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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /lib/kobject.c
Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'lib/kobject.c')
-rw-r--r--lib/kobject.c544
1 files changed, 544 insertions, 0 deletions
diff --git a/lib/kobject.c b/lib/kobject.c
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index 000000000000..ff9491986b38
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+++ b/lib/kobject.c
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1/*
2 * kobject.c - library routines for handling generic kernel objects
3 *
4 * Copyright (c) 2002-2003 Patrick Mochel <mochel@osdl.org>
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
18/**
19 * populate_dir - populate directory with attributes.
20 * @kobj: object we're working on.
21 *
22 * Most subsystems have a set of default attributes that
23 * are associated with an object that registers with them.
24 * This is a helper called during object registration that
25 * loops through the default attributes of the subsystem
26 * and creates attributes files for them in sysfs.
27 *
28 */
29
30static int populate_dir(struct kobject * kobj)
31{
32 struct kobj_type * t = get_ktype(kobj);
33 struct attribute * attr;
34 int error = 0;
35 int i;
36
37 if (t && t->default_attrs) {
38 for (i = 0; (attr = t->default_attrs[i]) != NULL; i++) {
39 if ((error = sysfs_create_file(kobj,attr)))
40 break;
41 }
42 }
43 return error;
44}
45
46static int create_dir(struct kobject * kobj)
47{
48 int error = 0;
49 if (kobject_name(kobj)) {
50 error = sysfs_create_dir(kobj);
51 if (!error) {
52 if ((error = populate_dir(kobj)))
53 sysfs_remove_dir(kobj);
54 }
55 }
56 return error;
57}
58
59static inline struct kobject * to_kobj(struct list_head * entry)
60{
61 return container_of(entry,struct kobject,entry);
62}
63
64static int get_kobj_path_length(struct kobject *kobj)
65{
66 int length = 1;
67 struct kobject * parent = kobj;
68
69 /* walk up the ancestors until we hit the one pointing to the
70 * root.
71 * Add 1 to strlen for leading '/' of each level.
72 */
73 do {
74 length += strlen(kobject_name(parent)) + 1;
75 parent = parent->parent;
76 } while (parent);
77 return length;
78}
79
80static void fill_kobj_path(struct kobject *kobj, char *path, int length)
81{
82 struct kobject * parent;
83
84 --length;
85 for (parent = kobj; parent; parent = parent->parent) {
86 int cur = strlen(kobject_name(parent));
87 /* back up enough to print this name with '/' */
88 length -= cur;
89 strncpy (path + length, kobject_name(parent), cur);
90 *(path + --length) = '/';
91 }
92
93 pr_debug("%s: path = '%s'\n",__FUNCTION__,path);
94}
95
96/**
97 * kobject_get_path - generate and return the path associated with a given kobj
98 * and kset pair. The result must be freed by the caller with kfree().
99 *
100 * @kobj: kobject in question, with which to build the path
101 * @gfp_mask: the allocation type used to allocate the path
102 */
103char *kobject_get_path(struct kobject *kobj, int gfp_mask)
104{
105 char *path;
106 int len;
107
108 len = get_kobj_path_length(kobj);
109 path = kmalloc(len, gfp_mask);
110 if (!path)
111 return NULL;
112 memset(path, 0x00, len);
113 fill_kobj_path(kobj, path, len);
114
115 return path;
116}
117
118/**
119 * kobject_init - initialize object.
120 * @kobj: object in question.
121 */
122void kobject_init(struct kobject * kobj)
123{
124 kref_init(&kobj->kref);
125 INIT_LIST_HEAD(&kobj->entry);
126 kobj->kset = kset_get(kobj->kset);
127}
128
129
130/**
131 * unlink - remove kobject from kset list.
132 * @kobj: kobject.
133 *
134 * Remove the kobject from the kset list and decrement
135 * its parent's refcount.
136 * This is separated out, so we can use it in both
137 * kobject_del() and kobject_add() on error.
138 */
139
140static void unlink(struct kobject * kobj)
141{
142 if (kobj->kset) {
143 spin_lock(&kobj->kset->list_lock);
144 list_del_init(&kobj->entry);
145 spin_unlock(&kobj->kset->list_lock);
146 }
147 kobject_put(kobj);
148}
149
150/**
151 * kobject_add - add an object to the hierarchy.
152 * @kobj: object.
153 */
154
155int kobject_add(struct kobject * kobj)
156{
157 int error = 0;
158 struct kobject * parent;
159
160 if (!(kobj = kobject_get(kobj)))
161 return -ENOENT;
162 if (!kobj->k_name)
163 kobj->k_name = kobj->name;
164 parent = kobject_get(kobj->parent);
165
166 pr_debug("kobject %s: registering. parent: %s, set: %s\n",
167 kobject_name(kobj), parent ? kobject_name(parent) : "<NULL>",
168 kobj->kset ? kobj->kset->kobj.name : "<NULL>" );
169
170 if (kobj->kset) {
171 spin_lock(&kobj->kset->list_lock);
172
173 if (!parent)
174 parent = kobject_get(&kobj->kset->kobj);
175
176 list_add_tail(&kobj->entry,&kobj->kset->list);
177 spin_unlock(&kobj->kset->list_lock);
178 }
179 kobj->parent = parent;
180
181 error = create_dir(kobj);
182 if (error) {
183 /* unlink does the kobject_put() for us */
184 unlink(kobj);
185 if (parent)
186 kobject_put(parent);
187 } else {
188 kobject_hotplug(kobj, KOBJ_ADD);
189 }
190
191 return error;
192}
193
194
195/**
196 * kobject_register - initialize and add an object.
197 * @kobj: object in question.
198 */
199
200int kobject_register(struct kobject * kobj)
201{
202 int error = 0;
203 if (kobj) {
204 kobject_init(kobj);
205 error = kobject_add(kobj);
206 if (error) {
207 printk("kobject_register failed for %s (%d)\n",
208 kobject_name(kobj),error);
209 dump_stack();
210 }
211 } else
212 error = -EINVAL;
213 return error;
214}
215
216
217/**
218 * kobject_set_name - Set the name of an object
219 * @kobj: object.
220 * @name: name.
221 *
222 * If strlen(name) >= KOBJ_NAME_LEN, then use a dynamically allocated
223 * string that @kobj->k_name points to. Otherwise, use the static
224 * @kobj->name array.
225 */
226
227int kobject_set_name(struct kobject * kobj, const char * fmt, ...)
228{
229 int error = 0;
230 int limit = KOBJ_NAME_LEN;
231 int need;
232 va_list args;
233 char * name;
234
235 /*
236 * First, try the static array
237 */
238 va_start(args,fmt);
239 need = vsnprintf(kobj->name,limit,fmt,args);
240 va_end(args);
241 if (need < limit)
242 name = kobj->name;
243 else {
244 /*
245 * Need more space? Allocate it and try again
246 */
247 limit = need + 1;
248 name = kmalloc(limit,GFP_KERNEL);
249 if (!name) {
250 error = -ENOMEM;
251 goto Done;
252 }
253 va_start(args,fmt);
254 need = vsnprintf(name,limit,fmt,args);
255 va_end(args);
256
257 /* Still? Give up. */
258 if (need >= limit) {
259 kfree(name);
260 error = -EFAULT;
261 goto Done;
262 }
263 }
264
265 /* Free the old name, if necessary. */
266 if (kobj->k_name && kobj->k_name != kobj->name)
267 kfree(kobj->k_name);
268
269 /* Now, set the new name */
270 kobj->k_name = name;
271 Done:
272 return error;
273}
274
275EXPORT_SYMBOL(kobject_set_name);
276
277
278/**
279 * kobject_rename - change the name of an object
280 * @kobj: object in question.
281 * @new_name: object's new name
282 */
283
284int kobject_rename(struct kobject * kobj, char *new_name)
285{
286 int error = 0;
287
288 kobj = kobject_get(kobj);
289 if (!kobj)
290 return -EINVAL;
291 error = sysfs_rename_dir(kobj, new_name);
292 kobject_put(kobj);
293
294 return error;
295}
296
297/**
298 * kobject_del - unlink kobject from hierarchy.
299 * @kobj: object.
300 */
301
302void kobject_del(struct kobject * kobj)
303{
304 kobject_hotplug(kobj, KOBJ_REMOVE);
305 sysfs_remove_dir(kobj);
306 unlink(kobj);
307}
308
309/**
310 * kobject_unregister - remove object from hierarchy and decrement refcount.
311 * @kobj: object going away.
312 */
313
314void kobject_unregister(struct kobject * kobj)
315{
316 pr_debug("kobject %s: unregistering\n",kobject_name(kobj));
317 kobject_del(kobj);
318 kobject_put(kobj);
319}
320
321/**
322 * kobject_get - increment refcount for object.
323 * @kobj: object.
324 */
325
326struct kobject * kobject_get(struct kobject * kobj)
327{
328 if (kobj)
329 kref_get(&kobj->kref);
330 return kobj;
331}
332
333/**
334 * kobject_cleanup - free kobject resources.
335 * @kobj: object.
336 */
337
338void kobject_cleanup(struct kobject * kobj)
339{
340 struct kobj_type * t = get_ktype(kobj);
341 struct kset * s = kobj->kset;
342 struct kobject * parent = kobj->parent;
343
344 pr_debug("kobject %s: cleaning up\n",kobject_name(kobj));
345 if (kobj->k_name != kobj->name)
346 kfree(kobj->k_name);
347 kobj->k_name = NULL;
348 if (t && t->release)
349 t->release(kobj);
350 if (s)
351 kset_put(s);
352 if (parent)
353 kobject_put(parent);
354}
355
356static void kobject_release(struct kref *kref)
357{
358 kobject_cleanup(container_of(kref, struct kobject, kref));
359}
360
361/**
362 * kobject_put - decrement refcount for object.
363 * @kobj: object.
364 *
365 * Decrement the refcount, and if 0, call kobject_cleanup().
366 */
367void kobject_put(struct kobject * kobj)
368{
369 if (kobj)
370 kref_put(&kobj->kref, kobject_release);
371}
372
373
374/**
375 * kset_init - initialize a kset for use
376 * @k: kset
377 */
378
379void kset_init(struct kset * k)
380{
381 kobject_init(&k->kobj);
382 INIT_LIST_HEAD(&k->list);
383 spin_lock_init(&k->list_lock);
384}
385
386
387/**
388 * kset_add - add a kset object to the hierarchy.
389 * @k: kset.
390 *
391 * Simply, this adds the kset's embedded kobject to the
392 * hierarchy.
393 * We also try to make sure that the kset's embedded kobject
394 * has a parent before it is added. We only care if the embedded
395 * kobject is not part of a kset itself, since kobject_add()
396 * assigns a parent in that case.
397 * If that is the case, and the kset has a controlling subsystem,
398 * then we set the kset's parent to be said subsystem.
399 */
400
401int kset_add(struct kset * k)
402{
403 if (!k->kobj.parent && !k->kobj.kset && k->subsys)
404 k->kobj.parent = &k->subsys->kset.kobj;
405
406 return kobject_add(&k->kobj);
407}
408
409
410/**
411 * kset_register - initialize and add a kset.
412 * @k: kset.
413 */
414
415int kset_register(struct kset * k)
416{
417 kset_init(k);
418 return kset_add(k);
419}
420
421
422/**
423 * kset_unregister - remove a kset.
424 * @k: kset.
425 */
426
427void kset_unregister(struct kset * k)
428{
429 kobject_unregister(&k->kobj);
430}
431
432
433/**
434 * kset_find_obj - search for object in kset.
435 * @kset: kset we're looking in.
436 * @name: object's name.
437 *
438 * Lock kset via @kset->subsys, and iterate over @kset->list,
439 * looking for a matching kobject. If matching object is found
440 * take a reference and return the object.
441 */
442
443struct kobject * kset_find_obj(struct kset * kset, const char * name)
444{
445 struct list_head * entry;
446 struct kobject * ret = NULL;
447
448 spin_lock(&kset->list_lock);
449 list_for_each(entry,&kset->list) {
450 struct kobject * k = to_kobj(entry);
451 if (kobject_name(k) && !strcmp(kobject_name(k),name)) {
452 ret = kobject_get(k);
453 break;
454 }
455 }
456 spin_unlock(&kset->list_lock);
457 return ret;
458}
459
460
461void subsystem_init(struct subsystem * s)
462{
463 init_rwsem(&s->rwsem);
464 kset_init(&s->kset);
465}
466
467/**
468 * subsystem_register - register a subsystem.
469 * @s: the subsystem we're registering.
470 *
471 * Once we register the subsystem, we want to make sure that
472 * the kset points back to this subsystem for correct usage of
473 * the rwsem.
474 */
475
476int subsystem_register(struct subsystem * s)
477{
478 int error;
479
480 subsystem_init(s);
481 pr_debug("subsystem %s: registering\n",s->kset.kobj.name);
482
483 if (!(error = kset_add(&s->kset))) {
484 if (!s->kset.subsys)
485 s->kset.subsys = s;
486 }
487 return error;
488}
489
490void subsystem_unregister(struct subsystem * s)
491{
492 pr_debug("subsystem %s: unregistering\n",s->kset.kobj.name);
493 kset_unregister(&s->kset);
494}
495
496
497/**
498 * subsystem_create_file - export sysfs attribute file.
499 * @s: subsystem.
500 * @a: subsystem attribute descriptor.
501 */
502
503int subsys_create_file(struct subsystem * s, struct subsys_attribute * a)
504{
505 int error = 0;
506 if (subsys_get(s)) {
507 error = sysfs_create_file(&s->kset.kobj,&a->attr);
508 subsys_put(s);
509 }
510 return error;
511}
512
513
514/**
515 * subsystem_remove_file - remove sysfs attribute file.
516 * @s: subsystem.
517 * @a: attribute desciptor.
518 */
519
520void subsys_remove_file(struct subsystem * s, struct subsys_attribute * a)
521{
522 if (subsys_get(s)) {
523 sysfs_remove_file(&s->kset.kobj,&a->attr);
524 subsys_put(s);
525 }
526}
527
528EXPORT_SYMBOL(kobject_init);
529EXPORT_SYMBOL(kobject_register);
530EXPORT_SYMBOL(kobject_unregister);
531EXPORT_SYMBOL(kobject_get);
532EXPORT_SYMBOL(kobject_put);
533EXPORT_SYMBOL(kobject_add);
534EXPORT_SYMBOL(kobject_del);
535
536EXPORT_SYMBOL(kset_register);
537EXPORT_SYMBOL(kset_unregister);
538EXPORT_SYMBOL(kset_find_obj);
539
540EXPORT_SYMBOL(subsystem_init);
541EXPORT_SYMBOL(subsystem_register);
542EXPORT_SYMBOL(subsystem_unregister);
543EXPORT_SYMBOL(subsys_create_file);
544EXPORT_SYMBOL(subsys_remove_file);