| /* |
| * vim: noexpandtab ts=8 sts=0 sw=8: |
| * |
| * configfs_example.c - This file is a demonstration module containing |
| * a number of configfs subsystems. |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public |
| * License as published by the Free Software Foundation; either |
| * version 2 of the License, or (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public |
| * License along with this program; if not, write to the |
| * Free Software Foundation, Inc., 59 Temple Place - Suite 330, |
| * Boston, MA 021110-1307, USA. |
| * |
| * Based on sysfs: |
| * sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel |
| * |
| * configfs Copyright (C) 2005 Oracle. All rights reserved. |
| */ |
| |
| #include <linux/init.h> |
| #include <linux/module.h> |
| #include <linux/slab.h> |
| |
| #include <linux/configfs.h> |
| |
| |
| |
| /* |
| * 01-childless |
| * |
| * This first example is a childless subsystem. It cannot create |
| * any config_items. It just has attributes. |
| * |
| * Note that we are enclosing the configfs_subsystem inside a container. |
| * This is not necessary if a subsystem has no attributes directly |
| * on the subsystem. See the next example, 02-simple-children, for |
| * such a subsystem. |
| */ |
| |
| struct childless { |
| struct configfs_subsystem subsys; |
| int showme; |
| int storeme; |
| }; |
| |
| struct childless_attribute { |
| struct configfs_attribute attr; |
| ssize_t (*show)(struct childless *, char *); |
| ssize_t (*store)(struct childless *, const char *, size_t); |
| }; |
| |
| static inline struct childless *to_childless(struct config_item *item) |
| { |
| return item ? container_of(to_configfs_subsystem(to_config_group(item)), struct childless, subsys) : NULL; |
| } |
| |
| static ssize_t childless_showme_read(struct childless *childless, |
| char *page) |
| { |
| ssize_t pos; |
| |
| pos = sprintf(page, "%d\n", childless->showme); |
| childless->showme++; |
| |
| return pos; |
| } |
| |
| static ssize_t childless_storeme_read(struct childless *childless, |
| char *page) |
| { |
| return sprintf(page, "%d\n", childless->storeme); |
| } |
| |
| static ssize_t childless_storeme_write(struct childless *childless, |
| const char *page, |
| size_t count) |
| { |
| unsigned long tmp; |
| char *p = (char *) page; |
| |
| tmp = simple_strtoul(p, &p, 10); |
| if (!p || (*p && (*p != '\n'))) |
| return -EINVAL; |
| |
| if (tmp > INT_MAX) |
| return -ERANGE; |
| |
| childless->storeme = tmp; |
| |
| return count; |
| } |
| |
| static ssize_t childless_description_read(struct childless *childless, |
| char *page) |
| { |
| return sprintf(page, |
| "[01-childless]\n" |
| "\n" |
| "The childless subsystem is the simplest possible subsystem in\n" |
| "configfs. It does not support the creation of child config_items.\n" |
| "It only has a few attributes. In fact, it isn't much different\n" |
| "than a directory in /proc.\n"); |
| } |
| |
| static struct childless_attribute childless_attr_showme = { |
| .attr = { .ca_owner = THIS_MODULE, .ca_name = "showme", .ca_mode = S_IRUGO }, |
| .show = childless_showme_read, |
| }; |
| static struct childless_attribute childless_attr_storeme = { |
| .attr = { .ca_owner = THIS_MODULE, .ca_name = "storeme", .ca_mode = S_IRUGO | S_IWUSR }, |
| .show = childless_storeme_read, |
| .store = childless_storeme_write, |
| }; |
| static struct childless_attribute childless_attr_description = { |
| .attr = { .ca_owner = THIS_MODULE, .ca_name = "description", .ca_mode = S_IRUGO }, |
| .show = childless_description_read, |
| }; |
| |
| static struct configfs_attribute *childless_attrs[] = { |
| &childless_attr_showme.attr, |
| &childless_attr_storeme.attr, |
| &childless_attr_description.attr, |
| NULL, |
| }; |
| |
| static ssize_t childless_attr_show(struct config_item *item, |
| struct configfs_attribute *attr, |
| char *page) |
| { |
| struct childless *childless = to_childless(item); |
| struct childless_attribute *childless_attr = |
| container_of(attr, struct childless_attribute, attr); |
| ssize_t ret = 0; |
| |
| if (childless_attr->show) |
| ret = childless_attr->show(childless, page); |
| return ret; |
| } |
| |
| static ssize_t childless_attr_store(struct config_item *item, |
| struct configfs_attribute *attr, |
| const char *page, size_t count) |
| { |
| struct childless *childless = to_childless(item); |
| struct childless_attribute *childless_attr = |
| container_of(attr, struct childless_attribute, attr); |
| ssize_t ret = -EINVAL; |
| |
| if (childless_attr->store) |
| ret = childless_attr->store(childless, page, count); |
| return ret; |
| } |
| |
| static struct configfs_item_operations childless_item_ops = { |
| .show_attribute = childless_attr_show, |
| .store_attribute = childless_attr_store, |
| }; |
| |
| static struct config_item_type childless_type = { |
| .ct_item_ops = &childless_item_ops, |
| .ct_attrs = childless_attrs, |
| .ct_owner = THIS_MODULE, |
| }; |
| |
| static struct childless childless_subsys = { |
| .subsys = { |
| .su_group = { |
| .cg_item = { |
| .ci_namebuf = "01-childless", |
| .ci_type = &childless_type, |
| }, |
| }, |
| }, |
| }; |
| |
| |
| /* ----------------------------------------------------------------- */ |
| |
| /* |
| * 02-simple-children |
| * |
| * This example merely has a simple one-attribute child. Note that |
| * there is no extra attribute structure, as the child's attribute is |
| * known from the get-go. Also, there is no container for the |
| * subsystem, as it has no attributes of its own. |
| */ |
| |
| struct simple_child { |
| struct config_item item; |
| int storeme; |
| }; |
| |
| static inline struct simple_child *to_simple_child(struct config_item *item) |
| { |
| return item ? container_of(item, struct simple_child, item) : NULL; |
| } |
| |
| static struct configfs_attribute simple_child_attr_storeme = { |
| .ca_owner = THIS_MODULE, |
| .ca_name = "storeme", |
| .ca_mode = S_IRUGO | S_IWUSR, |
| }; |
| |
| static struct configfs_attribute *simple_child_attrs[] = { |
| &simple_child_attr_storeme, |
| NULL, |
| }; |
| |
| static ssize_t simple_child_attr_show(struct config_item *item, |
| struct configfs_attribute *attr, |
| char *page) |
| { |
| ssize_t count; |
| struct simple_child *simple_child = to_simple_child(item); |
| |
| count = sprintf(page, "%d\n", simple_child->storeme); |
| |
| return count; |
| } |
| |
| static ssize_t simple_child_attr_store(struct config_item *item, |
| struct configfs_attribute *attr, |
| const char *page, size_t count) |
| { |
| struct simple_child *simple_child = to_simple_child(item); |
| unsigned long tmp; |
| char *p = (char *) page; |
| |
| tmp = simple_strtoul(p, &p, 10); |
| if (!p || (*p && (*p != '\n'))) |
| return -EINVAL; |
| |
| if (tmp > INT_MAX) |
| return -ERANGE; |
| |
| simple_child->storeme = tmp; |
| |
| return count; |
| } |
| |
| static void simple_child_release(struct config_item *item) |
| { |
| kfree(to_simple_child(item)); |
| } |
| |
| static struct configfs_item_operations simple_child_item_ops = { |
| .release = simple_child_release, |
| .show_attribute = simple_child_attr_show, |
| .store_attribute = simple_child_attr_store, |
| }; |
| |
| static struct config_item_type simple_child_type = { |
| .ct_item_ops = &simple_child_item_ops, |
| .ct_attrs = simple_child_attrs, |
| .ct_owner = THIS_MODULE, |
| }; |
| |
| |
| static struct config_item *simple_children_make_item(struct config_group *group, const char *name) |
| { |
| struct simple_child *simple_child; |
| |
| simple_child = kmalloc(sizeof(struct simple_child), GFP_KERNEL); |
| if (!simple_child) |
| return NULL; |
| |
| memset(simple_child, 0, sizeof(struct simple_child)); |
| |
| config_item_init_type_name(&simple_child->item, name, |
| &simple_child_type); |
| |
| simple_child->storeme = 0; |
| |
| return &simple_child->item; |
| } |
| |
| static struct configfs_attribute simple_children_attr_description = { |
| .ca_owner = THIS_MODULE, |
| .ca_name = "description", |
| .ca_mode = S_IRUGO, |
| }; |
| |
| static struct configfs_attribute *simple_children_attrs[] = { |
| &simple_children_attr_description, |
| NULL, |
| }; |
| |
| static ssize_t simple_children_attr_show(struct config_item *item, |
| struct configfs_attribute *attr, |
| char *page) |
| { |
| return sprintf(page, |
| "[02-simple-children]\n" |
| "\n" |
| "This subsystem allows the creation of child config_items. These\n" |
| "items have only one attribute that is readable and writeable.\n"); |
| } |
| |
| static struct configfs_item_operations simple_children_item_ops = { |
| .show_attribute = simple_children_attr_show, |
| }; |
| |
| /* |
| * Note that, since no extra work is required on ->drop_item(), |
| * no ->drop_item() is provided. |
| */ |
| static struct configfs_group_operations simple_children_group_ops = { |
| .make_item = simple_children_make_item, |
| }; |
| |
| static struct config_item_type simple_children_type = { |
| .ct_item_ops = &simple_children_item_ops, |
| .ct_group_ops = &simple_children_group_ops, |
| .ct_attrs = simple_children_attrs, |
| }; |
| |
| static struct configfs_subsystem simple_children_subsys = { |
| .su_group = { |
| .cg_item = { |
| .ci_namebuf = "02-simple-children", |
| .ci_type = &simple_children_type, |
| }, |
| }, |
| }; |
| |
| |
| /* ----------------------------------------------------------------- */ |
| |
| /* |
| * 03-group-children |
| * |
| * This example reuses the simple_children group from above. However, |
| * the simple_children group is not the subsystem itself, it is a |
| * child of the subsystem. Creation of a group in the subsystem creates |
| * a new simple_children group. That group can then have simple_child |
| * children of its own. |
| */ |
| |
| struct simple_children { |
| struct config_group group; |
| }; |
| |
| static struct config_group *group_children_make_group(struct config_group *group, const char *name) |
| { |
| struct simple_children *simple_children; |
| |
| simple_children = kmalloc(sizeof(struct simple_children), |
| GFP_KERNEL); |
| if (!simple_children) |
| return NULL; |
| |
| memset(simple_children, 0, sizeof(struct simple_children)); |
| |
| config_group_init_type_name(&simple_children->group, name, |
| &simple_children_type); |
| |
| return &simple_children->group; |
| } |
| |
| static struct configfs_attribute group_children_attr_description = { |
| .ca_owner = THIS_MODULE, |
| .ca_name = "description", |
| .ca_mode = S_IRUGO, |
| }; |
| |
| static struct configfs_attribute *group_children_attrs[] = { |
| &group_children_attr_description, |
| NULL, |
| }; |
| |
| static ssize_t group_children_attr_show(struct config_item *item, |
| struct configfs_attribute *attr, |
| char *page) |
| { |
| return sprintf(page, |
| "[03-group-children]\n" |
| "\n" |
| "This subsystem allows the creation of child config_groups. These\n" |
| "groups are like the subsystem simple-children.\n"); |
| } |
| |
| static struct configfs_item_operations group_children_item_ops = { |
| .show_attribute = group_children_attr_show, |
| }; |
| |
| /* |
| * Note that, since no extra work is required on ->drop_item(), |
| * no ->drop_item() is provided. |
| */ |
| static struct configfs_group_operations group_children_group_ops = { |
| .make_group = group_children_make_group, |
| }; |
| |
| static struct config_item_type group_children_type = { |
| .ct_item_ops = &group_children_item_ops, |
| .ct_group_ops = &group_children_group_ops, |
| .ct_attrs = group_children_attrs, |
| }; |
| |
| static struct configfs_subsystem group_children_subsys = { |
| .su_group = { |
| .cg_item = { |
| .ci_namebuf = "03-group-children", |
| .ci_type = &group_children_type, |
| }, |
| }, |
| }; |
| |
| /* ----------------------------------------------------------------- */ |
| |
| /* |
| * We're now done with our subsystem definitions. |
| * For convenience in this module, here's a list of them all. It |
| * allows the init function to easily register them. Most modules |
| * will only have one subsystem, and will only call register_subsystem |
| * on it directly. |
| */ |
| static struct configfs_subsystem *example_subsys[] = { |
| &childless_subsys.subsys, |
| &simple_children_subsys, |
| &group_children_subsys, |
| NULL, |
| }; |
| |
| static int __init configfs_example_init(void) |
| { |
| int ret; |
| int i; |
| struct configfs_subsystem *subsys; |
| |
| for (i = 0; example_subsys[i]; i++) { |
| subsys = example_subsys[i]; |
| |
| config_group_init(&subsys->su_group); |
| init_MUTEX(&subsys->su_sem); |
| ret = configfs_register_subsystem(subsys); |
| if (ret) { |
| printk(KERN_ERR "Error %d while registering subsystem %s\n", |
| ret, |
| subsys->su_group.cg_item.ci_namebuf); |
| goto out_unregister; |
| } |
| } |
| |
| return 0; |
| |
| out_unregister: |
| for (; i >= 0; i--) { |
| configfs_unregister_subsystem(example_subsys[i]); |
| } |
| |
| return ret; |
| } |
| |
| static void __exit configfs_example_exit(void) |
| { |
| int i; |
| |
| for (i = 0; example_subsys[i]; i++) { |
| configfs_unregister_subsystem(example_subsys[i]); |
| } |
| } |
| |
| module_init(configfs_example_init); |
| module_exit(configfs_example_exit); |
| MODULE_LICENSE("GPL"); |