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1/*
2 * fs/sysfs/group.c - Operations for adding/removing multiple files at once.
3 *
4 * Copyright (c) 2003 Patrick Mochel
5 * Copyright (c) 2003 Open Source Development Lab
6 *
7 * This file is released undert the GPL v2.
8 *
9 */
10
11#include <linux/kobject.h>
12#include <linux/module.h>
13#include <linux/dcache.h>
14#include <linux/namei.h>
15#include <linux/err.h>
16#include "sysfs.h"
17
18
19static void remove_files(struct sysfs_dirent *dir_sd, struct kobject *kobj,
20 const struct attribute_group *grp)
21{
22 struct attribute *const* attr;
23 int i;
24
25 for (i = 0, attr = grp->attrs; *attr; i++, attr++)
26 sysfs_hash_and_remove(dir_sd, NULL, (*attr)->name);
27}
28
29static int create_files(struct sysfs_dirent *dir_sd, struct kobject *kobj,
30 const struct attribute_group *grp, int update)
31{
32 struct attribute *const* attr;
33 int error = 0, i;
34
35 for (i = 0, attr = grp->attrs; *attr && !error; i++, attr++) {
36 mode_t mode = 0;
37
38 /* in update mode, we're changing the permissions or
39 * visibility. Do this by first removing then
40 * re-adding (if required) the file */
41 if (update)
42 sysfs_hash_and_remove(dir_sd, NULL, (*attr)->name);
43 if (grp->is_visible) {
44 mode = grp->is_visible(kobj, *attr, i);
45 if (!mode)
46 continue;
47 }
48 error = sysfs_add_file_mode(dir_sd, *attr, SYSFS_KOBJ_ATTR,
49 (*attr)->mode | mode);
50 if (unlikely(error))
51 break;
52 }
53 if (error)
54 remove_files(dir_sd, kobj, grp);
55 return error;
56}
57
58
59static int internal_create_group(struct kobject *kobj, int update,
60 const struct attribute_group *grp)
61{
62 struct sysfs_dirent *sd;
63 int error;
64
65 BUG_ON(!kobj || (!update && !kobj->sd));
66
67 /* Updates may happen before the object has been instantiated */
68 if (unlikely(update && !kobj->sd))
69 return -EINVAL;
70
71 if (grp->name) {
72 error = sysfs_create_subdir(kobj, grp->name, &sd);
73 if (error)
74 return error;
75 } else
76 sd = kobj->sd;
77 sysfs_get(sd);
78 error = create_files(sd, kobj, grp, update);
79 if (error) {
80 if (grp->name)
81 sysfs_remove_subdir(sd);
82 }
83 sysfs_put(sd);
84 return error;
85}
86
87/**
88 * sysfs_create_group - given a directory kobject, create an attribute group
89 * @kobj: The kobject to create the group on
90 * @grp: The attribute group to create
91 *
92 * This function creates a group for the first time. It will explicitly
93 * warn and error if any of the attribute files being created already exist.
94 *
95 * Returns 0 on success or error.
96 */
97int sysfs_create_group(struct kobject *kobj,
98 const struct attribute_group *grp)
99{
100 return internal_create_group(kobj, 0, grp);
101}
102
103/**
104 * sysfs_update_group - given a directory kobject, update an attribute group
105 * @kobj: The kobject to update the group on
106 * @grp: The attribute group to update
107 *
108 * This function updates an attribute group. Unlike
109 * sysfs_create_group(), it will explicitly not warn or error if any
110 * of the attribute files being created already exist. Furthermore,
111 * if the visibility of the files has changed through the is_visible()
112 * callback, it will update the permissions and add or remove the
113 * relevant files.
114 *
115 * The primary use for this function is to call it after making a change
116 * that affects group visibility.
117 *
118 * Returns 0 on success or error.
119 */
120int sysfs_update_group(struct kobject *kobj,
121 const struct attribute_group *grp)
122{
123 return internal_create_group(kobj, 1, grp);
124}
125
126
127
128void sysfs_remove_group(struct kobject * kobj,
129 const struct attribute_group * grp)
130{
131 struct sysfs_dirent *dir_sd = kobj->sd;
132 struct sysfs_dirent *sd;
133
134 if (grp->name) {
135 sd = sysfs_get_dirent(dir_sd, NULL, grp->name);
136 if (!sd) {
137 WARN(!sd, KERN_WARNING "sysfs group %p not found for "
138 "kobject '%s'\n", grp, kobject_name(kobj));
139 return;
140 }
141 } else
142 sd = sysfs_get(dir_sd);
143
144 remove_files(sd, kobj, grp);
145 if (grp->name)
146 sysfs_remove_subdir(sd);
147
148 sysfs_put(sd);
149}
150
151/**
152 * sysfs_merge_group - merge files into a pre-existing attribute group.
153 * @kobj: The kobject containing the group.
154 * @grp: The files to create and the attribute group they belong to.
155 *
156 * This function returns an error if the group doesn't exist or any of the
157 * files already exist in that group, in which case none of the new files
158 * are created.
159 */
160int sysfs_merge_group(struct kobject *kobj,
161 const struct attribute_group *grp)
162{
163 struct sysfs_dirent *dir_sd;
164 int error = 0;
165 struct attribute *const *attr;
166 int i;
167
168 dir_sd = sysfs_get_dirent(kobj->sd, NULL, grp->name);
169 if (!dir_sd)
170 return -ENOENT;
171
172 for ((i = 0, attr = grp->attrs); *attr && !error; (++i, ++attr))
173 error = sysfs_add_file(dir_sd, *attr, SYSFS_KOBJ_ATTR);
174 if (error) {
175 while (--i >= 0)
176 sysfs_hash_and_remove(dir_sd, NULL, (*--attr)->name);
177 }
178 sysfs_put(dir_sd);
179
180 return error;
181}
182EXPORT_SYMBOL_GPL(sysfs_merge_group);
183
184/**
185 * sysfs_unmerge_group - remove files from a pre-existing attribute group.
186 * @kobj: The kobject containing the group.
187 * @grp: The files to remove and the attribute group they belong to.
188 */
189void sysfs_unmerge_group(struct kobject *kobj,
190 const struct attribute_group *grp)
191{
192 struct sysfs_dirent *dir_sd;
193 struct attribute *const *attr;
194
195 dir_sd = sysfs_get_dirent(kobj->sd, NULL, grp->name);
196 if (dir_sd) {
197 for (attr = grp->attrs; *attr; ++attr)
198 sysfs_hash_and_remove(dir_sd, NULL, (*attr)->name);
199 sysfs_put(dir_sd);
200 }
201}
202EXPORT_SYMBOL_GPL(sysfs_unmerge_group);
203
204
205EXPORT_SYMBOL_GPL(sysfs_create_group);
206EXPORT_SYMBOL_GPL(sysfs_update_group);
207EXPORT_SYMBOL_GPL(sysfs_remove_group);
1/*
2 * fs/sysfs/group.c - Operations for adding/removing multiple files at once.
3 *
4 * Copyright (c) 2003 Patrick Mochel
5 * Copyright (c) 2003 Open Source Development Lab
6 * Copyright (c) 2013 Greg Kroah-Hartman
7 * Copyright (c) 2013 The Linux Foundation
8 *
9 * This file is released undert the GPL v2.
10 *
11 */
12
13#include <linux/kobject.h>
14#include <linux/module.h>
15#include <linux/dcache.h>
16#include <linux/namei.h>
17#include <linux/err.h>
18#include "sysfs.h"
19
20
21static void remove_files(struct kernfs_node *parent,
22 const struct attribute_group *grp)
23{
24 struct attribute *const *attr;
25 struct bin_attribute *const *bin_attr;
26
27 if (grp->attrs)
28 for (attr = grp->attrs; *attr; attr++)
29 kernfs_remove_by_name(parent, (*attr)->name);
30 if (grp->bin_attrs)
31 for (bin_attr = grp->bin_attrs; *bin_attr; bin_attr++)
32 kernfs_remove_by_name(parent, (*bin_attr)->attr.name);
33}
34
35static int create_files(struct kernfs_node *parent, struct kobject *kobj,
36 const struct attribute_group *grp, int update)
37{
38 struct attribute *const *attr;
39 struct bin_attribute *const *bin_attr;
40 int error = 0, i;
41
42 if (grp->attrs) {
43 for (i = 0, attr = grp->attrs; *attr && !error; i++, attr++) {
44 umode_t mode = (*attr)->mode;
45
46 /*
47 * In update mode, we're changing the permissions or
48 * visibility. Do this by first removing then
49 * re-adding (if required) the file.
50 */
51 if (update)
52 kernfs_remove_by_name(parent, (*attr)->name);
53 if (grp->is_visible) {
54 mode = grp->is_visible(kobj, *attr, i);
55 if (!mode)
56 continue;
57 }
58
59 WARN(mode & ~(SYSFS_PREALLOC | 0664),
60 "Attribute %s: Invalid permissions 0%o\n",
61 (*attr)->name, mode);
62
63 mode &= SYSFS_PREALLOC | 0664;
64 error = sysfs_add_file_mode_ns(parent, *attr, false,
65 mode, NULL);
66 if (unlikely(error))
67 break;
68 }
69 if (error) {
70 remove_files(parent, grp);
71 goto exit;
72 }
73 }
74
75 if (grp->bin_attrs) {
76 for (i = 0, bin_attr = grp->bin_attrs; *bin_attr; i++, bin_attr++) {
77 umode_t mode = (*bin_attr)->attr.mode;
78
79 if (update)
80 kernfs_remove_by_name(parent,
81 (*bin_attr)->attr.name);
82 if (grp->is_bin_visible) {
83 mode = grp->is_bin_visible(kobj, *bin_attr, i);
84 if (!mode)
85 continue;
86 }
87
88 WARN(mode & ~(SYSFS_PREALLOC | 0664),
89 "Attribute %s: Invalid permissions 0%o\n",
90 (*bin_attr)->attr.name, mode);
91
92 mode &= SYSFS_PREALLOC | 0664;
93 error = sysfs_add_file_mode_ns(parent,
94 &(*bin_attr)->attr, true,
95 mode, NULL);
96 if (error)
97 break;
98 }
99 if (error)
100 remove_files(parent, grp);
101 }
102exit:
103 return error;
104}
105
106
107static int internal_create_group(struct kobject *kobj, int update,
108 const struct attribute_group *grp)
109{
110 struct kernfs_node *kn;
111 int error;
112
113 BUG_ON(!kobj || (!update && !kobj->sd));
114
115 /* Updates may happen before the object has been instantiated */
116 if (unlikely(update && !kobj->sd))
117 return -EINVAL;
118 if (!grp->attrs && !grp->bin_attrs) {
119 WARN(1, "sysfs: (bin_)attrs not set by subsystem for group: %s/%s\n",
120 kobj->name, grp->name ?: "");
121 return -EINVAL;
122 }
123 if (grp->name) {
124 kn = kernfs_create_dir(kobj->sd, grp->name,
125 S_IRWXU | S_IRUGO | S_IXUGO, kobj);
126 if (IS_ERR(kn)) {
127 if (PTR_ERR(kn) == -EEXIST)
128 sysfs_warn_dup(kobj->sd, grp->name);
129 return PTR_ERR(kn);
130 }
131 } else
132 kn = kobj->sd;
133 kernfs_get(kn);
134 error = create_files(kn, kobj, grp, update);
135 if (error) {
136 if (grp->name)
137 kernfs_remove(kn);
138 }
139 kernfs_put(kn);
140 return error;
141}
142
143/**
144 * sysfs_create_group - given a directory kobject, create an attribute group
145 * @kobj: The kobject to create the group on
146 * @grp: The attribute group to create
147 *
148 * This function creates a group for the first time. It will explicitly
149 * warn and error if any of the attribute files being created already exist.
150 *
151 * Returns 0 on success or error code on failure.
152 */
153int sysfs_create_group(struct kobject *kobj,
154 const struct attribute_group *grp)
155{
156 return internal_create_group(kobj, 0, grp);
157}
158EXPORT_SYMBOL_GPL(sysfs_create_group);
159
160/**
161 * sysfs_create_groups - given a directory kobject, create a bunch of attribute groups
162 * @kobj: The kobject to create the group on
163 * @groups: The attribute groups to create, NULL terminated
164 *
165 * This function creates a bunch of attribute groups. If an error occurs when
166 * creating a group, all previously created groups will be removed, unwinding
167 * everything back to the original state when this function was called.
168 * It will explicitly warn and error if any of the attribute files being
169 * created already exist.
170 *
171 * Returns 0 on success or error code from sysfs_create_group on failure.
172 */
173int sysfs_create_groups(struct kobject *kobj,
174 const struct attribute_group **groups)
175{
176 int error = 0;
177 int i;
178
179 if (!groups)
180 return 0;
181
182 for (i = 0; groups[i]; i++) {
183 error = sysfs_create_group(kobj, groups[i]);
184 if (error) {
185 while (--i >= 0)
186 sysfs_remove_group(kobj, groups[i]);
187 break;
188 }
189 }
190 return error;
191}
192EXPORT_SYMBOL_GPL(sysfs_create_groups);
193
194/**
195 * sysfs_update_group - given a directory kobject, update an attribute group
196 * @kobj: The kobject to update the group on
197 * @grp: The attribute group to update
198 *
199 * This function updates an attribute group. Unlike
200 * sysfs_create_group(), it will explicitly not warn or error if any
201 * of the attribute files being created already exist. Furthermore,
202 * if the visibility of the files has changed through the is_visible()
203 * callback, it will update the permissions and add or remove the
204 * relevant files.
205 *
206 * The primary use for this function is to call it after making a change
207 * that affects group visibility.
208 *
209 * Returns 0 on success or error code on failure.
210 */
211int sysfs_update_group(struct kobject *kobj,
212 const struct attribute_group *grp)
213{
214 return internal_create_group(kobj, 1, grp);
215}
216EXPORT_SYMBOL_GPL(sysfs_update_group);
217
218/**
219 * sysfs_remove_group: remove a group from a kobject
220 * @kobj: kobject to remove the group from
221 * @grp: group to remove
222 *
223 * This function removes a group of attributes from a kobject. The attributes
224 * previously have to have been created for this group, otherwise it will fail.
225 */
226void sysfs_remove_group(struct kobject *kobj,
227 const struct attribute_group *grp)
228{
229 struct kernfs_node *parent = kobj->sd;
230 struct kernfs_node *kn;
231
232 if (grp->name) {
233 kn = kernfs_find_and_get(parent, grp->name);
234 if (!kn) {
235 WARN(!kn, KERN_WARNING
236 "sysfs group '%s' not found for kobject '%s'\n",
237 grp->name, kobject_name(kobj));
238 return;
239 }
240 } else {
241 kn = parent;
242 kernfs_get(kn);
243 }
244
245 remove_files(kn, grp);
246 if (grp->name)
247 kernfs_remove(kn);
248
249 kernfs_put(kn);
250}
251EXPORT_SYMBOL_GPL(sysfs_remove_group);
252
253/**
254 * sysfs_remove_groups - remove a list of groups
255 *
256 * @kobj: The kobject for the groups to be removed from
257 * @groups: NULL terminated list of groups to be removed
258 *
259 * If groups is not NULL, remove the specified groups from the kobject.
260 */
261void sysfs_remove_groups(struct kobject *kobj,
262 const struct attribute_group **groups)
263{
264 int i;
265
266 if (!groups)
267 return;
268 for (i = 0; groups[i]; i++)
269 sysfs_remove_group(kobj, groups[i]);
270}
271EXPORT_SYMBOL_GPL(sysfs_remove_groups);
272
273/**
274 * sysfs_merge_group - merge files into a pre-existing attribute group.
275 * @kobj: The kobject containing the group.
276 * @grp: The files to create and the attribute group they belong to.
277 *
278 * This function returns an error if the group doesn't exist or any of the
279 * files already exist in that group, in which case none of the new files
280 * are created.
281 */
282int sysfs_merge_group(struct kobject *kobj,
283 const struct attribute_group *grp)
284{
285 struct kernfs_node *parent;
286 int error = 0;
287 struct attribute *const *attr;
288 int i;
289
290 parent = kernfs_find_and_get(kobj->sd, grp->name);
291 if (!parent)
292 return -ENOENT;
293
294 for ((i = 0, attr = grp->attrs); *attr && !error; (++i, ++attr))
295 error = sysfs_add_file(parent, *attr, false);
296 if (error) {
297 while (--i >= 0)
298 kernfs_remove_by_name(parent, (*--attr)->name);
299 }
300 kernfs_put(parent);
301
302 return error;
303}
304EXPORT_SYMBOL_GPL(sysfs_merge_group);
305
306/**
307 * sysfs_unmerge_group - remove files from a pre-existing attribute group.
308 * @kobj: The kobject containing the group.
309 * @grp: The files to remove and the attribute group they belong to.
310 */
311void sysfs_unmerge_group(struct kobject *kobj,
312 const struct attribute_group *grp)
313{
314 struct kernfs_node *parent;
315 struct attribute *const *attr;
316
317 parent = kernfs_find_and_get(kobj->sd, grp->name);
318 if (parent) {
319 for (attr = grp->attrs; *attr; ++attr)
320 kernfs_remove_by_name(parent, (*attr)->name);
321 kernfs_put(parent);
322 }
323}
324EXPORT_SYMBOL_GPL(sysfs_unmerge_group);
325
326/**
327 * sysfs_add_link_to_group - add a symlink to an attribute group.
328 * @kobj: The kobject containing the group.
329 * @group_name: The name of the group.
330 * @target: The target kobject of the symlink to create.
331 * @link_name: The name of the symlink to create.
332 */
333int sysfs_add_link_to_group(struct kobject *kobj, const char *group_name,
334 struct kobject *target, const char *link_name)
335{
336 struct kernfs_node *parent;
337 int error = 0;
338
339 parent = kernfs_find_and_get(kobj->sd, group_name);
340 if (!parent)
341 return -ENOENT;
342
343 error = sysfs_create_link_sd(parent, target, link_name);
344 kernfs_put(parent);
345
346 return error;
347}
348EXPORT_SYMBOL_GPL(sysfs_add_link_to_group);
349
350/**
351 * sysfs_remove_link_from_group - remove a symlink from an attribute group.
352 * @kobj: The kobject containing the group.
353 * @group_name: The name of the group.
354 * @link_name: The name of the symlink to remove.
355 */
356void sysfs_remove_link_from_group(struct kobject *kobj, const char *group_name,
357 const char *link_name)
358{
359 struct kernfs_node *parent;
360
361 parent = kernfs_find_and_get(kobj->sd, group_name);
362 if (parent) {
363 kernfs_remove_by_name(parent, link_name);
364 kernfs_put(parent);
365 }
366}
367EXPORT_SYMBOL_GPL(sysfs_remove_link_from_group);
368
369/**
370 * __compat_only_sysfs_link_entry_to_kobj - add a symlink to a kobject pointing
371 * to a group or an attribute
372 * @kobj: The kobject containing the group.
373 * @target_kobj: The target kobject.
374 * @target_name: The name of the target group or attribute.
375 */
376int __compat_only_sysfs_link_entry_to_kobj(struct kobject *kobj,
377 struct kobject *target_kobj,
378 const char *target_name)
379{
380 struct kernfs_node *target;
381 struct kernfs_node *entry;
382 struct kernfs_node *link;
383
384 /*
385 * We don't own @target_kobj and it may be removed at any time.
386 * Synchronize using sysfs_symlink_target_lock. See sysfs_remove_dir()
387 * for details.
388 */
389 spin_lock(&sysfs_symlink_target_lock);
390 target = target_kobj->sd;
391 if (target)
392 kernfs_get(target);
393 spin_unlock(&sysfs_symlink_target_lock);
394 if (!target)
395 return -ENOENT;
396
397 entry = kernfs_find_and_get(target_kobj->sd, target_name);
398 if (!entry) {
399 kernfs_put(target);
400 return -ENOENT;
401 }
402
403 link = kernfs_create_link(kobj->sd, target_name, entry);
404 if (IS_ERR(link) && PTR_ERR(link) == -EEXIST)
405 sysfs_warn_dup(kobj->sd, target_name);
406
407 kernfs_put(entry);
408 kernfs_put(target);
409 return IS_ERR(link) ? PTR_ERR(link) : 0;
410}
411EXPORT_SYMBOL_GPL(__compat_only_sysfs_link_entry_to_kobj);