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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 | /* * kobject.c - library routines for handling generic kernel objects * * Copyright (c) 2002-2003 Patrick Mochel <mochel@osdl.org> * * This file is released under the GPLv2. * * * Please see the file Documentation/kobject.txt for critical information * about using the kobject interface. */ #include <linux/kobject.h> #include <linux/string.h> #include <linux/module.h> #include <linux/stat.h> #include <linux/slab.h> /** * populate_dir - populate directory with attributes. * @kobj: object we're working on. * * Most subsystems have a set of default attributes that * are associated with an object that registers with them. * This is a helper called during object registration that * loops through the default attributes of the subsystem * and creates attributes files for them in sysfs. * */ static int populate_dir(struct kobject * kobj) { struct kobj_type * t = get_ktype(kobj); struct attribute * attr; int error = 0; int i; if (t && t->default_attrs) { for (i = 0; (attr = t->default_attrs[i]) != NULL; i++) { if ((error = sysfs_create_file(kobj,attr))) break; } } return error; } static int create_dir(struct kobject * kobj) { int error = 0; if (kobject_name(kobj)) { error = sysfs_create_dir(kobj); if (!error) { if ((error = populate_dir(kobj))) sysfs_remove_dir(kobj); } } return error; } static inline struct kobject * to_kobj(struct list_head * entry) { return container_of(entry,struct kobject,entry); } static int get_kobj_path_length(struct kobject *kobj) { int length = 1; struct kobject * parent = kobj; /* walk up the ancestors until we hit the one pointing to the * root. * Add 1 to strlen for leading '/' of each level. */ do { if (kobject_name(parent) == NULL) return 0; length += strlen(kobject_name(parent)) + 1; parent = parent->parent; } while (parent); return length; } static void fill_kobj_path(struct kobject *kobj, char *path, int length) { struct kobject * parent; --length; for (parent = kobj; parent; parent = parent->parent) { int cur = strlen(kobject_name(parent)); /* back up enough to print this name with '/' */ length -= cur; strncpy (path + length, kobject_name(parent), cur); *(path + --length) = '/'; } pr_debug("%s: path = '%s'\n",__FUNCTION__,path); } /** * kobject_get_path - generate and return the path associated with a given kobj * and kset pair. The result must be freed by the caller with kfree(). * * @kobj: kobject in question, with which to build the path * @gfp_mask: the allocation type used to allocate the path */ char *kobject_get_path(struct kobject *kobj, gfp_t gfp_mask) { char *path; int len; len = get_kobj_path_length(kobj); if (len == 0) return NULL; path = kmalloc(len, gfp_mask); if (!path) return NULL; memset(path, 0x00, len); fill_kobj_path(kobj, path, len); return path; } /** * kobject_init - initialize object. * @kobj: object in question. */ void kobject_init(struct kobject * kobj) { kref_init(&kobj->kref); INIT_LIST_HEAD(&kobj->entry); kobj->kset = kset_get(kobj->kset); } /** * unlink - remove kobject from kset list. * @kobj: kobject. * * Remove the kobject from the kset list and decrement * its parent's refcount. * This is separated out, so we can use it in both * kobject_del() and kobject_add() on error. */ static void unlink(struct kobject * kobj) { if (kobj->kset) { spin_lock(&kobj->kset->list_lock); list_del_init(&kobj->entry); spin_unlock(&kobj->kset->list_lock); } kobject_put(kobj); } /** * kobject_add - add an object to the hierarchy. * @kobj: object. */ int kobject_add(struct kobject * kobj) { int error = 0; struct kobject * parent; if (!(kobj = kobject_get(kobj))) return -ENOENT; if (!kobj->k_name) kobj->k_name = kobj->name; if (!kobj->k_name) { pr_debug("kobject attempted to be registered with no name!\n"); WARN_ON(1); return -EINVAL; } parent = kobject_get(kobj->parent); pr_debug("kobject %s: registering. parent: %s, set: %s\n", kobject_name(kobj), parent ? kobject_name(parent) : "<NULL>", kobj->kset ? kobj->kset->kobj.name : "<NULL>" ); if (kobj->kset) { spin_lock(&kobj->kset->list_lock); if (!parent) parent = kobject_get(&kobj->kset->kobj); list_add_tail(&kobj->entry,&kobj->kset->list); spin_unlock(&kobj->kset->list_lock); } kobj->parent = parent; error = create_dir(kobj); if (error) { /* unlink does the kobject_put() for us */ unlink(kobj); if (parent) kobject_put(parent); } return error; } /** * kobject_register - initialize and add an object. * @kobj: object in question. */ int kobject_register(struct kobject * kobj) { int error = 0; if (kobj) { kobject_init(kobj); error = kobject_add(kobj); if (error) { printk("kobject_register failed for %s (%d)\n", kobject_name(kobj),error); dump_stack(); } else kobject_uevent(kobj, KOBJ_ADD); } else error = -EINVAL; return error; } /** * kobject_set_name - Set the name of an object * @kobj: object. * @fmt: format string used to build the name * * If strlen(name) >= KOBJ_NAME_LEN, then use a dynamically allocated * string that @kobj->k_name points to. Otherwise, use the static * @kobj->name array. */ int kobject_set_name(struct kobject * kobj, const char * fmt, ...) { int error = 0; int limit = KOBJ_NAME_LEN; int need; va_list args; char * name; /* * First, try the static array */ va_start(args,fmt); need = vsnprintf(kobj->name,limit,fmt,args); va_end(args); if (need < limit) name = kobj->name; else { /* * Need more space? Allocate it and try again */ limit = need + 1; name = kmalloc(limit,GFP_KERNEL); if (!name) { error = -ENOMEM; goto Done; } va_start(args,fmt); need = vsnprintf(name,limit,fmt,args); va_end(args); /* Still? Give up. */ if (need >= limit) { kfree(name); error = -EFAULT; goto Done; } } /* Free the old name, if necessary. */ if (kobj->k_name && kobj->k_name != kobj->name) kfree(kobj->k_name); /* Now, set the new name */ kobj->k_name = name; Done: return error; } EXPORT_SYMBOL(kobject_set_name); /** * kobject_rename - change the name of an object * @kobj: object in question. * @new_name: object's new name */ int kobject_rename(struct kobject * kobj, const char *new_name) { int error = 0; kobj = kobject_get(kobj); if (!kobj) return -EINVAL; error = sysfs_rename_dir(kobj, new_name); kobject_put(kobj); return error; } /** * kobject_del - unlink kobject from hierarchy. * @kobj: object. */ void kobject_del(struct kobject * kobj) { sysfs_remove_dir(kobj); unlink(kobj); } /** * kobject_unregister - remove object from hierarchy and decrement refcount. * @kobj: object going away. */ void kobject_unregister(struct kobject * kobj) { pr_debug("kobject %s: unregistering\n",kobject_name(kobj)); kobject_uevent(kobj, KOBJ_REMOVE); kobject_del(kobj); kobject_put(kobj); } /** * kobject_get - increment refcount for object. * @kobj: object. */ struct kobject * kobject_get(struct kobject * kobj) { if (kobj) kref_get(&kobj->kref); return kobj; } /** * kobject_cleanup - free kobject resources. * @kobj: object. */ void kobject_cleanup(struct kobject * kobj) { struct kobj_type * t = get_ktype(kobj); struct kset * s = kobj->kset; struct kobject * parent = kobj->parent; pr_debug("kobject %s: cleaning up\n",kobject_name(kobj)); if (kobj->k_name != kobj->name) kfree(kobj->k_name); kobj->k_name = NULL; if (t && t->release) t->release(kobj); if (s) kset_put(s); if (parent) kobject_put(parent); } static void kobject_release(struct kref *kref) { kobject_cleanup(container_of(kref, struct kobject, kref)); } /** * kobject_put - decrement refcount for object. * @kobj: object. * * Decrement the refcount, and if 0, call kobject_cleanup(). */ void kobject_put(struct kobject * kobj) { if (kobj) kref_put(&kobj->kref, kobject_release); } /** * kset_init - initialize a kset for use * @k: kset */ void kset_init(struct kset * k) { kobject_init(&k->kobj); INIT_LIST_HEAD(&k->list); spin_lock_init(&k->list_lock); } /** * kset_add - add a kset object to the hierarchy. * @k: kset. * * Simply, this adds the kset's embedded kobject to the * hierarchy. * We also try to make sure that the kset's embedded kobject * has a parent before it is added. We only care if the embedded * kobject is not part of a kset itself, since kobject_add() * assigns a parent in that case. * If that is the case, and the kset has a controlling subsystem, * then we set the kset's parent to be said subsystem. */ int kset_add(struct kset * k) { if (!k->kobj.parent && !k->kobj.kset && k->subsys) k->kobj.parent = &k->subsys->kset.kobj; return kobject_add(&k->kobj); } /** * kset_register - initialize and add a kset. * @k: kset. */ int kset_register(struct kset * k) { kset_init(k); return kset_add(k); } /** * kset_unregister - remove a kset. * @k: kset. */ void kset_unregister(struct kset * k) { kobject_unregister(&k->kobj); } /** * kset_find_obj - search for object in kset. * @kset: kset we're looking in. * @name: object's name. * * Lock kset via @kset->subsys, and iterate over @kset->list, * looking for a matching kobject. If matching object is found * take a reference and return the object. */ struct kobject * kset_find_obj(struct kset * kset, const char * name) { struct list_head * entry; struct kobject * ret = NULL; spin_lock(&kset->list_lock); list_for_each(entry,&kset->list) { struct kobject * k = to_kobj(entry); if (kobject_name(k) && !strcmp(kobject_name(k),name)) { ret = kobject_get(k); break; } } spin_unlock(&kset->list_lock); return ret; } void subsystem_init(struct subsystem * s) { init_rwsem(&s->rwsem); kset_init(&s->kset); } /** * subsystem_register - register a subsystem. * @s: the subsystem we're registering. * * Once we register the subsystem, we want to make sure that * the kset points back to this subsystem for correct usage of * the rwsem. */ int subsystem_register(struct subsystem * s) { int error; subsystem_init(s); pr_debug("subsystem %s: registering\n",s->kset.kobj.name); if (!(error = kset_add(&s->kset))) { if (!s->kset.subsys) s->kset.subsys = s; } return error; } void subsystem_unregister(struct subsystem * s) { pr_debug("subsystem %s: unregistering\n",s->kset.kobj.name); kset_unregister(&s->kset); } /** * subsystem_create_file - export sysfs attribute file. * @s: subsystem. * @a: subsystem attribute descriptor. */ int subsys_create_file(struct subsystem * s, struct subsys_attribute * a) { int error = 0; if (subsys_get(s)) { error = sysfs_create_file(&s->kset.kobj,&a->attr); subsys_put(s); } return error; } /** * subsystem_remove_file - remove sysfs attribute file. * @s: subsystem. * @a: attribute desciptor. */ void subsys_remove_file(struct subsystem * s, struct subsys_attribute * a) { if (subsys_get(s)) { sysfs_remove_file(&s->kset.kobj,&a->attr); subsys_put(s); } } EXPORT_SYMBOL(kobject_init); EXPORT_SYMBOL(kobject_register); EXPORT_SYMBOL(kobject_unregister); EXPORT_SYMBOL(kobject_get); EXPORT_SYMBOL(kobject_put); EXPORT_SYMBOL(kobject_add); EXPORT_SYMBOL(kobject_del); EXPORT_SYMBOL(kset_register); EXPORT_SYMBOL(kset_unregister); EXPORT_SYMBOL(kset_find_obj); EXPORT_SYMBOL(subsystem_init); EXPORT_SYMBOL(subsystem_register); EXPORT_SYMBOL(subsystem_unregister); EXPORT_SYMBOL(subsys_create_file); EXPORT_SYMBOL(subsys_remove_file); |