diff options
Diffstat (limited to 'lib/kobject.c')
| -rw-r--r-- | lib/kobject.c | 850 |
1 files changed, 850 insertions, 0 deletions
diff --git a/lib/kobject.c b/lib/kobject.c new file mode 100644 index 0000000..0487d1f --- /dev/null +++ b/lib/kobject.c @@ -0,0 +1,850 @@ +/* + * 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. + * + * This file is released under the GPLv2. + * + * + * Please see the file Documentation/kobject.txt for critical information + * about using the kobject interface. + */ + +#include <linux/kobject.h> +#include <linux/string.h> +#include <linux/module.h> +#include <linux/stat.h> +#include <linux/slab.h> + +/* + * populate_dir - populate directory with attributes. + * @kobj: object we're working on. + * + * Most subsystems have a set of default attributes that are associated + * with an object that registers with them. This is a helper called during + * object registration that loops through the default attributes of the + * subsystem and creates attributes files for them in sysfs. + */ +static int populate_dir(struct kobject *kobj) +{ + struct kobj_type *t = get_ktype(kobj); + struct attribute *attr; + int error = 0; + int i; + + if (t && t->default_attrs) { + for (i = 0; (attr = t->default_attrs[i]) != NULL; i++) { + error = sysfs_create_file(kobj, attr); + if (error) + break; + } + } + return error; +} + +static int create_dir(struct kobject *kobj) +{ + int error = 0; + if (kobject_name(kobj)) { + error = sysfs_create_dir(kobj); + if (!error) { + error = populate_dir(kobj); + if (error) + sysfs_remove_dir(kobj); + } + } + return error; +} + +static int get_kobj_path_length(struct kobject *kobj) +{ + int length = 1; + 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 void fill_kobj_path(struct kobject *kobj, char *path, int length) +{ + 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; + strncpy(path + length, kobject_name(parent), cur); + *(path + --length) = '/'; + } + + pr_debug("kobject: '%s' (%p): %s: path = '%s'\n", kobject_name(kobj), + kobj, __func__, path); +} + +/** + * kobject_get_path - generate and return the path associated with a given kobj and kset pair. + * + * @kobj: kobject in question, with which to build the path + * @gfp_mask: the allocation type used to allocate the path + * + * The result must be freed by the caller with kfree(). + */ +char *kobject_get_path(struct kobject *kobj, gfp_t gfp_mask) +{ + char *path; + int len; + + len = get_kobj_path_length(kobj); + if (len == 0) + return NULL; + path = kzalloc(len, gfp_mask); + if (!path) + return NULL; + fill_kobj_path(kobj, path, len); + + 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) + printk(KERN_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 + printk(KERN_ERR "%s failed for %s (%d)\n", + __func__, kobject_name(kobj), error); + dump_stack(); + } else + kobj->state_in_sysfs = 1; + + return error; +} + +/** + * kobject_set_name_vargs - Set the name of an kobject + * @kobj: struct kobject to set the name of + * @fmt: format string used to build the name + * @vargs: vargs to format the string. + */ +static int kobject_set_name_vargs(struct kobject *kobj, const char *fmt, + va_list vargs) +{ + const char *old_name = kobj->name; + char *s; + + kobj->name = kvasprintf(GFP_KERNEL, fmt, vargs); + if (!kobj->name) + return -ENOMEM; + + /* ewww... some of these buggers have '/' in the name ... */ + while ((s = strchr(kobj->name, '/'))) + s[0] = '!'; + + kfree(old_name); + 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, 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 */ + printk(KERN_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: + printk(KERN_ERR "kobject (%p): %s\n", kobj, err_str); + dump_stack(); +} +EXPORT_SYMBOL(kobject_init); + +static 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) { + printk(KERN_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 associted 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. + * + * 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. + * + * 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. + */ +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) { + printk(KERN_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(). 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, 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) + 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(new_name, GFP_KERNEL); + if (!name) { + error = -ENOMEM; + goto out; + } + + error = sysfs_rename_dir(kobj, new_name); + 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(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(kobj, new_parent); + 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; +} + +/** + * kobject_del - unlink kobject from hierarchy. + * @kobj: object. + */ +void kobject_del(struct kobject *kobj) +{ + if (!kobj) + return; + + sysfs_remove_dir(kobj); + kobj->state_in_sysfs = 0; + kobj_kset_leave(kobj); + kobject_put(kobj->parent); + kobj->parent = NULL; +} + +/** + * kobject_get - increment refcount for object. + * @kobj: object. + */ +struct kobject *kobject_get(struct kobject *kobj) +{ + if (kobj) + kref_get(&kobj->kref); + return kobj; +} + +/* + * kobject_cleanup - free kobject resources. + * @kobj: object to cleanup + */ +static void kobject_cleanup(struct kobject *kobj) +{ + struct kobj_type *t = get_ktype(kobj); + const char *name = kobj->name; + + pr_debug("kobject: '%s' (%p): %s\n", + kobject_name(kobj), kobj, __func__); + + if (t && !t->release) + pr_debug("kobject: '%s' (%p): does not have a release() " + "function, it is broken and must be fixed.\n", + kobject_name(kobj), kobj); + + /* 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); + } + + /* 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); + } + + 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(name); + } +} + +static void kobject_release(struct kref *kref) +{ + kobject_cleanup(container_of(kref, struct kobject, kref)); +} + +/** + * 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); + } +} + +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. + */ +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 kset + * @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) { + printk(KERN_WARNING "%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; +} + +struct sysfs_ops kobj_sysfs_ops = { + .show = kobj_attr_show, + .store = kobj_attr_store, +}; + +/** + * kset_register - initialize and add a kset. + * @k: kset. + */ +int kset_register(struct kset *k) +{ + int err; + + if (!k) + return -EINVAL; + + kset_init(k); + err = kobject_add_internal(&k->kobj); + if (err) + return err; + kobject_uevent(&k->kobj, KOBJ_ADD); + return 0; +} + +/** + * kset_unregister - remove a kset. + * @k: kset. + */ +void kset_unregister(struct kset *k) +{ + if (!k) + return; + kobject_put(&k->kobj); +} + +/** + * 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(k); + break; + } + } + spin_unlock(&kset->list_lock); + return ret; +} + +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 struct kobj_type kset_ktype = { + .sysfs_ops = &kobj_sysfs_ops, + .release = kset_release, +}; + +/** + * 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, + struct kset_uevent_ops *uevent_ops, + struct kobject *parent_kobj) +{ + struct kset *kset; + + kset = kzalloc(sizeof(*kset), GFP_KERNEL); + if (!kset) + return NULL; + kobject_set_name(&kset->kobj, name); + 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, + 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); + +EXPORT_SYMBOL(kobject_get); +EXPORT_SYMBOL(kobject_put); +EXPORT_SYMBOL(kobject_del); + +EXPORT_SYMBOL(kset_register); +EXPORT_SYMBOL(kset_unregister); |
