1 // SPDX-License-Identifier: GPL-2.0
3 * fs/sysfs/group.c - Operations for adding/removing multiple files at once.
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
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>
19 static void remove_files(struct kernfs_node *parent,
20 const struct attribute_group *grp)
22 struct attribute *const *attr;
23 struct bin_attribute *const *bin_attr;
26 for (attr = grp->attrs; *attr; attr++)
27 kernfs_remove_by_name(parent, (*attr)->name);
29 for (bin_attr = grp->bin_attrs; *bin_attr; bin_attr++)
30 kernfs_remove_by_name(parent, (*bin_attr)->attr.name);
33 static int create_files(struct kernfs_node *parent, struct kobject *kobj,
34 kuid_t uid, kgid_t gid,
35 const struct attribute_group *grp, int update)
37 struct attribute *const *attr;
38 struct bin_attribute *const *bin_attr;
42 for (i = 0, attr = grp->attrs; *attr && !error; i++, attr++) {
43 umode_t mode = (*attr)->mode;
46 * In update mode, we're changing the permissions or
47 * visibility. Do this by first removing then
48 * re-adding (if required) the file.
51 kernfs_remove_by_name(parent, (*attr)->name);
52 if (grp->is_visible) {
53 mode = grp->is_visible(kobj, *attr, i);
58 WARN(mode & ~(SYSFS_PREALLOC | 0664),
59 "Attribute %s: Invalid permissions 0%o\n",
62 mode &= SYSFS_PREALLOC | 0664;
63 error = sysfs_add_file_mode_ns(parent, *attr, false,
64 mode, uid, gid, NULL);
69 remove_files(parent, grp);
75 for (i = 0, bin_attr = grp->bin_attrs; *bin_attr; i++, bin_attr++) {
76 umode_t mode = (*bin_attr)->attr.mode;
79 kernfs_remove_by_name(parent,
80 (*bin_attr)->attr.name);
81 if (grp->is_bin_visible) {
82 mode = grp->is_bin_visible(kobj, *bin_attr, i);
87 WARN(mode & ~(SYSFS_PREALLOC | 0664),
88 "Attribute %s: Invalid permissions 0%o\n",
89 (*bin_attr)->attr.name, mode);
91 mode &= SYSFS_PREALLOC | 0664;
92 error = sysfs_add_file_mode_ns(parent,
93 &(*bin_attr)->attr, true,
100 remove_files(parent, grp);
107 static int internal_create_group(struct kobject *kobj, int update,
108 const struct attribute_group *grp)
110 struct kernfs_node *kn;
115 BUG_ON(!kobj || (!update && !kobj->sd));
117 /* Updates may happen before the object has been instantiated */
118 if (unlikely(update && !kobj->sd))
120 if (!grp->attrs && !grp->bin_attrs) {
121 WARN(1, "sysfs: (bin_)attrs not set by subsystem for group: %s/%s\n",
122 kobj->name, grp->name ?: "");
125 kobject_get_ownership(kobj, &uid, &gid);
128 kn = kernfs_find_and_get(kobj->sd, grp->name);
130 pr_warn("Can't update unknown attr grp name: %s/%s\n",
131 kobj->name, grp->name);
135 kn = kernfs_create_dir_ns(kobj->sd, grp->name,
136 S_IRWXU | S_IRUGO | S_IXUGO,
137 uid, gid, kobj, NULL);
139 if (PTR_ERR(kn) == -EEXIST)
140 sysfs_warn_dup(kobj->sd, grp->name);
147 error = create_files(kn, kobj, uid, gid, grp, update);
154 if (grp->name && update)
161 * sysfs_create_group - given a directory kobject, create an attribute group
162 * @kobj: The kobject to create the group on
163 * @grp: The attribute group to create
165 * This function creates a group for the first time. It will explicitly
166 * warn and error if any of the attribute files being created already exist.
168 * Returns 0 on success or error code on failure.
170 int sysfs_create_group(struct kobject *kobj,
171 const struct attribute_group *grp)
173 return internal_create_group(kobj, 0, grp);
175 EXPORT_SYMBOL_GPL(sysfs_create_group);
178 * sysfs_create_groups - given a directory kobject, create a bunch of attribute groups
179 * @kobj: The kobject to create the group on
180 * @groups: The attribute groups to create, NULL terminated
182 * This function creates a bunch of attribute groups. If an error occurs when
183 * creating a group, all previously created groups will be removed, unwinding
184 * everything back to the original state when this function was called.
185 * It will explicitly warn and error if any of the attribute files being
186 * created already exist.
188 * Returns 0 on success or error code from sysfs_create_group on failure.
190 int sysfs_create_groups(struct kobject *kobj,
191 const struct attribute_group **groups)
199 for (i = 0; groups[i]; i++) {
200 error = sysfs_create_group(kobj, groups[i]);
203 sysfs_remove_group(kobj, groups[i]);
209 EXPORT_SYMBOL_GPL(sysfs_create_groups);
212 * sysfs_update_group - given a directory kobject, update an attribute group
213 * @kobj: The kobject to update the group on
214 * @grp: The attribute group to update
216 * This function updates an attribute group. Unlike
217 * sysfs_create_group(), it will explicitly not warn or error if any
218 * of the attribute files being created already exist. Furthermore,
219 * if the visibility of the files has changed through the is_visible()
220 * callback, it will update the permissions and add or remove the
221 * relevant files. Changing a group's name (subdirectory name under
222 * kobj's directory in sysfs) is not allowed.
224 * The primary use for this function is to call it after making a change
225 * that affects group visibility.
227 * Returns 0 on success or error code on failure.
229 int sysfs_update_group(struct kobject *kobj,
230 const struct attribute_group *grp)
232 return internal_create_group(kobj, 1, grp);
234 EXPORT_SYMBOL_GPL(sysfs_update_group);
237 * sysfs_remove_group: remove a group from a kobject
238 * @kobj: kobject to remove the group from
239 * @grp: group to remove
241 * This function removes a group of attributes from a kobject. The attributes
242 * previously have to have been created for this group, otherwise it will fail.
244 void sysfs_remove_group(struct kobject *kobj,
245 const struct attribute_group *grp)
247 struct kernfs_node *parent = kobj->sd;
248 struct kernfs_node *kn;
251 kn = kernfs_find_and_get(parent, grp->name);
253 WARN(!kn, KERN_WARNING
254 "sysfs group '%s' not found for kobject '%s'\n",
255 grp->name, kobject_name(kobj));
263 remove_files(kn, grp);
269 EXPORT_SYMBOL_GPL(sysfs_remove_group);
272 * sysfs_remove_groups - remove a list of groups
274 * @kobj: The kobject for the groups to be removed from
275 * @groups: NULL terminated list of groups to be removed
277 * If groups is not NULL, remove the specified groups from the kobject.
279 void sysfs_remove_groups(struct kobject *kobj,
280 const struct attribute_group **groups)
286 for (i = 0; groups[i]; i++)
287 sysfs_remove_group(kobj, groups[i]);
289 EXPORT_SYMBOL_GPL(sysfs_remove_groups);
292 * sysfs_merge_group - merge files into a pre-existing attribute group.
293 * @kobj: The kobject containing the group.
294 * @grp: The files to create and the attribute group they belong to.
296 * This function returns an error if the group doesn't exist or any of the
297 * files already exist in that group, in which case none of the new files
300 int sysfs_merge_group(struct kobject *kobj,
301 const struct attribute_group *grp)
303 struct kernfs_node *parent;
307 struct attribute *const *attr;
310 parent = kernfs_find_and_get(kobj->sd, grp->name);
314 kobject_get_ownership(kobj, &uid, &gid);
316 for ((i = 0, attr = grp->attrs); *attr && !error; (++i, ++attr))
317 error = sysfs_add_file_mode_ns(parent, *attr, false,
318 (*attr)->mode, uid, gid, NULL);
321 kernfs_remove_by_name(parent, (*--attr)->name);
327 EXPORT_SYMBOL_GPL(sysfs_merge_group);
330 * sysfs_unmerge_group - remove files from a pre-existing attribute group.
331 * @kobj: The kobject containing the group.
332 * @grp: The files to remove and the attribute group they belong to.
334 void sysfs_unmerge_group(struct kobject *kobj,
335 const struct attribute_group *grp)
337 struct kernfs_node *parent;
338 struct attribute *const *attr;
340 parent = kernfs_find_and_get(kobj->sd, grp->name);
342 for (attr = grp->attrs; *attr; ++attr)
343 kernfs_remove_by_name(parent, (*attr)->name);
347 EXPORT_SYMBOL_GPL(sysfs_unmerge_group);
350 * sysfs_add_link_to_group - add a symlink to an attribute group.
351 * @kobj: The kobject containing the group.
352 * @group_name: The name of the group.
353 * @target: The target kobject of the symlink to create.
354 * @link_name: The name of the symlink to create.
356 int sysfs_add_link_to_group(struct kobject *kobj, const char *group_name,
357 struct kobject *target, const char *link_name)
359 struct kernfs_node *parent;
362 parent = kernfs_find_and_get(kobj->sd, group_name);
366 error = sysfs_create_link_sd(parent, target, link_name);
371 EXPORT_SYMBOL_GPL(sysfs_add_link_to_group);
374 * sysfs_remove_link_from_group - remove a symlink from an attribute group.
375 * @kobj: The kobject containing the group.
376 * @group_name: The name of the group.
377 * @link_name: The name of the symlink to remove.
379 void sysfs_remove_link_from_group(struct kobject *kobj, const char *group_name,
380 const char *link_name)
382 struct kernfs_node *parent;
384 parent = kernfs_find_and_get(kobj->sd, group_name);
386 kernfs_remove_by_name(parent, link_name);
390 EXPORT_SYMBOL_GPL(sysfs_remove_link_from_group);
393 * __compat_only_sysfs_link_entry_to_kobj - add a symlink to a kobject pointing
394 * to a group or an attribute
395 * @kobj: The kobject containing the group.
396 * @target_kobj: The target kobject.
397 * @target_name: The name of the target group or attribute.
399 int __compat_only_sysfs_link_entry_to_kobj(struct kobject *kobj,
400 struct kobject *target_kobj,
401 const char *target_name)
403 struct kernfs_node *target;
404 struct kernfs_node *entry;
405 struct kernfs_node *link;
408 * We don't own @target_kobj and it may be removed at any time.
409 * Synchronize using sysfs_symlink_target_lock. See sysfs_remove_dir()
412 spin_lock(&sysfs_symlink_target_lock);
413 target = target_kobj->sd;
416 spin_unlock(&sysfs_symlink_target_lock);
420 entry = kernfs_find_and_get(target_kobj->sd, target_name);
426 link = kernfs_create_link(kobj->sd, target_name, entry);
427 if (IS_ERR(link) && PTR_ERR(link) == -EEXIST)
428 sysfs_warn_dup(kobj->sd, target_name);
432 return PTR_ERR_OR_ZERO(link);
434 EXPORT_SYMBOL_GPL(__compat_only_sysfs_link_entry_to_kobj);