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/*

 * kobject.c - library routines for handling generic kernel objects

 *

 * Copyright (c) 2002-2003 Patrick Mochel <mochel@osdl.org>

 *

 * This file is released under the GPLv2.

 *

 *

 * Please see the file Documentation/kobject.txt for critical information

 * about using the kobject interface.

 */

#undef DEBUG

#include <ll/stdarg.h>

#include <linuxcomp.h>

#include <linux/kobject.h>

#include <linux/string.h>

#include <linux/module.h>

#include <linux/stat.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 create_dir(struct kobject * kobj)

{

        int error = 0;

        if (kobject_name(kobj)) {

        }

        return error;

}

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

{

        return container_of(entry,struct kobject,entry);

}

#ifdef CONFIG_HOTPLUG

static int get_kobj_path_length(struct kset *kset, 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 {

                length += strlen(kobject_name(parent)) + 1;

                parent = parent->parent;

        } while (parent);

        return length;

}

static void fill_kobj_path(struct kset *kset, 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);

}

#define BUFFER_SIZE     1024    /* should be enough memory for the env */

#define NUM_ENVP        32      /* number of env pointers */

static unsigned long sequence_num;

static spinlock_t sequence_lock = SPIN_LOCK_UNLOCKED;

static void kset_hotplug(const char *action, struct kset *kset,

                         struct kobject *kobj)

{

        char *argv [3];

        char **envp = NULL;

        char *buffer = NULL;

        char *scratch;

        int i = 0;

        int retval;

        int kobj_path_length;

        char *kobj_path = NULL;

        char *name = NULL;

        unsigned long seq;

        /* If the kset has a filter operation, call it. If it returns

           failure, no hotplug event is required. */

        if (kset->hotplug_ops->filter) {

                if (!kset->hotplug_ops->filter(kset, kobj))

                        return;

        }

        pr_debug ("%s\n", __FUNCTION__);

        if (!hotplug_path[0])

                return;

        envp = kmalloc(NUM_ENVP * sizeof (char *), GFP_KERNEL);

        if (!envp)

                return;

        memset (envp, 0x00, NUM_ENVP * sizeof (char *));

        buffer = kmalloc(BUFFER_SIZE, GFP_KERNEL);

        if (!buffer)

                goto exit;

        if (kset->hotplug_ops->name)

                name = kset->hotplug_ops->name(kset, kobj);

        if (name == NULL)

                name = kset->kobj.name;

        argv [0] = hotplug_path;

        argv [1] = name;

        argv [2] = 0;

        /* minimal command environment */

        envp [i++] = "HOME=/";

        envp [i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";

        scratch = buffer;

        envp [i++] = scratch;

        scratch += sprintf(scratch, "ACTION=%s", action) + 1;

        spin_lock(&sequence_lock);

        seq = sequence_num++;

        spin_unlock(&sequence_lock);

        envp [i++] = scratch;

        scratch += sprintf(scratch, "SEQNUM=%ld", seq) + 1;

        kobj_path_length = get_kobj_path_length (kset, kobj);

        kobj_path = kmalloc (kobj_path_length, GFP_KERNEL);

        if (!kobj_path)

                goto exit;

        memset (kobj_path, 0x00, kobj_path_length);

        fill_kobj_path (kset, kobj, kobj_path, kobj_path_length);

        envp [i++] = scratch;

        scratch += sprintf (scratch, "DEVPATH=%s", kobj_path) + 1;

        if (kset->hotplug_ops->hotplug) {

                /* have the kset specific function add its stuff */

                retval = kset->hotplug_ops->hotplug (kset, kobj,

                                  &envp[i], NUM_ENVP - i, scratch,

                                  BUFFER_SIZE - (scratch - buffer));

                if (retval) {

                        pr_debug ("%s - hotplug() returned %d\n",

                                  __FUNCTION__, retval);

                        goto exit;

                }

        }

        pr_debug ("%s: %s %s %s %s %s %s\n", __FUNCTION__, argv[0], argv[1],

                  envp[0], envp[1], envp[2], envp[3]);

        retval = call_usermodehelper (argv[0], argv, envp, 0);

        if (retval)

                pr_debug ("%s - call_usermodehelper returned %d\n",

                          __FUNCTION__, retval);

exit:

        kfree(kobj_path);

        kfree(buffer);

        kfree(envp);

        return;

}

#else

static void kset_hotplug(const char *action, struct kset *kset,

                         struct kobject *kobj)

{

        return;

}

#endif  /* CONFIG_HOTPLUG */

/**

 *      kobject_init - initialize object.

 *      @kobj:  object in question.

 */

void kobject_init(struct kobject * kobj)

{

        atomic_set(&kobj->refcount,1);

        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) {

                list_del_init(&kobj->entry);

        }

        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;

        struct kobject * top_kobj;

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

                return -ENOENT;

        if (!kobj->k_name)

                kobj->k_name = kobj->name;

        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 ? kobj->kset->kobj.name : "<NULL>" );

        if (kobj->kset) {

                if (!parent)

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

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

        }

        kobj->parent = parent;

        error = create_dir(kobj);

        if (error) {

                unlink(kobj);

                if (parent)

                        kobject_put(parent);

        } else {

                /* If this kobj does not belong to a kset,

                   try to find a parent that does. */

                top_kobj = kobj;

                if (!top_kobj->kset && top_kobj->parent) {

                        do {

                                top_kobj = top_kobj->parent;

                        } while (!top_kobj->kset && top_kobj->parent);

                }

                if (top_kobj->kset && top_kobj->kset->hotplug_ops)

                        kset_hotplug("add", top_kobj->kset, kobj);

        }

        return error;

}

/**

 *      kobject_register - initialize and add an object.

 *      @kobj:  object in question.

 */

int kobject_register(struct kobject * kobj)

{

        int error = 0;

        if (kobj) {

                kobject_init(kobj);

                error = kobject_add(kobj);

                if (error) {

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

                               kobject_name(kobj),error);

                        dump_stack();

                }

        } else

                error = -EINVAL;

        return error;

}

/**

 *      kobject_set_name - Set the name of an object

 *      @kobj:  object.

 *      @name:  name.

 *

 *      If strlen(name) < KOBJ_NAME_LEN, then use a dynamically allocated

 *      string that @kobj->k_name points to. Otherwise, use the static

 *      @kobj->name array.

 */

int kobject_set_name(struct kobject * kobj, const char * fmt, ...)

{

        int error = 0;

        int limit = KOBJ_NAME_LEN;

        int need;

        va_list args;

        char * name;

        va_start(args,fmt);

        /*

         * First, try the static array

         */

        need = vsnprintf(kobj->name,limit,fmt,args);

        if (need < limit)

                name = kobj->name;

        else {

                /*

                 * Need more space? Allocate it and try again

                 */

                name = kmalloc(need,GFP_KERNEL);

                if (!name) {

                        error = -ENOMEM;

                        goto Done;

                }

                limit = need;

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

                /* Still? Give up. */

                if (need > limit) {

                        kfree(name);

                        error = -EFAULT;

                        goto Done;

                }

        }

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

        if (kobj->k_name && kobj->k_name != kobj->name)

                kfree(kobj->k_name);

        /* Now, set the new name */

        kobj->k_name = name;

 Done:

        va_end(args);

        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

 */

void kobject_rename(struct kobject * kobj, char *new_name)

{

        kobj = kobject_get(kobj);

        if (!kobj)

                return;

        kobject_put(kobj);

}

/**

 *      kobject_del - unlink kobject from hierarchy.

 *      @kobj:  object.

 */

void kobject_del(struct kobject * kobj)

{

        struct kobject * top_kobj;

        /* If this kobj does not belong to a kset,

           try to find a parent that does. */

        top_kobj = kobj;

        if (!top_kobj->kset && top_kobj->parent) {

                do {

                        top_kobj = top_kobj->parent;

                } while (!top_kobj->kset && top_kobj->parent);

        }

        if (top_kobj->kset && top_kobj->kset->hotplug_ops)

                kset_hotplug("remove", top_kobj->kset, kobj);

        unlink(kobj);

}

/**

 *      kobject_unregister - remove object from hierarchy and decrement refcount.

 *      @kobj:  object going away.

 */

void kobject_unregister(struct kobject * kobj)

{

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

        kobject_del(kobj);

        kobject_put(kobj);

}

/**

 *      kobject_get - increment refcount for object.

 *      @kobj:  object.

 */

struct kobject * kobject_get(struct kobject * kobj)

{

        struct kobject * ret = kobj;

        if (kobj) {

                WARN_ON(!atomic_read(&kobj->refcount));

                atomic_inc(&kobj->refcount);

        } else

                ret = NULL;

        return ret;

}

/**

 *      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;

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

        if (kobj->k_name != kobj->name)

                kfree(kobj->k_name);

        kobj->k_name = NULL;

        if (t && t->release)

                t->release(kobj);

        if (s)

                kset_put(s);

        if (parent)

                kobject_put(parent);

}

/**

 *      kobject_put - decrement refcount for object.

 *      @kobj:  object.

 *

 *      Decrement the refcount, and if 0, call kobject_cleanup().

 */

void kobject_put(struct kobject * kobj)

{

        if (atomic_dec_and_test(&kobj->refcount))

                kobject_cleanup(kobj);

}

/**

 *      kset_init - initialize a kset for use

 *      @k:     kset

 */

void kset_init(struct kset * k)

{

        kobject_init(&k->kobj);

        INIT_LIST_HEAD(&k->list);

}

/**

 *      kset_add - add a kset object to the hierarchy.

 *      @k:     kset.

 *

 *      Simply, this adds the kset's embedded kobject to the

 *      hierarchy.

 *      We also try to make sure that the kset's embedded kobject

 *      has a parent before it is added. We only care if the embedded

 *      kobject is not part of a kset itself, since kobject_add()

 *      assigns a parent in that case.

 *      If that is the case, and the kset has a controlling subsystem,

 *      then we set the kset's parent to be said subsystem.

 */

int kset_add(struct kset * k)

{

        if (!k->kobj.parent && !k->kobj.kset && k->subsys)

                k->kobj.parent = &k->subsys->kset.kobj;

        return kobject_add(&k->kobj);

}

/**

 *      kset_register - initialize and add a kset.

 *      @k:     kset.

 */

int kset_register(struct kset * k)

{

        kset_init(k);

        return kset_add(k);

}

/**

 *      kset_unregister - remove a kset.

 *      @k:     kset.

 */

void kset_unregister(struct kset * k)

{

        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. Return object if found.

 */

struct kobject * kset_find_obj(struct kset * kset, const char * name)

{

        struct list_head * entry;

        struct kobject * ret = NULL;

        list_for_each(entry,&kset->list) {

                struct kobject * k = to_kobj(entry);

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

                        ret = k;

                        break;

                }

        }

        return ret;

}

void subsystem_init(struct subsystem * s)

{

        kset_init(&s->kset);

}

/**

 *      subsystem_register - register a subsystem.

 *      @s:     the subsystem we're registering.

 *

 *      Once we register the subsystem, we want to make sure that

 *      the kset points back to this subsystem for correct usage of

 *      the rwsem.

 */

int subsystem_register(struct subsystem * s)

{

        int error;

        subsystem_init(s);

        pr_debug("subsystem %s: registering\n",s->kset.kobj.name);

        if (!(error = kset_add(&s->kset))) {

                if (!s->kset.subsys)

                        s->kset.subsys = s;

        }

        return error;

}

void subsystem_unregister(struct subsystem * s)

{

        pr_debug("subsystem %s: unregistering\n",s->kset.kobj.name);

        kset_unregister(&s->kset);

}

/**

 *      subsystem_create_file - export sysfs attribute file.

 *      @s:     subsystem.

 *      @a:     subsystem attribute descriptor.

 */

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

{

        int error = 0;

        if (subsys_get(s)) {

                subsys_put(s);

        }

        return error;

}

/**

 *      subsystem_remove_file - remove sysfs attribute file.

 *      @s:     subsystem.

 *      @a:     attribute desciptor.

 */

void subsys_remove_file(struct subsystem * s, struct subsys_attribute * a)

{

        if (subsys_get(s)) {

                subsys_put(s);

        }

}

EXPORT_SYMBOL(kobject_init);

EXPORT_SYMBOL(kobject_register);

EXPORT_SYMBOL(kobject_unregister);

EXPORT_SYMBOL(kobject_get);

EXPORT_SYMBOL(kobject_put);

EXPORT_SYMBOL(kset_register);

EXPORT_SYMBOL(kset_unregister);

EXPORT_SYMBOL(kset_find_obj);

EXPORT_SYMBOL(subsystem_init);

EXPORT_SYMBOL(subsystem_register);

EXPORT_SYMBOL(subsystem_unregister);

EXPORT_SYMBOL(subsys_create_file);

EXPORT_SYMBOL(subsys_remove_file);