projects/linux·blob v2.6.21 · refs

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1/*
2 * kobject.c - library routines for handling generic kernel objects
3 *
4 * Copyright (c) 2002-2003 Patrick Mochel <[email protected]>
5 *
6 * This file is released under the GPLv2.
7 *
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/module.h>
16#include <linux/stat.h>
17#include <linux/slab.h>
18
19/**
20 * populate_dir - populate directory with attributes.
21 * @kobj: object we're working on.
22 *
23 * Most subsystems have a set of default attributes that
24 * are associated with an object that registers with them.
25 * This is a helper called during object registration that
26 * loops through the default attributes of the subsystem
27 * and creates attributes files for them in sysfs.
28 *
29 */
30
31static int populate_dir(struct kobject * kobj)
32{
33 struct kobj_type * t = get_ktype(kobj);
34 struct attribute * attr;
35 int error = 0;
36 int i;
37
38 if (t && t->default_attrs) {
39 for (i = 0; (attr = t->default_attrs[i]) != NULL; i++) {
40 if ((error = sysfs_create_file(kobj,attr)))
41 break;
42 }
43 }
44 return error;
45}
46
47static int create_dir(struct kobject * kobj, struct dentry *shadow_parent)
48{
49 int error = 0;
50 if (kobject_name(kobj)) {
51 error = sysfs_create_dir(kobj, shadow_parent);
52 if (!error) {
53 if ((error = populate_dir(kobj)))
54 sysfs_remove_dir(kobj);
55 }
56 }
57 return error;
58}
59
60static inline struct kobject * to_kobj(struct list_head * entry)
61{
62 return container_of(entry,struct kobject,entry);
63}
64
65static int get_kobj_path_length(struct kobject *kobj)
66{
67 int length = 1;
68 struct kobject * parent = kobj;
69
70 /* walk up the ancestors until we hit the one pointing to the
71 * root.
72 * Add 1 to strlen for leading '/' of each level.
73 */
74 do {
75 if (kobject_name(parent) == NULL)
76 return 0;
77 length += strlen(kobject_name(parent)) + 1;
78 parent = parent->parent;
79 } while (parent);
80 return length;
81}
82
83static void fill_kobj_path(struct kobject *kobj, char *path, int length)
84{
85 struct kobject * parent;
86
87 --length;
88 for (parent = kobj; parent; parent = parent->parent) {
89 int cur = strlen(kobject_name(parent));
90 /* back up enough to print this name with '/' */
91 length -= cur;
92 strncpy (path + length, kobject_name(parent), cur);
93 *(path + --length) = '/';
94 }
95
96 pr_debug("%s: path = '%s'\n",__FUNCTION__,path);
97}
98
99/**
100 * kobject_get_path - generate and return the path associated with a given kobj and kset pair.
101 *
102 * @kobj: kobject in question, with which to build the path
103 * @gfp_mask: the allocation type used to allocate the path
104 *
105 * The result must be freed by the caller with kfree().
106 */
107char *kobject_get_path(struct kobject *kobj, gfp_t gfp_mask)
108{
109 char *path;
110 int len;
111
112 len = get_kobj_path_length(kobj);
113 if (len == 0)
114 return NULL;
115 path = kzalloc(len, gfp_mask);
116 if (!path)
117 return NULL;
118 fill_kobj_path(kobj, path, len);
119
120 return path;
121}
122EXPORT_SYMBOL_GPL(kobject_get_path);
123
124/**
125 * kobject_init - initialize object.
126 * @kobj: object in question.
127 */
128void kobject_init(struct kobject * kobj)
129{
130 if (!kobj)
131 return;
132 kref_init(&kobj->kref);
133 INIT_LIST_HEAD(&kobj->entry);
134 init_waitqueue_head(&kobj->poll);
135 kobj->kset = kset_get(kobj->kset);
136}
137
138
139/**
140 * unlink - remove kobject from kset list.
141 * @kobj: kobject.
142 *
143 * Remove the kobject from the kset list and decrement
144 * its parent's refcount.
145 * This is separated out, so we can use it in both
146 * kobject_del() and kobject_add() on error.
147 */
148
149static void unlink(struct kobject * kobj)
150{
151 if (kobj->kset) {
152 spin_lock(&kobj->kset->list_lock);
153 list_del_init(&kobj->entry);
154 spin_unlock(&kobj->kset->list_lock);
155 }
156 kobject_put(kobj);
157}
158
159/**
160 * kobject_add - add an object to the hierarchy.
161 * @kobj: object.
162 * @shadow_parent: sysfs directory to add to.
163 */
164
165int kobject_shadow_add(struct kobject * kobj, struct dentry *shadow_parent)
166{
167 int error = 0;
168 struct kobject * parent;
169
170 if (!(kobj = kobject_get(kobj)))
171 return -ENOENT;
172 if (!kobj->k_name)
173 kobj->k_name = kobj->name;
174 if (!*kobj->k_name) {
175 pr_debug("kobject attempted to be registered with no name!\n");
176 WARN_ON(1);
177 return -EINVAL;
178 }
179 parent = kobject_get(kobj->parent);
180
181 pr_debug("kobject %s: registering. parent: %s, set: %s\n",
182 kobject_name(kobj), parent ? kobject_name(parent) : "<NULL>",
183 kobj->kset ? kobj->kset->kobj.name : "<NULL>" );
184
185 if (kobj->kset) {
186 spin_lock(&kobj->kset->list_lock);
187
188 if (!parent)
189 parent = kobject_get(&kobj->kset->kobj);
190
191 list_add_tail(&kobj->entry,&kobj->kset->list);
192 spin_unlock(&kobj->kset->list_lock);
193 }
194 kobj->parent = parent;
195
196 error = create_dir(kobj, shadow_parent);
197 if (error) {
198 /* unlink does the kobject_put() for us */
199 unlink(kobj);
200 kobject_put(parent);
201
202 /* be noisy on error issues */
203 if (error == -EEXIST)
204 printk("kobject_add failed for %s with -EEXIST, "
205 "don't try to register things with the "
206 "same name in the same directory.\n",
207 kobject_name(kobj));
208 else
209 printk("kobject_add failed for %s (%d)\n",
210 kobject_name(kobj), error);
211 dump_stack();
212 }
213
214 return error;
215}
216
217/**
218 * kobject_add - add an object to the hierarchy.
219 * @kobj: object.
220 */
221int kobject_add(struct kobject * kobj)
222{
223 return kobject_shadow_add(kobj, NULL);
224}
225
226
227/**
228 * kobject_register - initialize and add an object.
229 * @kobj: object in question.
230 */
231
232int kobject_register(struct kobject * kobj)
233{
234 int error = -EINVAL;
235 if (kobj) {
236 kobject_init(kobj);
237 error = kobject_add(kobj);
238 if (!error)
239 kobject_uevent(kobj, KOBJ_ADD);
240 }
241 return error;
242}
243
244
245/**
246 * kobject_set_name - Set the name of an object
247 * @kobj: object.
248 * @fmt: format string used to build the name
249 *
250 * If strlen(name) >= KOBJ_NAME_LEN, then use a dynamically allocated
251 * string that @kobj->k_name points to. Otherwise, use the static
252 * @kobj->name array.
253 */
254int kobject_set_name(struct kobject * kobj, const char * fmt, ...)
255{
256 int error = 0;
257 int limit = KOBJ_NAME_LEN;
258 int need;
259 va_list args;
260 char * name;
261
262 /*
263 * First, try the static array
264 */
265 va_start(args,fmt);
266 need = vsnprintf(kobj->name,limit,fmt,args);
267 va_end(args);
268 if (need < limit)
269 name = kobj->name;
270 else {
271 /*
272 * Need more space? Allocate it and try again
273 */
274 limit = need + 1;
275 name = kmalloc(limit,GFP_KERNEL);
276 if (!name) {
277 error = -ENOMEM;
278 goto Done;
279 }
280 va_start(args,fmt);
281 need = vsnprintf(name,limit,fmt,args);
282 va_end(args);
283
284 /* Still? Give up. */
285 if (need >= limit) {
286 kfree(name);
287 error = -EFAULT;
288 goto Done;
289 }
290 }
291
292 /* Free the old name, if necessary. */
293 if (kobj->k_name && kobj->k_name != kobj->name)
294 kfree(kobj->k_name);
295
296 /* Now, set the new name */
297 kobj->k_name = name;
298 Done:
299 return error;
300}
301
302EXPORT_SYMBOL(kobject_set_name);
303
304
305/**
306 * kobject_rename - change the name of an object
307 * @kobj: object in question.
308 * @new_name: object's new name
309 */
310
311int kobject_rename(struct kobject * kobj, const char *new_name)
312{
313 int error = 0;
314
315 kobj = kobject_get(kobj);
316 if (!kobj)
317 return -EINVAL;
318 if (!kobj->parent)
319 return -EINVAL;
320 error = sysfs_rename_dir(kobj, kobj->parent->dentry, new_name);
321 kobject_put(kobj);
322
323 return error;
324}
325
326/**
327 * kobject_rename - change the name of an object
328 * @kobj: object in question.
329 * @new_parent: object's new parent
330 * @new_name: object's new name
331 */
332
333int kobject_shadow_rename(struct kobject * kobj, struct dentry *new_parent,
334 const char *new_name)
335{
336 int error = 0;
337
338 kobj = kobject_get(kobj);
339 if (!kobj)
340 return -EINVAL;
341 error = sysfs_rename_dir(kobj, new_parent, new_name);
342 kobject_put(kobj);
343
344 return error;
345}
346
347/**
348 * kobject_move - move object to another parent
349 * @kobj: object in question.
350 * @new_parent: object's new parent (can be NULL)
351 */
352
353int kobject_move(struct kobject *kobj, struct kobject *new_parent)
354{
355 int error;
356 struct kobject *old_parent;
357 const char *devpath = NULL;
358 char *devpath_string = NULL;
359 char *envp[2];
360
361 kobj = kobject_get(kobj);
362 if (!kobj)
363 return -EINVAL;
364 new_parent = kobject_get(new_parent);
365 if (!new_parent) {
366 if (kobj->kset)
367 new_parent = kobject_get(&kobj->kset->kobj);
368 }
369 /* old object path */
370 devpath = kobject_get_path(kobj, GFP_KERNEL);
371 if (!devpath) {
372 error = -ENOMEM;
373 goto out;
374 }
375 devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
376 if (!devpath_string) {
377 error = -ENOMEM;
378 goto out;
379 }
380 sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
381 envp[0] = devpath_string;
382 envp[1] = NULL;
383 error = sysfs_move_dir(kobj, new_parent);
384 if (error)
385 goto out;
386 old_parent = kobj->parent;
387 kobj->parent = new_parent;
388 new_parent = NULL;
389 kobject_put(old_parent);
390 kobject_uevent_env(kobj, KOBJ_MOVE, envp);
391out:
392 kobject_put(new_parent);
393 kobject_put(kobj);
394 kfree(devpath_string);
395 kfree(devpath);
396 return error;
397}
398
399/**
400 * kobject_del - unlink kobject from hierarchy.
401 * @kobj: object.
402 */
403
404void kobject_del(struct kobject * kobj)
405{
406 if (!kobj)
407 return;
408 sysfs_remove_dir(kobj);
409 unlink(kobj);
410}
411
412/**
413 * kobject_unregister - remove object from hierarchy and decrement refcount.
414 * @kobj: object going away.
415 */
416
417void kobject_unregister(struct kobject * kobj)
418{
419 if (!kobj)
420 return;
421 pr_debug("kobject %s: unregistering\n",kobject_name(kobj));
422 kobject_uevent(kobj, KOBJ_REMOVE);
423 kobject_del(kobj);
424 kobject_put(kobj);
425}
426
427/**
428 * kobject_get - increment refcount for object.
429 * @kobj: object.
430 */
431
432struct kobject * kobject_get(struct kobject * kobj)
433{
434 if (kobj)
435 kref_get(&kobj->kref);
436 return kobj;
437}
438
439/**
440 * kobject_cleanup - free kobject resources.
441 * @kobj: object.
442 */
443
444void kobject_cleanup(struct kobject * kobj)
445{
446 struct kobj_type * t = get_ktype(kobj);
447 struct kset * s = kobj->kset;
448 struct kobject * parent = kobj->parent;
449
450 pr_debug("kobject %s: cleaning up\n",kobject_name(kobj));
451 if (kobj->k_name != kobj->name)
452 kfree(kobj->k_name);
453 kobj->k_name = NULL;
454 if (t && t->release)
455 t->release(kobj);
456 if (s)
457 kset_put(s);
458 kobject_put(parent);
459}
460
461static void kobject_release(struct kref *kref)
462{
463 kobject_cleanup(container_of(kref, struct kobject, kref));
464}
465
466/**
467 * kobject_put - decrement refcount for object.
468 * @kobj: object.
469 *
470 * Decrement the refcount, and if 0, call kobject_cleanup().
471 */
472void kobject_put(struct kobject * kobj)
473{
474 if (kobj)
475 kref_put(&kobj->kref, kobject_release);
476}
477
478
479static void dir_release(struct kobject *kobj)
480{
481 kfree(kobj);
482}
483
484static struct kobj_type dir_ktype = {
485 .release = dir_release,
486 .sysfs_ops = NULL,
487 .default_attrs = NULL,
488};
489
490/**
491 * kobject_add_dir - add sub directory of object.
492 * @parent: object in which a directory is created.
493 * @name: directory name.
494 *
495 * Add a plain directory object as child of given object.
496 */
497struct kobject *kobject_add_dir(struct kobject *parent, const char *name)
498{
499 struct kobject *k;
500 int ret;
501
502 if (!parent)
503 return NULL;
504
505 k = kzalloc(sizeof(*k), GFP_KERNEL);
506 if (!k)
507 return NULL;
508
509 k->parent = parent;
510 k->ktype = &dir_ktype;
511 kobject_set_name(k, name);
512 ret = kobject_register(k);
513 if (ret < 0) {
514 printk(KERN_WARNING "kobject_add_dir: "
515 "kobject_register error: %d\n", ret);
516 kobject_del(k);
517 return NULL;
518 }
519
520 return k;
521}
522
523/**
524 * kset_init - initialize a kset for use
525 * @k: kset
526 */
527
528void kset_init(struct kset * k)
529{
530 kobject_init(&k->kobj);
531 INIT_LIST_HEAD(&k->list);
532 spin_lock_init(&k->list_lock);
533}
534
535
536/**
537 * kset_add - add a kset object to the hierarchy.
538 * @k: kset.
539 *
540 * Simply, this adds the kset's embedded kobject to the
541 * hierarchy.
542 * We also try to make sure that the kset's embedded kobject
543 * has a parent before it is added. We only care if the embedded
544 * kobject is not part of a kset itself, since kobject_add()
545 * assigns a parent in that case.
546 * If that is the case, and the kset has a controlling subsystem,
547 * then we set the kset's parent to be said subsystem.
548 */
549
550int kset_add(struct kset * k)
551{
552 if (!k->kobj.parent && !k->kobj.kset && k->subsys)
553 k->kobj.parent = &k->subsys->kset.kobj;
554
555 return kobject_add(&k->kobj);
556}
557
558
559/**
560 * kset_register - initialize and add a kset.
561 * @k: kset.
562 */
563
564int kset_register(struct kset * k)
565{
566 if (!k)
567 return -EINVAL;
568 kset_init(k);
569 return kset_add(k);
570}
571
572
573/**
574 * kset_unregister - remove a kset.
575 * @k: kset.
576 */
577
578void kset_unregister(struct kset * k)
579{
580 if (!k)
581 return;
582 kobject_unregister(&k->kobj);
583}
584
585
586/**
587 * kset_find_obj - search for object in kset.
588 * @kset: kset we're looking in.
589 * @name: object's name.
590 *
591 * Lock kset via @kset->subsys, and iterate over @kset->list,
592 * looking for a matching kobject. If matching object is found
593 * take a reference and return the object.
594 */
595
596struct kobject * kset_find_obj(struct kset * kset, const char * name)
597{
598 struct list_head * entry;
599 struct kobject * ret = NULL;
600
601 spin_lock(&kset->list_lock);
602 list_for_each(entry,&kset->list) {
603 struct kobject * k = to_kobj(entry);
604 if (kobject_name(k) && !strcmp(kobject_name(k),name)) {
605 ret = kobject_get(k);
606 break;
607 }
608 }
609 spin_unlock(&kset->list_lock);
610 return ret;
611}
612
613
614void subsystem_init(struct subsystem * s)
615{
616 init_rwsem(&s->rwsem);
617 kset_init(&s->kset);
618}
619
620/**
621 * subsystem_register - register a subsystem.
622 * @s: the subsystem we're registering.
623 *
624 * Once we register the subsystem, we want to make sure that
625 * the kset points back to this subsystem for correct usage of
626 * the rwsem.
627 */
628
629int subsystem_register(struct subsystem * s)
630{
631 int error;
632
633 if (!s)
634 return -EINVAL;
635
636 subsystem_init(s);
637 pr_debug("subsystem %s: registering\n",s->kset.kobj.name);
638
639 if (!(error = kset_add(&s->kset))) {
640 if (!s->kset.subsys)
641 s->kset.subsys = s;
642 }
643 return error;
644}
645
646void subsystem_unregister(struct subsystem * s)
647{
648 if (!s)
649 return;
650 pr_debug("subsystem %s: unregistering\n",s->kset.kobj.name);
651 kset_unregister(&s->kset);
652}
653
654
655/**
656 * subsystem_create_file - export sysfs attribute file.
657 * @s: subsystem.
658 * @a: subsystem attribute descriptor.
659 */
660
661int subsys_create_file(struct subsystem * s, struct subsys_attribute * a)
662{
663 int error = 0;
664
665 if (!s || !a)
666 return -EINVAL;
667
668 if (subsys_get(s)) {
669 error = sysfs_create_file(&s->kset.kobj,&a->attr);
670 subsys_put(s);
671 }
672 return error;
673}
674
675
676/**
677 * subsystem_remove_file - remove sysfs attribute file.
678 * @s: subsystem.
679 * @a: attribute desciptor.
680 */
681#if 0
682void subsys_remove_file(struct subsystem * s, struct subsys_attribute * a)
683{
684 if (subsys_get(s)) {
685 sysfs_remove_file(&s->kset.kobj,&a->attr);
686 subsys_put(s);
687 }
688}
689#endif /* 0 */
690
691EXPORT_SYMBOL(kobject_init);
692EXPORT_SYMBOL(kobject_register);
693EXPORT_SYMBOL(kobject_unregister);
694EXPORT_SYMBOL(kobject_get);
695EXPORT_SYMBOL(kobject_put);
696EXPORT_SYMBOL(kobject_add);
697EXPORT_SYMBOL(kobject_del);
698
699EXPORT_SYMBOL(kset_register);
700EXPORT_SYMBOL(kset_unregister);
701
702EXPORT_SYMBOL(subsystem_register);
703EXPORT_SYMBOL(subsystem_unregister);
704EXPORT_SYMBOL(subsys_create_file);