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369 lines
9.0 KiB
369 lines
9.0 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* vim: noexpandtab ts=8 sts=0 sw=8: |
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* |
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* configfs_example_macros.c - This file is a demonstration module |
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* containing a number of configfs subsystems. It uses the helper |
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* macros defined by configfs.h |
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* |
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* Based on sysfs: |
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* sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel |
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* |
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* configfs Copyright (C) 2005 Oracle. All rights reserved. |
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*/ |
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#include <linux/init.h> |
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#include <linux/kernel.h> |
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#include <linux/module.h> |
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#include <linux/slab.h> |
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#include <linux/configfs.h> |
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/* |
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* 01-childless |
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* |
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* This first example is a childless subsystem. It cannot create |
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* any config_items. It just has attributes. |
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* |
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* Note that we are enclosing the configfs_subsystem inside a container. |
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* This is not necessary if a subsystem has no attributes directly |
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* on the subsystem. See the next example, 02-simple-children, for |
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* such a subsystem. |
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*/ |
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struct childless { |
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struct configfs_subsystem subsys; |
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int showme; |
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int storeme; |
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}; |
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static inline struct childless *to_childless(struct config_item *item) |
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{ |
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return container_of(to_configfs_subsystem(to_config_group(item)), |
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struct childless, subsys); |
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} |
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static ssize_t childless_showme_show(struct config_item *item, char *page) |
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{ |
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struct childless *childless = to_childless(item); |
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ssize_t pos; |
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pos = sprintf(page, "%d\n", childless->showme); |
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childless->showme++; |
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return pos; |
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} |
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static ssize_t childless_storeme_show(struct config_item *item, char *page) |
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{ |
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return sprintf(page, "%d\n", to_childless(item)->storeme); |
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} |
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static ssize_t childless_storeme_store(struct config_item *item, |
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const char *page, size_t count) |
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{ |
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struct childless *childless = to_childless(item); |
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int ret; |
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ret = kstrtoint(page, 10, &childless->storeme); |
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if (ret) |
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return ret; |
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return count; |
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} |
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static ssize_t childless_description_show(struct config_item *item, char *page) |
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{ |
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return sprintf(page, |
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"[01-childless]\n" |
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"\n" |
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"The childless subsystem is the simplest possible subsystem in\n" |
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"configfs. It does not support the creation of child config_items.\n" |
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"It only has a few attributes. In fact, it isn't much different\n" |
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"than a directory in /proc.\n"); |
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} |
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CONFIGFS_ATTR_RO(childless_, showme); |
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CONFIGFS_ATTR(childless_, storeme); |
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CONFIGFS_ATTR_RO(childless_, description); |
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static struct configfs_attribute *childless_attrs[] = { |
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&childless_attr_showme, |
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&childless_attr_storeme, |
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&childless_attr_description, |
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NULL, |
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}; |
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static const struct config_item_type childless_type = { |
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.ct_attrs = childless_attrs, |
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.ct_owner = THIS_MODULE, |
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}; |
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static struct childless childless_subsys = { |
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.subsys = { |
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.su_group = { |
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.cg_item = { |
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.ci_namebuf = "01-childless", |
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.ci_type = &childless_type, |
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}, |
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}, |
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}, |
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}; |
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/* ----------------------------------------------------------------- */ |
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/* |
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* 02-simple-children |
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* |
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* This example merely has a simple one-attribute child. Note that |
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* there is no extra attribute structure, as the child's attribute is |
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* known from the get-go. Also, there is no container for the |
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* subsystem, as it has no attributes of its own. |
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*/ |
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struct simple_child { |
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struct config_item item; |
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int storeme; |
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}; |
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static inline struct simple_child *to_simple_child(struct config_item *item) |
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{ |
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return container_of(item, struct simple_child, item); |
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} |
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static ssize_t simple_child_storeme_show(struct config_item *item, char *page) |
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{ |
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return sprintf(page, "%d\n", to_simple_child(item)->storeme); |
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} |
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static ssize_t simple_child_storeme_store(struct config_item *item, |
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const char *page, size_t count) |
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{ |
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struct simple_child *simple_child = to_simple_child(item); |
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int ret; |
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ret = kstrtoint(page, 10, &simple_child->storeme); |
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if (ret) |
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return ret; |
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return count; |
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} |
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CONFIGFS_ATTR(simple_child_, storeme); |
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static struct configfs_attribute *simple_child_attrs[] = { |
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&simple_child_attr_storeme, |
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NULL, |
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}; |
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static void simple_child_release(struct config_item *item) |
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{ |
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kfree(to_simple_child(item)); |
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} |
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static struct configfs_item_operations simple_child_item_ops = { |
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.release = simple_child_release, |
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}; |
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static const struct config_item_type simple_child_type = { |
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.ct_item_ops = &simple_child_item_ops, |
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.ct_attrs = simple_child_attrs, |
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.ct_owner = THIS_MODULE, |
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}; |
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struct simple_children { |
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struct config_group group; |
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}; |
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static inline struct simple_children *to_simple_children(struct config_item *item) |
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{ |
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return container_of(to_config_group(item), |
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struct simple_children, group); |
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} |
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static struct config_item *simple_children_make_item(struct config_group *group, |
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const char *name) |
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{ |
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struct simple_child *simple_child; |
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simple_child = kzalloc(sizeof(struct simple_child), GFP_KERNEL); |
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if (!simple_child) |
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return ERR_PTR(-ENOMEM); |
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config_item_init_type_name(&simple_child->item, name, |
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&simple_child_type); |
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return &simple_child->item; |
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} |
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static ssize_t simple_children_description_show(struct config_item *item, |
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char *page) |
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{ |
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return sprintf(page, |
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"[02-simple-children]\n" |
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"\n" |
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"This subsystem allows the creation of child config_items. These\n" |
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"items have only one attribute that is readable and writeable.\n"); |
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} |
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CONFIGFS_ATTR_RO(simple_children_, description); |
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static struct configfs_attribute *simple_children_attrs[] = { |
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&simple_children_attr_description, |
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NULL, |
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}; |
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static void simple_children_release(struct config_item *item) |
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{ |
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kfree(to_simple_children(item)); |
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} |
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static struct configfs_item_operations simple_children_item_ops = { |
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.release = simple_children_release, |
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}; |
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/* |
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* Note that, since no extra work is required on ->drop_item(), |
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* no ->drop_item() is provided. |
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*/ |
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static struct configfs_group_operations simple_children_group_ops = { |
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.make_item = simple_children_make_item, |
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}; |
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static const struct config_item_type simple_children_type = { |
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.ct_item_ops = &simple_children_item_ops, |
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.ct_group_ops = &simple_children_group_ops, |
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.ct_attrs = simple_children_attrs, |
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.ct_owner = THIS_MODULE, |
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}; |
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static struct configfs_subsystem simple_children_subsys = { |
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.su_group = { |
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.cg_item = { |
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.ci_namebuf = "02-simple-children", |
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.ci_type = &simple_children_type, |
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}, |
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}, |
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}; |
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/* ----------------------------------------------------------------- */ |
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/* |
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* 03-group-children |
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* |
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* This example reuses the simple_children group from above. However, |
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* the simple_children group is not the subsystem itself, it is a |
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* child of the subsystem. Creation of a group in the subsystem creates |
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* a new simple_children group. That group can then have simple_child |
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* children of its own. |
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*/ |
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static struct config_group *group_children_make_group( |
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struct config_group *group, const char *name) |
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{ |
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struct simple_children *simple_children; |
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simple_children = kzalloc(sizeof(struct simple_children), |
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GFP_KERNEL); |
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if (!simple_children) |
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return ERR_PTR(-ENOMEM); |
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config_group_init_type_name(&simple_children->group, name, |
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&simple_children_type); |
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return &simple_children->group; |
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} |
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static ssize_t group_children_description_show(struct config_item *item, |
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char *page) |
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{ |
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return sprintf(page, |
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"[03-group-children]\n" |
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"\n" |
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"This subsystem allows the creation of child config_groups. These\n" |
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"groups are like the subsystem simple-children.\n"); |
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} |
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CONFIGFS_ATTR_RO(group_children_, description); |
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static struct configfs_attribute *group_children_attrs[] = { |
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&group_children_attr_description, |
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NULL, |
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}; |
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/* |
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* Note that, since no extra work is required on ->drop_item(), |
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* no ->drop_item() is provided. |
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*/ |
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static struct configfs_group_operations group_children_group_ops = { |
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.make_group = group_children_make_group, |
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}; |
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static const struct config_item_type group_children_type = { |
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.ct_group_ops = &group_children_group_ops, |
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.ct_attrs = group_children_attrs, |
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.ct_owner = THIS_MODULE, |
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}; |
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static struct configfs_subsystem group_children_subsys = { |
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.su_group = { |
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.cg_item = { |
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.ci_namebuf = "03-group-children", |
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.ci_type = &group_children_type, |
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}, |
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}, |
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}; |
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/* ----------------------------------------------------------------- */ |
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/* |
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* We're now done with our subsystem definitions. |
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* For convenience in this module, here's a list of them all. It |
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* allows the init function to easily register them. Most modules |
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* will only have one subsystem, and will only call register_subsystem |
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* on it directly. |
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*/ |
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static struct configfs_subsystem *example_subsys[] = { |
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&childless_subsys.subsys, |
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&simple_children_subsys, |
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&group_children_subsys, |
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NULL, |
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}; |
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static int __init configfs_example_init(void) |
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{ |
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struct configfs_subsystem *subsys; |
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int ret, i; |
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for (i = 0; example_subsys[i]; i++) { |
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subsys = example_subsys[i]; |
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config_group_init(&subsys->su_group); |
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mutex_init(&subsys->su_mutex); |
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ret = configfs_register_subsystem(subsys); |
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if (ret) { |
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pr_err("Error %d while registering subsystem %s\n", |
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ret, subsys->su_group.cg_item.ci_namebuf); |
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goto out_unregister; |
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} |
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} |
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return 0; |
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out_unregister: |
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for (i--; i >= 0; i--) |
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configfs_unregister_subsystem(example_subsys[i]); |
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return ret; |
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} |
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static void __exit configfs_example_exit(void) |
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{ |
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int i; |
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for (i = 0; example_subsys[i]; i++) |
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configfs_unregister_subsystem(example_subsys[i]); |
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} |
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module_init(configfs_example_init); |
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module_exit(configfs_example_exit); |
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MODULE_LICENSE("GPL");
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