linux/lib/kobject.c
Kay Sievers 312c004d36 [PATCH] driver core: replace "hotplug" by "uevent"
Leave the overloaded "hotplug" word to susbsystems which are handling
real devices. The driver core does not "plug" anything, it just exports
the state to userspace and generates events.

Signed-off-by: Kay Sievers <kay.sievers@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-01-04 16:18:08 -08:00

543 lines
11 KiB
C

/*
* 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.
*/
#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 {
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. The result must be freed by the caller with kfree().
*
* @kobj: kobject in question, with which to build the path
* @gfp_mask: the allocation type used to allocate the path
*/
char *kobject_get_path(struct kobject *kobj, gfp_t gfp_mask)
{
char *path;
int len;
len = get_kobj_path_length(kobj);
path = kmalloc(len, gfp_mask);
if (!path)
return NULL;
memset(path, 0x00, len);
fill_kobj_path(kobj, path, len);
return path;
}
/**
* kobject_init - initialize object.
* @kobj: object in question.
*/
void kobject_init(struct kobject * kobj)
{
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)
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) {
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);
if (parent)
kobject_put(parent);
}
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
kobject_uevent(kobj, KOBJ_ADD);
} else
error = -EINVAL;
return error;
}
/**
* kobject_set_name - Set the name of an object
* @kobj: object.
* @fmt: format string used to build the 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;
/*
* First, try the static array
*/
va_start(args,fmt);
need = vsnprintf(kobj->name,limit,fmt,args);
va_end(args);
if (need < limit)
name = kobj->name;
else {
/*
* Need more space? Allocate it and try again
*/
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);
/* 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:
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;
kobj = kobject_get(kobj);
if (!kobj)
return -EINVAL;
error = sysfs_rename_dir(kobj, new_name);
kobject_put(kobj);
return error;
}
/**
* kobject_del - unlink kobject from hierarchy.
* @kobj: object.
*/
void kobject_del(struct kobject * kobj)
{
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)
{
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;
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);
}
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);
}
/**
* 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.
*
* 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. 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;
}
void subsystem_init(struct subsystem * s)
{
init_rwsem(&s->rwsem);
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)) {
error = sysfs_create_file(&s->kset.kobj,&a->attr);
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)) {
sysfs_remove_file(&s->kset.kobj,&a->attr);
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(kobject_add);
EXPORT_SYMBOL(kobject_del);
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);