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         char *s;
 261
 262         if (kobj->name && !fmt)
 263                 return 0;
 264
 265         s = kvasprintf(GFP_KERNEL, fmt, vargs);
 266         if (!s)
 267                 return -ENOMEM;
 268
 269         /* ewww... some of these buggers have '/' in the name ... */
 270         strreplace(s, '/', '!');
 271         kfree(kobj->name);
 272         kobj->name = s;
 273
 274         return 0;
 275 }
 276
 277 /**
 278  * kobject_set_name - Set the name of a kobject
 279  * @kobj: struct kobject to set the name of
 280  * @fmt: format string used to build the name
 281  *
 282  * This sets the name of the kobject.  If you have already added the
 283  * kobject to the system, you must call kobject_rename() in order to
 284  * change the name of the kobject.
 285  */
 286 int kobject_set_name(struct kobject *kobj, const char *fmt, ...)
 287 {
 288         va_list vargs;
 289         int retval;
 290
 291         va_start(vargs, fmt);
 292         retval = kobject_set_name_vargs(kobj, fmt, vargs);
 293         va_end(vargs);
 294
 295         return retval;
 296 }
 297 EXPORT_SYMBOL(kobject_set_name);
 298
 299 /**
 300  * kobject_init - initialize a kobject structure
 301  * @kobj: pointer to the kobject to initialize
 302  * @ktype: pointer to the ktype for this kobject.
 303  *
 304  * This function will properly initialize a kobject such that it can then
 305  * be passed to the kobject_add() call.
 306  *
 307  * After this function is called, the kobject MUST be cleaned up by a call
 308  * to kobject_put(), not by a call to kfree directly to ensure that all of
 309  * the memory is cleaned up properly.
 310  */
 311 void kobject_init(struct kobject *kobj, struct kobj_type *ktype)
 312 {
 313         char *err_str;
 314
 315         if (!kobj) {
 316                 err_str = "invalid kobject pointer!";
 317                 goto error;
 318         }
 319         if (!ktype) {
 320                 err_str = "must have a ktype to be initialized properly!\n";
 321                 goto error;
 322         }
 323         if (kobj->state_initialized) {
 324                 /* do not error out as sometimes we can recover */
 325                 printk(KERN_ERR "kobject (%p): tried to init an initialized "
 326                        "object, something is seriously wrong.\n", kobj);
 327                 dump_stack();
 328         }
 329
 330         kobject_init_internal(kobj);
 331         kobj->ktype = ktype;
 332         return;
 333
 334 error:
 335         printk(KERN_ERR "kobject (%p): %s\n", kobj, err_str);
 336         dump_stack();
 337 }
 338 EXPORT_SYMBOL(kobject_init);
 339
 340 static __printf(3, 0) int kobject_add_varg(struct kobject *kobj,
 341                                            struct kobject *parent,
 342                                            const char *fmt, va_list vargs)
 343 {
 344         int retval;
 345
 346         retval = kobject_set_name_vargs(kobj, fmt, vargs);
 347         if (retval) {
 348                 printk(KERN_ERR "kobject: can not set name properly!\n");
 349                 return retval;
 350         }
 351         kobj->parent = parent;
 352         return kobject_add_internal(kobj);
 353 }
 354
 355 /**
 356  * kobject_add - the main kobject add function
 357  * @kobj: the kobject to add
 358  * @parent: pointer to the parent of the kobject.
 359  * @fmt: format to name the kobject with.
 360  *
 361  * The kobject name is set and added to the kobject hierarchy in this
 362  * function.
 363  *
 364  * If @parent is set, then the parent of the @kobj will be set to it.
 365  * If @parent is NULL, then the parent of the @kobj will be set to the
 366  * kobject associated with the kset assigned to this kobject.  If no kset
 367  * is assigned to the kobject, then the kobject will be located in the
 368  * root of the sysfs tree.
 369  *
 370  * If this function returns an error, kobject_put() must be called to
 371  * properly clean up the memory associated with the object.
 372  * Under no instance should the kobject that is passed to this function
 373  * be directly freed with a call to kfree(), that can leak memory.
 374  *
 375  * Note, no "add" uevent will be created with this call, the caller should set
 376  * up all of the necessary sysfs files for the object and then call
 377  * kobject_uevent() with the UEVENT_ADD parameter to ensure that
 378  * userspace is properly notified of this kobject's creation.
 379  */
 380 int kobject_add(struct kobject *kobj, struct kobject *parent,
 381                 const char *fmt, ...)
 382 {
 383         va_list args;
 384         int retval;
 385
 386         if (!kobj)
 387                 return -EINVAL;
 388
 389         if (!kobj->state_initialized) {
 390                 printk(KERN_ERR "kobject '%s' (%p): tried to add an "
 391                        "uninitialized object, something is seriously wrong.\n",
 392                        kobject_name(kobj), kobj);
 393                 dump_stack();
 394                 return -EINVAL;
 395         }
 396         va_start(args, fmt);
 397         retval = kobject_add_varg(kobj, parent, fmt, args);
 398         va_end(args);
 399
 400         return retval;
 401 }
 402 EXPORT_SYMBOL(kobject_add);
 403
 404 /**
 405  * kobject_init_and_add - initialize a kobject structure and add it to the kobject hierarchy
 406  * @kobj: pointer to the kobject to initialize
 407  * @ktype: pointer to the ktype for this kobject.
 408  * @parent: pointer to the parent of this kobject.
 409  * @fmt: the name of the kobject.
 410  *
 411  * This function combines the call to kobject_init() and
 412  * kobject_add().  The same type of error handling after a call to
 413  * kobject_add() and kobject lifetime rules are the same here.
 414  */
 415 int kobject_init_and_add(struct kobject *kobj, struct kobj_type *ktype,
 416                          struct kobject *parent, const char *fmt, ...)
 417 {
 418         va_list args;
 419         int retval;
 420
 421         kobject_init(kobj, ktype);
 422
 423         va_start(args, fmt);
 424         retval = kobject_add_varg(kobj, parent, fmt, args);
 425         va_end(args);
 426
 427         return retval;
 428 }
 429 EXPORT_SYMBOL_GPL(kobject_init_and_add);
 430
 431 /**
 432  * kobject_rename - change the name of an object
 433  * @kobj: object in question.
 434  * @new_name: object's new name
 435  *
 436  * It is the responsibility of the caller to provide mutual
 437  * exclusion between two different calls of kobject_rename
 438  * on the same kobject and to ensure that new_name is valid and
 439  * won't conflict with other kobjects.
 440  */
 441 int kobject_rename(struct kobject *kobj, const char *new_name)
 442 {
 443         int error = 0;
 444         const char *devpath = NULL;
 445         const char *dup_name = NULL, *name;
 446         char *devpath_string = NULL;
 447         char *envp[2];
 448
 449         kobj = kobject_get(kobj);
 450         if (!kobj)
 451                 return -EINVAL;
 452         if (!kobj->parent)
 453                 return -EINVAL;
 454
 455         devpath = kobject_get_path(kobj, GFP_KERNEL);
 456         if (!devpath) {
 457                 error = -ENOMEM;
 458                 goto out;
 459         }
 460         devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
 461         if (!devpath_string) {
 462                 error = -ENOMEM;
 463                 goto out;
 464         }
 465         sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
 466         envp[0] = devpath_string;
 467         envp[1] = NULL;
 468
 469         name = dup_name = kstrdup(new_name, GFP_KERNEL);
 470         if (!name) {
 471                 error = -ENOMEM;
 472                 goto out;
 473         }
 474
 475         error = sysfs_rename_dir_ns(kobj, new_name, kobject_namespace(kobj));
 476         if (error)
 477                 goto out;
 478
 479         /* Install the new kobject name */
 480         dup_name = kobj->name;
 481         kobj->name = name;
 482
 483         /* This function is mostly/only used for network interface.
 484          * Some hotplug package track interfaces by their name and
 485          * therefore want to know when the name is changed by the user. */
 486         kobject_uevent_env(kobj, KOBJ_MOVE, envp);
 487
 488 out:
 489         kfree(dup_name);
 490         kfree(devpath_string);
 491         kfree(devpath);
 492         kobject_put(kobj);
 493
 494         return error;
 495 }
 496 EXPORT_SYMBOL_GPL(kobject_rename);
 497
 498 /**
 499  * kobject_move - move object to another parent
 500  * @kobj: object in question.
 501  * @new_parent: object's new parent (can be NULL)
 502  */
 503 int kobject_move(struct kobject *kobj, struct kobject *new_parent)
 504 {
 505         int error;
 506         struct kobject *old_parent;
 507         const char *devpath = NULL;
 508         char *devpath_string = NULL;
 509         char *envp[2];
 510
 511         kobj = kobject_get(kobj);
 512         if (!kobj)
 513                 return -EINVAL;
 514         new_parent = kobject_get(new_parent);
 515         if (!new_parent) {
 516                 if (kobj->kset)
 517                         new_parent = kobject_get(&kobj->kset->kobj);
 518         }
 519
 520         /* old object path */
 521         devpath = kobject_get_path(kobj, GFP_KERNEL);
 522         if (!devpath) {
 523                 error = -ENOMEM;
 524                 goto out;
 525         }
 526         devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
 527         if (!devpath_string) {
 528                 error = -ENOMEM;
 529                 goto out;
 530         }
 531         sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
 532         envp[0] = devpath_string;
 533         envp[1] = NULL;
 534         error = sysfs_move_dir_ns(kobj, new_parent, kobject_namespace(kobj));
 535         if (error)
 536                 goto out;
 537         old_parent = kobj->parent;
 538         kobj->parent = new_parent;
 539         new_parent = NULL;
 540         kobject_put(old_parent);
 541         kobject_uevent_env(kobj, KOBJ_MOVE, envp);
 542 out:
 543         kobject_put(new_parent);
 544         kobject_put(kobj);
 545         kfree(devpath_string);
 546         kfree(devpath);
 547         return error;
 548 }
 549 EXPORT_SYMBOL_GPL(kobject_move);
 550
 551 /**
 552  * kobject_del - unlink kobject from hierarchy.
 553  * @kobj: object.
 554  */
 555 void kobject_del(struct kobject *kobj)
 556 {
 557         struct kernfs_node *sd;
 558
 559         if (!kobj)
 560                 return;
 561
 562         sd = kobj->sd;
 563         sysfs_remove_dir(kobj);
 564         sysfs_put(sd);
 565
 566         kobj->state_in_sysfs = 0;
 567         kobj_kset_leave(kobj);
 568         kobject_put(kobj->parent);
 569         kobj->parent = NULL;
 570 }
 571
 572 /**
 573  * kobject_get - increment refcount for object.
 574  * @kobj: object.
 575  */
 576 struct kobject *kobject_get(struct kobject *kobj)
 577 {
 578         if (kobj) {
 579                 if (!kobj->state_initialized)
 580                         WARN(1, KERN_WARNING "kobject: '%s' (%p): is not "
 581                                "initialized, yet kobject_get() is being "
 582                                "called.\n", kobject_name(kobj), kobj);
 583                 kref_get(&kobj->kref);
 584         }
 585         return kobj;
 586 }
 587
 588 static struct kobject * __must_check kobject_get_unless_zero(struct kobject *kobj)
 589 {
 590         if (!kref_get_unless_zero(&kobj->kref))
 591                 kobj = NULL;
 592         return kobj;
 593 }
 594
 595 /*
 596  * kobject_cleanup - free kobject resources.
 597  * @kobj: object to cleanup
 598  */
 599 static void kobject_cleanup(struct kobject *kobj)
 600 {
 601         struct kobj_type *t = get_ktype(kobj);
 602         const char *name = kobj->name;
 603
 604         pr_debug("kobject: '%s' (%p): %s, parent %p\n",
 605                  kobject_name(kobj), kobj, __func__, kobj->parent);
 606
 607         if (t && !t->release)
 608                 pr_debug("kobject: '%s' (%p): does not have a release() "
 609                          "function, it is broken and must be fixed.\n",
 610                          kobject_name(kobj), kobj);
 611
 612         /* send "remove" if the caller did not do it but sent "add" */
 613         if (kobj->state_add_uevent_sent && !kobj->state_remove_uevent_sent) {
 614                 pr_debug("kobject: '%s' (%p): auto cleanup 'remove' event\n",
 615                          kobject_name(kobj), kobj);
 616                 kobject_uevent(kobj, KOBJ_REMOVE);
 617         }
 618
 619         /* remove from sysfs if the caller did not do it */
 620         if (kobj->state_in_sysfs) {
 621                 pr_debug("kobject: '%s' (%p): auto cleanup kobject_del\n",
 622                          kobject_name(kobj), kobj);
 623                 kobject_del(kobj);
 624         }
 625
 626         if (t && t->release) {
 627                 pr_debug("kobject: '%s' (%p): calling ktype release\n",
 628                          kobject_name(kobj), kobj);
 629                 t->release(kobj);
 630         }
 631
 632         /* free name if we allocated it */
 633         if (name) {
 634                 pr_debug("kobject: '%s': free name\n", name);
 635                 kfree(name);
 636         }
 637 }
 638
 639 #ifdef CONFIG_DEBUG_KOBJECT_RELEASE
 640 static void kobject_delayed_cleanup(struct work_struct *work)
 641 {
 642         kobject_cleanup(container_of(to_delayed_work(work),
 643                                      struct kobject, release));
 644 }
 645 #endif
 646
 647 static void kobject_release(struct kref *kref)
 648 {
 649         struct kobject *kobj = container_of(kref, struct kobject, kref);
 650 #ifdef CONFIG_DEBUG_KOBJECT_RELEASE
 651         unsigned long delay = HZ + HZ * (get_random_int() & 0x3);
 652         pr_info("kobject: '%s' (%p): %s, parent %p (delayed %ld)\n",
 653                  kobject_name(kobj), kobj, __func__, kobj->parent, delay);
 654         INIT_DELAYED_WORK(&kobj->release, kobject_delayed_cleanup);
 655
 656         schedule_delayed_work(&kobj->release, delay);
 657 #else
 658         kobject_cleanup(kobj);
 659 #endif
 660 }
 661
 662 /**
 663  * kobject_put - decrement refcount for object.
 664  * @kobj: object.
 665  *
 666  * Decrement the refcount, and if 0, call kobject_cleanup().
 667  */
 668 void kobject_put(struct kobject *kobj)
 669 {
 670         if (kobj) {
 671                 if (!kobj->state_initialized)
 672                         WARN(1, KERN_WARNING "kobject: '%s' (%p): is not "
 673                                "initialized, yet kobject_put() is being "
 674                                "called.\n", kobject_name(kobj), kobj);
 675                 kref_put(&kobj->kref, kobject_release);
 676         }
 677 }
 678
 679 static void dynamic_kobj_release(struct kobject *kobj)
 680 {
 681         pr_debug("kobject: (%p): %s\n", kobj, __func__);
 682         kfree(kobj);
 683 }
 684
 685 static struct kobj_type dynamic_kobj_ktype = {
 686         .release        = dynamic_kobj_release,
 687         .sysfs_ops      = &kobj_sysfs_ops,
 688 };
 689
 690 /**
 691  * kobject_create - create a struct kobject dynamically
 692  *
 693  * This function creates a kobject structure dynamically and sets it up
 694  * to be a "dynamic" kobject with a default release function set up.
 695  *
 696  * If the kobject was not able to be created, NULL will be returned.
 697  * The kobject structure returned from here must be cleaned up with a
 698  * call to kobject_put() and not kfree(), as kobject_init() has
 699  * already been called on this structure.
 700  */
 701 struct kobject *kobject_create(void)
 702 {
 703         struct kobject *kobj;
 704
 705         kobj = kzalloc(sizeof(*kobj), GFP_KERNEL);
 706         if (!kobj)
 707                 return NULL;
 708
 709         kobject_init(kobj, &dynamic_kobj_ktype);
 710         return kobj;
 711 }
 712
 713 /**
 714  * kobject_create_and_add - create a struct kobject dynamically and register it with sysfs
 715  *
 716  * @name: the name for the kobject
 717  * @parent: the parent kobject of this kobject, if any.
 718  *
 719  * This function creates a kobject structure dynamically and registers it
 720  * with sysfs.  When you are finished with this structure, call
 721  * kobject_put() and the structure will be dynamically freed when
 722  * it is no longer being used.
 723  *
 724  * If the kobject was not able to be created, NULL will be returned.
 725  */
 726 struct kobject *kobject_create_and_add(const char *name, struct kobject *parent)
 727 {
 728         struct kobject *kobj;
 729         int retval;
 730
 731         kobj = kobject_create();
 732         if (!kobj)
 733                 return NULL;
 734
 735         retval = kobject_add(kobj, parent, "%s", name);
 736         if (retval) {
 737                 printk(KERN_WARNING "%s: kobject_add error: %d\n",
 738                        __func__, retval);
 739                 kobject_put(kobj);
 740                 kobj = NULL;
 741         }
 742         return kobj;
 743 }
 744 EXPORT_SYMBOL_GPL(kobject_create_and_add);
 745
 746 /**
 747  * kset_init - initialize a kset for use
 748  * @k: kset
 749  */
 750 void kset_init(struct kset *k)
 751 {
 752         kobject_init_internal(&k->kobj);
 753         INIT_LIST_HEAD(&k->list);
 754         spin_lock_init(&k->list_lock);
 755 }
 756
 757 /* default kobject attribute operations */
 758 static ssize_t kobj_attr_show(struct kobject *kobj, struct attribute *attr,
 759                               char *buf)
 760 {
 761         struct kobj_attribute *kattr;
 762         ssize_t ret = -EIO;
 763
 764         kattr = container_of(attr, struct kobj_attribute, attr);
 765         if (kattr->show)
 766                 ret = kattr->show(kobj, kattr, buf);
 767         return ret;
 768 }
 769
 770 static ssize_t kobj_attr_store(struct kobject *kobj, struct attribute *attr,
 771                                const char *buf, size_t count)
 772 {
 773         struct kobj_attribute *kattr;
 774         ssize_t ret = -EIO;
 775
 776         kattr = container_of(attr, struct kobj_attribute, attr);
 777         if (kattr->store)
 778                 ret = kattr->store(kobj, kattr, buf, count);
 779         return ret;
 780 }
 781
 782 const struct sysfs_ops kobj_sysfs_ops = {
 783         .show   = kobj_attr_show,
 784         .store  = kobj_attr_store,
 785 };
 786 EXPORT_SYMBOL_GPL(kobj_sysfs_ops);
 787
 788 /**
 789  * kset_register - initialize and add a kset.
 790  * @k: kset.
 791  */
 792 int kset_register(struct kset *k)
 793 {
 794         int err;
 795
 796         if (!k)
 797                 return -EINVAL;
 798
 799         kset_init(k);
 800         err = kobject_add_internal(&k->kobj);
 801         if (err)
 802                 return err;
 803         kobject_uevent(&k->kobj, KOBJ_ADD);
 804         return 0;
 805 }
 806
 807 /**
 808  * kset_unregister - remove a kset.
 809  * @k: kset.
 810  */
 811 void kset_unregister(struct kset *k)
 812 {
 813         if (!k)
 814                 return;
 815         kobject_del(&k->kobj);
 816         kobject_put(&k->kobj);
 817 }
 818
 819 /**
 820  * kset_find_obj - search for object in kset.
 821  * @kset: kset we're looking in.
 822  * @name: object's name.
 823  *
 824  * Lock kset via @kset->subsys, and iterate over @kset->list,
 825  * looking for a matching kobject. If matching object is found
 826  * take a reference and return the object.
 827  */
 828 struct kobject *kset_find_obj(struct kset *kset, const char *name)
 829 {
 830         struct kobject *k;
 831         struct kobject *ret = NULL;
 832
 833         spin_lock(&kset->list_lock);
 834
 835         list_for_each_entry(k, &kset->list, entry) {
 836                 if (kobject_name(k) && !strcmp(kobject_name(k), name)) {
 837                         ret = kobject_get_unless_zero(k);
 838                         break;
 839                 }
 840         }
 841
 842         spin_unlock(&kset->list_lock);
 843         return ret;
 844 }
 845
 846 static void kset_release(struct kobject *kobj)
 847 {
 848         struct kset *kset = container_of(kobj, struct kset, kobj);
 849         pr_debug("kobject: '%s' (%p): %s\n",
 850                  kobject_name(kobj), kobj, __func__);
 851         kfree(kset);
 852 }
 853
 854 static struct kobj_type kset_ktype = {
 855         .sysfs_ops      = &kobj_sysfs_ops,
 856         .release = kset_release,
 857 };
 858
 859 /**
 860  * kset_create - create a struct kset dynamically
 861  *
 862  * @name: the name for the kset
 863  * @uevent_ops: a struct kset_uevent_ops for the kset
 864  * @parent_kobj: the parent kobject of this kset, if any.
 865  *
 866  * This function creates a kset structure dynamically.  This structure can
 867  * then be registered with the system and show up in sysfs with a call to
 868  * kset_register().  When you are finished with this structure, if
 869  * kset_register() has been called, call kset_unregister() and the
 870  * structure will be dynamically freed when it is no longer being used.
 871  *
 872  * If the kset was not able to be created, NULL will be returned.
 873  */
 874 static struct kset *kset_create(const char *name,
 875                                 const struct kset_uevent_ops *uevent_ops,
 876                                 struct kobject *parent_kobj)
 877 {
 878         struct kset *kset;
 879         int retval;
 880
 881         kset = kzalloc(sizeof(*kset), GFP_KERNEL);
 882         if (!kset)
 883                 return NULL;
 884         retval = kobject_set_name(&kset->kobj, "%s", name);
 885         if (retval) {
 886                 kfree(kset);
 887                 return NULL;
 888         }
 889         kset->uevent_ops = uevent_ops;
 890         kset->kobj.parent = parent_kobj;
 891
 892         /*
 893          * The kobject of this kset will have a type of kset_ktype and belong to
 894          * no kset itself.  That way we can properly free it when it is
 895          * finished being used.
 896          */
 897         kset->kobj.ktype = &kset_ktype;
 898         kset->kobj.kset = NULL;
 899
 900         return kset;
 901 }
 902
 903 /**
 904  * kset_create_and_add - create a struct kset dynamically and add it to sysfs
 905  *
 906  * @name: the name for the kset
 907  * @uevent_ops: a struct kset_uevent_ops for the kset
 908  * @parent_kobj: the parent kobject of this kset, if any.
 909  *
 910  * This function creates a kset structure dynamically and registers it
 911  * with sysfs.  When you are finished with this structure, call
 912  * kset_unregister() and the structure will be dynamically freed when it
 913  * is no longer being used.
 914  *
 915  * If the kset was not able to be created, NULL will be returned.
 916  */
 917 struct kset *kset_create_and_add(const char *name,
 918                                  const struct kset_uevent_ops *uevent_ops,
 919                                  struct kobject *parent_kobj)
 920 {
 921         struct kset *kset;
 922         int error;
 923
 924         kset = kset_create(name, uevent_ops, parent_kobj);
 925         if (!kset)
 926                 return NULL;
 927         error = kset_register(kset);
 928         if (error) {
 929                 kfree(kset);
 930                 return NULL;
 931         }
 932         return kset;
 933 }
 934 EXPORT_SYMBOL_GPL(kset_create_and_add);
 935
 936
 937 static DEFINE_SPINLOCK(kobj_ns_type_lock);
 938 static const struct kobj_ns_type_operations *kobj_ns_ops_tbl[KOBJ_NS_TYPES];
 939
 940 int kobj_ns_type_register(const struct kobj_ns_type_operations *ops)
 941 {
 942         enum kobj_ns_type type = ops->type;
 943         int error;
 944
 945         spin_lock(&kobj_ns_type_lock);
 946
 947         error = -EINVAL;
 948         if (type >= KOBJ_NS_TYPES)
 949                 goto out;
 950
 951         error = -EINVAL;
 952         if (type <= KOBJ_NS_TYPE_NONE)
 953                 goto out;
 954
 955         error = -EBUSY;
 956         if (kobj_ns_ops_tbl[type])
 957                 goto out;
 958
 959         error = 0;
 960         kobj_ns_ops_tbl[type] = ops;
 961
 962 out:
 963         spin_unlock(&kobj_ns_type_lock);
 964         return error;
 965 }
 966
 967 int kobj_ns_type_registered(enum kobj_ns_type type)
 968 {
 969         int registered = 0;
 970
 971         spin_lock(&kobj_ns_type_lock);
 972         if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES))
 973                 registered = kobj_ns_ops_tbl[type] != NULL;
 974         spin_unlock(&kobj_ns_type_lock);
 975
 976         return registered;
 977 }
 978
 979 const struct kobj_ns_type_operations *kobj_child_ns_ops(struct kobject *parent)
 980 {
 981         const struct kobj_ns_type_operations *ops = NULL;
 982
 983         if (parent && parent->ktype && parent->ktype->child_ns_type)
 984                 ops = parent->ktype->child_ns_type(parent);
 985
 986         return ops;
 987 }
 988
 989 const struct kobj_ns_type_operations *kobj_ns_ops(struct kobject *kobj)
 990 {
 991         return kobj_child_ns_ops(kobj->parent);
 992 }
 993
 994 bool kobj_ns_current_may_mount(enum kobj_ns_type type)
 995 {
 996         bool may_mount = true;
 997
 998         spin_lock(&kobj_ns_type_lock);
 999         if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1000             kobj_ns_ops_tbl[type])
1001                 may_mount = kobj_ns_ops_tbl[type]->current_may_mount();
1002         spin_unlock(&kobj_ns_type_lock);
1003
1004         return may_mount;
1005 }
1006
1007 void *kobj_ns_grab_current(enum kobj_ns_type type)
1008 {
1009         void *ns = NULL;
1010
1011         spin_lock(&kobj_ns_type_lock);
1012         if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1013             kobj_ns_ops_tbl[type])
1014                 ns = kobj_ns_ops_tbl[type]->grab_current_ns();
1015         spin_unlock(&kobj_ns_type_lock);
1016
1017         return ns;
1018 }
1019
1020 const void *kobj_ns_netlink(enum kobj_ns_type type, struct sock *sk)
1021 {
1022         const void *ns = NULL;
1023
1024         spin_lock(&kobj_ns_type_lock);
1025         if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1026             kobj_ns_ops_tbl[type])
1027                 ns = kobj_ns_ops_tbl[type]->netlink_ns(sk);
1028         spin_unlock(&kobj_ns_type_lock);
1029
1030         return ns;
1031 }
1032
1033 const void *kobj_ns_initial(enum kobj_ns_type type)
1034 {
1035         const void *ns = NULL;
1036
1037         spin_lock(&kobj_ns_type_lock);
1038         if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1039             kobj_ns_ops_tbl[type])
1040                 ns = kobj_ns_ops_tbl[type]->initial_ns();
1041         spin_unlock(&kobj_ns_type_lock);
1042
1043         return ns;
1044 }
1045
1046 void kobj_ns_drop(enum kobj_ns_type type, void *ns)
1047 {
1048         spin_lock(&kobj_ns_type_lock);
1049         if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1050             kobj_ns_ops_tbl[type] && kobj_ns_ops_tbl[type]->drop_ns)
1051                 kobj_ns_ops_tbl[type]->drop_ns(ns);
1052         spin_unlock(&kobj_ns_type_lock);
1053 }
1054
1055 EXPORT_SYMBOL(kobject_get);
1056 EXPORT_SYMBOL(kobject_put);
1057 EXPORT_SYMBOL(kobject_del);
1058
1059 EXPORT_SYMBOL(kset_register);
1060 EXPORT_SYMBOL(kset_unregister);