blob: 76dc4c3e5d5180079aa7d35d2c368f77fcabdfd5 [file] [log] [blame]
Joel Becker7063fbf2005-12-15 14:29:43 -08001/* -*- mode: c; c-basic-offset: 8; -*-
2 * vim: noexpandtab sw=8 ts=8 sts=0:
3 *
4 * item.c - library routines for handling generic config items
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 kobject:
22 * kobject is Copyright (c) 2002-2003 Patrick Mochel
23 *
24 * configfs Copyright (C) 2005 Oracle. All rights reserved.
25 *
26 * Please see the file Documentation/filesystems/configfs.txt for
27 * critical information about using the config_item interface.
28 */
29
30#include <linux/string.h>
31#include <linux/module.h>
32#include <linux/stat.h>
33#include <linux/slab.h>
34
35#include <linux/configfs.h>
36
37
38static inline struct config_item * to_item(struct list_head * entry)
39{
40 return container_of(entry,struct config_item,ci_entry);
41}
42
43/* Evil kernel */
44static void config_item_release(struct kref *kref);
45
46/**
47 * config_item_init - initialize item.
48 * @item: item in question.
49 */
50void config_item_init(struct config_item * item)
51{
52 kref_init(&item->ci_kref);
53 INIT_LIST_HEAD(&item->ci_entry);
54}
55
56/**
57 * config_item_set_name - Set the name of an item
58 * @item: item.
59 * @name: name.
60 *
61 * If strlen(name) >= CONFIGFS_ITEM_NAME_LEN, then use a
62 * dynamically allocated string that @item->ci_name points to.
63 * Otherwise, use the static @item->ci_namebuf array.
64 */
Joel Becker7063fbf2005-12-15 14:29:43 -080065int config_item_set_name(struct config_item * item, const char * fmt, ...)
66{
67 int error = 0;
68 int limit = CONFIGFS_ITEM_NAME_LEN;
69 int need;
70 va_list args;
71 char * name;
72
73 /*
74 * First, try the static array
75 */
76 va_start(args,fmt);
77 need = vsnprintf(item->ci_namebuf,limit,fmt,args);
78 va_end(args);
79 if (need < limit)
80 name = item->ci_namebuf;
81 else {
82 /*
83 * Need more space? Allocate it and try again
84 */
85 limit = need + 1;
86 name = kmalloc(limit,GFP_KERNEL);
87 if (!name) {
88 error = -ENOMEM;
89 goto Done;
90 }
91 va_start(args,fmt);
92 need = vsnprintf(name,limit,fmt,args);
93 va_end(args);
94
95 /* Still? Give up. */
96 if (need >= limit) {
97 kfree(name);
98 error = -EFAULT;
99 goto Done;
100 }
101 }
102
103 /* Free the old name, if necessary. */
104 if (item->ci_name && item->ci_name != item->ci_namebuf)
105 kfree(item->ci_name);
106
107 /* Now, set the new name */
108 item->ci_name = name;
109 Done:
110 return error;
111}
112
113EXPORT_SYMBOL(config_item_set_name);
114
115void config_item_init_type_name(struct config_item *item,
116 const char *name,
117 struct config_item_type *type)
118{
119 config_item_set_name(item, name);
120 item->ci_type = type;
121 config_item_init(item);
122}
123EXPORT_SYMBOL(config_item_init_type_name);
124
125void config_group_init_type_name(struct config_group *group, const char *name,
126 struct config_item_type *type)
127{
128 config_item_set_name(&group->cg_item, name);
129 group->cg_item.ci_type = type;
130 config_group_init(group);
131}
132EXPORT_SYMBOL(config_group_init_type_name);
133
134struct config_item * config_item_get(struct config_item * item)
135{
136 if (item)
137 kref_get(&item->ci_kref);
138 return item;
139}
140
Satyam Sharma4c62b532007-06-27 16:02:14 +0530141static void config_item_cleanup(struct config_item * item)
Joel Becker7063fbf2005-12-15 14:29:43 -0800142{
143 struct config_item_type * t = item->ci_type;
144 struct config_group * s = item->ci_group;
145 struct config_item * parent = item->ci_parent;
146
147 pr_debug("config_item %s: cleaning up\n",config_item_name(item));
148 if (item->ci_name != item->ci_namebuf)
149 kfree(item->ci_name);
150 item->ci_name = NULL;
151 if (t && t->ct_item_ops && t->ct_item_ops->release)
152 t->ct_item_ops->release(item);
153 if (s)
154 config_group_put(s);
155 if (parent)
156 config_item_put(parent);
157}
158
159static void config_item_release(struct kref *kref)
160{
161 config_item_cleanup(container_of(kref, struct config_item, ci_kref));
162}
163
164/**
165 * config_item_put - decrement refcount for item.
166 * @item: item.
167 *
168 * Decrement the refcount, and if 0, call config_item_cleanup().
169 */
170void config_item_put(struct config_item * item)
171{
172 if (item)
173 kref_put(&item->ci_kref, config_item_release);
174}
175
Joel Becker7063fbf2005-12-15 14:29:43 -0800176/**
177 * config_group_init - initialize a group for use
178 * @k: group
179 */
Joel Becker7063fbf2005-12-15 14:29:43 -0800180void config_group_init(struct config_group *group)
181{
182 config_item_init(&group->cg_item);
183 INIT_LIST_HEAD(&group->cg_children);
184}
185
Joel Becker7063fbf2005-12-15 14:29:43 -0800186/**
Satyam Sharma3fe6c5c2007-07-04 16:37:16 +0530187 * config_group_find_item - search for item in group.
Joel Becker7063fbf2005-12-15 14:29:43 -0800188 * @group: group we're looking in.
189 * @name: item's name.
190 *
Satyam Sharma3fe6c5c2007-07-04 16:37:16 +0530191 * Iterate over @group->cg_list, looking for a matching config_item.
192 * If matching item is found take a reference and return the item.
193 * Caller must have locked group via @group->cg_subsys->su_mtx.
Joel Becker7063fbf2005-12-15 14:29:43 -0800194 */
Satyam Sharma3fe6c5c2007-07-04 16:37:16 +0530195struct config_item *config_group_find_item(struct config_group *group,
196 const char *name)
Joel Becker7063fbf2005-12-15 14:29:43 -0800197{
198 struct list_head * entry;
199 struct config_item * ret = NULL;
200
Joel Becker7063fbf2005-12-15 14:29:43 -0800201 list_for_each(entry,&group->cg_children) {
202 struct config_item * item = to_item(entry);
203 if (config_item_name(item) &&
Satyam Sharma3fe6c5c2007-07-04 16:37:16 +0530204 !strcmp(config_item_name(item), name)) {
Joel Becker7063fbf2005-12-15 14:29:43 -0800205 ret = config_item_get(item);
206 break;
207 }
208 }
209 return ret;
210}
211
Joel Becker7063fbf2005-12-15 14:29:43 -0800212EXPORT_SYMBOL(config_item_init);
213EXPORT_SYMBOL(config_group_init);
214EXPORT_SYMBOL(config_item_get);
215EXPORT_SYMBOL(config_item_put);
Satyam Sharma3fe6c5c2007-07-04 16:37:16 +0530216EXPORT_SYMBOL(config_group_find_item);