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1// SPDX-License-Identifier: GPL-2.02/*3 * kobject.c - library routines for handling generic kernel objects4 *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 information10 * about using the kobject interface.11 */12 13#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt14 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 question25 *26 * Returns namespace tag of @kobj if its parent has namespace ops enabled27 * and thus @kobj should have a namespace tag associated with it. Returns28 * %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 question43 * @uid: kernel user ID for sysfs objects44 * @gid: kernel group ID for sysfs objects45 *46 * Returns initial uid/gid pair that should be used when creating sysfs47 * representation of given kobject. Normally used to adjust ownership of48 * 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 an87 * 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 on93 * 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 the112 * 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 path148 * @gfp_mask: the allocation type used to allocate the path149 *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 else251 pr_err("%s failed for %s (error: %d parent: %s)\n",252 __func__, kobject_name(kobj), error,253 parent ? kobject_name(parent) : "'none'");254 } else255 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 of263 * @fmt: format string used to build the name264 * @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 ... If280 * that's the case, we need to make sure we have an actual281 * allocated copy to modify, since kvasprintf_const may have282 * 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 of302 * @fmt: format string used to build the name303 *304 * This sets the name of the kobject. If you have already added the305 * kobject to the system, you must call kobject_rename() in order to306 * 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 initialize324 * @ktype: pointer to the ktype for this kobject.325 *326 * This function will properly initialize a kobject such that it can then327 * be passed to the kobject_add() call.328 *329 * After this function is called, the kobject MUST be cleaned up by a call330 * to kobject_put(), not by a call to kfree directly to ensure that all of331 * 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 add380 * @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 this384 * 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 the388 * kobject associated with the kset assigned to this kobject. If no kset389 * is assigned to the kobject, then the kobject will be located in the390 * root of the sysfs tree.391 *392 * Note, no "add" uevent will be created with this call, the caller should set393 * up all of the necessary sysfs files for the object and then call394 * kobject_uevent() with the UEVENT_ADD parameter to ensure that395 * userspace is properly notified of this kobject's creation.396 *397 * Return: If this function returns an error, kobject_put() must be398 * called to properly clean up the memory associated with the399 * object. Under no instance should the kobject that is passed400 * 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 called404 * 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 called407 * when the use of the object is finished in order to properly free408 * 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 to435 * the kobject hierarchy.436 * @kobj: pointer to the kobject to initialize437 * @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 to444 * properly clean up the memory associated with the object. This is the445 * same type of error handling after a call to kobject_add() and kobject446 * 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 name468 *469 * It is the responsibility of the caller to provide mutual470 * exclusion between two different calls of kobject_rename471 * on the same kobject and to ensure that new_name is valid and472 * 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 and520 * 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 object617 * 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_WARNING641 "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 cleanup662 */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_RELEASE702static void kobject_delayed_cleanup(struct work_struct *work)703{704 kobject_cleanup(container_of(to_delayed_work(work),705 struct kobject, release));706}707#endif708 709static void kobject_release(struct kref *kref)710{711 struct kobject *kobj = container_of(kref, struct kobject, kref);712#ifdef CONFIG_DEBUG_KOBJECT_RELEASE713 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#else720 kobject_cleanup(kobj);721#endif722}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_WARNING735 "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 up757 * 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 a761 * call to kobject_put() and not kfree(), as kobject_init() has762 * 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 and778 * register it with sysfs.779 * @name: the name for the kobject780 * @parent: the parent kobject of this kobject, if any.781 *782 * This function creates a kobject structure dynamically and registers it783 * with sysfs. When you are finished with this structure, call784 * kobject_put() and the structure will be dynamically freed when785 * 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: kset811 */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 found902 * 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 kset947 * @uevent_ops: a struct kset_uevent_ops for the kset948 * @parent_kobj: the parent kobject of this kset, if any.949 *950 * This function creates a kset structure dynamically. This structure can951 * then be registered with the system and show up in sysfs with a call to952 * kset_register(). When you are finished with this structure, if953 * kset_register() has been called, call kset_unregister() and the954 * 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 to978 * no kset itself. That way we can properly free it when it is979 * 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 kset991 * @uevent_ops: a struct kset_uevent_ops for the kset992 * @parent_kobj: the parent kobject of this kset, if any.993 *994 * This function creates a kset structure dynamically and registers it995 * with sysfs. When you are finished with this structure, call996 * kset_unregister() and the structure will be dynamically freed when it997 * 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);1132