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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 | 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 | 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 | */ | |
65 | ||
66 | int config_item_set_name(struct config_item * item, const char * fmt, ...) | |
67 | { | |
68 | int error = 0; | |
69 | int limit = CONFIGFS_ITEM_NAME_LEN; | |
70 | int need; | |
71 | va_list args; | |
72 | char * name; | |
73 | ||
74 | /* | |
75 | * First, try the static array | |
76 | */ | |
77 | va_start(args,fmt); | |
78 | need = vsnprintf(item->ci_namebuf,limit,fmt,args); | |
79 | va_end(args); | |
80 | if (need < limit) | |
81 | name = item->ci_namebuf; | |
82 | else { | |
83 | /* | |
84 | * Need more space? Allocate it and try again | |
85 | */ | |
86 | limit = need + 1; | |
87 | name = kmalloc(limit,GFP_KERNEL); | |
88 | if (!name) { | |
89 | error = -ENOMEM; | |
90 | goto Done; | |
91 | } | |
92 | va_start(args,fmt); | |
93 | need = vsnprintf(name,limit,fmt,args); | |
94 | va_end(args); | |
95 | ||
96 | /* Still? Give up. */ | |
97 | if (need >= limit) { | |
98 | kfree(name); | |
99 | error = -EFAULT; | |
100 | goto Done; | |
101 | } | |
102 | } | |
103 | ||
104 | /* Free the old name, if necessary. */ | |
105 | if (item->ci_name && item->ci_name != item->ci_namebuf) | |
106 | kfree(item->ci_name); | |
107 | ||
108 | /* Now, set the new name */ | |
109 | item->ci_name = name; | |
110 | Done: | |
111 | return error; | |
112 | } | |
113 | ||
114 | EXPORT_SYMBOL(config_item_set_name); | |
115 | ||
116 | void config_item_init_type_name(struct config_item *item, | |
117 | const char *name, | |
118 | struct config_item_type *type) | |
119 | { | |
120 | config_item_set_name(item, name); | |
121 | item->ci_type = type; | |
122 | config_item_init(item); | |
123 | } | |
124 | EXPORT_SYMBOL(config_item_init_type_name); | |
125 | ||
126 | void config_group_init_type_name(struct config_group *group, const char *name, | |
127 | struct config_item_type *type) | |
128 | { | |
129 | config_item_set_name(&group->cg_item, name); | |
130 | group->cg_item.ci_type = type; | |
131 | config_group_init(group); | |
132 | } | |
133 | EXPORT_SYMBOL(config_group_init_type_name); | |
134 | ||
135 | struct config_item * config_item_get(struct config_item * item) | |
136 | { | |
137 | if (item) | |
138 | kref_get(&item->ci_kref); | |
139 | return item; | |
140 | } | |
141 | ||
142 | /** | |
143 | * config_item_cleanup - free config_item resources. | |
144 | * @item: item. | |
145 | */ | |
146 | ||
147 | void config_item_cleanup(struct config_item * item) | |
148 | { | |
149 | struct config_item_type * t = item->ci_type; | |
150 | struct config_group * s = item->ci_group; | |
151 | struct config_item * parent = item->ci_parent; | |
152 | ||
153 | pr_debug("config_item %s: cleaning up\n",config_item_name(item)); | |
154 | if (item->ci_name != item->ci_namebuf) | |
155 | kfree(item->ci_name); | |
156 | item->ci_name = NULL; | |
157 | if (t && t->ct_item_ops && t->ct_item_ops->release) | |
158 | t->ct_item_ops->release(item); | |
159 | if (s) | |
160 | config_group_put(s); | |
161 | if (parent) | |
162 | config_item_put(parent); | |
163 | } | |
164 | ||
165 | static void config_item_release(struct kref *kref) | |
166 | { | |
167 | config_item_cleanup(container_of(kref, struct config_item, ci_kref)); | |
168 | } | |
169 | ||
170 | /** | |
171 | * config_item_put - decrement refcount for item. | |
172 | * @item: item. | |
173 | * | |
174 | * Decrement the refcount, and if 0, call config_item_cleanup(). | |
175 | */ | |
176 | void config_item_put(struct config_item * item) | |
177 | { | |
178 | if (item) | |
179 | kref_put(&item->ci_kref, config_item_release); | |
180 | } | |
181 | ||
182 | ||
183 | /** | |
184 | * config_group_init - initialize a group for use | |
185 | * @k: group | |
186 | */ | |
187 | ||
188 | void config_group_init(struct config_group *group) | |
189 | { | |
190 | config_item_init(&group->cg_item); | |
191 | INIT_LIST_HEAD(&group->cg_children); | |
192 | } | |
193 | ||
194 | ||
195 | /** | |
196 | * config_group_find_obj - search for item in group. | |
197 | * @group: group we're looking in. | |
198 | * @name: item's name. | |
199 | * | |
200 | * Lock group via @group->cg_subsys, and iterate over @group->cg_list, | |
201 | * looking for a matching config_item. If matching item is found | |
202 | * take a reference and return the item. | |
203 | */ | |
204 | ||
205 | struct config_item * config_group_find_obj(struct config_group * group, const char * name) | |
206 | { | |
207 | struct list_head * entry; | |
208 | struct config_item * ret = NULL; | |
209 | ||
210 | /* XXX LOCKING! */ | |
211 | list_for_each(entry,&group->cg_children) { | |
212 | struct config_item * item = to_item(entry); | |
213 | if (config_item_name(item) && | |
214 | !strcmp(config_item_name(item), name)) { | |
215 | ret = config_item_get(item); | |
216 | break; | |
217 | } | |
218 | } | |
219 | return ret; | |
220 | } | |
221 | ||
222 | ||
223 | EXPORT_SYMBOL(config_item_init); | |
224 | EXPORT_SYMBOL(config_group_init); | |
225 | EXPORT_SYMBOL(config_item_get); | |
226 | EXPORT_SYMBOL(config_item_put); | |
227 |