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/*

 * 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++) {

                        if ((error = sysfs_create_file(kobj,attr)))

                                break;

                }

        }

        return error;

}

static int create_dir(struct kobject * kobj)

{

        int error = 0;

        if (kobject_name(kobj)) {

                error = sysfs_create_dir(kobj);

                if (!error) {

                        if ((error = populate_dir(kobj)))

                                sysfs_remove_dir(kobj);

                }

        }

        return error;

}

static inline struct kobject * to_kobj(struct list_head * entry)

{

        return container_of(entry,struct kobject,entry);

}

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("%s: path = '%s'\n",__FUNCTION__,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);

/**

 *      kobject_init - initialize object.

 *      @kobj:  object in question.

 */

void kobject_init(struct kobject * kobj)

{

        if (!kobj)

                return;

        kref_init(&kobj->kref);

        INIT_LIST_HEAD(&kobj->entry);

        kobj->kset = kset_get(kobj->kset);

}

/**

 *      unlink - remove kobject from kset list.

 *      @kobj:  kobject.

 *

 *      Remove the kobject from the kset list and decrement

 *      its parent's refcount.

 *      This is separated out, so we can use it in both

 *      kobject_del() and kobject_add() on error.

 */

static void unlink(struct kobject * kobj)

{

        if (kobj->kset) {

                spin_lock(&kobj->kset->list_lock);

                list_del_init(&kobj->entry);

                spin_unlock(&kobj->kset->list_lock);

        }

        kobject_put(kobj);

}

/**

 *      kobject_add - add an object to the hierarchy.

 *      @kobj:  object.

 */

int kobject_add(struct kobject * kobj)

{

        int error = 0;

        struct kobject * parent;

        if (!(kobj = kobject_get(kobj)))

                return -ENOENT;

        if (!kobj->k_name)

                kobject_set_name(kobj, "NO_NAME");

        if (!*kobj->k_name) {

                pr_debug("kobject attempted to be registered with no name!\n");

                WARN_ON(1);

                kobject_put(kobj);

                return -EINVAL;

        }

        parent = kobject_get(kobj->parent);

        pr_debug("kobject %s: registering. parent: %s, set: %s\n",

                 kobject_name(kobj), parent ? kobject_name(parent) : "<NULL>",

                 kobj->kset ? kobject_name(&kobj->kset->kobj) : "<NULL>" );

        if (kobj->kset) {

                spin_lock(&kobj->kset->list_lock);

                if (!parent)

                        parent = kobject_get(&kobj->kset->kobj);

                list_add_tail(&kobj->entry,&kobj->kset->list);

                spin_unlock(&kobj->kset->list_lock);

                kobj->parent = parent;

        }

        error = create_dir(kobj);

        if (error) {

                /* unlink does the kobject_put() for us */

                unlink(kobj);

                kobject_put(parent);

                /* be noisy on error issues */

                if (error == -EEXIST)

                        printk(KERN_ERR "kobject_add failed for %s with "

                               "-EEXIST, don't try to register things with "

                               "the same name in the same directory.\n",

                               kobject_name(kobj));

                else

                        printk(KERN_ERR "kobject_add failed for %s (%d)\n",

                               kobject_name(kobj), error);

                dump_stack();

        }

        return error;

}

/**

 *      kobject_register - initialize and add an object.

 *      @kobj:  object in question.

 */

int kobject_register(struct kobject * kobj)

{

        int error = -EINVAL;

        if (kobj) {

                kobject_init(kobj);

                error = kobject_add(kobj);

                if (!error)

                        kobject_uevent(kobj, KOBJ_ADD);

        }

        return error;

}

/**

 * kobject_set_name - Set the name of a kobject

 * @kobj: kobject to name

 * @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, ...)

{

        int error = 0;

        int limit;

        int need;

        va_list args;

        char *name;

        /* find out how big a buffer we need */

        name = kmalloc(1024, GFP_KERNEL);

        if (!name) {

                error = -ENOMEM;

                goto done;

        }

        va_start(args, fmt);

        need = vsnprintf(name, 1024, fmt, args);

        va_end(args);

        kfree(name);

        /* Allocate the new space and copy the string in */

        limit = need + 1;

        name = kmalloc(limit, GFP_KERNEL);

        if (!name) {

                error = -ENOMEM;

                goto done;

        }

        va_start(args, fmt);

        need = vsnprintf(name, limit, fmt, args);

        va_end(args);

        /* something wrong with the string we copied? */

        if (need >= limit) {

                kfree(name);

                error = -EFAULT;

                goto done;

        }

        /* Free the old name, if necessary. */

        kfree(kobj->k_name);

        /* Now, set the new name */

        kobj->k_name = name;

done:

        return error;

}

EXPORT_SYMBOL(kobject_set_name);

/**

 *      kobject_rename - change the name of an object

 *      @kobj:  object in question.

 *      @new_name: object's new name

 */

int kobject_rename(struct kobject * kobj, const char *new_name)

{

        int error = 0;

        const char *devpath = NULL;

        char *devpath_string = NULL;

        char *envp[2];

        kobj = kobject_get(kobj);

        if (!kobj)

                return -EINVAL;

        if (!kobj->parent)

                return -EINVAL;

        /* see if this name is already in use */

        if (kobj->kset) {

                struct kobject *temp_kobj;

                temp_kobj = kset_find_obj(kobj->kset, new_name);

                if (temp_kobj) {

                        printk(KERN_WARNING "kobject '%s' cannot be renamed "

                               "to '%s' as '%s' is already in existence.\n",

                               kobject_name(kobj), new_name, new_name);

                        kobject_put(temp_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;

        /* Note : if we want to send the new name alone, not the full path,

         * we could probably use kobject_name(kobj); */

        error = sysfs_rename_dir(kobj, new_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. */

        if (!error)

                kobject_uevent_env(kobj, KOBJ_MOVE, envp);

out:

        kfree(devpath_string);

        kfree(devpath);

        kobject_put(kobj);

        return error;

}

/**

 *      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);

        unlink(kobj);

}

/**

 *      kobject_unregister - remove object from hierarchy and decrement refcount.

 *      @kobj:  object going away.

 */

void kobject_unregister(struct kobject * kobj)

{

        if (!kobj)

                return;

        pr_debug("kobject %s: unregistering\n",kobject_name(kobj));

        kobject_uevent(kobj, KOBJ_REMOVE);

        kobject_del(kobj);

        kobject_put(kobj);

}

/**

 *      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.

 */

void kobject_cleanup(struct kobject * kobj)

{

        struct kobj_type * t = get_ktype(kobj);

        struct kset * s = kobj->kset;

        struct kobject * parent = kobj->parent;

        const char *name = kobj->k_name;

        pr_debug("kobject %s: cleaning up\n",kobject_name(kobj));

        if (t && t->release) {

                t->release(kobj);

                /* If we have a release function, we can guess that this was

                 * not a statically allocated kobject, so we should be safe to

                 * free the name */

                kfree(name);

        }

        if (s)

                kset_put(s);

        kobject_put(parent);

}

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)

                kref_put(&kobj->kref, kobject_release);

}

static void dir_release(struct kobject *kobj)

{

        kfree(kobj);

}

static struct kobj_type dir_ktype = {

        .release        = dir_release,

        .sysfs_ops      = NULL,

        .default_attrs  = NULL,

};

/**

 *      kobject_kset_add_dir - add sub directory of object.

 *      @kset:          kset the directory is belongs to.

 *      @parent:        object in which a directory is created.

 *      @name:  directory name.

 *

 *      Add a plain directory object as child of given object.

 */

struct kobject *kobject_kset_add_dir(struct kset *kset,

                                     struct kobject *parent, const char *name)

{

        struct kobject *k;

        int ret;

        if (!parent)

                return NULL;

        k = kzalloc(sizeof(*k), GFP_KERNEL);

        if (!k)

                return NULL;

        k->kset = kset;

        k->parent = parent;

        k->ktype = &dir_ktype;

        kobject_set_name(k, name);

        ret = kobject_register(k);

        if (ret < 0) {

                printk(KERN_WARNING "%s: kobject_register error: %d\n",

                        __func__, ret);

                kobject_del(k);

                return NULL;

        }

        return k;

}

/**

 *      kobject_add_dir - add sub directory of object.

 *      @parent:        object in which a directory is created.

 *      @name:  directory name.

 *

 *      Add a plain directory object as child of given object.

 */

struct kobject *kobject_add_dir(struct kobject *parent, const char *name)

{

        return kobject_kset_add_dir(NULL, parent, name);

}

/**

 *      kset_init - initialize a kset for use

 *      @k:     kset

 */

void kset_init(struct kset * k)

{

        kobject_init(&k->kobj);

        INIT_LIST_HEAD(&k->list);

        spin_lock_init(&k->list_lock);

}

/**

 *      kset_add - add a kset object to the hierarchy.

 *      @k:     kset.

 */

int kset_add(struct kset * k)

{

        return kobject_add(&k->kobj);

}

/**

 *      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 = kset_add(k);

        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_unregister(&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 list_head * entry;

        struct kobject * ret = NULL;

        spin_lock(&kset->list_lock);

        list_for_each(entry,&kset->list) {

                struct kobject * k = to_kobj(entry);

                if (kobject_name(k) && !strcmp(kobject_name(k),name)) {

                        ret = kobject_get(k);

                        break;

                }

        }

        spin_unlock(&kset->list_lock);

        return ret;

}

int subsystem_register(struct kset *s)

{

        return kset_register(s);

}

void subsystem_unregister(struct kset *s)

{

        kset_unregister(s);

}

/**

 *      subsystem_create_file - export sysfs attribute file.

 *      @s:     subsystem.

 *      @a:     subsystem attribute descriptor.

 */

int subsys_create_file(struct kset *s, struct subsys_attribute *a)

{

        int error = 0;

        if (!s || !a)

                return -EINVAL;

        if (kset_get(s)) {

                error = sysfs_create_file(&s->kobj, &a->attr);

                kset_put(s);

        }

        return error;

}

EXPORT_SYMBOL(kobject_init);

EXPORT_SYMBOL(kobject_register);

EXPORT_SYMBOL(kobject_unregister);

EXPORT_SYMBOL(kobject_get);

EXPORT_SYMBOL(kobject_put);

EXPORT_SYMBOL(kobject_add);

EXPORT_SYMBOL(kobject_del);

EXPORT_SYMBOL(kset_register);

EXPORT_SYMBOL(kset_unregister);

EXPORT_SYMBOL(subsystem_register);

EXPORT_SYMBOL(subsystem_unregister);

EXPORT_SYMBOL(subsys_create_file);