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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  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 */
  30const void *kobject_namespace(const 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 * kobject_get_ownership() - Get sysfs ownership data for @kobj.
  42 * @kobj: kobject in question
  43 * @uid: kernel user ID for sysfs objects
  44 * @gid: kernel group ID for sysfs objects
  45 *
  46 * Returns initial uid/gid pair that should be used when creating sysfs
  47 * representation of given kobject. Normally used to adjust ownership of
  48 * objects in a container.
  49 */
  50void kobject_get_ownership(const struct kobject *kobj, kuid_t *uid, kgid_t *gid)
  51{
  52	*uid = GLOBAL_ROOT_UID;
  53	*gid = GLOBAL_ROOT_GID;
  54
  55	if (kobj->ktype->get_ownership)
  56		kobj->ktype->get_ownership(kobj, uid, gid);
  57}
  58
  59static bool kobj_ns_type_is_valid(enum kobj_ns_type type)
  60{
  61	if ((type <= KOBJ_NS_TYPE_NONE) || (type >= KOBJ_NS_TYPES))
  62		return false;
  63
  64	return true;
  65}
  66
  67static int create_dir(struct kobject *kobj)
  68{
  69	const struct kobj_type *ktype = get_ktype(kobj);
  70	const struct kobj_ns_type_operations *ops;
  71	int error;
  72
  73	error = sysfs_create_dir_ns(kobj, kobject_namespace(kobj));
  74	if (error)
  75		return error;
  76
  77	if (ktype) {
  78		error = sysfs_create_groups(kobj, ktype->default_groups);
  79		if (error) {
  80			sysfs_remove_dir(kobj);
  81			return error;
  82		}
  83	}
  84
  85	/*
  86	 * @kobj->sd may be deleted by an ancestor going away.  Hold an
  87	 * extra reference so that it stays until @kobj is gone.
  88	 */
  89	sysfs_get(kobj->sd);
  90
  91	/*
  92	 * If @kobj has ns_ops, its children need to be filtered based on
  93	 * their namespace tags.  Enable namespace support on @kobj->sd.
  94	 */
  95	ops = kobj_child_ns_ops(kobj);
  96	if (ops) {
  97		BUG_ON(!kobj_ns_type_is_valid(ops->type));
  98		BUG_ON(!kobj_ns_type_registered(ops->type));
  99
 100		sysfs_enable_ns(kobj->sd);
 101	}
 102
 103	return 0;
 104}
 105
 106static int get_kobj_path_length(const struct kobject *kobj)
 107{
 108	int length = 1;
 109	const struct kobject *parent = kobj;
 110
 111	/* walk up the ancestors until we hit the one pointing to the
 112	 * root.
 113	 * Add 1 to strlen for leading '/' of each level.
 114	 */
 115	do {
 116		if (kobject_name(parent) == NULL)
 117			return 0;
 118		length += strlen(kobject_name(parent)) + 1;
 119		parent = parent->parent;
 120	} while (parent);
 121	return length;
 122}
 123
 124static int fill_kobj_path(const struct kobject *kobj, char *path, int length)
 125{
 126	const struct kobject *parent;
 127
 128	--length;
 129	for (parent = kobj; parent; parent = parent->parent) {
 130		int cur = strlen(kobject_name(parent));
 131		/* back up enough to print this name with '/' */
 132		length -= cur;
 133		if (length <= 0)
 134			return -EINVAL;
 135		memcpy(path + length, kobject_name(parent), cur);
 136		*(path + --length) = '/';
 137	}
 138
 139	pr_debug("'%s' (%p): %s: path = '%s'\n", kobject_name(kobj),
 140		 kobj, __func__, path);
 141
 142	return 0;
 143}
 144
 145/**
 146 * kobject_get_path() - Allocate memory and fill in the path for @kobj.
 147 * @kobj:	kobject in question, with which to build the path
 148 * @gfp_mask:	the allocation type used to allocate the path
 149 *
 150 * Return: The newly allocated memory, caller must free with kfree().
 151 */
 152char *kobject_get_path(const struct kobject *kobj, gfp_t gfp_mask)
 153{
 154	char *path;
 155	int len;
 156
 157retry:
 158	len = get_kobj_path_length(kobj);
 159	if (len == 0)
 160		return NULL;
 161	path = kzalloc(len, gfp_mask);
 162	if (!path)
 163		return NULL;
 164	if (fill_kobj_path(kobj, path, len)) {
 165		kfree(path);
 166		goto retry;
 167	}
 168
 169	return path;
 170}
 171EXPORT_SYMBOL_GPL(kobject_get_path);
 172
 173/* add the kobject to its kset's list */
 174static void kobj_kset_join(struct kobject *kobj)
 175{
 176	if (!kobj->kset)
 177		return;
 178
 179	kset_get(kobj->kset);
 180	spin_lock(&kobj->kset->list_lock);
 181	list_add_tail(&kobj->entry, &kobj->kset->list);
 182	spin_unlock(&kobj->kset->list_lock);
 183}
 184
 185/* remove the kobject from its kset's list */
 186static void kobj_kset_leave(struct kobject *kobj)
 187{
 188	if (!kobj->kset)
 189		return;
 190
 191	spin_lock(&kobj->kset->list_lock);
 192	list_del_init(&kobj->entry);
 193	spin_unlock(&kobj->kset->list_lock);
 194	kset_put(kobj->kset);
 195}
 196
 197static void kobject_init_internal(struct kobject *kobj)
 198{
 199	if (!kobj)
 200		return;
 201	kref_init(&kobj->kref);
 202	INIT_LIST_HEAD(&kobj->entry);
 203	kobj->state_in_sysfs = 0;
 204	kobj->state_add_uevent_sent = 0;
 205	kobj->state_remove_uevent_sent = 0;
 206	kobj->state_initialized = 1;
 207}
 208
 209
 210static int kobject_add_internal(struct kobject *kobj)
 211{
 212	int error = 0;
 213	struct kobject *parent;
 214
 215	if (!kobj)
 216		return -ENOENT;
 217
 218	if (!kobj->name || !kobj->name[0]) {
 219		WARN(1,
 220		     "kobject: (%p): attempted to be registered with empty name!\n",
 221		     kobj);
 222		return -EINVAL;
 223	}
 224
 225	parent = kobject_get(kobj->parent);
 226
 227	/* join kset if set, use it as parent if we do not already have one */
 228	if (kobj->kset) {
 229		if (!parent)
 230			parent = kobject_get(&kobj->kset->kobj);
 231		kobj_kset_join(kobj);
 232		kobj->parent = parent;
 233	}
 234
 235	pr_debug("'%s' (%p): %s: parent: '%s', set: '%s'\n",
 236		 kobject_name(kobj), kobj, __func__,
 237		 parent ? kobject_name(parent) : "<NULL>",
 238		 kobj->kset ? kobject_name(&kobj->kset->kobj) : "<NULL>");
 239
 240	error = create_dir(kobj);
 241	if (error) {
 242		kobj_kset_leave(kobj);
 243		kobject_put(parent);
 244		kobj->parent = NULL;
 245
 246		/* be noisy on error issues */
 247		if (error == -EEXIST)
 248			pr_err("%s failed for %s with -EEXIST, don't try to register things with the same name in the same directory.\n",
 249			       __func__, kobject_name(kobj));
 250		else
 251			pr_err("%s failed for %s (error: %d parent: %s)\n",
 252			       __func__, kobject_name(kobj), error,
 253			       parent ? kobject_name(parent) : "'none'");
 254	} else
 255		kobj->state_in_sysfs = 1;
 256
 257	return error;
 258}
 259
 260/**
 261 * kobject_set_name_vargs() - Set the name of a kobject.
 262 * @kobj: struct kobject to set the name of
 263 * @fmt: format string used to build the name
 264 * @vargs: vargs to format the string.
 265 */
 266int kobject_set_name_vargs(struct kobject *kobj, const char *fmt,
 267				  va_list vargs)
 268{
 269	const char *s;
 270
 271	if (kobj->name && !fmt)
 272		return 0;
 273
 274	s = kvasprintf_const(GFP_KERNEL, fmt, vargs);
 275	if (!s)
 276		return -ENOMEM;
 277
 278	/*
 279	 * ewww... some of these buggers have '/' in the name ... If
 280	 * that's the case, we need to make sure we have an actual
 281	 * allocated copy to modify, since kvasprintf_const may have
 282	 * returned something from .rodata.
 283	 */
 284	if (strchr(s, '/')) {
 285		char *t;
 286
 287		t = kstrdup(s, GFP_KERNEL);
 288		kfree_const(s);
 289		if (!t)
 290			return -ENOMEM;
 291		s = strreplace(t, '/', '!');
 292	}
 293	kfree_const(kobj->name);
 294	kobj->name = s;
 295
 296	return 0;
 297}
 298
 299/**
 300 * kobject_set_name() - Set the name of a kobject.
 301 * @kobj: struct kobject to set the name of
 302 * @fmt: format string used to build the name
 303 *
 304 * This sets the name of the kobject.  If you have already added the
 305 * kobject to the system, you must call kobject_rename() in order to
 306 * change the name of the kobject.
 307 */
 308int kobject_set_name(struct kobject *kobj, const char *fmt, ...)
 309{
 310	va_list vargs;
 311	int retval;
 312
 313	va_start(vargs, fmt);
 314	retval = kobject_set_name_vargs(kobj, fmt, vargs);
 315	va_end(vargs);
 316
 317	return retval;
 318}
 319EXPORT_SYMBOL(kobject_set_name);
 320
 321/**
 322 * kobject_init() - Initialize a kobject structure.
 323 * @kobj: pointer to the kobject to initialize
 324 * @ktype: pointer to the ktype for this kobject.
 325 *
 326 * This function will properly initialize a kobject such that it can then
 327 * be passed to the kobject_add() call.
 328 *
 329 * After this function is called, the kobject MUST be cleaned up by a call
 330 * to kobject_put(), not by a call to kfree directly to ensure that all of
 331 * the memory is cleaned up properly.
 332 */
 333void kobject_init(struct kobject *kobj, const struct kobj_type *ktype)
 334{
 335	char *err_str;
 336
 337	if (!kobj) {
 338		err_str = "invalid kobject pointer!";
 339		goto error;
 340	}
 341	if (!ktype) {
 342		err_str = "must have a ktype to be initialized properly!\n";
 343		goto error;
 344	}
 345	if (kobj->state_initialized) {
 346		/* do not error out as sometimes we can recover */
 347		pr_err("kobject (%p): tried to init an initialized object, something is seriously wrong.\n",
 348		       kobj);
 349		dump_stack_lvl(KERN_ERR);
 350	}
 351
 352	kobject_init_internal(kobj);
 353	kobj->ktype = ktype;
 354	return;
 355
 356error:
 357	pr_err("kobject (%p): %s\n", kobj, err_str);
 358	dump_stack_lvl(KERN_ERR);
 359}
 360EXPORT_SYMBOL(kobject_init);
 361
 362static __printf(3, 0) int kobject_add_varg(struct kobject *kobj,
 363					   struct kobject *parent,
 364					   const char *fmt, va_list vargs)
 365{
 366	int retval;
 367
 368	retval = kobject_set_name_vargs(kobj, fmt, vargs);
 369	if (retval) {
 370		pr_err("can not set name properly!\n");
 371		return retval;
 372	}
 373	kobj->parent = parent;
 374	return kobject_add_internal(kobj);
 375}
 376
 377/**
 378 * kobject_add() - The main kobject add function.
 379 * @kobj: the kobject to add
 380 * @parent: pointer to the parent of the kobject.
 381 * @fmt: format to name the kobject with.
 382 *
 383 * The kobject name is set and added to the kobject hierarchy in this
 384 * function.
 385 *
 386 * If @parent is set, then the parent of the @kobj will be set to it.
 387 * If @parent is NULL, then the parent of the @kobj will be set to the
 388 * kobject associated with the kset assigned to this kobject.  If no kset
 389 * is assigned to the kobject, then the kobject will be located in the
 390 * root of the sysfs tree.
 391 *
 392 * Note, no "add" uevent will be created with this call, the caller should set
 393 * up all of the necessary sysfs files for the object and then call
 394 * kobject_uevent() with the UEVENT_ADD parameter to ensure that
 395 * userspace is properly notified of this kobject's creation.
 396 *
 397 * Return: If this function returns an error, kobject_put() must be
 398 *         called to properly clean up the memory associated with the
 399 *         object.  Under no instance should the kobject that is passed
 400 *         to this function be directly freed with a call to kfree(),
 401 *         that can leak memory.
 402 *
 403 *         If this function returns success, kobject_put() must also be called
 404 *         in order to properly clean up the memory associated with the object.
 405 *
 406 *         In short, once this function is called, kobject_put() MUST be called
 407 *         when the use of the object is finished in order to properly free
 408 *         everything.
 409 */
 410int kobject_add(struct kobject *kobj, struct kobject *parent,
 411		const char *fmt, ...)
 412{
 413	va_list args;
 414	int retval;
 415
 416	if (!kobj)
 417		return -EINVAL;
 418
 419	if (!kobj->state_initialized) {
 420		pr_err("kobject '%s' (%p): tried to add an uninitialized object, something is seriously wrong.\n",
 421		       kobject_name(kobj), kobj);
 422		dump_stack_lvl(KERN_ERR);
 423		return -EINVAL;
 424	}
 425	va_start(args, fmt);
 426	retval = kobject_add_varg(kobj, parent, fmt, args);
 427	va_end(args);
 428
 429	return retval;
 430}
 431EXPORT_SYMBOL(kobject_add);
 432
 433/**
 434 * kobject_init_and_add() - Initialize a kobject structure and add it to
 435 *                          the kobject hierarchy.
 436 * @kobj: pointer to the kobject to initialize
 437 * @ktype: pointer to the ktype for this kobject.
 438 * @parent: pointer to the parent of this kobject.
 439 * @fmt: the name of the kobject.
 440 *
 441 * This function combines the call to kobject_init() and kobject_add().
 442 *
 443 * If this function returns an error, kobject_put() must be called to
 444 * properly clean up the memory associated with the object.  This is the
 445 * same type of error handling after a call to kobject_add() and kobject
 446 * lifetime rules are the same here.
 447 */
 448int kobject_init_and_add(struct kobject *kobj, const struct kobj_type *ktype,
 449			 struct kobject *parent, const char *fmt, ...)
 450{
 451	va_list args;
 452	int retval;
 453
 454	kobject_init(kobj, ktype);
 455
 456	va_start(args, fmt);
 457	retval = kobject_add_varg(kobj, parent, fmt, args);
 458	va_end(args);
 459
 460	return retval;
 461}
 462EXPORT_SYMBOL_GPL(kobject_init_and_add);
 463
 464/**
 465 * kobject_rename() - Change the name of an object.
 466 * @kobj: object in question.
 467 * @new_name: object's new name
 468 *
 469 * It is the responsibility of the caller to provide mutual
 470 * exclusion between two different calls of kobject_rename
 471 * on the same kobject and to ensure that new_name is valid and
 472 * won't conflict with other kobjects.
 473 */
 474int kobject_rename(struct kobject *kobj, const char *new_name)
 475{
 476	int error = 0;
 477	const char *devpath = NULL;
 478	const char *dup_name = NULL, *name;
 479	char *devpath_string = NULL;
 480	char *envp[2];
 481
 482	kobj = kobject_get(kobj);
 483	if (!kobj)
 484		return -EINVAL;
 485	if (!kobj->parent) {
 486		kobject_put(kobj);
 487		return -EINVAL;
 488	}
 489
 490	devpath = kobject_get_path(kobj, GFP_KERNEL);
 491	if (!devpath) {
 492		error = -ENOMEM;
 493		goto out;
 494	}
 495	devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
 496	if (!devpath_string) {
 497		error = -ENOMEM;
 498		goto out;
 499	}
 500	sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
 501	envp[0] = devpath_string;
 502	envp[1] = NULL;
 503
 504	name = dup_name = kstrdup_const(new_name, GFP_KERNEL);
 505	if (!name) {
 506		error = -ENOMEM;
 507		goto out;
 508	}
 509
 510	error = sysfs_rename_dir_ns(kobj, new_name, kobject_namespace(kobj));
 511	if (error)
 512		goto out;
 513
 514	/* Install the new kobject name */
 515	dup_name = kobj->name;
 516	kobj->name = name;
 517
 518	/* This function is mostly/only used for network interface.
 519	 * Some hotplug package track interfaces by their name and
 520	 * therefore want to know when the name is changed by the user. */
 521	kobject_uevent_env(kobj, KOBJ_MOVE, envp);
 522
 523out:
 524	kfree_const(dup_name);
 525	kfree(devpath_string);
 526	kfree(devpath);
 527	kobject_put(kobj);
 528
 529	return error;
 530}
 531EXPORT_SYMBOL_GPL(kobject_rename);
 532
 533/**
 534 * kobject_move() - Move object to another parent.
 535 * @kobj: object in question.
 536 * @new_parent: object's new parent (can be NULL)
 537 */
 538int kobject_move(struct kobject *kobj, struct kobject *new_parent)
 539{
 540	int error;
 541	struct kobject *old_parent;
 542	const char *devpath = NULL;
 543	char *devpath_string = NULL;
 544	char *envp[2];
 545
 546	kobj = kobject_get(kobj);
 547	if (!kobj)
 548		return -EINVAL;
 549	new_parent = kobject_get(new_parent);
 550	if (!new_parent) {
 551		if (kobj->kset)
 552			new_parent = kobject_get(&kobj->kset->kobj);
 553	}
 554
 555	/* old object path */
 556	devpath = kobject_get_path(kobj, GFP_KERNEL);
 557	if (!devpath) {
 558		error = -ENOMEM;
 559		goto out;
 560	}
 561	devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
 562	if (!devpath_string) {
 563		error = -ENOMEM;
 564		goto out;
 565	}
 566	sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
 567	envp[0] = devpath_string;
 568	envp[1] = NULL;
 569	error = sysfs_move_dir_ns(kobj, new_parent, kobject_namespace(kobj));
 570	if (error)
 571		goto out;
 572	old_parent = kobj->parent;
 573	kobj->parent = new_parent;
 574	new_parent = NULL;
 575	kobject_put(old_parent);
 576	kobject_uevent_env(kobj, KOBJ_MOVE, envp);
 577out:
 578	kobject_put(new_parent);
 579	kobject_put(kobj);
 580	kfree(devpath_string);
 581	kfree(devpath);
 582	return error;
 583}
 584EXPORT_SYMBOL_GPL(kobject_move);
 585
 586static void __kobject_del(struct kobject *kobj)
 587{
 588	struct kernfs_node *sd;
 589	const struct kobj_type *ktype;
 590
 591	sd = kobj->sd;
 592	ktype = get_ktype(kobj);
 593
 594	if (ktype)
 595		sysfs_remove_groups(kobj, ktype->default_groups);
 596
 597	/* send "remove" if the caller did not do it but sent "add" */
 598	if (kobj->state_add_uevent_sent && !kobj->state_remove_uevent_sent) {
 599		pr_debug("'%s' (%p): auto cleanup 'remove' event\n",
 600			 kobject_name(kobj), kobj);
 601		kobject_uevent(kobj, KOBJ_REMOVE);
 602	}
 603
 604	sysfs_remove_dir(kobj);
 605	sysfs_put(sd);
 606
 607	kobj->state_in_sysfs = 0;
 608	kobj_kset_leave(kobj);
 609	kobj->parent = NULL;
 610}
 611
 612/**
 613 * kobject_del() - Unlink kobject from hierarchy.
 614 * @kobj: object.
 615 *
 616 * This is the function that should be called to delete an object
 617 * successfully added via kobject_add().
 618 */
 619void kobject_del(struct kobject *kobj)
 620{
 621	struct kobject *parent;
 622
 623	if (!kobj)
 624		return;
 625
 626	parent = kobj->parent;
 627	__kobject_del(kobj);
 628	kobject_put(parent);
 629}
 630EXPORT_SYMBOL(kobject_del);
 631
 632/**
 633 * kobject_get() - Increment refcount for object.
 634 * @kobj: object.
 635 */
 636struct kobject *kobject_get(struct kobject *kobj)
 637{
 638	if (kobj) {
 639		if (!kobj->state_initialized)
 640			WARN(1, KERN_WARNING
 641				"kobject: '%s' (%p): is not initialized, yet kobject_get() is being called.\n",
 642			     kobject_name(kobj), kobj);
 643		kref_get(&kobj->kref);
 644	}
 645	return kobj;
 646}
 647EXPORT_SYMBOL(kobject_get);
 648
 649struct kobject * __must_check kobject_get_unless_zero(struct kobject *kobj)
 650{
 651	if (!kobj)
 652		return NULL;
 653	if (!kref_get_unless_zero(&kobj->kref))
 654		kobj = NULL;
 655	return kobj;
 656}
 657EXPORT_SYMBOL(kobject_get_unless_zero);
 658
 659/*
 660 * kobject_cleanup - free kobject resources.
 661 * @kobj: object to cleanup
 662 */
 663static void kobject_cleanup(struct kobject *kobj)
 664{
 665	struct kobject *parent = kobj->parent;
 666	const struct kobj_type *t = get_ktype(kobj);
 667	const char *name = kobj->name;
 668
 669	pr_debug("'%s' (%p): %s, parent %p\n",
 670		 kobject_name(kobj), kobj, __func__, kobj->parent);
 671
 672	if (t && !t->release)
 673		pr_debug("'%s' (%p): does not have a release() function, it is broken and must be fixed. See Documentation/core-api/kobject.rst.\n",
 674			 kobject_name(kobj), kobj);
 675
 676	/* remove from sysfs if the caller did not do it */
 677	if (kobj->state_in_sysfs) {
 678		pr_debug("'%s' (%p): auto cleanup kobject_del\n",
 679			 kobject_name(kobj), kobj);
 680		__kobject_del(kobj);
 681	} else {
 682		/* avoid dropping the parent reference unnecessarily */
 683		parent = NULL;
 684	}
 685
 686	if (t && t->release) {
 687		pr_debug("'%s' (%p): calling ktype release\n",
 688			 kobject_name(kobj), kobj);
 689		t->release(kobj);
 690	}
 691
 692	/* free name if we allocated it */
 693	if (name) {
 694		pr_debug("'%s': free name\n", name);
 695		kfree_const(name);
 696	}
 697
 698	kobject_put(parent);
 699}
 700
 701#ifdef CONFIG_DEBUG_KOBJECT_RELEASE
 702static void kobject_delayed_cleanup(struct work_struct *work)
 703{
 704	kobject_cleanup(container_of(to_delayed_work(work),
 705				     struct kobject, release));
 706}
 707#endif
 708
 709static void kobject_release(struct kref *kref)
 710{
 711	struct kobject *kobj = container_of(kref, struct kobject, kref);
 712#ifdef CONFIG_DEBUG_KOBJECT_RELEASE
 713	unsigned long delay = HZ + HZ * get_random_u32_below(4);
 714	pr_info("'%s' (%p): %s, parent %p (delayed %ld)\n",
 715		kobject_name(kobj), kobj, __func__, kobj->parent, delay);
 716	INIT_DELAYED_WORK(&kobj->release, kobject_delayed_cleanup);
 717
 718	schedule_delayed_work(&kobj->release, delay);
 719#else
 720	kobject_cleanup(kobj);
 721#endif
 722}
 723
 724/**
 725 * kobject_put() - Decrement refcount for object.
 726 * @kobj: object.
 727 *
 728 * Decrement the refcount, and if 0, call kobject_cleanup().
 729 */
 730void kobject_put(struct kobject *kobj)
 731{
 732	if (kobj) {
 733		if (!kobj->state_initialized)
 734			WARN(1, KERN_WARNING
 735				"kobject: '%s' (%p): is not initialized, yet kobject_put() is being called.\n",
 736			     kobject_name(kobj), kobj);
 737		kref_put(&kobj->kref, kobject_release);
 738	}
 739}
 740EXPORT_SYMBOL(kobject_put);
 741
 742static void dynamic_kobj_release(struct kobject *kobj)
 743{
 744	pr_debug("(%p): %s\n", kobj, __func__);
 745	kfree(kobj);
 746}
 747
 748static const struct kobj_type dynamic_kobj_ktype = {
 749	.release	= dynamic_kobj_release,
 750	.sysfs_ops	= &kobj_sysfs_ops,
 751};
 752
 753/**
 754 * kobject_create() - Create a struct kobject dynamically.
 755 *
 756 * This function creates a kobject structure dynamically and sets it up
 757 * to be a "dynamic" kobject with a default release function set up.
 758 *
 759 * If the kobject was not able to be created, NULL will be returned.
 760 * The kobject structure returned from here must be cleaned up with a
 761 * call to kobject_put() and not kfree(), as kobject_init() has
 762 * already been called on this structure.
 763 */
 764static struct kobject *kobject_create(void)
 765{
 766	struct kobject *kobj;
 767
 768	kobj = kzalloc(sizeof(*kobj), GFP_KERNEL);
 769	if (!kobj)
 770		return NULL;
 771
 772	kobject_init(kobj, &dynamic_kobj_ktype);
 773	return kobj;
 774}
 775
 776/**
 777 * kobject_create_and_add() - Create a struct kobject dynamically and
 778 *                            register it with sysfs.
 779 * @name: the name for the kobject
 780 * @parent: the parent kobject of this kobject, if any.
 781 *
 782 * This function creates a kobject structure dynamically and registers it
 783 * with sysfs.  When you are finished with this structure, call
 784 * kobject_put() and the structure will be dynamically freed when
 785 * it is no longer being used.
 786 *
 787 * If the kobject was not able to be created, NULL will be returned.
 788 */
 789struct kobject *kobject_create_and_add(const char *name, struct kobject *parent)
 790{
 791	struct kobject *kobj;
 792	int retval;
 793
 794	kobj = kobject_create();
 795	if (!kobj)
 796		return NULL;
 797
 798	retval = kobject_add(kobj, parent, "%s", name);
 799	if (retval) {
 800		pr_warn("%s: kobject_add error: %d\n", __func__, retval);
 801		kobject_put(kobj);
 802		kobj = NULL;
 803	}
 804	return kobj;
 805}
 806EXPORT_SYMBOL_GPL(kobject_create_and_add);
 807
 808/**
 809 * kset_init() - Initialize a kset for use.
 810 * @k: kset
 811 */
 812void kset_init(struct kset *k)
 813{
 814	kobject_init_internal(&k->kobj);
 815	INIT_LIST_HEAD(&k->list);
 816	spin_lock_init(&k->list_lock);
 817}
 818
 819/* default kobject attribute operations */
 820static ssize_t kobj_attr_show(struct kobject *kobj, struct attribute *attr,
 821			      char *buf)
 822{
 823	struct kobj_attribute *kattr;
 824	ssize_t ret = -EIO;
 825
 826	kattr = container_of(attr, struct kobj_attribute, attr);
 827	if (kattr->show)
 828		ret = kattr->show(kobj, kattr, buf);
 829	return ret;
 830}
 831
 832static ssize_t kobj_attr_store(struct kobject *kobj, struct attribute *attr,
 833			       const char *buf, size_t count)
 834{
 835	struct kobj_attribute *kattr;
 836	ssize_t ret = -EIO;
 837
 838	kattr = container_of(attr, struct kobj_attribute, attr);
 839	if (kattr->store)
 840		ret = kattr->store(kobj, kattr, buf, count);
 841	return ret;
 842}
 843
 844const struct sysfs_ops kobj_sysfs_ops = {
 845	.show	= kobj_attr_show,
 846	.store	= kobj_attr_store,
 847};
 848EXPORT_SYMBOL_GPL(kobj_sysfs_ops);
 849
 850/**
 851 * kset_register() - Initialize and add a kset.
 852 * @k: kset.
 853 *
 854 * NOTE: On error, the kset.kobj.name allocated by() kobj_set_name()
 855 * is freed, it can not be used any more.
 856 */
 857int kset_register(struct kset *k)
 858{
 859	int err;
 860
 861	if (!k)
 862		return -EINVAL;
 863
 864	if (!k->kobj.ktype) {
 865		pr_err("must have a ktype to be initialized properly!\n");
 866		return -EINVAL;
 867	}
 868
 869	kset_init(k);
 870	err = kobject_add_internal(&k->kobj);
 871	if (err) {
 872		kfree_const(k->kobj.name);
 873		/* Set it to NULL to avoid accessing bad pointer in callers. */
 874		k->kobj.name = NULL;
 875		return err;
 876	}
 877	kobject_uevent(&k->kobj, KOBJ_ADD);
 878	return 0;
 879}
 880EXPORT_SYMBOL(kset_register);
 881
 882/**
 883 * kset_unregister() - Remove a kset.
 884 * @k: kset.
 885 */
 886void kset_unregister(struct kset *k)
 887{
 888	if (!k)
 889		return;
 890	kobject_del(&k->kobj);
 891	kobject_put(&k->kobj);
 892}
 893EXPORT_SYMBOL(kset_unregister);
 894
 895/**
 896 * kset_find_obj() - Search for object in kset.
 897 * @kset: kset we're looking in.
 898 * @name: object's name.
 899 *
 900 * Lock kset via @kset->subsys, and iterate over @kset->list,
 901 * looking for a matching kobject. If matching object is found
 902 * take a reference and return the object.
 903 */
 904struct kobject *kset_find_obj(struct kset *kset, const char *name)
 905{
 906	struct kobject *k;
 907	struct kobject *ret = NULL;
 908
 909	spin_lock(&kset->list_lock);
 910
 911	list_for_each_entry(k, &kset->list, entry) {
 912		if (kobject_name(k) && !strcmp(kobject_name(k), name)) {
 913			ret = kobject_get_unless_zero(k);
 914			break;
 915		}
 916	}
 917
 918	spin_unlock(&kset->list_lock);
 919	return ret;
 920}
 921EXPORT_SYMBOL_GPL(kset_find_obj);
 922
 923static void kset_release(struct kobject *kobj)
 924{
 925	struct kset *kset = container_of(kobj, struct kset, kobj);
 926	pr_debug("'%s' (%p): %s\n",
 927		 kobject_name(kobj), kobj, __func__);
 928	kfree(kset);
 929}
 930
 931static void kset_get_ownership(const struct kobject *kobj, kuid_t *uid, kgid_t *gid)
 932{
 933	if (kobj->parent)
 934		kobject_get_ownership(kobj->parent, uid, gid);
 935}
 936
 937static const struct kobj_type kset_ktype = {
 938	.sysfs_ops	= &kobj_sysfs_ops,
 939	.release	= kset_release,
 940	.get_ownership	= kset_get_ownership,
 941};
 942
 943/**
 944 * kset_create() - Create a struct kset dynamically.
 945 *
 946 * @name: the name for the kset
 947 * @uevent_ops: a struct kset_uevent_ops for the kset
 948 * @parent_kobj: the parent kobject of this kset, if any.
 949 *
 950 * This function creates a kset structure dynamically.  This structure can
 951 * then be registered with the system and show up in sysfs with a call to
 952 * kset_register().  When you are finished with this structure, if
 953 * kset_register() has been called, call kset_unregister() and the
 954 * structure will be dynamically freed when it is no longer being used.
 955 *
 956 * If the kset was not able to be created, NULL will be returned.
 957 */
 958static struct kset *kset_create(const char *name,
 959				const struct kset_uevent_ops *uevent_ops,
 960				struct kobject *parent_kobj)
 961{
 962	struct kset *kset;
 963	int retval;
 964
 965	kset = kzalloc(sizeof(*kset), GFP_KERNEL);
 966	if (!kset)
 967		return NULL;
 968	retval = kobject_set_name(&kset->kobj, "%s", name);
 969	if (retval) {
 970		kfree(kset);
 971		return NULL;
 972	}
 973	kset->uevent_ops = uevent_ops;
 974	kset->kobj.parent = parent_kobj;
 975
 976	/*
 977	 * The kobject of this kset will have a type of kset_ktype and belong to
 978	 * no kset itself.  That way we can properly free it when it is
 979	 * finished being used.
 980	 */
 981	kset->kobj.ktype = &kset_ktype;
 982	kset->kobj.kset = NULL;
 983
 984	return kset;
 985}
 986
 987/**
 988 * kset_create_and_add() - Create a struct kset dynamically and add it to sysfs.
 989 *
 990 * @name: the name for the kset
 991 * @uevent_ops: a struct kset_uevent_ops for the kset
 992 * @parent_kobj: the parent kobject of this kset, if any.
 993 *
 994 * This function creates a kset structure dynamically and registers it
 995 * with sysfs.  When you are finished with this structure, call
 996 * kset_unregister() and the structure will be dynamically freed when it
 997 * is no longer being used.
 998 *
 999 * If the kset was not able to be created, NULL will be returned.
1000 */
1001struct kset *kset_create_and_add(const char *name,
1002				 const struct kset_uevent_ops *uevent_ops,
1003				 struct kobject *parent_kobj)
1004{
1005	struct kset *kset;
1006	int error;
1007
1008	kset = kset_create(name, uevent_ops, parent_kobj);
1009	if (!kset)
1010		return NULL;
1011	error = kset_register(kset);
1012	if (error) {
1013		kfree(kset);
1014		return NULL;
1015	}
1016	return kset;
1017}
1018EXPORT_SYMBOL_GPL(kset_create_and_add);
1019
1020
1021static DEFINE_SPINLOCK(kobj_ns_type_lock);
1022static const struct kobj_ns_type_operations *kobj_ns_ops_tbl[KOBJ_NS_TYPES];
1023
1024int kobj_ns_type_register(const struct kobj_ns_type_operations *ops)
1025{
1026	enum kobj_ns_type type = ops->type;
1027	int error;
1028
1029	spin_lock(&kobj_ns_type_lock);
1030
1031	error = -EINVAL;
1032	if (!kobj_ns_type_is_valid(type))
1033		goto out;
1034
1035	error = -EBUSY;
1036	if (kobj_ns_ops_tbl[type])
1037		goto out;
1038
1039	error = 0;
1040	kobj_ns_ops_tbl[type] = ops;
1041
1042out:
1043	spin_unlock(&kobj_ns_type_lock);
1044	return error;
1045}
1046
1047int kobj_ns_type_registered(enum kobj_ns_type type)
1048{
1049	int registered = 0;
1050
1051	spin_lock(&kobj_ns_type_lock);
1052	if (kobj_ns_type_is_valid(type))
1053		registered = kobj_ns_ops_tbl[type] != NULL;
1054	spin_unlock(&kobj_ns_type_lock);
1055
1056	return registered;
1057}
1058
1059const struct kobj_ns_type_operations *kobj_child_ns_ops(const struct kobject *parent)
1060{
1061	const struct kobj_ns_type_operations *ops = NULL;
1062
1063	if (parent && parent->ktype && parent->ktype->child_ns_type)
1064		ops = parent->ktype->child_ns_type(parent);
1065
1066	return ops;
1067}
1068
1069const struct kobj_ns_type_operations *kobj_ns_ops(const struct kobject *kobj)
1070{
1071	return kobj_child_ns_ops(kobj->parent);
1072}
1073
1074bool kobj_ns_current_may_mount(enum kobj_ns_type type)
1075{
1076	bool may_mount = true;
1077
1078	spin_lock(&kobj_ns_type_lock);
1079	if (kobj_ns_type_is_valid(type) && kobj_ns_ops_tbl[type])
1080		may_mount = kobj_ns_ops_tbl[type]->current_may_mount();
1081	spin_unlock(&kobj_ns_type_lock);
1082
1083	return may_mount;
1084}
1085
1086void *kobj_ns_grab_current(enum kobj_ns_type type)
1087{
1088	void *ns = NULL;
1089
1090	spin_lock(&kobj_ns_type_lock);
1091	if (kobj_ns_type_is_valid(type) && kobj_ns_ops_tbl[type])
1092		ns = kobj_ns_ops_tbl[type]->grab_current_ns();
1093	spin_unlock(&kobj_ns_type_lock);
1094
1095	return ns;
1096}
1097EXPORT_SYMBOL_GPL(kobj_ns_grab_current);
1098
1099const void *kobj_ns_netlink(enum kobj_ns_type type, struct sock *sk)
1100{
1101	const void *ns = NULL;
1102
1103	spin_lock(&kobj_ns_type_lock);
1104	if (kobj_ns_type_is_valid(type) && kobj_ns_ops_tbl[type])
1105		ns = kobj_ns_ops_tbl[type]->netlink_ns(sk);
1106	spin_unlock(&kobj_ns_type_lock);
1107
1108	return ns;
1109}
1110
1111const void *kobj_ns_initial(enum kobj_ns_type type)
1112{
1113	const void *ns = NULL;
1114
1115	spin_lock(&kobj_ns_type_lock);
1116	if (kobj_ns_type_is_valid(type) && kobj_ns_ops_tbl[type])
1117		ns = kobj_ns_ops_tbl[type]->initial_ns();
1118	spin_unlock(&kobj_ns_type_lock);
1119
1120	return ns;
1121}
1122
1123void kobj_ns_drop(enum kobj_ns_type type, void *ns)
1124{
1125	spin_lock(&kobj_ns_type_lock);
1126	if (kobj_ns_type_is_valid(type) &&
1127	    kobj_ns_ops_tbl[type] && kobj_ns_ops_tbl[type]->drop_ns)
1128		kobj_ns_ops_tbl[type]->drop_ns(ns);
1129	spin_unlock(&kobj_ns_type_lock);
1130}
1131EXPORT_SYMBOL_GPL(kobj_ns_drop);