1/* -*- mode: c; c-basic-offset: 8; -*-
2 * vim: noexpandtab sw=8 ts=8 sts=0:
3 *
4 * configfs.h - definitions for the device driver filesystem
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public
8 * License as published by the Free Software Foundation; either
9 * version 2 of the License, or (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14 * General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public
17 * License along with this program; if not, write to the
18 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
19 * Boston, MA 021110-1307, USA.
20 *
21 * Based on sysfs:
22 * 	sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel
23 *
24 * Based on kobject.h:
25 *      Copyright (c) 2002-2003	Patrick Mochel
26 *      Copyright (c) 2002-2003	Open Source Development Labs
27 *
28 * configfs Copyright (C) 2005 Oracle.  All rights reserved.
29 *
30 * Please read Documentation/filesystems/configfs.txt before using the
31 * configfs interface, ESPECIALLY the parts about reference counts and
32 * item destructors.
33 */
34
35#ifndef _CONFIGFS_H_
36#define _CONFIGFS_H_
37
38#ifdef __KERNEL__
39
40#include <linux/types.h>
41#include <linux/list.h>
42#include <linux/kref.h>
43
44#include <asm/atomic.h>
45#include <asm/semaphore.h>
46
47#define CONFIGFS_ITEM_NAME_LEN	20
48
49struct module;
50
51struct configfs_item_operations;
52struct configfs_group_operations;
53struct configfs_attribute;
54struct configfs_subsystem;
55
56struct config_item {
57	char			*ci_name;
58	char			ci_namebuf[CONFIGFS_ITEM_NAME_LEN];
59	struct kref		ci_kref;
60	struct list_head	ci_entry;
61	struct config_item	*ci_parent;
62	struct config_group	*ci_group;
63	struct config_item_type	*ci_type;
64	struct dentry		*ci_dentry;
65};
66
67extern int config_item_set_name(struct config_item *, const char *, ...);
68
69static inline char *config_item_name(struct config_item * item)
70{
71	return item->ci_name;
72}
73
74extern void config_item_init(struct config_item *);
75extern void config_item_init_type_name(struct config_item *item,
76				       const char *name,
77				       struct config_item_type *type);
78extern void config_item_cleanup(struct config_item *);
79
80extern struct config_item * config_item_get(struct config_item *);
81extern void config_item_put(struct config_item *);
82
83struct config_item_type {
84	struct module				*ct_owner;
85	struct configfs_item_operations		*ct_item_ops;
86	struct configfs_group_operations	*ct_group_ops;
87	struct configfs_attribute		**ct_attrs;
88};
89
90
91/**
92 *	group - a group of config_items of a specific type, belonging
93 *	to a specific subsystem.
94 */
95
96struct config_group {
97	struct config_item		cg_item;
98	struct list_head		cg_children;
99	struct configfs_subsystem 	*cg_subsys;
100	struct config_group		**default_groups;
101};
102
103
104extern void config_group_init(struct config_group *group);
105extern void config_group_init_type_name(struct config_group *group,
106					const char *name,
107					struct config_item_type *type);
108
109
110static inline struct config_group *to_config_group(struct config_item *item)
111{
112	return item ? container_of(item,struct config_group,cg_item) : NULL;
113}
114
115static inline struct config_group *config_group_get(struct config_group *group)
116{
117	return group ? to_config_group(config_item_get(&group->cg_item)) : NULL;
118}
119
120static inline void config_group_put(struct config_group *group)
121{
122	config_item_put(&group->cg_item);
123}
124
125extern struct config_item *config_group_find_obj(struct config_group *, const char *);
126
127
128struct configfs_attribute {
129	const char		*ca_name;
130	struct module 		*ca_owner;
131	mode_t			ca_mode;
132};
133
134
135/*
136 * If allow_link() exists, the item can symlink(2) out to other
137 * items.  If the item is a group, it may support mkdir(2).
138 * Groups supply one of make_group() and make_item().  If the
139 * group supports make_group(), one can create group children.  If it
140 * supports make_item(), one can create config_item children.  If it has
141 * default_groups on group->default_groups, it has automatically created
142 * group children.  default_groups may coexist alongsize make_group() or
143 * make_item(), but if the group wishes to have only default_groups
144 * children (disallowing mkdir(2)), it need not provide either function.
145 * If the group has commit(), it supports pending and commited (active)
146 * items.
147 */
148struct configfs_item_operations {
149	void (*release)(struct config_item *);
150	ssize_t	(*show_attribute)(struct config_item *, struct configfs_attribute *,char *);
151	ssize_t	(*store_attribute)(struct config_item *,struct configfs_attribute *,const char *, size_t);
152	int (*allow_link)(struct config_item *src, struct config_item *target);
153	int (*drop_link)(struct config_item *src, struct config_item *target);
154};
155
156struct configfs_group_operations {
157	struct config_item *(*make_item)(struct config_group *group, const char *name);
158	struct config_group *(*make_group)(struct config_group *group, const char *name);
159	int (*commit_item)(struct config_item *item);
160	void (*drop_item)(struct config_group *group, struct config_item *item);
161};
162
163struct configfs_subsystem {
164	struct config_group	su_group;
165	struct semaphore	su_sem;
166};
167
168static inline struct configfs_subsystem *to_configfs_subsystem(struct config_group *group)
169{
170	return group ?
171		container_of(group, struct configfs_subsystem, su_group) :
172		NULL;
173}
174
175int configfs_register_subsystem(struct configfs_subsystem *subsys);
176void configfs_unregister_subsystem(struct configfs_subsystem *subsys);
177
178#endif  /* __KERNEL__ */
179
180#endif /* _CONFIGFS_H_ */
181