diff options
Diffstat (limited to 'lib/kobject.c')
| -rw-r--r-- | lib/kobject.c | 1124 |
1 files changed, 1124 insertions, 0 deletions
diff --git a/lib/kobject.c b/lib/kobject.c new file mode 100644 index 000000000..207fd22ad --- /dev/null +++ b/lib/kobject.c @@ -0,0 +1,1124 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * kobject.c - library routines for handling generic kernel objects + * + * Copyright (c) 2002-2003 Patrick Mochel <mochel@osdl.org> + * Copyright (c) 2006-2007 Greg Kroah-Hartman <greg@kroah.com> + * Copyright (c) 2006-2007 Novell Inc. + * + * Please see the file Documentation/core-api/kobject.rst for critical information + * about using the kobject interface. + */ + +#include <linux/kobject.h> +#include <linux/string.h> +#include <linux/export.h> +#include <linux/stat.h> +#include <linux/slab.h> +#include <linux/random.h> + +/** + * kobject_namespace() - Return @kobj's namespace tag. + * @kobj: kobject in question + * + * Returns namespace tag of @kobj if its parent has namespace ops enabled + * and thus @kobj should have a namespace tag associated with it. Returns + * %NULL otherwise. + */ +const void *kobject_namespace(struct kobject *kobj) +{ + const struct kobj_ns_type_operations *ns_ops = kobj_ns_ops(kobj); + + if (!ns_ops || ns_ops->type == KOBJ_NS_TYPE_NONE) + return NULL; + + return kobj->ktype->namespace(kobj); +} + +/** + * kobject_get_ownership() - Get sysfs ownership data for @kobj. + * @kobj: kobject in question + * @uid: kernel user ID for sysfs objects + * @gid: kernel group ID for sysfs objects + * + * Returns initial uid/gid pair that should be used when creating sysfs + * representation of given kobject. Normally used to adjust ownership of + * objects in a container. + */ +void kobject_get_ownership(struct kobject *kobj, kuid_t *uid, kgid_t *gid) +{ + *uid = GLOBAL_ROOT_UID; + *gid = GLOBAL_ROOT_GID; + + if (kobj->ktype->get_ownership) + kobj->ktype->get_ownership(kobj, uid, gid); +} + +static int create_dir(struct kobject *kobj) +{ + const struct kobj_type *ktype = get_ktype(kobj); + const struct kobj_ns_type_operations *ops; + int error; + + error = sysfs_create_dir_ns(kobj, kobject_namespace(kobj)); + if (error) + return error; + + if (ktype) { + error = sysfs_create_groups(kobj, ktype->default_groups); + if (error) { + sysfs_remove_dir(kobj); + return error; + } + } + + /* + * @kobj->sd may be deleted by an ancestor going away. Hold an + * extra reference so that it stays until @kobj is gone. + */ + sysfs_get(kobj->sd); + + /* + * If @kobj has ns_ops, its children need to be filtered based on + * their namespace tags. Enable namespace support on @kobj->sd. + */ + ops = kobj_child_ns_ops(kobj); + if (ops) { + BUG_ON(ops->type <= KOBJ_NS_TYPE_NONE); + BUG_ON(ops->type >= KOBJ_NS_TYPES); + BUG_ON(!kobj_ns_type_registered(ops->type)); + + sysfs_enable_ns(kobj->sd); + } + + return 0; +} + +static int get_kobj_path_length(const struct kobject *kobj) +{ + int length = 1; + const struct kobject *parent = kobj; + + /* walk up the ancestors until we hit the one pointing to the + * root. + * Add 1 to strlen for leading '/' of each level. + */ + do { + if (kobject_name(parent) == NULL) + return 0; + length += strlen(kobject_name(parent)) + 1; + parent = parent->parent; + } while (parent); + return length; +} + +static int fill_kobj_path(const struct kobject *kobj, char *path, int length) +{ + const struct kobject *parent; + + --length; + for (parent = kobj; parent; parent = parent->parent) { + int cur = strlen(kobject_name(parent)); + /* back up enough to print this name with '/' */ + length -= cur; + if (length <= 0) + return -EINVAL; + memcpy(path + length, kobject_name(parent), cur); + *(path + --length) = '/'; + } + + pr_debug("kobject: '%s' (%p): %s: path = '%s'\n", kobject_name(kobj), + kobj, __func__, path); + + return 0; +} + +/** + * kobject_get_path() - Allocate memory and fill in the path for @kobj. + * @kobj: kobject in question, with which to build the path + * @gfp_mask: the allocation type used to allocate the path + * + * Return: The newly allocated memory, caller must free with kfree(). + */ +char *kobject_get_path(const struct kobject *kobj, gfp_t gfp_mask) +{ + char *path; + int len; + +retry: + len = get_kobj_path_length(kobj); + if (len == 0) + return NULL; + path = kzalloc(len, gfp_mask); + if (!path) + return NULL; + if (fill_kobj_path(kobj, path, len)) { + kfree(path); + goto retry; + } + + return path; +} +EXPORT_SYMBOL_GPL(kobject_get_path); + +/* add the kobject to its kset's list */ +static void kobj_kset_join(struct kobject *kobj) +{ + if (!kobj->kset) + return; + + kset_get(kobj->kset); + spin_lock(&kobj->kset->list_lock); + list_add_tail(&kobj->entry, &kobj->kset->list); + spin_unlock(&kobj->kset->list_lock); +} + +/* remove the kobject from its kset's list */ +static void kobj_kset_leave(struct kobject *kobj) +{ + if (!kobj->kset) + return; + + spin_lock(&kobj->kset->list_lock); + list_del_init(&kobj->entry); + spin_unlock(&kobj->kset->list_lock); + kset_put(kobj->kset); +} + +static void kobject_init_internal(struct kobject *kobj) +{ + if (!kobj) + return; + kref_init(&kobj->kref); + INIT_LIST_HEAD(&kobj->entry); + kobj->state_in_sysfs = 0; + kobj->state_add_uevent_sent = 0; + kobj->state_remove_uevent_sent = 0; + kobj->state_initialized = 1; +} + + +static int kobject_add_internal(struct kobject *kobj) +{ + int error = 0; + struct kobject *parent; + + if (!kobj) + return -ENOENT; + + if (!kobj->name || !kobj->name[0]) { + WARN(1, + "kobject: (%p): attempted to be registered with empty name!\n", + kobj); + return -EINVAL; + } + + parent = kobject_get(kobj->parent); + + /* join kset if set, use it as parent if we do not already have one */ + if (kobj->kset) { + if (!parent) + parent = kobject_get(&kobj->kset->kobj); + kobj_kset_join(kobj); + kobj->parent = parent; + } + + pr_debug("kobject: '%s' (%p): %s: parent: '%s', set: '%s'\n", + kobject_name(kobj), kobj, __func__, + parent ? kobject_name(parent) : "<NULL>", + kobj->kset ? kobject_name(&kobj->kset->kobj) : "<NULL>"); + + error = create_dir(kobj); + if (error) { + kobj_kset_leave(kobj); + kobject_put(parent); + kobj->parent = NULL; + + /* be noisy on error issues */ + if (error == -EEXIST) + pr_err("%s failed for %s with -EEXIST, don't try to register things with the same name in the same directory.\n", + __func__, kobject_name(kobj)); + else + pr_err("%s failed for %s (error: %d parent: %s)\n", + __func__, kobject_name(kobj), error, + parent ? kobject_name(parent) : "'none'"); + } else + kobj->state_in_sysfs = 1; + + return error; +} + +/** + * kobject_set_name_vargs() - Set the name of a kobject. + * @kobj: struct kobject to set the name of + * @fmt: format string used to build the name + * @vargs: vargs to format the string. + */ +int kobject_set_name_vargs(struct kobject *kobj, const char *fmt, + va_list vargs) +{ + const char *s; + + if (kobj->name && !fmt) + return 0; + + s = kvasprintf_const(GFP_KERNEL, fmt, vargs); + if (!s) + return -ENOMEM; + + /* + * ewww... some of these buggers have '/' in the name ... If + * that's the case, we need to make sure we have an actual + * allocated copy to modify, since kvasprintf_const may have + * returned something from .rodata. + */ + if (strchr(s, '/')) { + char *t; + + t = kstrdup(s, GFP_KERNEL); + kfree_const(s); + if (!t) + return -ENOMEM; + strreplace(t, '/', '!'); + s = t; + } + kfree_const(kobj->name); + kobj->name = s; + + return 0; +} + +/** + * kobject_set_name() - Set the name of a kobject. + * @kobj: struct kobject to set the name of + * @fmt: format string used to build the name + * + * This sets the name of the kobject. If you have already added the + * kobject to the system, you must call kobject_rename() in order to + * change the name of the kobject. + */ +int kobject_set_name(struct kobject *kobj, const char *fmt, ...) +{ + va_list vargs; + int retval; + + va_start(vargs, fmt); + retval = kobject_set_name_vargs(kobj, fmt, vargs); + va_end(vargs); + + return retval; +} +EXPORT_SYMBOL(kobject_set_name); + +/** + * kobject_init() - Initialize a kobject structure. + * @kobj: pointer to the kobject to initialize + * @ktype: pointer to the ktype for this kobject. + * + * This function will properly initialize a kobject such that it can then + * be passed to the kobject_add() call. + * + * After this function is called, the kobject MUST be cleaned up by a call + * to kobject_put(), not by a call to kfree directly to ensure that all of + * the memory is cleaned up properly. + */ +void kobject_init(struct kobject *kobj, const struct kobj_type *ktype) +{ + char *err_str; + + if (!kobj) { + err_str = "invalid kobject pointer!"; + goto error; + } + if (!ktype) { + err_str = "must have a ktype to be initialized properly!\n"; + goto error; + } + if (kobj->state_initialized) { + /* do not error out as sometimes we can recover */ + pr_err("kobject (%p): tried to init an initialized object, something is seriously wrong.\n", + kobj); + dump_stack(); + } + + kobject_init_internal(kobj); + kobj->ktype = ktype; + return; + +error: + pr_err("kobject (%p): %s\n", kobj, err_str); + dump_stack(); +} +EXPORT_SYMBOL(kobject_init); + +static __printf(3, 0) int kobject_add_varg(struct kobject *kobj, + struct kobject *parent, + const char *fmt, va_list vargs) +{ + int retval; + + retval = kobject_set_name_vargs(kobj, fmt, vargs); + if (retval) { + pr_err("kobject: can not set name properly!\n"); + return retval; + } + kobj->parent = parent; + return kobject_add_internal(kobj); +} + +/** + * kobject_add() - The main kobject add function. + * @kobj: the kobject to add + * @parent: pointer to the parent of the kobject. + * @fmt: format to name the kobject with. + * + * The kobject name is set and added to the kobject hierarchy in this + * function. + * + * If @parent is set, then the parent of the @kobj will be set to it. + * If @parent is NULL, then the parent of the @kobj will be set to the + * kobject associated with the kset assigned to this kobject. If no kset + * is assigned to the kobject, then the kobject will be located in the + * root of the sysfs tree. + * + * Note, no "add" uevent will be created with this call, the caller should set + * up all of the necessary sysfs files for the object and then call + * kobject_uevent() with the UEVENT_ADD parameter to ensure that + * userspace is properly notified of this kobject's creation. + * + * Return: If this function returns an error, kobject_put() must be + * called to properly clean up the memory associated with the + * object. Under no instance should the kobject that is passed + * to this function be directly freed with a call to kfree(), + * that can leak memory. + * + * If this function returns success, kobject_put() must also be called + * in order to properly clean up the memory associated with the object. + * + * In short, once this function is called, kobject_put() MUST be called + * when the use of the object is finished in order to properly free + * everything. + */ +int kobject_add(struct kobject *kobj, struct kobject *parent, + const char *fmt, ...) +{ + va_list args; + int retval; + + if (!kobj) + return -EINVAL; + + if (!kobj->state_initialized) { + pr_err("kobject '%s' (%p): tried to add an uninitialized object, something is seriously wrong.\n", + kobject_name(kobj), kobj); + dump_stack(); + return -EINVAL; + } + va_start(args, fmt); + retval = kobject_add_varg(kobj, parent, fmt, args); + va_end(args); + + return retval; +} +EXPORT_SYMBOL(kobject_add); + +/** + * kobject_init_and_add() - Initialize a kobject structure and add it to + * the kobject hierarchy. + * @kobj: pointer to the kobject to initialize + * @ktype: pointer to the ktype for this kobject. + * @parent: pointer to the parent of this kobject. + * @fmt: the name of the kobject. + * + * This function combines the call to kobject_init() and kobject_add(). + * + * If this function returns an error, kobject_put() must be called to + * properly clean up the memory associated with the object. This is the + * same type of error handling after a call to kobject_add() and kobject + * lifetime rules are the same here. + */ +int kobject_init_and_add(struct kobject *kobj, const struct kobj_type *ktype, + struct kobject *parent, const char *fmt, ...) +{ + va_list args; + int retval; + + kobject_init(kobj, ktype); + + va_start(args, fmt); + retval = kobject_add_varg(kobj, parent, fmt, args); + va_end(args); + + return retval; +} +EXPORT_SYMBOL_GPL(kobject_init_and_add); + +/** + * kobject_rename() - Change the name of an object. + * @kobj: object in question. + * @new_name: object's new name + * + * It is the responsibility of the caller to provide mutual + * exclusion between two different calls of kobject_rename + * on the same kobject and to ensure that new_name is valid and + * won't conflict with other kobjects. + */ +int kobject_rename(struct kobject *kobj, const char *new_name) +{ + int error = 0; + const char *devpath = NULL; + const char *dup_name = NULL, *name; + char *devpath_string = NULL; + char *envp[2]; + + kobj = kobject_get(kobj); + if (!kobj) + return -EINVAL; + if (!kobj->parent) { + kobject_put(kobj); + return -EINVAL; + } + + devpath = kobject_get_path(kobj, GFP_KERNEL); + if (!devpath) { + error = -ENOMEM; + goto out; + } + devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL); + if (!devpath_string) { + error = -ENOMEM; + goto out; + } + sprintf(devpath_string, "DEVPATH_OLD=%s", devpath); + envp[0] = devpath_string; + envp[1] = NULL; + + name = dup_name = kstrdup_const(new_name, GFP_KERNEL); + if (!name) { + error = -ENOMEM; + goto out; + } + + error = sysfs_rename_dir_ns(kobj, new_name, kobject_namespace(kobj)); + if (error) + goto out; + + /* Install the new kobject name */ + dup_name = kobj->name; + kobj->name = name; + + /* This function is mostly/only used for network interface. + * Some hotplug package track interfaces by their name and + * therefore want to know when the name is changed by the user. */ + kobject_uevent_env(kobj, KOBJ_MOVE, envp); + +out: + kfree_const(dup_name); + kfree(devpath_string); + kfree(devpath); + kobject_put(kobj); + + return error; +} +EXPORT_SYMBOL_GPL(kobject_rename); + +/** + * kobject_move() - Move object to another parent. + * @kobj: object in question. + * @new_parent: object's new parent (can be NULL) + */ +int kobject_move(struct kobject *kobj, struct kobject *new_parent) +{ + int error; + struct kobject *old_parent; + const char *devpath = NULL; + char *devpath_string = NULL; + char *envp[2]; + + kobj = kobject_get(kobj); + if (!kobj) + return -EINVAL; + new_parent = kobject_get(new_parent); + if (!new_parent) { + if (kobj->kset) + new_parent = kobject_get(&kobj->kset->kobj); + } + + /* old object path */ + devpath = kobject_get_path(kobj, GFP_KERNEL); + if (!devpath) { + error = -ENOMEM; + goto out; + } + devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL); + if (!devpath_string) { + error = -ENOMEM; + goto out; + } + sprintf(devpath_string, "DEVPATH_OLD=%s", devpath); + envp[0] = devpath_string; + envp[1] = NULL; + error = sysfs_move_dir_ns(kobj, new_parent, kobject_namespace(kobj)); + if (error) + goto out; + old_parent = kobj->parent; + kobj->parent = new_parent; + new_parent = NULL; + kobject_put(old_parent); + kobject_uevent_env(kobj, KOBJ_MOVE, envp); +out: + kobject_put(new_parent); + kobject_put(kobj); + kfree(devpath_string); + kfree(devpath); + return error; +} +EXPORT_SYMBOL_GPL(kobject_move); + +static void __kobject_del(struct kobject *kobj) +{ + struct kernfs_node *sd; + const struct kobj_type *ktype; + + sd = kobj->sd; + ktype = get_ktype(kobj); + + if (ktype) + sysfs_remove_groups(kobj, ktype->default_groups); + + /* send "remove" if the caller did not do it but sent "add" */ + if (kobj->state_add_uevent_sent && !kobj->state_remove_uevent_sent) { + pr_debug("kobject: '%s' (%p): auto cleanup 'remove' event\n", + kobject_name(kobj), kobj); + kobject_uevent(kobj, KOBJ_REMOVE); + } + + sysfs_remove_dir(kobj); + sysfs_put(sd); + + kobj->state_in_sysfs = 0; + kobj_kset_leave(kobj); + kobj->parent = NULL; +} + +/** + * kobject_del() - Unlink kobject from hierarchy. + * @kobj: object. + * + * This is the function that should be called to delete an object + * successfully added via kobject_add(). + */ +void kobject_del(struct kobject *kobj) +{ + struct kobject *parent; + + if (!kobj) + return; + + parent = kobj->parent; + __kobject_del(kobj); + kobject_put(parent); +} +EXPORT_SYMBOL(kobject_del); + +/** + * kobject_get() - Increment refcount for object. + * @kobj: object. + */ +struct kobject *kobject_get(struct kobject *kobj) +{ + if (kobj) { + if (!kobj->state_initialized) + WARN(1, KERN_WARNING + "kobject: '%s' (%p): is not initialized, yet kobject_get() is being called.\n", + kobject_name(kobj), kobj); + kref_get(&kobj->kref); + } + return kobj; +} +EXPORT_SYMBOL(kobject_get); + +struct kobject * __must_check kobject_get_unless_zero(struct kobject *kobj) +{ + if (!kobj) + return NULL; + if (!kref_get_unless_zero(&kobj->kref)) + kobj = NULL; + return kobj; +} +EXPORT_SYMBOL(kobject_get_unless_zero); + +/* + * kobject_cleanup - free kobject resources. + * @kobj: object to cleanup + */ +static void kobject_cleanup(struct kobject *kobj) +{ + struct kobject *parent = kobj->parent; + const struct kobj_type *t = get_ktype(kobj); + const char *name = kobj->name; + + pr_debug("kobject: '%s' (%p): %s, parent %p\n", + kobject_name(kobj), kobj, __func__, kobj->parent); + + if (t && !t->release) + 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", + kobject_name(kobj), kobj); + + /* remove from sysfs if the caller did not do it */ + if (kobj->state_in_sysfs) { + pr_debug("kobject: '%s' (%p): auto cleanup kobject_del\n", + kobject_name(kobj), kobj); + __kobject_del(kobj); + } else { + /* avoid dropping the parent reference unnecessarily */ + parent = NULL; + } + + if (t && t->release) { + pr_debug("kobject: '%s' (%p): calling ktype release\n", + kobject_name(kobj), kobj); + t->release(kobj); + } + + /* free name if we allocated it */ + if (name) { + pr_debug("kobject: '%s': free name\n", name); + kfree_const(name); + } + + kobject_put(parent); +} + +#ifdef CONFIG_DEBUG_KOBJECT_RELEASE +static void kobject_delayed_cleanup(struct work_struct *work) +{ + kobject_cleanup(container_of(to_delayed_work(work), + struct kobject, release)); +} +#endif + +static void kobject_release(struct kref *kref) +{ + struct kobject *kobj = container_of(kref, struct kobject, kref); +#ifdef CONFIG_DEBUG_KOBJECT_RELEASE + unsigned long delay = HZ + HZ * prandom_u32_max(4); + pr_info("kobject: '%s' (%p): %s, parent %p (delayed %ld)\n", + kobject_name(kobj), kobj, __func__, kobj->parent, delay); + INIT_DELAYED_WORK(&kobj->release, kobject_delayed_cleanup); + + schedule_delayed_work(&kobj->release, delay); +#else + kobject_cleanup(kobj); +#endif +} + +/** + * kobject_put() - Decrement refcount for object. + * @kobj: object. + * + * Decrement the refcount, and if 0, call kobject_cleanup(). + */ +void kobject_put(struct kobject *kobj) +{ + if (kobj) { + if (!kobj->state_initialized) + WARN(1, KERN_WARNING + "kobject: '%s' (%p): is not initialized, yet kobject_put() is being called.\n", + kobject_name(kobj), kobj); + kref_put(&kobj->kref, kobject_release); + } +} +EXPORT_SYMBOL(kobject_put); + +static void dynamic_kobj_release(struct kobject *kobj) +{ + pr_debug("kobject: (%p): %s\n", kobj, __func__); + kfree(kobj); +} + +static struct kobj_type dynamic_kobj_ktype = { + .release = dynamic_kobj_release, + .sysfs_ops = &kobj_sysfs_ops, +}; + +/** + * kobject_create() - Create a struct kobject dynamically. + * + * This function creates a kobject structure dynamically and sets it up + * to be a "dynamic" kobject with a default release function set up. + * + * If the kobject was not able to be created, NULL will be returned. + * The kobject structure returned from here must be cleaned up with a + * call to kobject_put() and not kfree(), as kobject_init() has + * already been called on this structure. + */ +static struct kobject *kobject_create(void) +{ + struct kobject *kobj; + + kobj = kzalloc(sizeof(*kobj), GFP_KERNEL); + if (!kobj) + return NULL; + + kobject_init(kobj, &dynamic_kobj_ktype); + return kobj; +} + +/** + * kobject_create_and_add() - Create a struct kobject dynamically and + * register it with sysfs. + * @name: the name for the kobject + * @parent: the parent kobject of this kobject, if any. + * + * This function creates a kobject structure dynamically and registers it + * with sysfs. When you are finished with this structure, call + * kobject_put() and the structure will be dynamically freed when + * it is no longer being used. + * + * If the kobject was not able to be created, NULL will be returned. + */ +struct kobject *kobject_create_and_add(const char *name, struct kobject *parent) +{ + struct kobject *kobj; + int retval; + + kobj = kobject_create(); + if (!kobj) + return NULL; + + retval = kobject_add(kobj, parent, "%s", name); + if (retval) { + pr_warn("%s: kobject_add error: %d\n", __func__, retval); + kobject_put(kobj); + kobj = NULL; + } + return kobj; +} +EXPORT_SYMBOL_GPL(kobject_create_and_add); + +/** + * kset_init() - Initialize a kset for use. + * @k: kset + */ +void kset_init(struct kset *k) +{ + kobject_init_internal(&k->kobj); + INIT_LIST_HEAD(&k->list); + spin_lock_init(&k->list_lock); +} + +/* default kobject attribute operations */ +static ssize_t kobj_attr_show(struct kobject *kobj, struct attribute *attr, + char *buf) +{ + struct kobj_attribute *kattr; + ssize_t ret = -EIO; + + kattr = container_of(attr, struct kobj_attribute, attr); + if (kattr->show) + ret = kattr->show(kobj, kattr, buf); + return ret; +} + +static ssize_t kobj_attr_store(struct kobject *kobj, struct attribute *attr, + const char *buf, size_t count) +{ + struct kobj_attribute *kattr; + ssize_t ret = -EIO; + + kattr = container_of(attr, struct kobj_attribute, attr); + if (kattr->store) + ret = kattr->store(kobj, kattr, buf, count); + return ret; +} + +const struct sysfs_ops kobj_sysfs_ops = { + .show = kobj_attr_show, + .store = kobj_attr_store, +}; +EXPORT_SYMBOL_GPL(kobj_sysfs_ops); + +/** + * kset_register() - Initialize and add a kset. + * @k: kset. + */ +int kset_register(struct kset *k) +{ + int err; + + if (!k) + return -EINVAL; + + if (!k->kobj.ktype) { + pr_err("must have a ktype to be initialized properly!\n"); + return -EINVAL; + } + + kset_init(k); + err = kobject_add_internal(&k->kobj); + if (err) + return err; + kobject_uevent(&k->kobj, KOBJ_ADD); + return 0; +} +EXPORT_SYMBOL(kset_register); + +/** + * kset_unregister() - Remove a kset. + * @k: kset. + */ +void kset_unregister(struct kset *k) +{ + if (!k) + return; + kobject_del(&k->kobj); + kobject_put(&k->kobj); +} +EXPORT_SYMBOL(kset_unregister); + +/** + * kset_find_obj() - Search for object in kset. + * @kset: kset we're looking in. + * @name: object's name. + * + * Lock kset via @kset->subsys, and iterate over @kset->list, + * looking for a matching kobject. If matching object is found + * take a reference and return the object. + */ +struct kobject *kset_find_obj(struct kset *kset, const char *name) +{ + struct kobject *k; + struct kobject *ret = NULL; + + spin_lock(&kset->list_lock); + + list_for_each_entry(k, &kset->list, entry) { + if (kobject_name(k) && !strcmp(kobject_name(k), name)) { + ret = kobject_get_unless_zero(k); + break; + } + } + + spin_unlock(&kset->list_lock); + return ret; +} +EXPORT_SYMBOL_GPL(kset_find_obj); + +static void kset_release(struct kobject *kobj) +{ + struct kset *kset = container_of(kobj, struct kset, kobj); + pr_debug("kobject: '%s' (%p): %s\n", + kobject_name(kobj), kobj, __func__); + kfree(kset); +} + +static void kset_get_ownership(struct kobject *kobj, kuid_t *uid, kgid_t *gid) +{ + if (kobj->parent) + kobject_get_ownership(kobj->parent, uid, gid); +} + +static struct kobj_type kset_ktype = { + .sysfs_ops = &kobj_sysfs_ops, + .release = kset_release, + .get_ownership = kset_get_ownership, +}; + +/** + * kset_create() - Create a struct kset dynamically. + * + * @name: the name for the kset + * @uevent_ops: a struct kset_uevent_ops for the kset + * @parent_kobj: the parent kobject of this kset, if any. + * + * This function creates a kset structure dynamically. This structure can + * then be registered with the system and show up in sysfs with a call to + * kset_register(). When you are finished with this structure, if + * kset_register() has been called, call kset_unregister() and the + * structure will be dynamically freed when it is no longer being used. + * + * If the kset was not able to be created, NULL will be returned. + */ +static struct kset *kset_create(const char *name, + const struct kset_uevent_ops *uevent_ops, + struct kobject *parent_kobj) +{ + struct kset *kset; + int retval; + + kset = kzalloc(sizeof(*kset), GFP_KERNEL); + if (!kset) + return NULL; + retval = kobject_set_name(&kset->kobj, "%s", name); + if (retval) { + kfree(kset); + return NULL; + } + kset->uevent_ops = uevent_ops; + kset->kobj.parent = parent_kobj; + + /* + * The kobject of this kset will have a type of kset_ktype and belong to + * no kset itself. That way we can properly free it when it is + * finished being used. + */ + kset->kobj.ktype = &kset_ktype; + kset->kobj.kset = NULL; + + return kset; +} + +/** + * kset_create_and_add() - Create a struct kset dynamically and add it to sysfs. + * + * @name: the name for the kset + * @uevent_ops: a struct kset_uevent_ops for the kset + * @parent_kobj: the parent kobject of this kset, if any. + * + * This function creates a kset structure dynamically and registers it + * with sysfs. When you are finished with this structure, call + * kset_unregister() and the structure will be dynamically freed when it + * is no longer being used. + * + * If the kset was not able to be created, NULL will be returned. + */ +struct kset *kset_create_and_add(const char *name, + const struct kset_uevent_ops *uevent_ops, + struct kobject *parent_kobj) +{ + struct kset *kset; + int error; + + kset = kset_create(name, uevent_ops, parent_kobj); + if (!kset) + return NULL; + error = kset_register(kset); + if (error) { + kfree(kset); + return NULL; + } + return kset; +} +EXPORT_SYMBOL_GPL(kset_create_and_add); + + +static DEFINE_SPINLOCK(kobj_ns_type_lock); +static const struct kobj_ns_type_operations *kobj_ns_ops_tbl[KOBJ_NS_TYPES]; + +int kobj_ns_type_register(const struct kobj_ns_type_operations *ops) +{ + enum kobj_ns_type type = ops->type; + int error; + + spin_lock(&kobj_ns_type_lock); + + error = -EINVAL; + if (type >= KOBJ_NS_TYPES) + goto out; + + error = -EINVAL; + if (type <= KOBJ_NS_TYPE_NONE) + goto out; + + error = -EBUSY; + if (kobj_ns_ops_tbl[type]) + goto out; + + error = 0; + kobj_ns_ops_tbl[type] = ops; + +out: + spin_unlock(&kobj_ns_type_lock); + return error; +} + +int kobj_ns_type_registered(enum kobj_ns_type type) +{ + int registered = 0; + + spin_lock(&kobj_ns_type_lock); + if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES)) + registered = kobj_ns_ops_tbl[type] != NULL; + spin_unlock(&kobj_ns_type_lock); + + return registered; +} + +const struct kobj_ns_type_operations *kobj_child_ns_ops(struct kobject *parent) +{ + const struct kobj_ns_type_operations *ops = NULL; + + if (parent && parent->ktype && parent->ktype->child_ns_type) + ops = parent->ktype->child_ns_type(parent); + + return ops; +} + +const struct kobj_ns_type_operations *kobj_ns_ops(struct kobject *kobj) +{ + return kobj_child_ns_ops(kobj->parent); +} + +bool kobj_ns_current_may_mount(enum kobj_ns_type type) +{ + bool may_mount = true; + + spin_lock(&kobj_ns_type_lock); + if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) && + kobj_ns_ops_tbl[type]) + may_mount = kobj_ns_ops_tbl[type]->current_may_mount(); + spin_unlock(&kobj_ns_type_lock); + + return may_mount; +} + +void *kobj_ns_grab_current(enum kobj_ns_type type) +{ + void *ns = NULL; + + spin_lock(&kobj_ns_type_lock); + if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) && + kobj_ns_ops_tbl[type]) + ns = kobj_ns_ops_tbl[type]->grab_current_ns(); + spin_unlock(&kobj_ns_type_lock); + + return ns; +} +EXPORT_SYMBOL_GPL(kobj_ns_grab_current); + +const void *kobj_ns_netlink(enum kobj_ns_type type, struct sock *sk) +{ + const void *ns = NULL; + + spin_lock(&kobj_ns_type_lock); + if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) && + kobj_ns_ops_tbl[type]) + ns = kobj_ns_ops_tbl[type]->netlink_ns(sk); + spin_unlock(&kobj_ns_type_lock); + + return ns; +} + +const void *kobj_ns_initial(enum kobj_ns_type type) +{ + const void *ns = NULL; + + spin_lock(&kobj_ns_type_lock); + if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) && + kobj_ns_ops_tbl[type]) + ns = kobj_ns_ops_tbl[type]->initial_ns(); + spin_unlock(&kobj_ns_type_lock); + + return ns; +} + +void kobj_ns_drop(enum kobj_ns_type type, void *ns) +{ + spin_lock(&kobj_ns_type_lock); + if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) && + kobj_ns_ops_tbl[type] && kobj_ns_ops_tbl[type]->drop_ns) + kobj_ns_ops_tbl[type]->drop_ns(ns); + spin_unlock(&kobj_ns_type_lock); +} +EXPORT_SYMBOL_GPL(kobj_ns_drop); |