projects/linux·blob v2.6.23 · 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 sysfs_dirent *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_shadow_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 sysfs_dirent *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 kobject_put(kobj);
178 return -EINVAL;
179 }
180 parent = kobject_get(kobj->parent);
181
182 pr_debug("kobject %s: registering. parent: %s, set: %s\n",
183 kobject_name(kobj), parent ? kobject_name(parent) : "<NULL>",
184 kobj->kset ? kobj->kset->kobj.name : "<NULL>" );
185
186 if (kobj->kset) {
187 spin_lock(&kobj->kset->list_lock);
188
189 if (!parent)
190 parent = kobject_get(&kobj->kset->kobj);
191
192 list_add_tail(&kobj->entry,&kobj->kset->list);
193 spin_unlock(&kobj->kset->list_lock);
194 kobj->parent = parent;
195 }
196
197 error = create_dir(kobj, shadow_parent);
198 if (error) {
199 /* unlink does the kobject_put() for us */
200 unlink(kobj);
201 kobject_put(parent);
202
203 /* be noisy on error issues */
204 if (error == -EEXIST)
205 printk(KERN_ERR "kobject_add failed for %s with "
206 "-EEXIST, don't try to register things with "
207 "the same name in the same directory.\n",
208 kobject_name(kobj));
209 else
210 printk(KERN_ERR "kobject_add failed for %s (%d)\n",
211 kobject_name(kobj), error);
212 dump_stack();
213 }
214
215 return error;
216}
217
218/**
219 * kobject_add - add an object to the hierarchy.
220 * @kobj: object.
221 */
222int kobject_add(struct kobject * kobj)
223{
224 return kobject_shadow_add(kobj, NULL);
225}
226
227
228/**
229 * kobject_register - initialize and add an object.
230 * @kobj: object in question.
231 */
232
233int kobject_register(struct kobject * kobj)
234{
235 int error = -EINVAL;
236 if (kobj) {
237 kobject_init(kobj);
238 error = kobject_add(kobj);
239 if (!error)
240 kobject_uevent(kobj, KOBJ_ADD);
241 }
242 return error;
243}
244
245
246/**
247 * kobject_set_name - Set the name of an object
248 * @kobj: object.
249 * @fmt: format string used to build the name
250 *
251 * If strlen(name) >= KOBJ_NAME_LEN, then use a dynamically allocated
252 * string that @kobj->k_name points to. Otherwise, use the static
253 * @kobj->name array.
254 */
255int kobject_set_name(struct kobject * kobj, const char * fmt, ...)
256{
257 int error = 0;
258 int limit = KOBJ_NAME_LEN;
259 int need;
260 va_list args;
261 char * name;
262
263 /*
264 * First, try the static array
265 */
266 va_start(args,fmt);
267 need = vsnprintf(kobj->name,limit,fmt,args);
268 va_end(args);
269 if (need < limit)
270 name = kobj->name;
271 else {
272 /*
273 * Need more space? Allocate it and try again
274 */
275 limit = need + 1;
276 name = kmalloc(limit,GFP_KERNEL);
277 if (!name) {
278 error = -ENOMEM;
279 goto Done;
280 }
281 va_start(args,fmt);
282 need = vsnprintf(name,limit,fmt,args);
283 va_end(args);
284
285 /* Still? Give up. */
286 if (need >= limit) {
287 kfree(name);
288 error = -EFAULT;
289 goto Done;
290 }
291 }
292
293 /* Free the old name, if necessary. */
294 if (kobj->k_name && kobj->k_name != kobj->name)
295 kfree(kobj->k_name);
296
297 /* Now, set the new name */
298 kobj->k_name = name;
299 Done:
300 return error;
301}
302
303EXPORT_SYMBOL(kobject_set_name);
304
305
306/**
307 * kobject_rename - change the name of an object
308 * @kobj: object in question.
309 * @new_name: object's new name
310 */
311
312int kobject_rename(struct kobject * kobj, const char *new_name)
313{
314 int error = 0;
315 const char *devpath = NULL;
316 char *devpath_string = NULL;
317 char *envp[2];
318
319 kobj = kobject_get(kobj);
320 if (!kobj)
321 return -EINVAL;
322 if (!kobj->parent)
323 return -EINVAL;
324
325 devpath = kobject_get_path(kobj, GFP_KERNEL);
326 if (!devpath) {
327 error = -ENOMEM;
328 goto out;
329 }
330 devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
331 if (!devpath_string) {
332 error = -ENOMEM;
333 goto out;
334 }
335 sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
336 envp[0] = devpath_string;
337 envp[1] = NULL;
338 /* Note : if we want to send the new name alone, not the full path,
339 * we could probably use kobject_name(kobj); */
340
341 error = sysfs_rename_dir(kobj, kobj->parent->sd, new_name);
342
343 /* This function is mostly/only used for network interface.
344 * Some hotplug package track interfaces by their name and
345 * therefore want to know when the name is changed by the user. */
346 if (!error)
347 kobject_uevent_env(kobj, KOBJ_MOVE, envp);
348
349out:
350 kfree(devpath_string);
351 kfree(devpath);
352 kobject_put(kobj);
353
354 return error;
355}
356
357/**
358 * kobject_rename - change the name of an object
359 * @kobj: object in question.
360 * @new_parent: object's new parent
361 * @new_name: object's new name
362 */
363
364int kobject_shadow_rename(struct kobject *kobj,
365 struct sysfs_dirent *new_parent, const char *new_name)
366{
367 int error = 0;
368
369 kobj = kobject_get(kobj);
370 if (!kobj)
371 return -EINVAL;
372 error = sysfs_rename_dir(kobj, new_parent, new_name);
373 kobject_put(kobj);
374
375 return error;
376}
377
378/**
379 * kobject_move - move object to another parent
380 * @kobj: object in question.
381 * @new_parent: object's new parent (can be NULL)
382 */
383
384int kobject_move(struct kobject *kobj, struct kobject *new_parent)
385{
386 int error;
387 struct kobject *old_parent;
388 const char *devpath = NULL;
389 char *devpath_string = NULL;
390 char *envp[2];
391
392 kobj = kobject_get(kobj);
393 if (!kobj)
394 return -EINVAL;
395 new_parent = kobject_get(new_parent);
396 if (!new_parent) {
397 if (kobj->kset)
398 new_parent = kobject_get(&kobj->kset->kobj);
399 }
400 /* old object path */
401 devpath = kobject_get_path(kobj, GFP_KERNEL);
402 if (!devpath) {
403 error = -ENOMEM;
404 goto out;
405 }
406 devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
407 if (!devpath_string) {
408 error = -ENOMEM;
409 goto out;
410 }
411 sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
412 envp[0] = devpath_string;
413 envp[1] = NULL;
414 error = sysfs_move_dir(kobj, new_parent);
415 if (error)
416 goto out;
417 old_parent = kobj->parent;
418 kobj->parent = new_parent;
419 new_parent = NULL;
420 kobject_put(old_parent);
421 kobject_uevent_env(kobj, KOBJ_MOVE, envp);
422out:
423 kobject_put(new_parent);
424 kobject_put(kobj);
425 kfree(devpath_string);
426 kfree(devpath);
427 return error;
428}
429
430/**
431 * kobject_del - unlink kobject from hierarchy.
432 * @kobj: object.
433 */
434
435void kobject_del(struct kobject * kobj)
436{
437 if (!kobj)
438 return;
439 sysfs_remove_dir(kobj);
440 unlink(kobj);
441}
442
443/**
444 * kobject_unregister - remove object from hierarchy and decrement refcount.
445 * @kobj: object going away.
446 */
447
448void kobject_unregister(struct kobject * kobj)
449{
450 if (!kobj)
451 return;
452 pr_debug("kobject %s: unregistering\n",kobject_name(kobj));
453 kobject_uevent(kobj, KOBJ_REMOVE);
454 kobject_del(kobj);
455 kobject_put(kobj);
456}
457
458/**
459 * kobject_get - increment refcount for object.
460 * @kobj: object.
461 */
462
463struct kobject * kobject_get(struct kobject * kobj)
464{
465 if (kobj)
466 kref_get(&kobj->kref);
467 return kobj;
468}
469
470/**
471 * kobject_cleanup - free kobject resources.
472 * @kobj: object.
473 */
474
475void kobject_cleanup(struct kobject * kobj)
476{
477 struct kobj_type * t = get_ktype(kobj);
478 struct kset * s = kobj->kset;
479 struct kobject * parent = kobj->parent;
480
481 pr_debug("kobject %s: cleaning up\n",kobject_name(kobj));
482 if (kobj->k_name != kobj->name)
483 kfree(kobj->k_name);
484 kobj->k_name = NULL;
485 if (t && t->release)
486 t->release(kobj);
487 if (s)
488 kset_put(s);
489 kobject_put(parent);
490}
491
492static void kobject_release(struct kref *kref)
493{
494 kobject_cleanup(container_of(kref, struct kobject, kref));
495}
496
497/**
498 * kobject_put - decrement refcount for object.
499 * @kobj: object.
500 *
501 * Decrement the refcount, and if 0, call kobject_cleanup().
502 */
503void kobject_put(struct kobject * kobj)
504{
505 if (kobj)
506 kref_put(&kobj->kref, kobject_release);
507}
508
509
510static void dir_release(struct kobject *kobj)
511{
512 kfree(kobj);
513}
514
515static struct kobj_type dir_ktype = {
516 .release = dir_release,
517 .sysfs_ops = NULL,
518 .default_attrs = NULL,
519};
520
521/**
522 * kobject_kset_add_dir - add sub directory of object.
523 * @kset: kset the directory is belongs to.
524 * @parent: object in which a directory is created.
525 * @name: directory name.
526 *
527 * Add a plain directory object as child of given object.
528 */
529struct kobject *kobject_kset_add_dir(struct kset *kset,
530 struct kobject *parent, const char *name)
531{
532 struct kobject *k;
533 int ret;
534
535 if (!parent)
536 return NULL;
537
538 k = kzalloc(sizeof(*k), GFP_KERNEL);
539 if (!k)
540 return NULL;
541
542 k->kset = kset;
543 k->parent = parent;
544 k->ktype = &dir_ktype;
545 kobject_set_name(k, name);
546 ret = kobject_register(k);
547 if (ret < 0) {
548 printk(KERN_WARNING "%s: kobject_register error: %d\n",
549 __func__, ret);
550 kobject_del(k);
551 return NULL;
552 }
553
554 return k;
555}
556
557/**
558 * kobject_add_dir - add sub directory of object.
559 * @parent: object in which a directory is created.
560 * @name: directory name.
561 *
562 * Add a plain directory object as child of given object.
563 */
564struct kobject *kobject_add_dir(struct kobject *parent, const char *name)
565{
566 return kobject_kset_add_dir(NULL, parent, name);
567}
568
569/**
570 * kset_init - initialize a kset for use
571 * @k: kset
572 */
573
574void kset_init(struct kset * k)
575{
576 kobject_init(&k->kobj);
577 INIT_LIST_HEAD(&k->list);
578 spin_lock_init(&k->list_lock);
579}
580
581
582/**
583 * kset_add - add a kset object to the hierarchy.
584 * @k: kset.
585 */
586
587int kset_add(struct kset * k)
588{
589 return kobject_add(&k->kobj);
590}
591
592
593/**
594 * kset_register - initialize and add a kset.
595 * @k: kset.
596 */
597
598int kset_register(struct kset * k)
599{
600 int err;
601
602 if (!k)
603 return -EINVAL;
604
605 kset_init(k);
606 err = kset_add(k);
607 if (err)
608 return err;
609 kobject_uevent(&k->kobj, KOBJ_ADD);
610 return 0;
611}
612
613
614/**
615 * kset_unregister - remove a kset.
616 * @k: kset.
617 */
618
619void kset_unregister(struct kset * k)
620{
621 if (!k)
622 return;
623 kobject_unregister(&k->kobj);
624}
625
626
627/**
628 * kset_find_obj - search for object in kset.
629 * @kset: kset we're looking in.
630 * @name: object's name.
631 *
632 * Lock kset via @kset->subsys, and iterate over @kset->list,
633 * looking for a matching kobject. If matching object is found
634 * take a reference and return the object.
635 */
636
637struct kobject * kset_find_obj(struct kset * kset, const char * name)
638{
639 struct list_head * entry;
640 struct kobject * ret = NULL;
641
642 spin_lock(&kset->list_lock);
643 list_for_each(entry,&kset->list) {
644 struct kobject * k = to_kobj(entry);
645 if (kobject_name(k) && !strcmp(kobject_name(k),name)) {
646 ret = kobject_get(k);
647 break;
648 }
649 }
650 spin_unlock(&kset->list_lock);
651 return ret;
652}
653
654void subsystem_init(struct kset *s)
655{
656 kset_init(s);
657}
658
659int subsystem_register(struct kset *s)
660{
661 return kset_register(s);
662}
663
664void subsystem_unregister(struct kset *s)
665{
666 kset_unregister(s);
667}
668
669/**
670 * subsystem_create_file - export sysfs attribute file.
671 * @s: subsystem.
672 * @a: subsystem attribute descriptor.
673 */
674
675int subsys_create_file(struct kset *s, struct subsys_attribute *a)
676{
677 int error = 0;
678
679 if (!s || !a)
680 return -EINVAL;
681
682 if (subsys_get(s)) {
683 error = sysfs_create_file(&s->kobj, &a->attr);
684 subsys_put(s);
685 }
686 return error;
687}
688
689EXPORT_SYMBOL(kobject_init);
690EXPORT_SYMBOL(kobject_register);
691EXPORT_SYMBOL(kobject_unregister);
692EXPORT_SYMBOL(kobject_get);
693EXPORT_SYMBOL(kobject_put);
694EXPORT_SYMBOL(kobject_add);
695EXPORT_SYMBOL(kobject_del);
696
697EXPORT_SYMBOL(kset_register);
698EXPORT_SYMBOL(kset_unregister);
699
700EXPORT_SYMBOL(subsystem_register);
701EXPORT_SYMBOL(subsystem_unregister);
702EXPORT_SYMBOL(subsys_create_file);