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/core-api/kobject.rst 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 */
  28const 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 */
  48void 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 */
  66static 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
  83static 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
 129static 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
 147static 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 */
 171char *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}
 186EXPORT_SYMBOL_GPL(kobject_get_path);
 187
 188/* add the kobject to its kset's list */
 189static 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 */
 201static 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
 212static 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
 225static 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 */
 281int 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 */
 324int 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}
 335EXPORT_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 */
 349void 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
 372error:
 373	pr_err("kobject (%p): %s\n", kobj, err_str);
 374	dump_stack();
 375}
 376EXPORT_SYMBOL(kobject_init);
 377
 378static __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 */
 426int 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}
 447EXPORT_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 */
 464int 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}
 478EXPORT_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 */
 490int 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
 539out:
 540	kfree_const(dup_name);
 541	kfree(devpath_string);
 542	kfree(devpath);
 543	kobject_put(kobj);
 544
 545	return error;
 546}
 547EXPORT_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 */
 554int 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);
 593out:
 594	kobject_put(new_parent);
 595	kobject_put(kobj);
 596	kfree(devpath_string);
 597	kfree(devpath);
 598	return error;
 599}
 600EXPORT_SYMBOL_GPL(kobject_move);
 601
 602static void __kobject_del(struct kobject *kobj)
 603{
 604	struct kernfs_node *sd;
 605	const struct kobj_type *ktype;
 606
 607	sd = kobj->sd;
 608	ktype = get_ktype(kobj);
 609
 610	if (ktype)
 611		sysfs_remove_groups(kobj, ktype->default_groups);
 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	sysfs_remove_dir(kobj);
 621	sysfs_put(sd);
 622
 623	kobj->state_in_sysfs = 0;
 624	kobj_kset_leave(kobj);
 625	kobj->parent = NULL;
 626}
 627
 628/**
 629 * kobject_del() - Unlink kobject from hierarchy.
 630 * @kobj: object.
 631 *
 632 * This is the function that should be called to delete an object
 633 * successfully added via kobject_add().
 634 */
 635void kobject_del(struct kobject *kobj)
 636{
 637	struct kobject *parent;
 638
 639	if (!kobj)
 640		return;
 641
 642	parent = kobj->parent;
 643	__kobject_del(kobj);
 644	kobject_put(parent);
 645}
 646EXPORT_SYMBOL(kobject_del);
 647
 648/**
 649 * kobject_get() - Increment refcount for object.
 650 * @kobj: object.
 651 */
 652struct kobject *kobject_get(struct kobject *kobj)
 653{
 654	if (kobj) {
 655		if (!kobj->state_initialized)
 656			WARN(1, KERN_WARNING
 657				"kobject: '%s' (%p): is not initialized, yet kobject_get() is being called.\n",
 658			     kobject_name(kobj), kobj);
 659		kref_get(&kobj->kref);
 660	}
 661	return kobj;
 662}
 663EXPORT_SYMBOL(kobject_get);
 664
 665struct kobject * __must_check kobject_get_unless_zero(struct kobject *kobj)
 666{
 667	if (!kobj)
 668		return NULL;
 669	if (!kref_get_unless_zero(&kobj->kref))
 670		kobj = NULL;
 671	return kobj;
 672}
 673EXPORT_SYMBOL(kobject_get_unless_zero);
 674
 675/*
 676 * kobject_cleanup - free kobject resources.
 677 * @kobj: object to cleanup
 678 */
 679static void kobject_cleanup(struct kobject *kobj)
 680{
 681	struct kobject *parent = kobj->parent;
 682	struct kobj_type *t = get_ktype(kobj);
 683	const char *name = kobj->name;
 684
 685	pr_debug("kobject: '%s' (%p): %s, parent %p\n",
 686		 kobject_name(kobj), kobj, __func__, kobj->parent);
 687
 688	if (t && !t->release)
 689		pr_debug("kobject: '%s' (%p): does not have a release() function, it is broken and must be fixed. See Documentation/core-api/kobject.rst.\n",
 690			 kobject_name(kobj), kobj);
 691
 692	/* remove from sysfs if the caller did not do it */
 693	if (kobj->state_in_sysfs) {
 694		pr_debug("kobject: '%s' (%p): auto cleanup kobject_del\n",
 695			 kobject_name(kobj), kobj);
 696		__kobject_del(kobj);
 697	} else {
 698		/* avoid dropping the parent reference unnecessarily */
 699		parent = NULL;
 700	}
 701
 702	if (t && t->release) {
 703		pr_debug("kobject: '%s' (%p): calling ktype release\n",
 704			 kobject_name(kobj), kobj);
 705		t->release(kobj);
 706	}
 707
 708	/* free name if we allocated it */
 709	if (name) {
 710		pr_debug("kobject: '%s': free name\n", name);
 711		kfree_const(name);
 712	}
 713
 714	kobject_put(parent);
 715}
 716
 717#ifdef CONFIG_DEBUG_KOBJECT_RELEASE
 718static void kobject_delayed_cleanup(struct work_struct *work)
 719{
 720	kobject_cleanup(container_of(to_delayed_work(work),
 721				     struct kobject, release));
 722}
 723#endif
 724
 725static void kobject_release(struct kref *kref)
 726{
 727	struct kobject *kobj = container_of(kref, struct kobject, kref);
 728#ifdef CONFIG_DEBUG_KOBJECT_RELEASE
 729	unsigned long delay = HZ + HZ * (get_random_int() & 0x3);
 730	pr_info("kobject: '%s' (%p): %s, parent %p (delayed %ld)\n",
 731		 kobject_name(kobj), kobj, __func__, kobj->parent, delay);
 732	INIT_DELAYED_WORK(&kobj->release, kobject_delayed_cleanup);
 733
 734	schedule_delayed_work(&kobj->release, delay);
 735#else
 736	kobject_cleanup(kobj);
 737#endif
 738}
 739
 740/**
 741 * kobject_put() - Decrement refcount for object.
 742 * @kobj: object.
 743 *
 744 * Decrement the refcount, and if 0, call kobject_cleanup().
 745 */
 746void kobject_put(struct kobject *kobj)
 747{
 748	if (kobj) {
 749		if (!kobj->state_initialized)
 750			WARN(1, KERN_WARNING
 751				"kobject: '%s' (%p): is not initialized, yet kobject_put() is being called.\n",
 752			     kobject_name(kobj), kobj);
 753		kref_put(&kobj->kref, kobject_release);
 754	}
 755}
 756EXPORT_SYMBOL(kobject_put);
 757
 758static void dynamic_kobj_release(struct kobject *kobj)
 759{
 760	pr_debug("kobject: (%p): %s\n", kobj, __func__);
 761	kfree(kobj);
 762}
 763
 764static struct kobj_type dynamic_kobj_ktype = {
 765	.release	= dynamic_kobj_release,
 766	.sysfs_ops	= &kobj_sysfs_ops,
 767};
 768
 769/**
 770 * kobject_create() - Create a struct kobject dynamically.
 771 *
 772 * This function creates a kobject structure dynamically and sets it up
 773 * to be a "dynamic" kobject with a default release function set up.
 774 *
 775 * If the kobject was not able to be created, NULL will be returned.
 776 * The kobject structure returned from here must be cleaned up with a
 777 * call to kobject_put() and not kfree(), as kobject_init() has
 778 * already been called on this structure.
 779 */
 780struct kobject *kobject_create(void)
 781{
 782	struct kobject *kobj;
 783
 784	kobj = kzalloc(sizeof(*kobj), GFP_KERNEL);
 785	if (!kobj)
 786		return NULL;
 787
 788	kobject_init(kobj, &dynamic_kobj_ktype);
 789	return kobj;
 790}
 791
 792/**
 793 * kobject_create_and_add() - Create a struct kobject dynamically and
 794 *                            register it with sysfs.
 795 * @name: the name for the kobject
 796 * @parent: the parent kobject of this kobject, if any.
 797 *
 798 * This function creates a kobject structure dynamically and registers it
 799 * with sysfs.  When you are finished with this structure, call
 800 * kobject_put() and the structure will be dynamically freed when
 801 * it is no longer being used.
 802 *
 803 * If the kobject was not able to be created, NULL will be returned.
 804 */
 805struct kobject *kobject_create_and_add(const char *name, struct kobject *parent)
 806{
 807	struct kobject *kobj;
 808	int retval;
 809
 810	kobj = kobject_create();
 811	if (!kobj)
 812		return NULL;
 813
 814	retval = kobject_add(kobj, parent, "%s", name);
 815	if (retval) {
 816		pr_warn("%s: kobject_add error: %d\n", __func__, retval);
 817		kobject_put(kobj);
 818		kobj = NULL;
 819	}
 820	return kobj;
 821}
 822EXPORT_SYMBOL_GPL(kobject_create_and_add);
 823
 824/**
 825 * kset_init() - Initialize a kset for use.
 826 * @k: kset
 827 */
 828void kset_init(struct kset *k)
 829{
 830	kobject_init_internal(&k->kobj);
 831	INIT_LIST_HEAD(&k->list);
 832	spin_lock_init(&k->list_lock);
 833}
 834
 835/* default kobject attribute operations */
 836static ssize_t kobj_attr_show(struct kobject *kobj, struct attribute *attr,
 837			      char *buf)
 838{
 839	struct kobj_attribute *kattr;
 840	ssize_t ret = -EIO;
 841
 842	kattr = container_of(attr, struct kobj_attribute, attr);
 843	if (kattr->show)
 844		ret = kattr->show(kobj, kattr, buf);
 845	return ret;
 846}
 847
 848static ssize_t kobj_attr_store(struct kobject *kobj, struct attribute *attr,
 849			       const char *buf, size_t count)
 850{
 851	struct kobj_attribute *kattr;
 852	ssize_t ret = -EIO;
 853
 854	kattr = container_of(attr, struct kobj_attribute, attr);
 855	if (kattr->store)
 856		ret = kattr->store(kobj, kattr, buf, count);
 857	return ret;
 858}
 859
 860const struct sysfs_ops kobj_sysfs_ops = {
 861	.show	= kobj_attr_show,
 862	.store	= kobj_attr_store,
 863};
 864EXPORT_SYMBOL_GPL(kobj_sysfs_ops);
 865
 866/**
 867 * kset_register() - Initialize and add a kset.
 868 * @k: kset.
 869 */
 870int kset_register(struct kset *k)
 871{
 872	int err;
 873
 874	if (!k)
 875		return -EINVAL;
 876
 877	kset_init(k);
 878	err = kobject_add_internal(&k->kobj);
 879	if (err)
 880		return err;
 881	kobject_uevent(&k->kobj, KOBJ_ADD);
 882	return 0;
 883}
 884EXPORT_SYMBOL(kset_register);
 885
 886/**
 887 * kset_unregister() - Remove a kset.
 888 * @k: kset.
 889 */
 890void kset_unregister(struct kset *k)
 891{
 892	if (!k)
 893		return;
 894	kobject_del(&k->kobj);
 895	kobject_put(&k->kobj);
 896}
 897EXPORT_SYMBOL(kset_unregister);
 898
 899/**
 900 * kset_find_obj() - Search for object in kset.
 901 * @kset: kset we're looking in.
 902 * @name: object's name.
 903 *
 904 * Lock kset via @kset->subsys, and iterate over @kset->list,
 905 * looking for a matching kobject. If matching object is found
 906 * take a reference and return the object.
 907 */
 908struct kobject *kset_find_obj(struct kset *kset, const char *name)
 909{
 910	struct kobject *k;
 911	struct kobject *ret = NULL;
 912
 913	spin_lock(&kset->list_lock);
 914
 915	list_for_each_entry(k, &kset->list, entry) {
 916		if (kobject_name(k) && !strcmp(kobject_name(k), name)) {
 917			ret = kobject_get_unless_zero(k);
 918			break;
 919		}
 920	}
 921
 922	spin_unlock(&kset->list_lock);
 923	return ret;
 924}
 925EXPORT_SYMBOL_GPL(kset_find_obj);
 926
 927static void kset_release(struct kobject *kobj)
 928{
 929	struct kset *kset = container_of(kobj, struct kset, kobj);
 930	pr_debug("kobject: '%s' (%p): %s\n",
 931		 kobject_name(kobj), kobj, __func__);
 932	kfree(kset);
 933}
 934
 935static void kset_get_ownership(struct kobject *kobj, kuid_t *uid, kgid_t *gid)
 936{
 937	if (kobj->parent)
 938		kobject_get_ownership(kobj->parent, uid, gid);
 939}
 940
 941static struct kobj_type kset_ktype = {
 942	.sysfs_ops	= &kobj_sysfs_ops,
 943	.release	= kset_release,
 944	.get_ownership	= kset_get_ownership,
 945};
 946
 947/**
 948 * kset_create() - Create a struct kset dynamically.
 949 *
 950 * @name: the name for the kset
 951 * @uevent_ops: a struct kset_uevent_ops for the kset
 952 * @parent_kobj: the parent kobject of this kset, if any.
 953 *
 954 * This function creates a kset structure dynamically.  This structure can
 955 * then be registered with the system and show up in sysfs with a call to
 956 * kset_register().  When you are finished with this structure, if
 957 * kset_register() has been called, call kset_unregister() and the
 958 * structure will be dynamically freed when it is no longer being used.
 959 *
 960 * If the kset was not able to be created, NULL will be returned.
 961 */
 962static struct kset *kset_create(const char *name,
 963				const struct kset_uevent_ops *uevent_ops,
 964				struct kobject *parent_kobj)
 965{
 966	struct kset *kset;
 967	int retval;
 968
 969	kset = kzalloc(sizeof(*kset), GFP_KERNEL);
 970	if (!kset)
 971		return NULL;
 972	retval = kobject_set_name(&kset->kobj, "%s", name);
 973	if (retval) {
 974		kfree(kset);
 975		return NULL;
 976	}
 977	kset->uevent_ops = uevent_ops;
 978	kset->kobj.parent = parent_kobj;
 979
 980	/*
 981	 * The kobject of this kset will have a type of kset_ktype and belong to
 982	 * no kset itself.  That way we can properly free it when it is
 983	 * finished being used.
 984	 */
 985	kset->kobj.ktype = &kset_ktype;
 986	kset->kobj.kset = NULL;
 987
 988	return kset;
 989}
 990
 991/**
 992 * kset_create_and_add() - Create a struct kset dynamically and add it to sysfs.
 993 *
 994 * @name: the name for the kset
 995 * @uevent_ops: a struct kset_uevent_ops for the kset
 996 * @parent_kobj: the parent kobject of this kset, if any.
 997 *
 998 * This function creates a kset structure dynamically and registers it
 999 * with sysfs.  When you are finished with this structure, call
1000 * kset_unregister() and the structure will be dynamically freed when it
1001 * is no longer being used.
1002 *
1003 * If the kset was not able to be created, NULL will be returned.
1004 */
1005struct kset *kset_create_and_add(const char *name,
1006				 const struct kset_uevent_ops *uevent_ops,
1007				 struct kobject *parent_kobj)
1008{
1009	struct kset *kset;
1010	int error;
1011
1012	kset = kset_create(name, uevent_ops, parent_kobj);
1013	if (!kset)
1014		return NULL;
1015	error = kset_register(kset);
1016	if (error) {
1017		kfree(kset);
1018		return NULL;
1019	}
1020	return kset;
1021}
1022EXPORT_SYMBOL_GPL(kset_create_and_add);
1023
1024
1025static DEFINE_SPINLOCK(kobj_ns_type_lock);
1026static const struct kobj_ns_type_operations *kobj_ns_ops_tbl[KOBJ_NS_TYPES];
1027
1028int kobj_ns_type_register(const struct kobj_ns_type_operations *ops)
1029{
1030	enum kobj_ns_type type = ops->type;
1031	int error;
1032
1033	spin_lock(&kobj_ns_type_lock);
1034
1035	error = -EINVAL;
1036	if (type >= KOBJ_NS_TYPES)
1037		goto out;
1038
1039	error = -EINVAL;
1040	if (type <= KOBJ_NS_TYPE_NONE)
1041		goto out;
1042
1043	error = -EBUSY;
1044	if (kobj_ns_ops_tbl[type])
1045		goto out;
1046
1047	error = 0;
1048	kobj_ns_ops_tbl[type] = ops;
1049
1050out:
1051	spin_unlock(&kobj_ns_type_lock);
1052	return error;
1053}
1054
1055int kobj_ns_type_registered(enum kobj_ns_type type)
1056{
1057	int registered = 0;
1058
1059	spin_lock(&kobj_ns_type_lock);
1060	if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES))
1061		registered = kobj_ns_ops_tbl[type] != NULL;
1062	spin_unlock(&kobj_ns_type_lock);
1063
1064	return registered;
1065}
1066
1067const struct kobj_ns_type_operations *kobj_child_ns_ops(struct kobject *parent)
1068{
1069	const struct kobj_ns_type_operations *ops = NULL;
1070
1071	if (parent && parent->ktype && parent->ktype->child_ns_type)
1072		ops = parent->ktype->child_ns_type(parent);
1073
1074	return ops;
1075}
1076
1077const struct kobj_ns_type_operations *kobj_ns_ops(struct kobject *kobj)
1078{
1079	return kobj_child_ns_ops(kobj->parent);
1080}
1081
1082bool kobj_ns_current_may_mount(enum kobj_ns_type type)
1083{
1084	bool may_mount = true;
1085
1086	spin_lock(&kobj_ns_type_lock);
1087	if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1088	    kobj_ns_ops_tbl[type])
1089		may_mount = kobj_ns_ops_tbl[type]->current_may_mount();
1090	spin_unlock(&kobj_ns_type_lock);
1091
1092	return may_mount;
1093}
1094
1095void *kobj_ns_grab_current(enum kobj_ns_type type)
1096{
1097	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]->grab_current_ns();
1103	spin_unlock(&kobj_ns_type_lock);
1104
1105	return ns;
1106}
1107EXPORT_SYMBOL_GPL(kobj_ns_grab_current);
1108
1109const void *kobj_ns_netlink(enum kobj_ns_type type, struct sock *sk)
1110{
1111	const void *ns = NULL;
1112
1113	spin_lock(&kobj_ns_type_lock);
1114	if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1115	    kobj_ns_ops_tbl[type])
1116		ns = kobj_ns_ops_tbl[type]->netlink_ns(sk);
1117	spin_unlock(&kobj_ns_type_lock);
1118
1119	return ns;
1120}
1121
1122const void *kobj_ns_initial(enum kobj_ns_type type)
1123{
1124	const void *ns = NULL;
1125
1126	spin_lock(&kobj_ns_type_lock);
1127	if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1128	    kobj_ns_ops_tbl[type])
1129		ns = kobj_ns_ops_tbl[type]->initial_ns();
1130	spin_unlock(&kobj_ns_type_lock);
1131
1132	return ns;
1133}
1134
1135void kobj_ns_drop(enum kobj_ns_type type, void *ns)
1136{
1137	spin_lock(&kobj_ns_type_lock);
1138	if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1139	    kobj_ns_ops_tbl[type] && kobj_ns_ops_tbl[type]->drop_ns)
1140		kobj_ns_ops_tbl[type]->drop_ns(ns);
1141	spin_unlock(&kobj_ns_type_lock);
1142}
1143EXPORT_SYMBOL_GPL(kobj_ns_drop);