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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// SPDX-License-Identifier: GPL-2.0
2/*
3 * fs/sysfs/group.c - Operations for adding/removing multiple files at once.
4 *
5 * Copyright (c) 2003 Patrick Mochel
6 * Copyright (c) 2003 Open Source Development Lab
7 * Copyright (c) 2013 Greg Kroah-Hartman
8 * Copyright (c) 2013 The Linux Foundation
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 kernfs_node *parent,
20 const struct attribute_group *grp)
21{
22 struct attribute *const *attr;
23 struct bin_attribute *const *bin_attr;
24
25 if (grp->attrs)
26 for (attr = grp->attrs; *attr; attr++)
27 kernfs_remove_by_name(parent, (*attr)->name);
28 if (grp->bin_attrs)
29 for (bin_attr = grp->bin_attrs; *bin_attr; bin_attr++)
30 kernfs_remove_by_name(parent, (*bin_attr)->attr.name);
31}
32
33static int create_files(struct kernfs_node *parent, struct kobject *kobj,
34 const struct attribute_group *grp, int update)
35{
36 struct attribute *const *attr;
37 struct bin_attribute *const *bin_attr;
38 int error = 0, i;
39
40 if (grp->attrs) {
41 for (i = 0, attr = grp->attrs; *attr && !error; i++, attr++) {
42 umode_t mode = (*attr)->mode;
43
44 /*
45 * In update mode, we're changing the permissions or
46 * visibility. Do this by first removing then
47 * re-adding (if required) the file.
48 */
49 if (update)
50 kernfs_remove_by_name(parent, (*attr)->name);
51 if (grp->is_visible) {
52 mode = grp->is_visible(kobj, *attr, i);
53 if (!mode)
54 continue;
55 }
56
57 WARN(mode & ~(SYSFS_PREALLOC | 0664),
58 "Attribute %s: Invalid permissions 0%o\n",
59 (*attr)->name, mode);
60
61 mode &= SYSFS_PREALLOC | 0664;
62 error = sysfs_add_file_mode_ns(parent, *attr, false,
63 mode, NULL);
64 if (unlikely(error))
65 break;
66 }
67 if (error) {
68 remove_files(parent, grp);
69 goto exit;
70 }
71 }
72
73 if (grp->bin_attrs) {
74 for (i = 0, bin_attr = grp->bin_attrs; *bin_attr; i++, bin_attr++) {
75 umode_t mode = (*bin_attr)->attr.mode;
76
77 if (update)
78 kernfs_remove_by_name(parent,
79 (*bin_attr)->attr.name);
80 if (grp->is_bin_visible) {
81 mode = grp->is_bin_visible(kobj, *bin_attr, i);
82 if (!mode)
83 continue;
84 }
85
86 WARN(mode & ~(SYSFS_PREALLOC | 0664),
87 "Attribute %s: Invalid permissions 0%o\n",
88 (*bin_attr)->attr.name, mode);
89
90 mode &= SYSFS_PREALLOC | 0664;
91 error = sysfs_add_file_mode_ns(parent,
92 &(*bin_attr)->attr, true,
93 mode, NULL);
94 if (error)
95 break;
96 }
97 if (error)
98 remove_files(parent, grp);
99 }
100exit:
101 return error;
102}
103
104
105static int internal_create_group(struct kobject *kobj, int update,
106 const struct attribute_group *grp)
107{
108 struct kernfs_node *kn;
109 int error;
110
111 BUG_ON(!kobj || (!update && !kobj->sd));
112
113 /* Updates may happen before the object has been instantiated */
114 if (unlikely(update && !kobj->sd))
115 return -EINVAL;
116 if (!grp->attrs && !grp->bin_attrs) {
117 WARN(1, "sysfs: (bin_)attrs not set by subsystem for group: %s/%s\n",
118 kobj->name, grp->name ?: "");
119 return -EINVAL;
120 }
121 if (grp->name) {
122 kn = kernfs_create_dir(kobj->sd, grp->name,
123 S_IRWXU | S_IRUGO | S_IXUGO, kobj);
124 if (IS_ERR(kn)) {
125 if (PTR_ERR(kn) == -EEXIST)
126 sysfs_warn_dup(kobj->sd, grp->name);
127 return PTR_ERR(kn);
128 }
129 } else
130 kn = kobj->sd;
131 kernfs_get(kn);
132 error = create_files(kn, kobj, grp, update);
133 if (error) {
134 if (grp->name)
135 kernfs_remove(kn);
136 }
137 kernfs_put(kn);
138 return error;
139}
140
141/**
142 * sysfs_create_group - given a directory kobject, create an attribute group
143 * @kobj: The kobject to create the group on
144 * @grp: The attribute group to create
145 *
146 * This function creates a group for the first time. It will explicitly
147 * warn and error if any of the attribute files being created already exist.
148 *
149 * Returns 0 on success or error code on failure.
150 */
151int sysfs_create_group(struct kobject *kobj,
152 const struct attribute_group *grp)
153{
154 return internal_create_group(kobj, 0, grp);
155}
156EXPORT_SYMBOL_GPL(sysfs_create_group);
157
158/**
159 * sysfs_create_groups - given a directory kobject, create a bunch of attribute groups
160 * @kobj: The kobject to create the group on
161 * @groups: The attribute groups to create, NULL terminated
162 *
163 * This function creates a bunch of attribute groups. If an error occurs when
164 * creating a group, all previously created groups will be removed, unwinding
165 * everything back to the original state when this function was called.
166 * It will explicitly warn and error if any of the attribute files being
167 * created already exist.
168 *
169 * Returns 0 on success or error code from sysfs_create_group on failure.
170 */
171int sysfs_create_groups(struct kobject *kobj,
172 const struct attribute_group **groups)
173{
174 int error = 0;
175 int i;
176
177 if (!groups)
178 return 0;
179
180 for (i = 0; groups[i]; i++) {
181 error = sysfs_create_group(kobj, groups[i]);
182 if (error) {
183 while (--i >= 0)
184 sysfs_remove_group(kobj, groups[i]);
185 break;
186 }
187 }
188 return error;
189}
190EXPORT_SYMBOL_GPL(sysfs_create_groups);
191
192/**
193 * sysfs_update_group - given a directory kobject, update an attribute group
194 * @kobj: The kobject to update the group on
195 * @grp: The attribute group to update
196 *
197 * This function updates an attribute group. Unlike
198 * sysfs_create_group(), it will explicitly not warn or error if any
199 * of the attribute files being created already exist. Furthermore,
200 * if the visibility of the files has changed through the is_visible()
201 * callback, it will update the permissions and add or remove the
202 * relevant files.
203 *
204 * The primary use for this function is to call it after making a change
205 * that affects group visibility.
206 *
207 * Returns 0 on success or error code on failure.
208 */
209int sysfs_update_group(struct kobject *kobj,
210 const struct attribute_group *grp)
211{
212 return internal_create_group(kobj, 1, grp);
213}
214EXPORT_SYMBOL_GPL(sysfs_update_group);
215
216/**
217 * sysfs_remove_group: remove a group from a kobject
218 * @kobj: kobject to remove the group from
219 * @grp: group to remove
220 *
221 * This function removes a group of attributes from a kobject. The attributes
222 * previously have to have been created for this group, otherwise it will fail.
223 */
224void sysfs_remove_group(struct kobject *kobj,
225 const struct attribute_group *grp)
226{
227 struct kernfs_node *parent = kobj->sd;
228 struct kernfs_node *kn;
229
230 if (grp->name) {
231 kn = kernfs_find_and_get(parent, grp->name);
232 if (!kn) {
233 WARN(!kn, KERN_WARNING
234 "sysfs group '%s' not found for kobject '%s'\n",
235 grp->name, kobject_name(kobj));
236 return;
237 }
238 } else {
239 kn = parent;
240 kernfs_get(kn);
241 }
242
243 remove_files(kn, grp);
244 if (grp->name)
245 kernfs_remove(kn);
246
247 kernfs_put(kn);
248}
249EXPORT_SYMBOL_GPL(sysfs_remove_group);
250
251/**
252 * sysfs_remove_groups - remove a list of groups
253 *
254 * @kobj: The kobject for the groups to be removed from
255 * @groups: NULL terminated list of groups to be removed
256 *
257 * If groups is not NULL, remove the specified groups from the kobject.
258 */
259void sysfs_remove_groups(struct kobject *kobj,
260 const struct attribute_group **groups)
261{
262 int i;
263
264 if (!groups)
265 return;
266 for (i = 0; groups[i]; i++)
267 sysfs_remove_group(kobj, groups[i]);
268}
269EXPORT_SYMBOL_GPL(sysfs_remove_groups);
270
271/**
272 * sysfs_merge_group - merge files into a pre-existing attribute group.
273 * @kobj: The kobject containing the group.
274 * @grp: The files to create and the attribute group they belong to.
275 *
276 * This function returns an error if the group doesn't exist or any of the
277 * files already exist in that group, in which case none of the new files
278 * are created.
279 */
280int sysfs_merge_group(struct kobject *kobj,
281 const struct attribute_group *grp)
282{
283 struct kernfs_node *parent;
284 int error = 0;
285 struct attribute *const *attr;
286 int i;
287
288 parent = kernfs_find_and_get(kobj->sd, grp->name);
289 if (!parent)
290 return -ENOENT;
291
292 for ((i = 0, attr = grp->attrs); *attr && !error; (++i, ++attr))
293 error = sysfs_add_file(parent, *attr, false);
294 if (error) {
295 while (--i >= 0)
296 kernfs_remove_by_name(parent, (*--attr)->name);
297 }
298 kernfs_put(parent);
299
300 return error;
301}
302EXPORT_SYMBOL_GPL(sysfs_merge_group);
303
304/**
305 * sysfs_unmerge_group - remove files from a pre-existing attribute group.
306 * @kobj: The kobject containing the group.
307 * @grp: The files to remove and the attribute group they belong to.
308 */
309void sysfs_unmerge_group(struct kobject *kobj,
310 const struct attribute_group *grp)
311{
312 struct kernfs_node *parent;
313 struct attribute *const *attr;
314
315 parent = kernfs_find_and_get(kobj->sd, grp->name);
316 if (parent) {
317 for (attr = grp->attrs; *attr; ++attr)
318 kernfs_remove_by_name(parent, (*attr)->name);
319 kernfs_put(parent);
320 }
321}
322EXPORT_SYMBOL_GPL(sysfs_unmerge_group);
323
324/**
325 * sysfs_add_link_to_group - add a symlink to an attribute group.
326 * @kobj: The kobject containing the group.
327 * @group_name: The name of the group.
328 * @target: The target kobject of the symlink to create.
329 * @link_name: The name of the symlink to create.
330 */
331int sysfs_add_link_to_group(struct kobject *kobj, const char *group_name,
332 struct kobject *target, const char *link_name)
333{
334 struct kernfs_node *parent;
335 int error = 0;
336
337 parent = kernfs_find_and_get(kobj->sd, group_name);
338 if (!parent)
339 return -ENOENT;
340
341 error = sysfs_create_link_sd(parent, target, link_name);
342 kernfs_put(parent);
343
344 return error;
345}
346EXPORT_SYMBOL_GPL(sysfs_add_link_to_group);
347
348/**
349 * sysfs_remove_link_from_group - remove a symlink from an attribute group.
350 * @kobj: The kobject containing the group.
351 * @group_name: The name of the group.
352 * @link_name: The name of the symlink to remove.
353 */
354void sysfs_remove_link_from_group(struct kobject *kobj, const char *group_name,
355 const char *link_name)
356{
357 struct kernfs_node *parent;
358
359 parent = kernfs_find_and_get(kobj->sd, group_name);
360 if (parent) {
361 kernfs_remove_by_name(parent, link_name);
362 kernfs_put(parent);
363 }
364}
365EXPORT_SYMBOL_GPL(sysfs_remove_link_from_group);
366
367/**
368 * __compat_only_sysfs_link_entry_to_kobj - add a symlink to a kobject pointing
369 * to a group or an attribute
370 * @kobj: The kobject containing the group.
371 * @target_kobj: The target kobject.
372 * @target_name: The name of the target group or attribute.
373 */
374int __compat_only_sysfs_link_entry_to_kobj(struct kobject *kobj,
375 struct kobject *target_kobj,
376 const char *target_name)
377{
378 struct kernfs_node *target;
379 struct kernfs_node *entry;
380 struct kernfs_node *link;
381
382 /*
383 * We don't own @target_kobj and it may be removed at any time.
384 * Synchronize using sysfs_symlink_target_lock. See sysfs_remove_dir()
385 * for details.
386 */
387 spin_lock(&sysfs_symlink_target_lock);
388 target = target_kobj->sd;
389 if (target)
390 kernfs_get(target);
391 spin_unlock(&sysfs_symlink_target_lock);
392 if (!target)
393 return -ENOENT;
394
395 entry = kernfs_find_and_get(target_kobj->sd, target_name);
396 if (!entry) {
397 kernfs_put(target);
398 return -ENOENT;
399 }
400
401 link = kernfs_create_link(kobj->sd, target_name, entry);
402 if (IS_ERR(link) && PTR_ERR(link) == -EEXIST)
403 sysfs_warn_dup(kobj->sd, target_name);
404
405 kernfs_put(entry);
406 kernfs_put(target);
407 return PTR_ERR_OR_ZERO(link);
408}
409EXPORT_SYMBOL_GPL(__compat_only_sysfs_link_entry_to_kobj);