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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /lib/kobject.c
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'lib/kobject.c')
-rw-r--r--lib/kobject.c544
1 files changed, 544 insertions, 0 deletions
diff --git a/lib/kobject.c b/lib/kobject.c
new file mode 100644
index 000000000000..ff9491986b38
--- /dev/null
+++ b/lib/kobject.c
@@ -0,0 +1,544 @@
+/*
+ * 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>
+
+/**
+ * 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, int 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);
+ } else {
+ kobject_hotplug(kobj, KOBJ_ADD);
+ }
+
+ 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;
+
+ /*
+ * 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, 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)
+{
+ kobject_hotplug(kobj, KOBJ_REMOVE);
+ 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_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);

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