lib/kobject.c

   1 /*
   2  * kobject.c - library routines for handling generic kernel objects
   3  *
   4  * Copyright (c) 2002-2003 Patrick Mochel <mochel@osdl.org>
   5  * Copyright (c) 2006-2007 Greg Kroah-Hartman <greg@kroah.com>
   6  * Copyright (c) 2006-2007 Novell Inc.
   7  *
   8  * This file is released under the GPLv2.
   9  *
  10  *
  11  * Please see the file Documentation/kobject.txt for critical information
  12  * about using the kobject interface.
  13  */
  14
  15 #include <linux/kobject.h>
  16 #include <linux/string.h>
  17 #include <linux/export.h>
  18 #include <linux/stat.h>
  19 #include <linux/slab.h>
  20 #include <linux/random.h>
  21
  22 /**
  23  * kobject_namespace - return @kobj's namespace tag
  24  * @kobj: kobject in question
  25  *
  26  * Returns namespace tag of @kobj if its parent has namespace ops enabled
  27  * and thus @kobj should have a namespace tag associated with it.  Returns
  28  * %NULL otherwise.
  29  */
  30 const void *kobject_namespace(struct kobject *kobj)
  31 {
  32         const struct kobj_ns_type_operations *ns_ops = kobj_ns_ops(kobj);
  33
  34         if (!ns_ops || ns_ops->type == KOBJ_NS_TYPE_NONE)
  35                 return NULL;
  36
  37         return kobj->ktype->namespace(kobj);
  38 }
  39
  40 /*
  41  * populate_dir - populate directory with attributes.
  42  * @kobj: object we're working on.
  43  *
  44  * Most subsystems have a set of default attributes that are associated
  45  * with an object that registers with them.  This is a helper called during
  46  * object registration that loops through the default attributes of the
  47  * subsystem and creates attributes files for them in sysfs.
  48  */
  49 static int populate_dir(struct kobject *kobj)
  50 {
  51         struct kobj_type *t = get_ktype(kobj);
  52         struct attribute *attr;
  53         int error = 0;
  54         int i;
  55
  56         if (t && t->default_attrs) {
  57                 for (i = 0; (attr = t->default_attrs[i]) != NULL; i++) {
  58                         error = sysfs_create_file(kobj, attr);
  59                         if (error)
  60                                 break;
  61                 }
  62         }
  63         return error;
  64 }
  65
  66 static int create_dir(struct kobject *kobj)
  67 {
  68         const struct kobj_ns_type_operations *ops;
  69         int error;
  70
  71         error = sysfs_create_dir_ns(kobj, kobject_namespace(kobj));
  72         if (error)
  73                 return error;
  74
  75         error = populate_dir(kobj);
  76         if (error) {
  77                 sysfs_remove_dir(kobj);
  78                 return error;
  79         }
  80
  81         /*
  82          * @kobj->sd may be deleted by an ancestor going away.  Hold an
  83          * extra reference so that it stays until @kobj is gone.
  84          */
  85         sysfs_get(kobj->sd);
  86
  87         /*
  88          * If @kobj has ns_ops, its children need to be filtered based on
  89          * their namespace tags.  Enable namespace support on @kobj->sd.
  90          */
  91         ops = kobj_child_ns_ops(kobj);
  92         if (ops) {
  93                 BUG_ON(ops->type <= KOBJ_NS_TYPE_NONE);
  94                 BUG_ON(ops->type >= KOBJ_NS_TYPES);
  95                 BUG_ON(!kobj_ns_type_registered(ops->type));
  96
  97                 sysfs_enable_ns(kobj->sd);
  98         }
  99
 100         return 0;
 101 }
 102
 103 static int get_kobj_path_length(struct kobject *kobj)
 104 {
 105         int length = 1;
 106         struct kobject *parent = kobj;
 107
 108         /* walk up the ancestors until we hit the one pointing to the
 109          * root.
 110          * Add 1 to strlen for leading '/' of each level.
 111          */
 112         do {
 113                 if (kobject_name(parent) == NULL)
 114                         return 0;
 115                 length += strlen(kobject_name(parent)) + 1;
 116                 parent = parent->parent;
 117         } while (parent);
 118         return length;
 119 }
 120
 121 static void fill_kobj_path(struct kobject *kobj, char *path, int length)
 122 {
 123         struct kobject *parent;
 124
 125         --length;
 126         for (parent = kobj; parent; parent = parent->parent) {
 127                 int cur = strlen(kobject_name(parent));
 128                 /* back up enough to print this name with '/' */
 129                 length -= cur;
 130                 strncpy(path + length, kobject_name(parent), cur);
 131                 *(path + --length) = '/';
 132         }
 133
 134         pr_debug("kobject: '%s' (%p): %s: path = '%s'\n", kobject_name(kobj),
 135                  kobj, __func__, path);
 136 }
 137
 138 /**
 139  * kobject_get_path - generate and return the path associated with a given kobj and kset pair.
 140  *
 141  * @kobj:       kobject in question, with which to build the path
 142  * @gfp_mask:   the allocation type used to allocate the path
 143  *
 144  * The result must be freed by the caller with kfree().
 145  */
 146 char *kobject_get_path(struct kobject *kobj, gfp_t gfp_mask)
 147 {
 148         char *path;
 149         int len;
 150
 151         len = get_kobj_path_length(kobj);
 152         if (len == 0)
 153                 return NULL;
 154         path = kzalloc(len, gfp_mask);
 155         if (!path)
 156                 return NULL;
 157         fill_kobj_path(kobj, path, len);
 158
 159         return path;
 160 }
 161 EXPORT_SYMBOL_GPL(kobject_get_path);
 162
 163 /* add the kobject to its kset's list */
 164 static void kobj_kset_join(struct kobject *kobj)
 165 {
 166         if (!kobj->kset)
 167                 return;
 168
 169         kset_get(kobj->kset);
 170         spin_lock(&kobj->kset->list_lock);
 171         list_add_tail(&kobj->entry, &kobj->kset->list);
 172         spin_unlock(&kobj->kset->list_lock);
 173 }
 174
 175 /* remove the kobject from its kset's list */
 176 static void kobj_kset_leave(struct kobject *kobj)
 177 {
 178         if (!kobj->kset)
 179                 return;
 180
 181         spin_lock(&kobj->kset->list_lock);
 182         list_del_init(&kobj->entry);
 183         spin_unlock(&kobj->kset->list_lock);
 184         kset_put(kobj->kset);
 185 }
 186
 187 static void kobject_init_internal(struct kobject *kobj)
 188 {
 189         if (!kobj)
 190                 return;
 191         kref_init(&kobj->kref);
 192         INIT_LIST_HEAD(&kobj->entry);
 193         kobj->state_in_sysfs = 0;
 194         kobj->state_add_uevent_sent = 0;
 195         kobj->state_remove_uevent_sent = 0;
 196         kobj->state_initialized = 1;
 197 }
 198
 199
 200 static int kobject_add_internal(struct kobject *kobj)
 201 {
 202         int error = 0;
 203         struct kobject *parent;
 204
 205         if (!kobj)
 206                 return -ENOENT;
 207
 208         if (!kobj->name || !kobj->name[0]) {
 209                 WARN(1, "kobject: (%p): attempted to be registered with empty "
 210                          "name!\n", kobj);
 211                 return -EINVAL;
 212         }
 213
 214         parent = kobject_get(kobj->parent);
 215
 216         /* join kset if set, use it as parent if we do not already have one */
 217         if (kobj->kset) {
 218                 if (!parent)
 219                         parent = kobject_get(&kobj->kset->kobj);
 220                 kobj_kset_join(kobj);
 221                 kobj->parent = parent;
 222         }
 223
 224         pr_debug("kobject: '%s' (%p): %s: parent: '%s', set: '%s'\n",
 225                  kobject_name(kobj), kobj, __func__,
 226                  parent ? kobject_name(parent) : "<NULL>",
 227                  kobj->kset ? kobject_name(&kobj->kset->kobj) : "<NULL>");
 228
 229         error = create_dir(kobj);
 230         if (error) {
 231                 kobj_kset_leave(kobj);
 232                 kobject_put(parent);
 233                 kobj->parent = NULL;
 234
 235                 /* be noisy on error issues */
 236                 if (error == -EEXIST)
 237                         WARN(1, "%s failed for %s with "
 238                              "-EEXIST, don't try to register things with "
 239                              "the same name in the same directory.\n",
 240                              __func__, kobject_name(kobj));
 241                 else
 242                         WARN(1, "%s failed for %s (error: %d parent: %s)\n",
 243                              __func__, kobject_name(kobj), error,
 244                              parent ? kobject_name(parent) : "'none'");
 245         } else
 246                 kobj->state_in_sysfs = 1;
 247
 248         return error;
 249 }
 250
 251 /**
 252  * kobject_set_name_vargs - Set the name of an kobject
 253  * @kobj: struct kobject to set the name of
 254  * @fmt: format string used to build the name
 255  * @vargs: vargs to format the string.
 256  */
 257 int kobject_set_name_vargs(struct kobject *kobj, const char *fmt,
 258                                   va_list vargs)
 259 {
 260         const char *old_name = kobj->name;
 261         char *s;
 262
 263         if (kobj->name && !fmt)
 264                 return 0;
 265
 266         kobj->name = kvasprintf(GFP_KERNEL, fmt, vargs);
 267         if (!kobj->name) {
 268                 kobj->name = old_name;
 269                 return -ENOMEM;
 270         }
 271
 272         /* ewww... some of these buggers have '/' in the name ... */
 273         while ((s = strchr(kobj->name, '/')))
 274                 s[0] = '!';
 275
 276         kfree(old_name);
 277         return 0;
 278 }
 279
 280 /**
 281  * kobject_set_name - Set the name of a kobject
 282  * @kobj: struct kobject to set the name of
 283  * @fmt: format string used to build the name
 284  *
 285  * This sets the name of the kobject.  If you have already added the
 286  * kobject to the system, you must call kobject_rename() in order to
 287  * change the name of the kobject.
 288  */
 289 int kobject_set_name(struct kobject *kobj, const char *fmt, ...)
 290 {
 291         va_list vargs;
 292         int retval;
 293
 294         va_start(vargs, fmt);
 295         retval = kobject_set_name_vargs(kobj, fmt, vargs);
 296         va_end(vargs);
 297
 298         return retval;
 299 }
 300 EXPORT_SYMBOL(kobject_set_name);
 301
 302 /**
 303  * kobject_init - initialize a kobject structure
 304  * @kobj: pointer to the kobject to initialize
 305  * @ktype: pointer to the ktype for this kobject.
 306  *
 307  * This function will properly initialize a kobject such that it can then
 308  * be passed to the kobject_add() call.
 309  *
 310  * After this function is called, the kobject MUST be cleaned up by a call
 311  * to kobject_put(), not by a call to kfree directly to ensure that all of
 312  * the memory is cleaned up properly.
 313  */
 314 void kobject_init(struct kobject *kobj, struct kobj_type *ktype)
 315 {
 316         char *err_str;
 317
 318         if (!kobj) {
 319                 err_str = "invalid kobject pointer!";
 320                 goto error;
 321         }
 322         if (!ktype) {
 323                 err_str = "must have a ktype to be initialized properly!\n";
 324                 goto error;
 325         }
 326         if (kobj->state_initialized) {
 327                 /* do not error out as sometimes we can recover */
 328                 printk(KERN_ERR "kobject (%p): tried to init an initialized "
 329                        "object, something is seriously wrong.\n", kobj);
 330                 dump_stack();
 331         }
 332
 333         kobject_init_internal(kobj);
 334         kobj->ktype = ktype;
 335         return;
 336
 337 error:
 338         printk(KERN_ERR "kobject (%p): %s\n", kobj, err_str);
 339         dump_stack();
 340 }
 341 EXPORT_SYMBOL(kobject_init);
 342
 343 static int kobject_add_varg(struct kobject *kobj, struct kobject *parent,
 344                             const char *fmt, va_list vargs)
 345 {
 346         int retval;
 347
 348         retval = kobject_set_name_vargs(kobj, fmt, vargs);
 349         if (retval) {
 350                 printk(KERN_ERR "kobject: can not set name properly!\n");
 351                 return retval;
 352         }
 353         kobj->parent = parent;
 354         return kobject_add_internal(kobj);
 355 }
 356
 357 /**
 358  * kobject_add - the main kobject add function
 359  * @kobj: the kobject to add
 360  * @parent: pointer to the parent of the kobject.
 361  * @fmt: format to name the kobject with.
 362  *
 363  * The kobject name is set and added to the kobject hierarchy in this
 364  * function.
 365  *
 366  * If @parent is set, then the parent of the @kobj will be set to it.
 367  * If @parent is NULL, then the parent of the @kobj will be set to the
 368  * kobject associated with the kset assigned to this kobject.  If no kset
 369  * is assigned to the kobject, then the kobject will be located in the
 370  * root of the sysfs tree.
 371  *
 372  * If this function returns an error, kobject_put() must be called to
 373  * properly clean up the memory associated with the object.
 374  * Under no instance should the kobject that is passed to this function
 375  * be directly freed with a call to kfree(), that can leak memory.
 376  *
 377  * Note, no "add" uevent will be created with this call, the caller should set
 378  * up all of the necessary sysfs files for the object and then call
 379  * kobject_uevent() with the UEVENT_ADD parameter to ensure that
 380  * userspace is properly notified of this kobject's creation.
 381  */
 382 int kobject_add(struct kobject *kobj, struct kobject *parent,
 383                 const char *fmt, ...)
 384 {
 385         va_list args;
 386         int retval;
 387
 388         if (!kobj)
 389                 return -EINVAL;
 390
 391         if (!kobj->state_initialized) {
 392                 printk(KERN_ERR "kobject '%s' (%p): tried to add an "
 393                        "uninitialized object, something is seriously wrong.\n",
 394                        kobject_name(kobj), kobj);
 395                 dump_stack();
 396                 return -EINVAL;
 397         }
 398         va_start(args, fmt);
 399         retval = kobject_add_varg(kobj, parent, fmt, args);
 400         va_end(args);
 401
 402         return retval;
 403 }
 404 EXPORT_SYMBOL(kobject_add);
 405
 406 /**
 407  * kobject_init_and_add - initialize a kobject structure and add it to the kobject hierarchy
 408  * @kobj: pointer to the kobject to initialize
 409  * @ktype: pointer to the ktype for this kobject.
 410  * @parent: pointer to the parent of this kobject.
 411  * @fmt: the name of the kobject.
 412  *
 413  * This function combines the call to kobject_init() and
 414  * kobject_add().  The same type of error handling after a call to
 415  * kobject_add() and kobject lifetime rules are the same here.
 416  */
 417 int kobject_init_and_add(struct kobject *kobj, struct kobj_type *ktype,
 418                          struct kobject *parent, const char *fmt, ...)
 419 {
 420         va_list args;
 421         int retval;
 422
 423         kobject_init(kobj, ktype);
 424
 425         va_start(args, fmt);
 426         retval = kobject_add_varg(kobj, parent, fmt, args);
 427         va_end(args);
 428
 429         return retval;
 430 }
 431 EXPORT_SYMBOL_GPL(kobject_init_and_add);
 432
 433 /**
 434  * kobject_rename - change the name of an object
 435  * @kobj: object in question.
 436  * @new_name: object's new name
 437  *
 438  * It is the responsibility of the caller to provide mutual
 439  * exclusion between two different calls of kobject_rename
 440  * on the same kobject and to ensure that new_name is valid and
 441  * won't conflict with other kobjects.
 442  */
 443 int kobject_rename(struct kobject *kobj, const char *new_name)
 444 {
 445         int error = 0;
 446         const char *devpath = NULL;
 447         const char *dup_name = NULL, *name;
 448         char *devpath_string = NULL;
 449         char *envp[2];
 450
 451         kobj = kobject_get(kobj);
 452         if (!kobj)
 453                 return -EINVAL;
 454         if (!kobj->parent)
 455                 return -EINVAL;
 456
 457         devpath = kobject_get_path(kobj, GFP_KERNEL);
 458         if (!devpath) {
 459                 error = -ENOMEM;
 460                 goto out;
 461         }
 462         devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
 463         if (!devpath_string) {
 464                 error = -ENOMEM;
 465                 goto out;
 466         }
 467         sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
 468         envp[0] = devpath_string;
 469         envp[1] = NULL;
 470
 471         name = dup_name = kstrdup(new_name, GFP_KERNEL);
 472         if (!name) {
 473                 error = -ENOMEM;
 474                 goto out;
 475         }
 476
 477         error = sysfs_rename_dir_ns(kobj, new_name, kobject_namespace(kobj));
 478         if (error)
 479                 goto out;
 480
 481         /* Install the new kobject name */
 482         dup_name = kobj->name;
 483         kobj->name = name;
 484
 485         /* This function is mostly/only used for network interface.
 486          * Some hotplug package track interfaces by their name and
 487          * therefore want to know when the name is changed by the user. */
 488         kobject_uevent_env(kobj, KOBJ_MOVE, envp);
 489
 490 out:
 491         kfree(dup_name);
 492         kfree(devpath_string);
 493         kfree(devpath);
 494         kobject_put(kobj);
 495
 496         return error;
 497 }
 498 EXPORT_SYMBOL_GPL(kobject_rename);
 499
 500 /**
 501  * kobject_move - move object to another parent
 502  * @kobj: object in question.
 503  * @new_parent: object's new parent (can be NULL)
 504  */
 505 int kobject_move(struct kobject *kobj, struct kobject *new_parent)
 506 {
 507         int error;
 508         struct kobject *old_parent;
 509         const char *devpath = NULL;
 510         char *devpath_string = NULL;
 511         char *envp[2];
 512
 513         kobj = kobject_get(kobj);
 514         if (!kobj)
 515                 return -EINVAL;
 516         new_parent = kobject_get(new_parent);
 517         if (!new_parent) {
 518                 if (kobj->kset)
 519                         new_parent = kobject_get(&kobj->kset->kobj);
 520         }
 521
 522         /* old object path */
 523         devpath = kobject_get_path(kobj, GFP_KERNEL);
 524         if (!devpath) {
 525                 error = -ENOMEM;
 526                 goto out;
 527         }
 528         devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
 529         if (!devpath_string) {
 530                 error = -ENOMEM;
 531                 goto out;
 532         }
 533         sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
 534         envp[0] = devpath_string;
 535         envp[1] = NULL;
 536         error = sysfs_move_dir_ns(kobj, new_parent, kobject_namespace(kobj));
 537         if (error)
 538                 goto out;
 539         old_parent = kobj->parent;
 540         kobj->parent = new_parent;
 541         new_parent = NULL;
 542         kobject_put(old_parent);
 543         kobject_uevent_env(kobj, KOBJ_MOVE, envp);
 544 out:
 545         kobject_put(new_parent);
 546         kobject_put(kobj);
 547         kfree(devpath_string);
 548         kfree(devpath);
 549         return error;
 550 }
 551
 552 /**
 553  * kobject_del - unlink kobject from hierarchy.
 554  * @kobj: object.
 555  */
 556 void kobject_del(struct kobject *kobj)
 557 {
 558         struct kernfs_node *sd;
 559
 560         if (!kobj)
 561                 return;
 562
 563         sd = kobj->sd;
 564         sysfs_remove_dir(kobj);
 565         sysfs_put(sd);
 566
 567         kobj->state_in_sysfs = 0;
 568         kobj_kset_leave(kobj);
 569         kobject_put(kobj->parent);
 570         kobj->parent = NULL;
 571 }
 572
 573 /**
 574  * kobject_get - increment refcount for object.
 575  * @kobj: object.
 576  */
 577 struct kobject *kobject_get(struct kobject *kobj)
 578 {
 579         if (kobj) {
 580                 if (!kobj->state_initialized)
 581                         WARN(1, KERN_WARNING "kobject: '%s' (%p): is not "
 582                                "initialized, yet kobject_get() is being "
 583                                "called.\n", kobject_name(kobj), kobj);
 584                 kref_get(&kobj->kref);
 585         }
 586         return kobj;
 587 }
 588
 589 static struct kobject * __must_check kobject_get_unless_zero(struct kobject *kobj)
 590 {
 591         if (!kref_get_unless_zero(&kobj->kref))
 592                 kobj = NULL;
 593         return kobj;
 594 }
 595
 596 /*
 597  * kobject_cleanup - free kobject resources.
 598  * @kobj: object to cleanup
 599  */
 600 static void kobject_cleanup(struct kobject *kobj)
 601 {
 602         struct kobj_type *t = get_ktype(kobj);
 603         const char *name = kobj->name;
 604
 605         pr_debug("kobject: '%s' (%p): %s, parent %p\n",
 606                  kobject_name(kobj), kobj, __func__, kobj->parent);
 607
 608         if (t && !t->release)
 609                 pr_debug("kobject: '%s' (%p): does not have a release() "
 610                          "function, it is broken and must be fixed.\n",
 611                          kobject_name(kobj), kobj);
 612
 613         /* send "remove" if the caller did not do it but sent "add" */
 614         if (kobj->state_add_uevent_sent && !kobj->state_remove_uevent_sent) {
 615                 pr_debug("kobject: '%s' (%p): auto cleanup 'remove' event\n",
 616                          kobject_name(kobj), kobj);
 617                 kobject_uevent(kobj, KOBJ_REMOVE);
 618         }
 619
 620         /* remove from sysfs if the caller did not do it */
 621         if (kobj->state_in_sysfs) {
 622                 pr_debug("kobject: '%s' (%p): auto cleanup kobject_del\n",
 623                          kobject_name(kobj), kobj);
 624                 kobject_del(kobj);
 625         }
 626
 627         if (t && t->release) {
 628                 pr_debug("kobject: '%s' (%p): calling ktype release\n",
 629                          kobject_name(kobj), kobj);
 630                 t->release(kobj);
 631         }
 632
 633         /* free name if we allocated it */
 634         if (name) {
 635                 pr_debug("kobject: '%s': free name\n", name);
 636                 kfree(name);
 637         }
 638 }
 639
 640 #ifdef CONFIG_DEBUG_KOBJECT_RELEASE
 641 static void kobject_delayed_cleanup(struct work_struct *work)
 642 {
 643         kobject_cleanup(container_of(to_delayed_work(work),
 644                                      struct kobject, release));
 645 }
 646 #endif
 647
 648 static void kobject_release(struct kref *kref)
 649 {
 650         struct kobject *kobj = container_of(kref, struct kobject, kref);
 651 #ifdef CONFIG_DEBUG_KOBJECT_RELEASE
 652         unsigned long delay = HZ + HZ * (get_random_int() & 0x3);
 653         pr_info("kobject: '%s' (%p): %s, parent %p (delayed %ld)\n",
 654                  kobject_name(kobj), kobj, __func__, kobj->parent, delay);
 655         INIT_DELAYED_WORK(&kobj->release, kobject_delayed_cleanup);
 656
 657         schedule_delayed_work(&kobj->release, delay);
 658 #else
 659         kobject_cleanup(kobj);
 660 #endif
 661 }
 662
 663 /**
 664  * kobject_put - decrement refcount for object.
 665  * @kobj: object.
 666  *
 667  * Decrement the refcount, and if 0, call kobject_cleanup().
 668  */
 669 void kobject_put(struct kobject *kobj)
 670 {
 671         if (kobj) {
 672                 if (!kobj->state_initialized)
 673                         WARN(1, KERN_WARNING "kobject: '%s' (%p): is not "
 674                                "initialized, yet kobject_put() is being "
 675                                "called.\n", kobject_name(kobj), kobj);
 676                 kref_put(&kobj->kref, kobject_release);
 677         }
 678 }
 679
 680 static void dynamic_kobj_release(struct kobject *kobj)
 681 {
 682         pr_debug("kobject: (%p): %s\n", kobj, __func__);
 683         kfree(kobj);
 684 }
 685
 686 static struct kobj_type dynamic_kobj_ktype = {
 687         .release        = dynamic_kobj_release,
 688         .sysfs_ops      = &kobj_sysfs_ops,
 689 };
 690
 691 /**
 692  * kobject_create - create a struct kobject dynamically
 693  *
 694  * This function creates a kobject structure dynamically and sets it up
 695  * to be a "dynamic" kobject with a default release function set up.
 696  *
 697  * If the kobject was not able to be created, NULL will be returned.
 698  * The kobject structure returned from here must be cleaned up with a
 699  * call to kobject_put() and not kfree(), as kobject_init() has
 700  * already been called on this structure.
 701  */
 702 struct kobject *kobject_create(void)
 703 {
 704         struct kobject *kobj;
 705
 706         kobj = kzalloc(sizeof(*kobj), GFP_KERNEL);
 707         if (!kobj)
 708                 return NULL;
 709
 710         kobject_init(kobj, &dynamic_kobj_ktype);
 711         return kobj;
 712 }
 713
 714 /**
 715  * kobject_create_and_add - create a struct kobject dynamically and register it with sysfs
 716  *
 717  * @name: the name for the kobject
 718  * @parent: the parent kobject of this kobject, if any.
 719  *
 720  * This function creates a kobject structure dynamically and registers it
 721  * with sysfs.  When you are finished with this structure, call
 722  * kobject_put() and the structure will be dynamically freed when
 723  * it is no longer being used.
 724  *
 725  * If the kobject was not able to be created, NULL will be returned.
 726  */
 727 struct kobject *kobject_create_and_add(const char *name, struct kobject *parent)
 728 {
 729         struct kobject *kobj;
 730         int retval;
 731
 732         kobj = kobject_create();
 733         if (!kobj)
 734                 return NULL;
 735
 736         retval = kobject_add(kobj, parent, "%s", name);
 737         if (retval) {
 738                 printk(KERN_WARNING "%s: kobject_add error: %d\n",
 739                        __func__, retval);
 740                 kobject_put(kobj);
 741                 kobj = NULL;
 742         }
 743         return kobj;
 744 }
 745 EXPORT_SYMBOL_GPL(kobject_create_and_add);
 746
 747 /**
 748  * kset_init - initialize a kset for use
 749  * @k: kset
 750  */
 751 void kset_init(struct kset *k)
 752 {
 753         kobject_init_internal(&k->kobj);
 754         INIT_LIST_HEAD(&k->list);
 755         spin_lock_init(&k->list_lock);
 756 }
 757
 758 /* default kobject attribute operations */
 759 static ssize_t kobj_attr_show(struct kobject *kobj, struct attribute *attr,
 760                               char *buf)
 761 {
 762         struct kobj_attribute *kattr;
 763         ssize_t ret = -EIO;
 764
 765         kattr = container_of(attr, struct kobj_attribute, attr);
 766         if (kattr->show)
 767                 ret = kattr->show(kobj, kattr, buf);
 768         return ret;
 769 }
 770
 771 static ssize_t kobj_attr_store(struct kobject *kobj, struct attribute *attr,
 772                                const char *buf, size_t count)
 773 {
 774         struct kobj_attribute *kattr;
 775         ssize_t ret = -EIO;
 776
 777         kattr = container_of(attr, struct kobj_attribute, attr);
 778         if (kattr->store)
 779                 ret = kattr->store(kobj, kattr, buf, count);
 780         return ret;
 781 }
 782
 783 const struct sysfs_ops kobj_sysfs_ops = {
 784         .show   = kobj_attr_show,
 785         .store  = kobj_attr_store,
 786 };
 787 EXPORT_SYMBOL_GPL(kobj_sysfs_ops);
 788
 789 /**
 790  * kset_register - initialize and add a kset.
 791  * @k: kset.
 792  */
 793 int kset_register(struct kset *k)
 794 {
 795         int err;
 796
 797         if (!k)
 798                 return -EINVAL;
 799
 800         kset_init(k);
 801         err = kobject_add_internal(&k->kobj);
 802         if (err)
 803                 return err;
 804         kobject_uevent(&k->kobj, KOBJ_ADD);
 805         return 0;
 806 }
 807
 808 /**
 809  * kset_unregister - remove a kset.
 810  * @k: kset.
 811  */
 812 void kset_unregister(struct kset *k)
 813 {
 814         if (!k)
 815                 return;
 816         kobject_del(&k->kobj);
 817         kobject_put(&k->kobj);
 818 }
 819
 820 /**
 821  * kset_find_obj - search for object in kset.
 822  * @kset: kset we're looking in.
 823  * @name: object's name.
 824  *
 825  * Lock kset via @kset->subsys, and iterate over @kset->list,
 826  * looking for a matching kobject. If matching object is found
 827  * take a reference and return the object.
 828  */
 829 struct kobject *kset_find_obj(struct kset *kset, const char *name)
 830 {
 831         struct kobject *k;
 832         struct kobject *ret = NULL;
 833
 834         spin_lock(&kset->list_lock);
 835
 836         list_for_each_entry(k, &kset->list, entry) {
 837                 if (kobject_name(k) && !strcmp(kobject_name(k), name)) {
 838                         ret = kobject_get_unless_zero(k);
 839                         break;
 840                 }
 841         }
 842
 843         spin_unlock(&kset->list_lock);
 844         return ret;
 845 }
 846
 847 static void kset_release(struct kobject *kobj)
 848 {
 849         struct kset *kset = container_of(kobj, struct kset, kobj);
 850         pr_debug("kobject: '%s' (%p): %s\n",
 851                  kobject_name(kobj), kobj, __func__);
 852         kfree(kset);
 853 }
 854
 855 static struct kobj_type kset_ktype = {
 856         .sysfs_ops      = &kobj_sysfs_ops,
 857         .release = kset_release,
 858 };
 859
 860 /**
 861  * kset_create - create a struct kset dynamically
 862  *
 863  * @name: the name for the kset
 864  * @uevent_ops: a struct kset_uevent_ops for the kset
 865  * @parent_kobj: the parent kobject of this kset, if any.
 866  *
 867  * This function creates a kset structure dynamically.  This structure can
 868  * then be registered with the system and show up in sysfs with a call to
 869  * kset_register().  When you are finished with this structure, if
 870  * kset_register() has been called, call kset_unregister() and the
 871  * structure will be dynamically freed when it is no longer being used.
 872  *
 873  * If the kset was not able to be created, NULL will be returned.
 874  */
 875 static struct kset *kset_create(const char *name,
 876                                 const struct kset_uevent_ops *uevent_ops,
 877                                 struct kobject *parent_kobj)
 878 {
 879         struct kset *kset;
 880         int retval;
 881
 882         kset = kzalloc(sizeof(*kset), GFP_KERNEL);
 883         if (!kset)
 884                 return NULL;
 885         retval = kobject_set_name(&kset->kobj, "%s", name);
 886         if (retval) {
 887                 kfree(kset);
 888                 return NULL;
 889         }
 890         kset->uevent_ops = uevent_ops;
 891         kset->kobj.parent = parent_kobj;
 892
 893         /*
 894          * The kobject of this kset will have a type of kset_ktype and belong to
 895          * no kset itself.  That way we can properly free it when it is
 896          * finished being used.
 897          */
 898         kset->kobj.ktype = &kset_ktype;
 899         kset->kobj.kset = NULL;
 900
 901         return kset;
 902 }
 903
 904 /**
 905  * kset_create_and_add - create a struct kset dynamically and add it to sysfs
 906  *
 907  * @name: the name for the kset
 908  * @uevent_ops: a struct kset_uevent_ops for the kset
 909  * @parent_kobj: the parent kobject of this kset, if any.
 910  *
 911  * This function creates a kset structure dynamically and registers it
 912  * with sysfs.  When you are finished with this structure, call
 913  * kset_unregister() and the structure will be dynamically freed when it
 914  * is no longer being used.
 915  *
 916  * If the kset was not able to be created, NULL will be returned.
 917  */
 918 struct kset *kset_create_and_add(const char *name,
 919                                  const struct kset_uevent_ops *uevent_ops,
 920                                  struct kobject *parent_kobj)
 921 {
 922         struct kset *kset;
 923         int error;
 924
 925         kset = kset_create(name, uevent_ops, parent_kobj);
 926         if (!kset)
 927                 return NULL;
 928         error = kset_register(kset);
 929         if (error) {
 930                 kfree(kset);
 931                 return NULL;
 932         }
 933         return kset;
 934 }
 935 EXPORT_SYMBOL_GPL(kset_create_and_add);
 936
 937
 938 static DEFINE_SPINLOCK(kobj_ns_type_lock);
 939 static const struct kobj_ns_type_operations *kobj_ns_ops_tbl[KOBJ_NS_TYPES];
 940
 941 int kobj_ns_type_register(const struct kobj_ns_type_operations *ops)
 942 {
 943         enum kobj_ns_type type = ops->type;
 944         int error;
 945
 946         spin_lock(&kobj_ns_type_lock);
 947
 948         error = -EINVAL;
 949         if (type >= KOBJ_NS_TYPES)
 950                 goto out;
 951
 952         error = -EINVAL;
 953         if (type <= KOBJ_NS_TYPE_NONE)
 954                 goto out;
 955
 956         error = -EBUSY;
 957         if (kobj_ns_ops_tbl[type])
 958                 goto out;
 959
 960         error = 0;
 961         kobj_ns_ops_tbl[type] = ops;
 962
 963 out:
 964         spin_unlock(&kobj_ns_type_lock);
 965         return error;
 966 }
 967
 968 int kobj_ns_type_registered(enum kobj_ns_type type)
 969 {
 970         int registered = 0;
 971
 972         spin_lock(&kobj_ns_type_lock);
 973         if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES))
 974                 registered = kobj_ns_ops_tbl[type] != NULL;
 975         spin_unlock(&kobj_ns_type_lock);
 976
 977         return registered;
 978 }
 979
 980 const struct kobj_ns_type_operations *kobj_child_ns_ops(struct kobject *parent)
 981 {
 982         const struct kobj_ns_type_operations *ops = NULL;
 983
 984         if (parent && parent->ktype && parent->ktype->child_ns_type)
 985                 ops = parent->ktype->child_ns_type(parent);
 986
 987         return ops;
 988 }
 989
 990 const struct kobj_ns_type_operations *kobj_ns_ops(struct kobject *kobj)
 991 {
 992         return kobj_child_ns_ops(kobj->parent);
 993 }
 994
 995 bool kobj_ns_current_may_mount(enum kobj_ns_type type)
 996 {
 997         bool may_mount = true;
 998
 999         spin_lock(&kobj_ns_type_lock);
1000         if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1001             kobj_ns_ops_tbl[type])
1002                 may_mount = kobj_ns_ops_tbl[type]->current_may_mount();
1003         spin_unlock(&kobj_ns_type_lock);
1004
1005         return may_mount;
1006 }
1007
1008 void *kobj_ns_grab_current(enum kobj_ns_type type)
1009 {
1010         void *ns = NULL;
1011
1012         spin_lock(&kobj_ns_type_lock);
1013         if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1014             kobj_ns_ops_tbl[type])
1015                 ns = kobj_ns_ops_tbl[type]->grab_current_ns();
1016         spin_unlock(&kobj_ns_type_lock);
1017
1018         return ns;
1019 }
1020
1021 const void *kobj_ns_netlink(enum kobj_ns_type type, struct sock *sk)
1022 {
1023         const void *ns = NULL;
1024
1025         spin_lock(&kobj_ns_type_lock);
1026         if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1027             kobj_ns_ops_tbl[type])
1028                 ns = kobj_ns_ops_tbl[type]->netlink_ns(sk);
1029         spin_unlock(&kobj_ns_type_lock);
1030
1031         return ns;
1032 }
1033
1034 const void *kobj_ns_initial(enum kobj_ns_type type)
1035 {
1036         const void *ns = NULL;
1037
1038         spin_lock(&kobj_ns_type_lock);
1039         if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1040             kobj_ns_ops_tbl[type])
1041                 ns = kobj_ns_ops_tbl[type]->initial_ns();
1042         spin_unlock(&kobj_ns_type_lock);
1043
1044         return ns;
1045 }
1046
1047 void kobj_ns_drop(enum kobj_ns_type type, void *ns)
1048 {
1049         spin_lock(&kobj_ns_type_lock);
1050         if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1051             kobj_ns_ops_tbl[type] && kobj_ns_ops_tbl[type]->drop_ns)
1052                 kobj_ns_ops_tbl[type]->drop_ns(ns);
1053         spin_unlock(&kobj_ns_type_lock);
1054 }
1055
1056 EXPORT_SYMBOL(kobject_get);
1057 EXPORT_SYMBOL(kobject_put);
1058 EXPORT_SYMBOL(kobject_del);
1059
1060 EXPORT_SYMBOL(kset_register);
1061 EXPORT_SYMBOL(kset_unregister);