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1 : /* -*- 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 :
38 : static inline struct config_item * to_item(struct list_head * entry)
39 : {
40 0 : return container_of(entry,struct config_item,ci_entry);
41 : }
42 :
43 : /* Evil kernel */
44 : static void config_item_release(struct kref *kref);
45 :
46 : /**
47 : * config_item_init - initialize item.
48 : * @item: item in question.
49 : */
50 : void config_item_init(struct config_item * item)
51 : {
52 0 : kref_init(&item->ci_kref);
53 0 : INIT_LIST_HEAD(&item->ci_entry);
54 0 : }
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 : */
65 : int config_item_set_name(struct config_item * item, const char * fmt, ...)
66 : {
67 0 : int error = 0;
68 0 : int limit = CONFIGFS_ITEM_NAME_LEN;
69 0 : int need;
70 0 : va_list args;
71 0 : char * name;
72 0 :
73 : /*
74 : * First, try the static array
75 : */
76 0 : va_start(args,fmt);
77 0 : need = vsnprintf(item->ci_namebuf,limit,fmt,args);
78 0 : va_end(args);
79 0 : if (need < limit)
80 0 : name = item->ci_namebuf;
81 : else {
82 : /*
83 : * Need more space? Allocate it and try again
84 : */
85 0 : limit = need + 1;
86 0 : name = kmalloc(limit,GFP_KERNEL);
87 0 : if (!name) {
88 0 : error = -ENOMEM;
89 0 : goto Done;
90 : }
91 0 : va_start(args,fmt);
92 0 : need = vsnprintf(name,limit,fmt,args);
93 0 : va_end(args);
94 :
95 : /* Still? Give up. */
96 0 : if (need >= limit) {
97 0 : kfree(name);
98 0 : error = -EFAULT;
99 0 : goto Done;
100 : }
101 : }
102 :
103 : /* Free the old name, if necessary. */
104 0 : if (item->ci_name && item->ci_name != item->ci_namebuf)
105 0 : kfree(item->ci_name);
106 :
107 : /* Now, set the new name */
108 0 : item->ci_name = name;
109 0 : Done:
110 0 : return error;
111 : }
112 :
113 : EXPORT_SYMBOL(config_item_set_name);
114 :
115 : void config_item_init_type_name(struct config_item *item,
116 : const char *name,
117 : struct config_item_type *type)
118 : {
119 0 : config_item_set_name(item, name);
120 0 : item->ci_type = type;
121 0 : config_item_init(item);
122 0 : }
123 : EXPORT_SYMBOL(config_item_init_type_name);
124 :
125 : void config_group_init_type_name(struct config_group *group, const char *name,
126 : struct config_item_type *type)
127 : {
128 0 : config_item_set_name(&group->cg_item, name);
129 0 : group->cg_item.ci_type = type;
130 0 : config_group_init(group);
131 0 : }
132 : EXPORT_SYMBOL(config_group_init_type_name);
133 :
134 : struct config_item * config_item_get(struct config_item * item)
135 : {
136 46 : if (item)
137 23 : kref_get(&item->ci_kref);
138 23 : return item;
139 : }
140 :
141 : static void config_item_cleanup(struct config_item * item)
142 : {
143 0 : struct config_item_type * t = item->ci_type;
144 0 : struct config_group * s = item->ci_group;
145 0 : struct config_item * parent = item->ci_parent;
146 :
147 : pr_debug("config_item %s: cleaning up\n",config_item_name(item));
148 0 : if (item->ci_name != item->ci_namebuf)
149 0 : kfree(item->ci_name);
150 0 : item->ci_name = NULL;
151 0 : if (t && t->ct_item_ops && t->ct_item_ops->release)
152 0 : t->ct_item_ops->release(item);
153 0 : if (s)
154 0 : config_group_put(s);
155 0 : if (parent)
156 0 : config_item_put(parent);
157 0 : }
158 :
159 : static void config_item_release(struct kref *kref)
160 : {
161 0 : config_item_cleanup(container_of(kref, struct config_item, ci_kref));
162 : }
163 0 :
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 : */
170 : void config_item_put(struct config_item * item)
171 : {
172 98 : if (item)
173 49 : kref_put(&item->ci_kref, config_item_release);
174 49 : }
175 :
176 : /**
177 : * config_group_init - initialize a group for use
178 : * @k: group
179 : */
180 : void config_group_init(struct config_group *group)
181 : {
182 0 : config_item_init(&group->cg_item);
183 0 : INIT_LIST_HEAD(&group->cg_children);
184 0 : }
185 :
186 : /**
187 : * config_group_find_item - search for item in group.
188 : * @group: group we're looking in.
189 : * @name: item's name.
190 : *
191 : * 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.
194 : */
195 : struct config_item *config_group_find_item(struct config_group *group,
196 : const char *name)
197 0 : {
198 0 : struct list_head * entry;
199 0 : struct config_item * ret = NULL;
200 0 :
201 0 : list_for_each(entry,&group->cg_children) {
202 0 : struct config_item * item = to_item(entry);
203 0 : if (config_item_name(item) &&
204 : !strcmp(config_item_name(item), name)) {
205 0 : ret = config_item_get(item);
206 0 : break;
207 0 : }
208 : }
209 0 : return ret;
210 : }
211 :
212 : EXPORT_SYMBOL(config_item_init);
213 : EXPORT_SYMBOL(config_group_init);
214 : EXPORT_SYMBOL(config_item_get);
215 : EXPORT_SYMBOL(config_item_put);
216 : EXPORT_SYMBOL(config_group_find_item);
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