + 1;
114 parent = parent->parent;
115 } while (parent);
116 return length;
117}
118
119static void fill_kobj_path(struct kobject *kobj, char *path, int length)
120{
121 struct kobject *parent;
122
123 --length;
124 for (parent = kobj; parent; parent = parent->parent) {
125 int cur = strlen(kobject_name(parent));
126 /* back up enough to print this name with '/' */
127 length -= cur;
128 strncpy(path + length, kobject_name(parent), cur);
129 *(path + --length) = '/';
130 }
131
132 pr_debug("kobject: '%s' (%p): %s: path = '%s'\n", kobject_name(kobj),
133 kobj, __func__, path);
134}
135
136/**
137 * kobject_get_path - generate and return the path associated with a given kobj and kset pair.
138 *
139 * @kobj: kobject in question, with which to build the path
140 * @gfp_mask: the allocation type used to allocate the path
141 *
142 * The result must be freed by the caller with kfree().
143 */
144char *kobject_get_path(struct kobject *kobj, gfp_t gfp_mask)
145{
146 char *path;
147 int len;
148
149 len = get_kobj_path_length(kobj);
150 if (len == 0)
151 return NULL;
152 path = kzalloc(len, gfp_mask);
153 if (!path)
154 return NULL;
155 fill_kobj_path(kobj, path, len);
156
157 return path;
158}
159EXPORT_SYMBOL_GPL(kobject_get_path);
160
161/* add the kobject to its kset's list */
162static void kobj_kset_join(struct kobject *kobj)
163{
164 if (!kobj->kset)
165 return;
166
167 kset_get(kobj->kset);
168 spin_lock(&kobj->kset->list_lock);
169 list_add_tail(&kobj->entry, &kobj->kset->list);
170 spin_unlock(&kobj->kset->list_lock);
171}
172
173/* remove the kobject from its kset's list */
174static void kobj_kset_leave(struct kobject *kobj)
175{
176 if (!kobj->kset)
177 return;
178
179 spin_lock(&kobj->kset->list_lock);
180 list_del_init(&kobj->entry);
181 spin_unlock(&kobj->kset->list_lock);
182 kset_put(kobj->kset);
183}
184
185static void kobject_init_internal(struct kobject *kobj)
186{
187 if (!kobj)
188 return;
189 kref_init(&kobj->kref);
190 INIT_LIST_HEAD(&kobj->entry);
191 kobj->state_in_sysfs = 0;
192 kobj->state_add_uevent_sent = 0;
193 kobj->state_remove_uevent_sent = 0;
194 kobj->state_initialized = 1;
195}
196
197
198static int kobject_add_internal(struct kobject *kobj)
199{
200 int error = 0;
201 struct kobject *parent;
202
203 if (!kobj)
204 return -ENOENT;
205
206 if (!kobj->name || !kobj->name[0]) {
207 WARN(1, "kobject: (%p): attempted to be registered with empty "
208 "name!\n", kobj);
209 return -EINVAL;
210 }
211
212 parent = kobject_get(kobj->parent);
213
214 /* join kset if set, use it as parent if we do not already have one */
215 if (kobj->kset) {
216 if (!parent)
217 parent = kobject_get(&kobj->kset->kobj);
218 kobj_kset_join(kobj);
219 kobj->parent = parent;
220 }
221
222 pr_debug("kobject: '%s' (%p): %s: parent: '%s', set: '%s'\n",
223 kobject_name(kobj), kobj, __func__,
224 parent ? kobject_name(parent) : "<NULL>",
225 kobj->kset ? kobject_name(&kobj->kset->kobj) : "<NULL>");
226
227 error = create_dir(kobj);
228 if (error) {
229 kobj_kset_leave(kobj);
230 kobject_put(parent);
231 kobj->parent = NULL;
232
233 /* be noisy on error issues */
234 if (error == -EEXIST)
235 WARN(1, "%s failed for %s with "
236 "-EEXIST, don't try to register things with "
237 "the same name in the same directory.\n",
238 __func__, kobject_name(kobj));
239 else
240 WARN(1, "%s failed for %s (error: %d parent: %s)\n",
241 __func__, kobject_name(kobj), error,
242 parent ? kobject_name(parent) : "'none'");
243 } else
244 kobj->state_in_sysfs = 1;
245
246 return error;
247}
248
249/**
250 * kobject_set_name_vargs - Set the name of an kobject
251 * @kobj: struct kobject to set the name of
252 * @fmt: format string used to build the name
253 * @vargs: vargs to format the string.
254 */
255int kobject_set_name_vargs(struct kobject *kobj, const char *fmt,
256 va_list vargs)
257{
258 const char *s;
259
260 if (kobj->name && !fmt)
261 return 0;
262
263 s = kvasprintf_const(GFP_KERNEL, fmt, vargs);
264 if (!s)
265 return -ENOMEM;
266
267 /*
268 * ewww... some of these buggers have '/' in the name ... If
269 * that's the case, we need to make sure we have an actual
270 * allocated copy to modify, since kvasprintf_const may have
271 * returned something from .rodata.
272 */
273 if (strchr(s, '/')) {
274 char *t;
275
276 t = kstrdup(s, GFP_KERNEL);
277 kfree_const(s);
278 if (!t)
279 return -ENOMEM;
280 strreplace(t, '/', '!');
281 s = t;
282 }
283 kfree_const(kobj->name);
284 kobj->name = s;
285
286 return 0;
287}
288
289/**
290 * kobject_set_name - Set the name of a kobject
291 * @kobj: struct kobject to set the name of
292 * @fmt: format string used to build the name
293 *
294 * This sets the name of the kobject. If you have already added the
295 * kobject to the system, you must call kobject_rename() in order to
296 * change the name of the kobject.
297 */
298int kobject_set_name(struct kobject *kobj, const char *fmt, ...)
299{
300 va_list vargs;
301 int retval;
302
303 va_start(vargs, fmt);
304 retval = kobject_set_name_vargs(kobj, fmt, vargs);
305 va_end(vargs);
306
307 return retval;
308}
309EXPORT_SYMBOL(kobject_set_name);
310
311/**
312 * kobject_init - initialize a kobject structure
313 * @kobj: pointer to the kobject to initialize
314 * @ktype: pointer to the ktype for this kobject.
315 *
316 * This function will properly initialize a kobject such that it can then
317 * be passed to the kobject_add() call.
318 *
319 * After this function is called, the kobject MUST be cleaned up by a call
320 * to kobject_put(), not by a call to kfree directly to ensure that all of
321 * the memory is cleaned up properly.
322 */
323void kobject_init(struct kobject *kobj, struct kobj_type *ktype)
324{
325 char *err_str;
326
327 if (!kobj) {
328 err_str = "invalid kobject pointer!";
329 goto error;
330 }
331 if (!ktype) {
332 err_str = "must have a ktype to be initialized properly!\n";
333 goto error;
334 }
335 if (kobj->state_initialized) {
336 /* do not error out as sometimes we can recover */
337 printk(KERN_ERR "kobject (%p): tried to init an initialized "
338 "object, something is seriously wrong.\n", kobj);
339 dump_stack();
340 }
341
342 kobject_init_internal(kobj);
343 kobj->ktype = ktype;
344 return;
345
346error:
347 printk(KERN_ERR "kobject (%p): %s\n", kobj, err_str);
348 dump_stack();
349}
350EXPORT_SYMBOL(kobject_init);
351
352static __printf(3, 0) int kobject_add_varg(struct kobject *kobj,
353 struct kobject *parent,
354 const char *fmt, va_list vargs)
355{
356 int retval;
357
358 retval = kobject_set_name_vargs(kobj, fmt, vargs);
359 if (retval) {
360 printk(KERN_ERR "kobject: can not set name properly!\n");
361 return retval;
362 }
363 kobj->parent = parent;
364 return kobject_add_internal(kobj);
365}
366
367/**
368 * kobject_add - the main kobject add function
369 * @kobj: the kobject to add
370 * @parent: pointer to the parent of the kobject.
371 * @fmt: format to name the kobject with.
372 *
373 * The kobject name is set and added to the kobject hierarchy in this
374 * function.
375 *
376 * If @parent is set, then the parent of the @kobj will be set to it.
377 * If @parent is NULL, then the parent of the @kobj will be set to the
378 * kobject associated with the kset assigned to this kobject. If no kset
379 * is assigned to the kobject, then the kobject will be located in the
380 * root of the sysfs tree.
381 *
382 * If this function returns an error, kobject_put() must be called to
383 * properly clean up the memory associated with the object.
384 * Under no instance should the kobject that is passed to this function
385 * be directly freed with a call to kfree(), that can leak memory.
386 *
387 * Note, no "add" uevent will be created with this call, the caller should set
388 * up all of the necessary sysfs files for the object and then call
389 * kobject_uevent() with the UEVENT_ADD parameter to ensure that
390 * userspace is properly notified of this kobject's creation.
391 */
392int kobject_add(struct kobject *kobj, struct kobject *parent,
393 const char *fmt, ...)
394{
395 va_list args;
396 int retval;
397
398 if (!kobj)
399 return -EINVAL;
400
401 if (!kobj->state_initialized) {
402 printk(KERN_ERR "kobject '%s' (%p): tried to add an "
403 "uninitialized object, something is seriously wrong.\n",
404 kobject_name(kobj), kobj);
405 dump_stack();
406 return -EINVAL;
407 }
408 va_start(args, fmt);
409 retval = kobject_add_varg(kobj, parent, fmt, args);
410 va_end(args);
411
412 return retval;
413}
414EXPORT_SYMBOL(kobject_add);
415
416/**
417 * kobject_init_and_add - initialize a kobject structure and add it to the kobject hierarchy
418 * @kobj: pointer to the kobject to initialize
419 * @ktype: pointer to the ktype for this kobject.
420 * @parent: pointer to the parent of this kobject.
421 * @fmt: the name of the kobject.
422 *
423 * This function combines the call to kobject_init() and
424 * kobject_add(). The same type of error handling after a call to
425 * kobject_add() and kobject lifetime rules are the same here.
426 */
427int kobject_init_and_add(struct kobject *kobj, struct kobj_type *ktype,
428 struct kobject *parent, const char *fmt, ...)
429{
430 va_list args;
431 int retval;
432
433 kobject_init(kobj, ktype);
434
435 va_start(args, fmt);
436 retval = kobject_add_varg(kobj, parent, fmt, args);
437 va_end(args);
438
439 return retval;
440}
441EXPORT_SYMBOL_GPL(kobject_init_and_add);
442
443/**
444 * kobject_rename - change the name of an object
445 * @kobj: object in question.
446 * @new_name: object's new name
447 *
448 * It is the responsibility of the caller to provide mutual
449 * exclusion between two different calls of kobject_rename
450 * on the same kobject and to ensure that new_name is valid and
451 * won't conflict with other kobjects.
452 */
453int kobject_rename(struct kobject *kobj, const char *new_name)
454{
455 int error = 0;
456 const char *devpath = NULL;
457 const char *dup_name = NULL, *name;
458 char *devpath_string = NULL;
459 char *envp[2];
460
461 kobj = kobject_get(kobj);
462 if (!kobj)
463 return -EINVAL;
464 if (!kobj->parent)
465 return -EINVAL;
466
467 devpath = kobject_get_path(kobj, GFP_KERNEL);
468 if (!devpath) {
469 error = -ENOMEM;
470 goto out;
471 }
472 devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
473 if (!devpath_string) {
474 error = -ENOMEM;
475 goto out;
476 }
477 sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
478 envp[0] = devpath_string;
479 envp[1] = NULL;
480
481 name = dup_name = kstrdup_const(new_name, GFP_KERNEL);
482 if (!name) {
483 error = -ENOMEM;
484 goto out;
485 }
486
487 error = sysfs_rename_dir_ns(kobj, new_name, kobject_namespace(kobj));
488 if (error)
489 goto out;
490
491 /* Install the new kobject name */
492 dup_name = kobj->name;
493 kobj->name = name;
494
495 /* This function is mostly/only used for network interface.
496 * Some hotplug package track interfaces by their name and
497 * therefore want to know when the name is changed by the user. */
498 kobject_uevent_env(kobj, KOBJ_MOVE, envp);
499
500out:
501 kfree_const(dup_name);
502 kfree(devpath_string);
503 kfree(devpath);
504 kobject_put(kobj);
505
506 return error;
507}
508EXPORT_SYMBOL_GPL(kobject_rename);
509
510/**
511 * kobject_move - move object to another parent
512 * @kobj: object in question.
513 * @new_parent: object's new parent (can be NULL)
514 */
515int kobject_move(struct kobject *kobj, struct kobject *new_parent)
516{
517 int error;
518 struct kobject *old_parent;
519 const char *devpath = NULL;
520 char *devpath_string = NULL;
521 char *envp[2];
522
523 kobj = kobject_get(kobj);
524 if (!kobj)
525 return -EINVAL;
526 new_parent = kobject_get(new_parent);
527 if (!new_parent) {
528 if (kobj->kset)
529 new_parent = kobject_get(&kobj->kset->kobj);
530 }
531
532 /* old object path */
533 devpath = kobject_get_path(kobj, GFP_KERNEL);
534 if (!devpath) {
535 error = -ENOMEM;
536 goto out;
537 }
538 devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
539 if (!devpath_string) {
540 error = -ENOMEM;
541 goto out;
542 }
543 sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
544 envp[0] = devpath_string;
545 envp[1] = NULL;
546 error = sysfs_move_dir_ns(kobj, new_parent, kobject_namespace(kobj));
547 if (error)
548 goto out;
549 old_parent = kobj->parent;
550 kobj->parent = new_parent;
551 new_parent = NULL;
552 kobject_put(old_parent);
553 kobject_uevent_env(kobj, KOBJ_MOVE, envp);
554out:
555 kobject_put(new_parent);
556 kobject_put(kobj);
557 kfree(devpath_string);
558 kfree(devpath);
559 return error;
560}
561EXPORT_SYMBOL_GPL(kobject_move);
562
563/**
564 * kobject_del - unlink kobject from hierarchy.
565 * @kobj: object.
566 */
567void kobject_del(struct kobject *kobj)
568{
569 struct kernfs_node *sd;
570
571 if (!kobj)
572 return;
573
574 sd = kobj->sd;
575 sysfs_remove_dir(kobj);
576 sysfs_put(sd);
577
578 kobj->state_in_sysfs = 0;
579 kobj_kset_leave(kobj);
580 kobject_put(kobj->parent);
581 kobj->parent = NULL;
582}
583EXPORT_SYMBOL(kobject_del);
584
585/**
586 * kobject_get - increment refcount for object.
587 * @kobj: object.
588 */
589struct kobject *kobject_get(struct kobject *kobj)
590{
591 if (kobj) {
592 if (!kobj->state_initialized)
593 WARN(1, KERN_WARNING "kobject: '%s' (%p): is not "
594 "initialized, yet kobject_get() is being "
595 "called.\n", kobject_name(kobj), kobj);
596 kref_get(&kobj->kref);
597 }
598 return kobj;
599}
600EXPORT_SYMBOL(kobject_get);
601
602struct kobject * __must_check kobject_get_unless_zero(struct kobject *kobj)
603{
604 if (!kobj)
605 return NULL;
606 if (!kref_get_unless_zero(&kobj->kref))
607 kobj = NULL;
608 return kobj;
609}
610EXPORT_SYMBOL(kobject_get_unless_zero);
611
612/*
613 * kobject_cleanup - free kobject resources.
614 * @kobj: object to cleanup
615 */
616static void kobject_cleanup(struct kobject *kobj)
617{
618 struct kobj_type *t = get_ktype(kobj);
619 const char *name = kobj->name;
620
621 pr_debug("kobject: '%s' (%p): %s, parent %p\n",
622 kobject_name(kobj), kobj, __func__, kobj->parent);
623
624 if (t && !t->release)
625 pr_debug("kobject: '%s' (%p): does not have a release() "
626 "function, it is broken and must be fixed.\n",
627 kobject_name(kobj), kobj);
628
629 /* send "remove" if the caller did not do it but sent "add" */
630 if (kobj->state_add_uevent_sent && !kobj->state_remove_uevent_sent) {
631 pr_debug("kobject: '%s' (%p): auto cleanup 'remove' event\n",
632 kobject_name(kobj), kobj);
633 kobject_uevent(kobj, KOBJ_REMOVE);
634 }
635
636 /* remove from sysfs if the caller did not do it */
637 if (kobj->state_in_sysfs) {
638 pr_debug("kobject: '%s' (%p): auto cleanup kobject_del\n",
639 kobject_name(kobj), kobj);
640 kobject_del(kobj);
641 }
642
643 if (t && t->release) {
644 pr_debug("kobject: '%s' (%p): calling ktype release\n",
645 kobject_name(kobj), kobj);
646 t->release(kobj);
647 }
648
649 /* free name if we allocated it */
650 if (name) {
651 pr_debug("kobject: '%s': free name\n", name);
652 kfree_const(name);
653 }
654}
655
656#ifdef CONFIG_DEBUG_KOBJECT_RELEASE
657static void kobject_delayed_cleanup(struct work_struct *work)
658{
659 kobject_cleanup(container_of(to_delayed_work(work),
660 struct kobject, release));
661}
662#endif
663
664static void kobject_release(struct kref *kref)
665{
666 struct kobject *kobj = container_of(kref, struct kobject, kref);
667#ifdef CONFIG_DEBUG_KOBJECT_RELEASE
668 unsigned long delay = HZ + HZ * (get_random_int() & 0x3);
669 pr_info("kobject: '%s' (%p): %s, parent %p (delayed %ld)\n",
670 kobject_name(kobj), kobj, __func__, kobj->parent, delay);
671 INIT_DELAYED_WORK(&kobj->release, kobject_delayed_cleanup);
672
673 schedule_delayed_work(&kobj->release, delay);
674#else
675 kobject_cleanup(kobj);
676#endif
677}
678
679/**
680 * kobject_put - decrement refcount for object.
681 * @kobj: object.
682 *
683 * Decrement the refcount, and if 0, call kobject_cleanup().
684 */
685void kobject_put(struct kobject *kobj)
686{
687 if (kobj) {
688 if (!kobj->state_initialized)
689 WARN(1, KERN_WARNING "kobject: '%s' (%p): is not "
690 "initialized, yet kobject_put() is being "
691 "called.\n", kobject_name(kobj), kobj);
692 kref_put(&kobj->kref, kobject_release);
693 }
694}
695EXPORT_SYMBOL(kobject_put);
696
697static void dynamic_kobj_release(struct kobject *kobj)
698{
699 pr_debug("kobject: (%p): %s\n", kobj, __func__);
700 kfree(kobj);
701}
702
703static struct kobj_type dynamic_kobj_ktype = {
704 .release = dynamic_kobj_release,
705 .sysfs_ops = &kobj_sysfs_ops,
706};
707
708/**
709 * kobject_create - create a struct kobject dynamically
710 *
711 * This function creates a kobject structure dynamically and sets it up
712 * to be a "dynamic" kobject with a default release function set up.
713 *
714 * If the kobject was not able to be created, NULL will be returned.
715 * The kobject structure returned from here must be cleaned up with a
716 * call to kobject_put() and not kfree(), as kobject_init() has
717 * already been called on this structure.
718 */
719struct kobject *kobject_create(void)
720{
721 struct kobject *kobj;
722
723 kobj = kzalloc(sizeof(*kobj), GFP_KERNEL);
724 if (!kobj)
725 return NULL;
726
727 kobject_init(kobj, &dynamic_kobj_ktype);
728 return kobj;
729}
730
731/**
732 * kobject_create_and_add - create a struct kobject dynamically and register it with sysfs
733 *
734 * @name: the name for the kobject
735 * @parent: the parent kobject of this kobject, if any.
736 *
737 * This function creates a kobject structure dynamically and registers it
738 * with sysfs. When you are finished with this structure, call
739 * kobject_put() and the structure will be dynamically freed when
740 * it is no longer being used.
741 *
742 * If the kobject was not able to be created, NULL will be returned.
743 */
744struct kobject *kobject_create_and_add(const char *name, struct kobject *parent)
745{
746 struct kobject *kobj;
747 int retval;
748
749 kobj = kobject_create();
750 if (!kobj)
751 return NULL;
752
753 retval = kobject_add(kobj, parent, "%s", name);
754 if (retval) {
755 printk(KERN_WARNING "%s: kobject_add error: %d\n",
756 __func__, retval);
757 kobject_put(kobj);
758 kobj = NULL;
759 }
760 return kobj;
761}
762EXPORT_SYMBOL_GPL(kobject_create_and_add);
763
764/**
765 * kset_init - initialize a kset for use
766 * @k: kset
767 */
768void kset_init(struct kset *k)
769{
770 kobject_init_internal(&k->kobj);
771 INIT_LIST_HEAD(&k->list);
772 spin_lock_init(&k->list_lock);
773}
774
775/* default kobject attribute operations */
776static ssize_t kobj_attr_show(struct kobject *kobj, struct attribute *attr,
777 char *buf)
778{
779 struct kobj_attribute *kattr;
780 ssize_t ret = -EIO;
781
782 kattr = container_of(attr, struct kobj_attribute, attr);
783 if (kattr->show)
784 ret = kattr->show(kobj, kattr, buf);
785 return ret;
786}
787
788static ssize_t kobj_attr_store(struct kobject *kobj, struct attribute *attr,
789 const char *buf, size_t count)
790{
791 struct kobj_attribute *kattr;
792 ssize_t ret = -EIO;
793
794 kattr = container_of(attr, struct kobj_attribute, attr);
795 if (kattr->store)
796 ret = kattr->store(kobj, kattr, buf, count);
797 return ret;
798}
799
800const struct sysfs_ops kobj_sysfs_ops = {
801 .show = kobj_attr_show,
802 .store = kobj_attr_store,
803};
804EXPORT_SYMBOL_GPL(kobj_sysfs_ops);
805
806/**
807 * kset_register - initialize and add a kset.
808 * @k: kset.
809 */
810int kset_register(struct kset *k)
811{
812 int err;
813
814 if (!k)
815 return -EINVAL;
816
817 kset_init(k);
818 err = kobject_add_internal(&k->kobj);
819 if (err)
820 return err;
821 kobject_uevent(&k->kobj, KOBJ_ADD);
822 return 0;
823}
824EXPORT_SYMBOL(kset_register);
825
826/**
827 * kset_unregister - remove a kset.
828 * @k: kset.
829 */
830void kset_unregister(struct kset *k)
831{
832 if (!k)
833 return;
834 kobject_del(&k->kobj);
835 kobject_put(&k->kobj);
836}
837EXPORT_SYMBOL(kset_unregister);
838
839/**
840 * kset_find_obj - search for object in kset.
841 * @kset: kset we're looking in.
842 * @name: object's name.
843 *
844 * Lock kset via @kset->subsys, and iterate over @kset->list,
845 * looking for a matching kobject. If matching object is found
846 * take a reference and return the object.
847 */
848struct kobject *kset_find_obj(struct kset *kset, const char *name)
849{
850 struct kobject *k;
851 struct kobject *ret = NULL;
852
853 spin_lock(&kset->list_lock);
854
855 list_for_each_entry(k, &kset->list, entry) {
856 if (kobject_name(k) && !strcmp(kobject_name(k), name)) {
857 ret = kobject_get_unless_zero(k);
858 break;
859 }
860 }
861
862 spin_unlock(&kset->list_lock);
863 return ret;
864}
865EXPORT_SYMBOL_GPL(kset_find_obj);
866
867static void kset_release(struct kobject *kobj)
868{
869 struct kset *kset = container_of(kobj, struct kset, kobj);
870 pr_debug("kobject: '%s' (%p): %s\n",
871 kobject_name(kobj), kobj, __func__);
872 kfree(kset);
873}
874
875static struct kobj_type kset_ktype = {
876 .sysfs_ops = &kobj_sysfs_ops,
877 .release = kset_release,
878};
879
880/**
881 * kset_create - create a struct kset dynamically
882 *
883 * @name: the name for the kset
884 * @uevent_ops: a struct kset_uevent_ops for the kset
885 * @parent_kobj: the parent kobject of this kset, if any.
886 *
887 * This function creates a kset structure dynamically. This structure can
888 * then be registered with the system and show up in sysfs with a call to
889 * kset_register(). When you are finished with this structure, if
890 * kset_register() has been called, call kset_unregister() and the
891 * structure will be dynamically freed when it is no longer being used.
892 *
893 * If the kset was not able to be created, NULL will be returned.
894 */
895static struct kset *kset_create(const char *name,
896 const struct kset_uevent_ops *uevent_ops,
897 struct kobject *parent_kobj)
898{
899 struct kset *kset;
900 int retval;
901
902 kset = kzalloc(sizeof(*kset), GFP_KERNEL);
903 if (!kset)
904 return NULL;
905 retval = kobject_set_name(&kset->kobj, "%s", name);
906 if (retval) {
907 kfree(kset);
908 return NULL;
909 }
910 kset->uevent_ops = uevent_ops;
911 kset->kobj.parent = parent_kobj;
912
913 /*
914 * The kobject of this kset will have a type of kset_ktype and belong to
915 * no kset itself. That way we can properly free it when it is
916 * finished being used.
917 */
918 kset->kobj.ktype = &kset_ktype;
919 kset->kobj.kset = NULL;
920
921 return kset;
922}
923
924/**
925 * kset_create_and_add - create a struct kset dynamically and add it to sysfs
926 *
927 * @name: the name for the kset
928 * @uevent_ops: a struct kset_uevent_ops for the kset
929 * @parent_kobj: the parent kobject of this kset, if any.
930 *
931 * This function creates a kset structure dynamically and registers it
932 * with sysfs. When you are finished with this structure, call
933 * kset_unregister() and the structure will be dynamically freed when it
934 * is no longer being used.
935 *
936 * If the kset was not able to be created, NULL will be returned.
937 */
938struct kset *kset_create_and_add(const char *name,
939 const struct kset_uevent_ops *uevent_ops,
940 struct kobject *parent_kobj)
941{
942 struct kset *kset;
943 int error;
944
945 kset = kset_create(name, uevent_ops, parent_kobj);
946 if (!kset)
947 return NULL;
948 error = kset_register(kset);
949 if (error) {
950 kfree(kset);
951 return NULL;
952 }
953 return kset;
954}
955EXPORT_SYMBOL_GPL(kset_create_and_add);
956
957
958static DEFINE_SPINLOCK(kobj_ns_type_lock);
959static const struct kobj_ns_type_operations *kobj_ns_ops_tbl[KOBJ_NS_TYPES];
960
961int kobj_ns_type_register(const struct kobj_ns_type_operations *ops)
962{
963 enum kobj_ns_type type = ops->type;
964 int error;
965
966 spin_lock(&kobj_ns_type_lock);
967
968 error = -EINVAL;
969 if (type >= KOBJ_NS_TYPES)
970 goto out;
971
972 error = -EINVAL;
973 if (type <= KOBJ_NS_TYPE_NONE)
974 goto out;
975
976 error = -EBUSY;
977 if (kobj_ns_ops_tbl[type])
978 goto out;
979
980 error = 0;
981 kobj_ns_ops_tbl[type] = ops;
982
983out:
984 spin_unlock(&kobj_ns_type_lock);
985 return error;
986}
987
988int kobj_ns_type_registered(enum kobj_ns_type type)
989{
990 int registered = 0;
991
992 spin_lock(&kobj_ns_type_lock);
993 if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES))
994 registered = kobj_ns_ops_tbl[type] != NULL;
995 spin_unlock(&kobj_ns_type_lock);
996
997 return registered;
998}
999
1000const struct kobj_ns_type_operations *kobj_child_ns_ops(struct kobject *parent)
1001{
1002 const struct kobj_ns_type_operations *ops = NULL;
1003
1004 if (parent && parent->ktype && parent->ktype->child_ns_type)
1005 ops = parent->ktype->child_ns_type(parent);
1006
1007 return ops;
1008}
1009
1010const struct kobj_ns_type_operations *kobj_ns_ops(struct kobject *kobj)
1011{
1012 return kobj_child_ns_ops(kobj->parent);
1013}
1014
1015bool kobj_ns_current_may_mount(enum kobj_ns_type type)
1016{
1017 bool may_mount = true;
1018
1019 spin_lock(&kobj_ns_type_lock);
1020 if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1021 kobj_ns_ops_tbl[type])
1022 may_mount = kobj_ns_ops_tbl[type]->current_may_mount();
1023 spin_unlock(&kobj_ns_type_lock);
1024
1025 return may_mount;
1026}
1027
1028void *kobj_ns_grab_current(enum kobj_ns_type type)
1029{
1030 void *ns = NULL;
1031
1032 spin_lock(&kobj_ns_type_lock);
1033 if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1034 kobj_ns_ops_tbl[type])
1035 ns = kobj_ns_ops_tbl[type]->grab_current_ns();
1036 spin_unlock(&kobj_ns_type_lock);
1037
1038 return ns;
1039}
1040EXPORT_SYMBOL_GPL(kobj_ns_grab_current);
1041
1042const void *kobj_ns_netlink(enum kobj_ns_type type, struct sock *sk)
1043{
1044 const void *ns = NULL;
1045
1046 spin_lock(&kobj_ns_type_lock);
1047 if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1048 kobj_ns_ops_tbl[type])
1049 ns = kobj_ns_ops_tbl[type]->netlink_ns(sk);
1050 spin_unlock(&kobj_ns_type_lock);
1051
1052 return ns;
1053}
1054
1055const void *kobj_ns_initial(enum kobj_ns_type type)
1056{
1057 const void *ns = NULL;
1058
1059 spin_lock(&kobj_ns_type_lock);
1060 if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1061 kobj_ns_ops_tbl[type])
1062 ns = kobj_ns_ops_tbl[type]->initial_ns();
1063 spin_unlock(&kobj_ns_type_lock);
1064
1065 return ns;
1066}
1067
1068void kobj_ns_drop(enum kobj_ns_type type, void *ns)
1069{
1070 spin_lock(&kobj_ns_type_lock);
1071 if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1072 kobj_ns_ops_tbl[type] && kobj_ns_ops_tbl[type]->drop_ns)
1073 kobj_ns_ops_tbl[type]->drop_ns(ns);
1074 spin_unlock(&kobj_ns_type_lock);
1075}
1076EXPORT_SYMBOL_GPL(kobj_ns_drop);