root/lib/kobject.c

DEFINITIONS

1. kobject_namespace
2. kobject_get_ownership
3. populate_dir
4. create_dir
5. get_kobj_path_length
6. fill_kobj_path
7. kobject_get_path
8. kobj_kset_join
9. kobj_kset_leave
10. kobject_init_internal
11. kobject_add_internal
12. kobject_set_name_vargs
13. kobject_set_name
14. kobject_init
15. __printf
16. kobject_add
17. kobject_init_and_add
18. kobject_rename
19. kobject_move
20. kobject_del
21. kobject_get
22. kobject_get_unless_zero
23. kobject_cleanup
24. kobject_delayed_cleanup
25. kobject_release
26. kobject_put
27. dynamic_kobj_release
28. kobject_create
29. kobject_create_and_add
30. kset_init
31. kobj_attr_show
32. kobj_attr_store
33. kset_register
34. kset_unregister
35. kset_find_obj
36. kset_release
37. kset_get_ownership
38. kset_create
39. kset_create_and_add
40. kobj_ns_type_register
41. kobj_ns_type_registered
42. kobj_child_ns_ops
43. kobj_ns_ops
44. kobj_ns_current_may_mount
45. kobj_ns_grab_current
46. kobj_ns_netlink
47. kobj_ns_initial
48. kobj_ns_drop

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * kobject.c - library routines for handling generic kernel objects
   4  *
   5  * Copyright (c) 2002-2003 Patrick Mochel <mochel@osdl.org>
   6  * Copyright (c) 2006-2007 Greg Kroah-Hartman <greg@kroah.com>
   7  * Copyright (c) 2006-2007 Novell Inc.
   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/export.h>
  16 #include <linux/stat.h>
  17 #include <linux/slab.h>
  18 #include <linux/random.h>
  19 
  20 /**
  21  * kobject_namespace() - Return @kobj's namespace tag.
  22  * @kobj: kobject in question
  23  *
  24  * Returns namespace tag of @kobj if its parent has namespace ops enabled
  25  * and thus @kobj should have a namespace tag associated with it.  Returns
  26  * %NULL otherwise.
  27  */
  28 const void *kobject_namespace(struct kobject *kobj)
  29 {
  30         const struct kobj_ns_type_operations *ns_ops = kobj_ns_ops(kobj);
  31 
  32         if (!ns_ops || ns_ops->type == KOBJ_NS_TYPE_NONE)
  33                 return NULL;
  34 
  35         return kobj->ktype->namespace(kobj);
  36 }
  37 
  38 /**
  39  * kobject_get_ownership() - Get sysfs ownership data for @kobj.
  40  * @kobj: kobject in question
  41  * @uid: kernel user ID for sysfs objects
  42  * @gid: kernel group ID for sysfs objects
  43  *
  44  * Returns initial uid/gid pair that should be used when creating sysfs
  45  * representation of given kobject. Normally used to adjust ownership of
  46  * objects in a container.
  47  */
  48 void kobject_get_ownership(struct kobject *kobj, kuid_t *uid, kgid_t *gid)
  49 {
  50         *uid = GLOBAL_ROOT_UID;
  51         *gid = GLOBAL_ROOT_GID;
  52 
  53         if (kobj->ktype->get_ownership)
  54                 kobj->ktype->get_ownership(kobj, uid, gid);
  55 }
  56 
  57 /*
  58  * populate_dir - populate directory with attributes.
  59  * @kobj: object we're working on.
  60  *
  61  * Most subsystems have a set of default attributes that are associated
  62  * with an object that registers with them.  This is a helper called during
  63  * object registration that loops through the default attributes of the
  64  * subsystem and creates attributes files for them in sysfs.
  65  */
  66 static int populate_dir(struct kobject *kobj)
  67 {
  68         struct kobj_type *t = get_ktype(kobj);
  69         struct attribute *attr;
  70         int error = 0;
  71         int i;
  72 
  73         if (t && t->default_attrs) {
  74                 for (i = 0; (attr = t->default_attrs[i]) != NULL; i++) {
  75                         error = sysfs_create_file(kobj, attr);
  76                         if (error)
  77                                 break;
  78                 }
  79         }
  80         return error;
  81 }
  82 
  83 static int create_dir(struct kobject *kobj)
  84 {
  85         const struct kobj_type *ktype = get_ktype(kobj);
  86         const struct kobj_ns_type_operations *ops;
  87         int error;
  88 
  89         error = sysfs_create_dir_ns(kobj, kobject_namespace(kobj));
  90         if (error)
  91                 return error;
  92 
  93         error = populate_dir(kobj);
  94         if (error) {
  95                 sysfs_remove_dir(kobj);
  96                 return error;
  97         }
  98 
  99         if (ktype) {
 100                 error = sysfs_create_groups(kobj, ktype->default_groups);
 101                 if (error) {
 102                         sysfs_remove_dir(kobj);
 103                         return error;
 104                 }
 105         }
 106 
 107         /*
 108          * @kobj->sd may be deleted by an ancestor going away.  Hold an
 109          * extra reference so that it stays until @kobj is gone.
 110          */
 111         sysfs_get(kobj->sd);
 112 
 113         /*
 114          * If @kobj has ns_ops, its children need to be filtered based on
 115          * their namespace tags.  Enable namespace support on @kobj->sd.
 116          */
 117         ops = kobj_child_ns_ops(kobj);
 118         if (ops) {
 119                 BUG_ON(ops->type <= KOBJ_NS_TYPE_NONE);
 120                 BUG_ON(ops->type >= KOBJ_NS_TYPES);
 121                 BUG_ON(!kobj_ns_type_registered(ops->type));
 122 
 123                 sysfs_enable_ns(kobj->sd);
 124         }
 125 
 126         return 0;
 127 }
 128 
 129 static int get_kobj_path_length(struct kobject *kobj)
 130 {
 131         int length = 1;
 132         struct kobject *parent = kobj;
 133 
 134         /* walk up the ancestors until we hit the one pointing to the
 135          * root.
 136          * Add 1 to strlen for leading '/' of each level.
 137          */
 138         do {
 139                 if (kobject_name(parent) == NULL)
 140                         return 0;
 141                 length += strlen(kobject_name(parent)) + 1;
 142                 parent = parent->parent;
 143         } while (parent);
 144         return length;
 145 }
 146 
 147 static void fill_kobj_path(struct kobject *kobj, char *path, int length)
 148 {
 149         struct kobject *parent;
 150 
 151         --length;
 152         for (parent = kobj; parent; parent = parent->parent) {
 153                 int cur = strlen(kobject_name(parent));
 154                 /* back up enough to print this name with '/' */
 155                 length -= cur;
 156                 memcpy(path + length, kobject_name(parent), cur);
 157                 *(path + --length) = '/';
 158         }
 159 
 160         pr_debug("kobject: '%s' (%p): %s: path = '%s'\n", kobject_name(kobj),
 161                  kobj, __func__, path);
 162 }
 163 
 164 /**
 165  * kobject_get_path() - Allocate memory and fill in the path for @kobj.
 166  * @kobj:       kobject in question, with which to build the path
 167  * @gfp_mask:   the allocation type used to allocate the path
 168  *
 169  * Return: The newly allocated memory, caller must free with kfree().
 170  */
 171 char *kobject_get_path(struct kobject *kobj, gfp_t gfp_mask)
 172 {
 173         char *path;
 174         int len;
 175 
 176         len = get_kobj_path_length(kobj);
 177         if (len == 0)
 178                 return NULL;
 179         path = kzalloc(len, gfp_mask);
 180         if (!path)
 181                 return NULL;
 182         fill_kobj_path(kobj, path, len);
 183 
 184         return path;
 185 }
 186 EXPORT_SYMBOL_GPL(kobject_get_path);
 187 
 188 /* add the kobject to its kset's list */
 189 static void kobj_kset_join(struct kobject *kobj)
 190 {
 191         if (!kobj->kset)
 192                 return;
 193 
 194         kset_get(kobj->kset);
 195         spin_lock(&kobj->kset->list_lock);
 196         list_add_tail(&kobj->entry, &kobj->kset->list);
 197         spin_unlock(&kobj->kset->list_lock);
 198 }
 199 
 200 /* remove the kobject from its kset's list */
 201 static void kobj_kset_leave(struct kobject *kobj)
 202 {
 203         if (!kobj->kset)
 204                 return;
 205 
 206         spin_lock(&kobj->kset->list_lock);
 207         list_del_init(&kobj->entry);
 208         spin_unlock(&kobj->kset->list_lock);
 209         kset_put(kobj->kset);
 210 }
 211 
 212 static void kobject_init_internal(struct kobject *kobj)
 213 {
 214         if (!kobj)
 215                 return;
 216         kref_init(&kobj->kref);
 217         INIT_LIST_HEAD(&kobj->entry);
 218         kobj->state_in_sysfs = 0;
 219         kobj->state_add_uevent_sent = 0;
 220         kobj->state_remove_uevent_sent = 0;
 221         kobj->state_initialized = 1;
 222 }
 223 
 224 
 225 static int kobject_add_internal(struct kobject *kobj)
 226 {
 227         int error = 0;
 228         struct kobject *parent;
 229 
 230         if (!kobj)
 231                 return -ENOENT;
 232 
 233         if (!kobj->name || !kobj->name[0]) {
 234                 WARN(1,
 235                      "kobject: (%p): attempted to be registered with empty name!\n",
 236                      kobj);
 237                 return -EINVAL;
 238         }
 239 
 240         parent = kobject_get(kobj->parent);
 241 
 242         /* join kset if set, use it as parent if we do not already have one */
 243         if (kobj->kset) {
 244                 if (!parent)
 245                         parent = kobject_get(&kobj->kset->kobj);
 246                 kobj_kset_join(kobj);
 247                 kobj->parent = parent;
 248         }
 249 
 250         pr_debug("kobject: '%s' (%p): %s: parent: '%s', set: '%s'\n",
 251                  kobject_name(kobj), kobj, __func__,
 252                  parent ? kobject_name(parent) : "<NULL>",
 253                  kobj->kset ? kobject_name(&kobj->kset->kobj) : "<NULL>");
 254 
 255         error = create_dir(kobj);
 256         if (error) {
 257                 kobj_kset_leave(kobj);
 258                 kobject_put(parent);
 259                 kobj->parent = NULL;
 260 
 261                 /* be noisy on error issues */
 262                 if (error == -EEXIST)
 263                         pr_err("%s failed for %s with -EEXIST, don't try to register things with the same name in the same directory.\n",
 264                                __func__, kobject_name(kobj));
 265                 else
 266                         pr_err("%s failed for %s (error: %d parent: %s)\n",
 267                                __func__, kobject_name(kobj), error,
 268                                parent ? kobject_name(parent) : "'none'");
 269         } else
 270                 kobj->state_in_sysfs = 1;
 271 
 272         return error;
 273 }
 274 
 275 /**
 276  * kobject_set_name_vargs() - Set the name of a kobject.
 277  * @kobj: struct kobject to set the name of
 278  * @fmt: format string used to build the name
 279  * @vargs: vargs to format the string.
 280  */
 281 int kobject_set_name_vargs(struct kobject *kobj, const char *fmt,
 282                                   va_list vargs)
 283 {
 284         const char *s;
 285 
 286         if (kobj->name && !fmt)
 287                 return 0;
 288 
 289         s = kvasprintf_const(GFP_KERNEL, fmt, vargs);
 290         if (!s)
 291                 return -ENOMEM;
 292 
 293         /*
 294          * ewww... some of these buggers have '/' in the name ... If
 295          * that's the case, we need to make sure we have an actual
 296          * allocated copy to modify, since kvasprintf_const may have
 297          * returned something from .rodata.
 298          */
 299         if (strchr(s, '/')) {
 300                 char *t;
 301 
 302                 t = kstrdup(s, GFP_KERNEL);
 303                 kfree_const(s);
 304                 if (!t)
 305                         return -ENOMEM;
 306                 strreplace(t, '/', '!');
 307                 s = t;
 308         }
 309         kfree_const(kobj->name);
 310         kobj->name = s;
 311 
 312         return 0;
 313 }
 314 
 315 /**
 316  * kobject_set_name() - Set the name of a kobject.
 317  * @kobj: struct kobject to set the name of
 318  * @fmt: format string used to build the name
 319  *
 320  * This sets the name of the kobject.  If you have already added the
 321  * kobject to the system, you must call kobject_rename() in order to
 322  * change the name of the kobject.
 323  */
 324 int kobject_set_name(struct kobject *kobj, const char *fmt, ...)
 325 {
 326         va_list vargs;
 327         int retval;
 328 
 329         va_start(vargs, fmt);
 330         retval = kobject_set_name_vargs(kobj, fmt, vargs);
 331         va_end(vargs);
 332 
 333         return retval;
 334 }
 335 EXPORT_SYMBOL(kobject_set_name);
 336 
 337 /**
 338  * kobject_init() - Initialize a kobject structure.
 339  * @kobj: pointer to the kobject to initialize
 340  * @ktype: pointer to the ktype for this kobject.
 341  *
 342  * This function will properly initialize a kobject such that it can then
 343  * be passed to the kobject_add() call.
 344  *
 345  * After this function is called, the kobject MUST be cleaned up by a call
 346  * to kobject_put(), not by a call to kfree directly to ensure that all of
 347  * the memory is cleaned up properly.
 348  */
 349 void kobject_init(struct kobject *kobj, struct kobj_type *ktype)
 350 {
 351         char *err_str;
 352 
 353         if (!kobj) {
 354                 err_str = "invalid kobject pointer!";
 355                 goto error;
 356         }
 357         if (!ktype) {
 358                 err_str = "must have a ktype to be initialized properly!\n";
 359                 goto error;
 360         }
 361         if (kobj->state_initialized) {
 362                 /* do not error out as sometimes we can recover */
 363                 pr_err("kobject (%p): tried to init an initialized object, something is seriously wrong.\n",
 364                        kobj);
 365                 dump_stack();
 366         }
 367 
 368         kobject_init_internal(kobj);
 369         kobj->ktype = ktype;
 370         return;
 371 
 372 error:
 373         pr_err("kobject (%p): %s\n", kobj, err_str);
 374         dump_stack();
 375 }
 376 EXPORT_SYMBOL(kobject_init);
 377 
 378 static __printf(3, 0) int kobject_add_varg(struct kobject *kobj,
 379                                            struct kobject *parent,
 380                                            const char *fmt, va_list vargs)
 381 {
 382         int retval;
 383 
 384         retval = kobject_set_name_vargs(kobj, fmt, vargs);
 385         if (retval) {
 386                 pr_err("kobject: can not set name properly!\n");
 387                 return retval;
 388         }
 389         kobj->parent = parent;
 390         return kobject_add_internal(kobj);
 391 }
 392 
 393 /**
 394  * kobject_add() - The main kobject add function.
 395  * @kobj: the kobject to add
 396  * @parent: pointer to the parent of the kobject.
 397  * @fmt: format to name the kobject with.
 398  *
 399  * The kobject name is set and added to the kobject hierarchy in this
 400  * function.
 401  *
 402  * If @parent is set, then the parent of the @kobj will be set to it.
 403  * If @parent is NULL, then the parent of the @kobj will be set to the
 404  * kobject associated with the kset assigned to this kobject.  If no kset
 405  * is assigned to the kobject, then the kobject will be located in the
 406  * root of the sysfs tree.
 407  *
 408  * Note, no "add" uevent will be created with this call, the caller should set
 409  * up all of the necessary sysfs files for the object and then call
 410  * kobject_uevent() with the UEVENT_ADD parameter to ensure that
 411  * userspace is properly notified of this kobject's creation.
 412  *
 413  * Return: If this function returns an error, kobject_put() must be
 414  *         called to properly clean up the memory associated with the
 415  *         object.  Under no instance should the kobject that is passed
 416  *         to this function be directly freed with a call to kfree(),
 417  *         that can leak memory.
 418  *
 419  *         If this function returns success, kobject_put() must also be called
 420  *         in order to properly clean up the memory associated with the object.
 421  *
 422  *         In short, once this function is called, kobject_put() MUST be called
 423  *         when the use of the object is finished in order to properly free
 424  *         everything.
 425  */
 426 int kobject_add(struct kobject *kobj, struct kobject *parent,
 427                 const char *fmt, ...)
 428 {
 429         va_list args;
 430         int retval;
 431 
 432         if (!kobj)
 433                 return -EINVAL;
 434 
 435         if (!kobj->state_initialized) {
 436                 pr_err("kobject '%s' (%p): tried to add an uninitialized object, something is seriously wrong.\n",
 437                        kobject_name(kobj), kobj);
 438                 dump_stack();
 439                 return -EINVAL;
 440         }
 441         va_start(args, fmt);
 442         retval = kobject_add_varg(kobj, parent, fmt, args);
 443         va_end(args);
 444 
 445         return retval;
 446 }
 447 EXPORT_SYMBOL(kobject_add);
 448 
 449 /**
 450  * kobject_init_and_add() - Initialize a kobject structure and add it to
 451  *                          the kobject hierarchy.
 452  * @kobj: pointer to the kobject to initialize
 453  * @ktype: pointer to the ktype for this kobject.
 454  * @parent: pointer to the parent of this kobject.
 455  * @fmt: the name of the kobject.
 456  *
 457  * This function combines the call to kobject_init() and kobject_add().
 458  *
 459  * If this function returns an error, kobject_put() must be called to
 460  * properly clean up the memory associated with the object.  This is the
 461  * same type of error handling after a call to kobject_add() and kobject
 462  * lifetime rules are the same here.
 463  */
 464 int kobject_init_and_add(struct kobject *kobj, struct kobj_type *ktype,
 465                          struct kobject *parent, const char *fmt, ...)
 466 {
 467         va_list args;
 468         int retval;
 469 
 470         kobject_init(kobj, ktype);
 471 
 472         va_start(args, fmt);
 473         retval = kobject_add_varg(kobj, parent, fmt, args);
 474         va_end(args);
 475 
 476         return retval;
 477 }
 478 EXPORT_SYMBOL_GPL(kobject_init_and_add);
 479 
 480 /**
 481  * kobject_rename() - Change the name of an object.
 482  * @kobj: object in question.
 483  * @new_name: object's new name
 484  *
 485  * It is the responsibility of the caller to provide mutual
 486  * exclusion between two different calls of kobject_rename
 487  * on the same kobject and to ensure that new_name is valid and
 488  * won't conflict with other kobjects.
 489  */
 490 int kobject_rename(struct kobject *kobj, const char *new_name)
 491 {
 492         int error = 0;
 493         const char *devpath = NULL;
 494         const char *dup_name = NULL, *name;
 495         char *devpath_string = NULL;
 496         char *envp[2];
 497 
 498         kobj = kobject_get(kobj);
 499         if (!kobj)
 500                 return -EINVAL;
 501         if (!kobj->parent) {
 502                 kobject_put(kobj);
 503                 return -EINVAL;
 504         }
 505 
 506         devpath = kobject_get_path(kobj, GFP_KERNEL);
 507         if (!devpath) {
 508                 error = -ENOMEM;
 509                 goto out;
 510         }
 511         devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
 512         if (!devpath_string) {
 513                 error = -ENOMEM;
 514                 goto out;
 515         }
 516         sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
 517         envp[0] = devpath_string;
 518         envp[1] = NULL;
 519 
 520         name = dup_name = kstrdup_const(new_name, GFP_KERNEL);
 521         if (!name) {
 522                 error = -ENOMEM;
 523                 goto out;
 524         }
 525 
 526         error = sysfs_rename_dir_ns(kobj, new_name, kobject_namespace(kobj));
 527         if (error)
 528                 goto out;
 529 
 530         /* Install the new kobject name */
 531         dup_name = kobj->name;
 532         kobj->name = name;
 533 
 534         /* This function is mostly/only used for network interface.
 535          * Some hotplug package track interfaces by their name and
 536          * therefore want to know when the name is changed by the user. */
 537         kobject_uevent_env(kobj, KOBJ_MOVE, envp);
 538 
 539 out:
 540         kfree_const(dup_name);
 541         kfree(devpath_string);
 542         kfree(devpath);
 543         kobject_put(kobj);
 544 
 545         return error;
 546 }
 547 EXPORT_SYMBOL_GPL(kobject_rename);
 548 
 549 /**
 550  * kobject_move() - Move object to another parent.
 551  * @kobj: object in question.
 552  * @new_parent: object's new parent (can be NULL)
 553  */
 554 int kobject_move(struct kobject *kobj, struct kobject *new_parent)
 555 {
 556         int error;
 557         struct kobject *old_parent;
 558         const char *devpath = NULL;
 559         char *devpath_string = NULL;
 560         char *envp[2];
 561 
 562         kobj = kobject_get(kobj);
 563         if (!kobj)
 564                 return -EINVAL;
 565         new_parent = kobject_get(new_parent);
 566         if (!new_parent) {
 567                 if (kobj->kset)
 568                         new_parent = kobject_get(&kobj->kset->kobj);
 569         }
 570 
 571         /* old object path */
 572         devpath = kobject_get_path(kobj, GFP_KERNEL);
 573         if (!devpath) {
 574                 error = -ENOMEM;
 575                 goto out;
 576         }
 577         devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
 578         if (!devpath_string) {
 579                 error = -ENOMEM;
 580                 goto out;
 581         }
 582         sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
 583         envp[0] = devpath_string;
 584         envp[1] = NULL;
 585         error = sysfs_move_dir_ns(kobj, new_parent, kobject_namespace(kobj));
 586         if (error)
 587                 goto out;
 588         old_parent = kobj->parent;
 589         kobj->parent = new_parent;
 590         new_parent = NULL;
 591         kobject_put(old_parent);
 592         kobject_uevent_env(kobj, KOBJ_MOVE, envp);
 593 out:
 594         kobject_put(new_parent);
 595         kobject_put(kobj);
 596         kfree(devpath_string);
 597         kfree(devpath);
 598         return error;
 599 }
 600 EXPORT_SYMBOL_GPL(kobject_move);
 601 
 602 /**
 603  * kobject_del() - Unlink kobject from hierarchy.
 604  * @kobj: object.
 605  *
 606  * This is the function that should be called to delete an object
 607  * successfully added via kobject_add().
 608  */
 609 void kobject_del(struct kobject *kobj)
 610 {
 611         struct kernfs_node *sd;
 612         const struct kobj_type *ktype;
 613 
 614         if (!kobj)
 615                 return;
 616 
 617         sd = kobj->sd;
 618         ktype = get_ktype(kobj);
 619 
 620         if (ktype)
 621                 sysfs_remove_groups(kobj, ktype->default_groups);
 622 
 623         sysfs_remove_dir(kobj);
 624         sysfs_put(sd);
 625 
 626         kobj->state_in_sysfs = 0;
 627         kobj_kset_leave(kobj);
 628         kobject_put(kobj->parent);
 629         kobj->parent = NULL;
 630 }
 631 EXPORT_SYMBOL(kobject_del);
 632 
 633 /**
 634  * kobject_get() - Increment refcount for object.
 635  * @kobj: object.
 636  */
 637 struct kobject *kobject_get(struct kobject *kobj)
 638 {
 639         if (kobj) {
 640                 if (!kobj->state_initialized)
 641                         WARN(1, KERN_WARNING
 642                                 "kobject: '%s' (%p): is not initialized, yet kobject_get() is being called.\n",
 643                              kobject_name(kobj), kobj);
 644                 kref_get(&kobj->kref);
 645         }
 646         return kobj;
 647 }
 648 EXPORT_SYMBOL(kobject_get);
 649 
 650 struct kobject * __must_check kobject_get_unless_zero(struct kobject *kobj)
 651 {
 652         if (!kobj)
 653                 return NULL;
 654         if (!kref_get_unless_zero(&kobj->kref))
 655                 kobj = NULL;
 656         return kobj;
 657 }
 658 EXPORT_SYMBOL(kobject_get_unless_zero);
 659 
 660 /*
 661  * kobject_cleanup - free kobject resources.
 662  * @kobj: object to cleanup
 663  */
 664 static void kobject_cleanup(struct kobject *kobj)
 665 {
 666         struct kobj_type *t = get_ktype(kobj);
 667         const char *name = kobj->name;
 668 
 669         pr_debug("kobject: '%s' (%p): %s, parent %p\n",
 670                  kobject_name(kobj), kobj, __func__, kobj->parent);
 671 
 672         if (t && !t->release)
 673                 pr_debug("kobject: '%s' (%p): does not have a release() function, it is broken and must be fixed. See Documentation/kobject.txt.\n",
 674                          kobject_name(kobj), kobj);
 675 
 676         /* send "remove" if the caller did not do it but sent "add" */
 677         if (kobj->state_add_uevent_sent && !kobj->state_remove_uevent_sent) {
 678                 pr_debug("kobject: '%s' (%p): auto cleanup 'remove' event\n",
 679                          kobject_name(kobj), kobj);
 680                 kobject_uevent(kobj, KOBJ_REMOVE);
 681         }
 682 
 683         /* remove from sysfs if the caller did not do it */
 684         if (kobj->state_in_sysfs) {
 685                 pr_debug("kobject: '%s' (%p): auto cleanup kobject_del\n",
 686                          kobject_name(kobj), kobj);
 687                 kobject_del(kobj);
 688         }
 689 
 690         if (t && t->release) {
 691                 pr_debug("kobject: '%s' (%p): calling ktype release\n",
 692                          kobject_name(kobj), kobj);
 693                 t->release(kobj);
 694         }
 695 
 696         /* free name if we allocated it */
 697         if (name) {
 698                 pr_debug("kobject: '%s': free name\n", name);
 699                 kfree_const(name);
 700         }
 701 }
 702 
 703 #ifdef CONFIG_DEBUG_KOBJECT_RELEASE
 704 static void kobject_delayed_cleanup(struct work_struct *work)
 705 {
 706         kobject_cleanup(container_of(to_delayed_work(work),
 707                                      struct kobject, release));
 708 }
 709 #endif
 710 
 711 static void kobject_release(struct kref *kref)
 712 {
 713         struct kobject *kobj = container_of(kref, struct kobject, kref);
 714 #ifdef CONFIG_DEBUG_KOBJECT_RELEASE
 715         unsigned long delay = HZ + HZ * (get_random_int() & 0x3);
 716         pr_info("kobject: '%s' (%p): %s, parent %p (delayed %ld)\n",
 717                  kobject_name(kobj), kobj, __func__, kobj->parent, delay);
 718         INIT_DELAYED_WORK(&kobj->release, kobject_delayed_cleanup);
 719 
 720         schedule_delayed_work(&kobj->release, delay);
 721 #else
 722         kobject_cleanup(kobj);
 723 #endif
 724 }
 725 
 726 /**
 727  * kobject_put() - Decrement refcount for object.
 728  * @kobj: object.
 729  *
 730  * Decrement the refcount, and if 0, call kobject_cleanup().
 731  */
 732 void kobject_put(struct kobject *kobj)
 733 {
 734         if (kobj) {
 735                 if (!kobj->state_initialized)
 736                         WARN(1, KERN_WARNING
 737                                 "kobject: '%s' (%p): is not initialized, yet kobject_put() is being called.\n",
 738                              kobject_name(kobj), kobj);
 739                 kref_put(&kobj->kref, kobject_release);
 740         }
 741 }
 742 EXPORT_SYMBOL(kobject_put);
 743 
 744 static void dynamic_kobj_release(struct kobject *kobj)
 745 {
 746         pr_debug("kobject: (%p): %s\n", kobj, __func__);
 747         kfree(kobj);
 748 }
 749 
 750 static struct kobj_type dynamic_kobj_ktype = {
 751         .release        = dynamic_kobj_release,
 752         .sysfs_ops      = &kobj_sysfs_ops,
 753 };
 754 
 755 /**
 756  * kobject_create() - Create a struct kobject dynamically.
 757  *
 758  * This function creates a kobject structure dynamically and sets it up
 759  * to be a "dynamic" kobject with a default release function set up.
 760  *
 761  * If the kobject was not able to be created, NULL will be returned.
 762  * The kobject structure returned from here must be cleaned up with a
 763  * call to kobject_put() and not kfree(), as kobject_init() has
 764  * already been called on this structure.
 765  */
 766 struct kobject *kobject_create(void)
 767 {
 768         struct kobject *kobj;
 769 
 770         kobj = kzalloc(sizeof(*kobj), GFP_KERNEL);
 771         if (!kobj)
 772                 return NULL;
 773 
 774         kobject_init(kobj, &dynamic_kobj_ktype);
 775         return kobj;
 776 }
 777 
 778 /**
 779  * kobject_create_and_add() - Create a struct kobject dynamically and
 780  *                            register it with sysfs.
 781  * @name: the name for the kobject
 782  * @parent: the parent kobject of this kobject, if any.
 783  *
 784  * This function creates a kobject structure dynamically and registers it
 785  * with sysfs.  When you are finished with this structure, call
 786  * kobject_put() and the structure will be dynamically freed when
 787  * it is no longer being used.
 788  *
 789  * If the kobject was not able to be created, NULL will be returned.
 790  */
 791 struct kobject *kobject_create_and_add(const char *name, struct kobject *parent)
 792 {
 793         struct kobject *kobj;
 794         int retval;
 795 
 796         kobj = kobject_create();
 797         if (!kobj)
 798                 return NULL;
 799 
 800         retval = kobject_add(kobj, parent, "%s", name);
 801         if (retval) {
 802                 pr_warn("%s: kobject_add error: %d\n", __func__, retval);
 803                 kobject_put(kobj);
 804                 kobj = NULL;
 805         }
 806         return kobj;
 807 }
 808 EXPORT_SYMBOL_GPL(kobject_create_and_add);
 809 
 810 /**
 811  * kset_init() - Initialize a kset for use.
 812  * @k: kset
 813  */
 814 void kset_init(struct kset *k)
 815 {
 816         kobject_init_internal(&k->kobj);
 817         INIT_LIST_HEAD(&k->list);
 818         spin_lock_init(&k->list_lock);
 819 }
 820 
 821 /* default kobject attribute operations */
 822 static ssize_t kobj_attr_show(struct kobject *kobj, struct attribute *attr,
 823                               char *buf)
 824 {
 825         struct kobj_attribute *kattr;
 826         ssize_t ret = -EIO;
 827 
 828         kattr = container_of(attr, struct kobj_attribute, attr);
 829         if (kattr->show)
 830                 ret = kattr->show(kobj, kattr, buf);
 831         return ret;
 832 }
 833 
 834 static ssize_t kobj_attr_store(struct kobject *kobj, struct attribute *attr,
 835                                const char *buf, size_t count)
 836 {
 837         struct kobj_attribute *kattr;
 838         ssize_t ret = -EIO;
 839 
 840         kattr = container_of(attr, struct kobj_attribute, attr);
 841         if (kattr->store)
 842                 ret = kattr->store(kobj, kattr, buf, count);
 843         return ret;
 844 }
 845 
 846 const struct sysfs_ops kobj_sysfs_ops = {
 847         .show   = kobj_attr_show,
 848         .store  = kobj_attr_store,
 849 };
 850 EXPORT_SYMBOL_GPL(kobj_sysfs_ops);
 851 
 852 /**
 853  * kset_register() - Initialize and add a kset.
 854  * @k: kset.
 855  */
 856 int kset_register(struct kset *k)
 857 {
 858         int err;
 859 
 860         if (!k)
 861                 return -EINVAL;
 862 
 863         kset_init(k);
 864         err = kobject_add_internal(&k->kobj);
 865         if (err)
 866                 return err;
 867         kobject_uevent(&k->kobj, KOBJ_ADD);
 868         return 0;
 869 }
 870 EXPORT_SYMBOL(kset_register);
 871 
 872 /**
 873  * kset_unregister() - Remove a kset.
 874  * @k: kset.
 875  */
 876 void kset_unregister(struct kset *k)
 877 {
 878         if (!k)
 879                 return;
 880         kobject_del(&k->kobj);
 881         kobject_put(&k->kobj);
 882 }
 883 EXPORT_SYMBOL(kset_unregister);
 884 
 885 /**
 886  * kset_find_obj() - Search for object in kset.
 887  * @kset: kset we're looking in.
 888  * @name: object's name.
 889  *
 890  * Lock kset via @kset->subsys, and iterate over @kset->list,
 891  * looking for a matching kobject. If matching object is found
 892  * take a reference and return the object.
 893  */
 894 struct kobject *kset_find_obj(struct kset *kset, const char *name)
 895 {
 896         struct kobject *k;
 897         struct kobject *ret = NULL;
 898 
 899         spin_lock(&kset->list_lock);
 900 
 901         list_for_each_entry(k, &kset->list, entry) {
 902                 if (kobject_name(k) && !strcmp(kobject_name(k), name)) {
 903                         ret = kobject_get_unless_zero(k);
 904                         break;
 905                 }
 906         }
 907 
 908         spin_unlock(&kset->list_lock);
 909         return ret;
 910 }
 911 EXPORT_SYMBOL_GPL(kset_find_obj);
 912 
 913 static void kset_release(struct kobject *kobj)
 914 {
 915         struct kset *kset = container_of(kobj, struct kset, kobj);
 916         pr_debug("kobject: '%s' (%p): %s\n",
 917                  kobject_name(kobj), kobj, __func__);
 918         kfree(kset);
 919 }
 920 
 921 static void kset_get_ownership(struct kobject *kobj, kuid_t *uid, kgid_t *gid)
 922 {
 923         if (kobj->parent)
 924                 kobject_get_ownership(kobj->parent, uid, gid);
 925 }
 926 
 927 static struct kobj_type kset_ktype = {
 928         .sysfs_ops      = &kobj_sysfs_ops,
 929         .release        = kset_release,
 930         .get_ownership  = kset_get_ownership,
 931 };
 932 
 933 /**
 934  * kset_create() - Create a struct kset dynamically.
 935  *
 936  * @name: the name for the kset
 937  * @uevent_ops: a struct kset_uevent_ops for the kset
 938  * @parent_kobj: the parent kobject of this kset, if any.
 939  *
 940  * This function creates a kset structure dynamically.  This structure can
 941  * then be registered with the system and show up in sysfs with a call to
 942  * kset_register().  When you are finished with this structure, if
 943  * kset_register() has been called, call kset_unregister() and the
 944  * structure will be dynamically freed when it is no longer being used.
 945  *
 946  * If the kset was not able to be created, NULL will be returned.
 947  */
 948 static struct kset *kset_create(const char *name,
 949                                 const struct kset_uevent_ops *uevent_ops,
 950                                 struct kobject *parent_kobj)
 951 {
 952         struct kset *kset;
 953         int retval;
 954 
 955         kset = kzalloc(sizeof(*kset), GFP_KERNEL);
 956         if (!kset)
 957                 return NULL;
 958         retval = kobject_set_name(&kset->kobj, "%s", name);
 959         if (retval) {
 960                 kfree(kset);
 961                 return NULL;
 962         }
 963         kset->uevent_ops = uevent_ops;
 964         kset->kobj.parent = parent_kobj;
 965 
 966         /*
 967          * The kobject of this kset will have a type of kset_ktype and belong to
 968          * no kset itself.  That way we can properly free it when it is
 969          * finished being used.
 970          */
 971         kset->kobj.ktype = &kset_ktype;
 972         kset->kobj.kset = NULL;
 973 
 974         return kset;
 975 }
 976 
 977 /**
 978  * kset_create_and_add() - Create a struct kset dynamically and add it to sysfs.
 979  *
 980  * @name: the name for the kset
 981  * @uevent_ops: a struct kset_uevent_ops for the kset
 982  * @parent_kobj: the parent kobject of this kset, if any.
 983  *
 984  * This function creates a kset structure dynamically and registers it
 985  * with sysfs.  When you are finished with this structure, call
 986  * kset_unregister() and the structure will be dynamically freed when it
 987  * is no longer being used.
 988  *
 989  * If the kset was not able to be created, NULL will be returned.
 990  */
 991 struct kset *kset_create_and_add(const char *name,
 992                                  const struct kset_uevent_ops *uevent_ops,
 993                                  struct kobject *parent_kobj)
 994 {
 995         struct kset *kset;
 996         int error;
 997 
 998         kset = kset_create(name, uevent_ops, parent_kobj);
 999         if (!kset)
1000                 return NULL;
1001         error = kset_register(kset);
1002         if (error) {
1003                 kfree(kset);
1004                 return NULL;
1005         }
1006         return kset;
1007 }
1008 EXPORT_SYMBOL_GPL(kset_create_and_add);
1009 
1010 
1011 static DEFINE_SPINLOCK(kobj_ns_type_lock);
1012 static const struct kobj_ns_type_operations *kobj_ns_ops_tbl[KOBJ_NS_TYPES];
1013 
1014 int kobj_ns_type_register(const struct kobj_ns_type_operations *ops)
1015 {
1016         enum kobj_ns_type type = ops->type;
1017         int error;
1018 
1019         spin_lock(&kobj_ns_type_lock);
1020 
1021         error = -EINVAL;
1022         if (type >= KOBJ_NS_TYPES)
1023                 goto out;
1024 
1025         error = -EINVAL;
1026         if (type <= KOBJ_NS_TYPE_NONE)
1027                 goto out;
1028 
1029         error = -EBUSY;
1030         if (kobj_ns_ops_tbl[type])
1031                 goto out;
1032 
1033         error = 0;
1034         kobj_ns_ops_tbl[type] = ops;
1035 
1036 out:
1037         spin_unlock(&kobj_ns_type_lock);
1038         return error;
1039 }
1040 
1041 int kobj_ns_type_registered(enum kobj_ns_type type)
1042 {
1043         int registered = 0;
1044 
1045         spin_lock(&kobj_ns_type_lock);
1046         if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES))
1047                 registered = kobj_ns_ops_tbl[type] != NULL;
1048         spin_unlock(&kobj_ns_type_lock);
1049 
1050         return registered;
1051 }
1052 
1053 const struct kobj_ns_type_operations *kobj_child_ns_ops(struct kobject *parent)
1054 {
1055         const struct kobj_ns_type_operations *ops = NULL;
1056 
1057         if (parent && parent->ktype && parent->ktype->child_ns_type)
1058                 ops = parent->ktype->child_ns_type(parent);
1059 
1060         return ops;
1061 }
1062 
1063 const struct kobj_ns_type_operations *kobj_ns_ops(struct kobject *kobj)
1064 {
1065         return kobj_child_ns_ops(kobj->parent);
1066 }
1067 
1068 bool kobj_ns_current_may_mount(enum kobj_ns_type type)
1069 {
1070         bool may_mount = true;
1071 
1072         spin_lock(&kobj_ns_type_lock);
1073         if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1074             kobj_ns_ops_tbl[type])
1075                 may_mount = kobj_ns_ops_tbl[type]->current_may_mount();
1076         spin_unlock(&kobj_ns_type_lock);
1077 
1078         return may_mount;
1079 }
1080 
1081 void *kobj_ns_grab_current(enum kobj_ns_type type)
1082 {
1083         void *ns = NULL;
1084 
1085         spin_lock(&kobj_ns_type_lock);
1086         if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1087             kobj_ns_ops_tbl[type])
1088                 ns = kobj_ns_ops_tbl[type]->grab_current_ns();
1089         spin_unlock(&kobj_ns_type_lock);
1090 
1091         return ns;
1092 }
1093 EXPORT_SYMBOL_GPL(kobj_ns_grab_current);
1094 
1095 const void *kobj_ns_netlink(enum kobj_ns_type type, struct sock *sk)
1096 {
1097         const void *ns = NULL;
1098 
1099         spin_lock(&kobj_ns_type_lock);
1100         if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1101             kobj_ns_ops_tbl[type])
1102                 ns = kobj_ns_ops_tbl[type]->netlink_ns(sk);
1103         spin_unlock(&kobj_ns_type_lock);
1104 
1105         return ns;
1106 }
1107 
1108 const void *kobj_ns_initial(enum kobj_ns_type type)
1109 {
1110         const void *ns = NULL;
1111 
1112         spin_lock(&kobj_ns_type_lock);
1113         if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1114             kobj_ns_ops_tbl[type])
1115                 ns = kobj_ns_ops_tbl[type]->initial_ns();
1116         spin_unlock(&kobj_ns_type_lock);
1117 
1118         return ns;
1119 }
1120 
1121 void kobj_ns_drop(enum kobj_ns_type type, void *ns)
1122 {
1123         spin_lock(&kobj_ns_type_lock);
1124         if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1125             kobj_ns_ops_tbl[type] && kobj_ns_ops_tbl[type]->drop_ns)
1126                 kobj_ns_ops_tbl[type]->drop_ns(ns);
1127         spin_unlock(&kobj_ns_type_lock);
1128 }
1129 EXPORT_SYMBOL_GPL(kobj_ns_drop);