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>
20 static void remove_files(struct kernfs_node *parent,
21 const struct attribute_group *grp)
23 struct attribute *const *attr;
24 struct bin_attribute *const *bin_attr;
27 for (attr = grp->attrs; *attr; attr++)
28 kernfs_remove_by_name(parent, (*attr)->name);
30 for (bin_attr = grp->bin_attrs; *bin_attr; bin_attr++)
31 kernfs_remove_by_name(parent, (*bin_attr)->attr.name);
34 static int create_files(struct kernfs_node *parent, struct kobject *kobj,
35 kuid_t uid, kgid_t gid,
36 const struct attribute_group *grp, int update)
38 struct attribute *const *attr;
39 struct bin_attribute *const *bin_attr;
43 for (i = 0, attr = grp->attrs; *attr && !error; i++, attr++) {
44 umode_t mode = (*attr)->mode;
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.
52 kernfs_remove_by_name(parent, (*attr)->name);
53 if (grp->is_visible) {
54 mode = grp->is_visible(kobj, *attr, i);
59 WARN(mode & ~(SYSFS_PREALLOC | 0664),
60 "Attribute %s: Invalid permissions 0%o\n",
63 mode &= SYSFS_PREALLOC | 0664;
64 error = sysfs_add_file_mode_ns(parent, *attr, mode, uid,
70 remove_files(parent, grp);
76 for (i = 0, bin_attr = grp->bin_attrs; *bin_attr; i++, bin_attr++) {
77 umode_t mode = (*bin_attr)->attr.mode;
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);
88 WARN(mode & ~(SYSFS_PREALLOC | 0664),
89 "Attribute %s: Invalid permissions 0%o\n",
90 (*bin_attr)->attr.name, mode);
92 mode &= SYSFS_PREALLOC | 0664;
93 error = sysfs_add_bin_file_mode_ns(parent, *bin_attr,
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 if (WARN_ON(!kobj || (!update && !kobj->sd)))
118 /* Updates may happen before the object has been instantiated */
119 if (unlikely(update && !kobj->sd))
121 if (!grp->attrs && !grp->bin_attrs) {
122 WARN(1, "sysfs: (bin_)attrs not set by subsystem for group: %s/%s\n",
123 kobj->name, grp->name ?: "");
126 kobject_get_ownership(kobj, &uid, &gid);
129 kn = kernfs_find_and_get(kobj->sd, grp->name);
131 pr_warn("Can't update unknown attr grp name: %s/%s\n",
132 kobj->name, grp->name);
136 kn = kernfs_create_dir_ns(kobj->sd, grp->name,
137 S_IRWXU | S_IRUGO | S_IXUGO,
138 uid, gid, kobj, NULL);
140 if (PTR_ERR(kn) == -EEXIST)
141 sysfs_warn_dup(kobj->sd, grp->name);
150 error = create_files(kn, kobj, uid, gid, grp, update);
157 if (grp->name && update)
164 * sysfs_create_group - given a directory kobject, create an attribute group
165 * @kobj: The kobject to create the group on
166 * @grp: The attribute group to create
168 * This function creates a group for the first time. It will explicitly
169 * warn and error if any of the attribute files being created already exist.
171 * Returns 0 on success or error code on failure.
173 int sysfs_create_group(struct kobject *kobj,
174 const struct attribute_group *grp)
176 return internal_create_group(kobj, 0, grp);
178 EXPORT_SYMBOL_GPL(sysfs_create_group);
180 static int internal_create_groups(struct kobject *kobj, int update,
181 const struct attribute_group **groups)
189 for (i = 0; groups[i]; i++) {
190 error = internal_create_group(kobj, update, groups[i]);
193 sysfs_remove_group(kobj, groups[i]);
201 * sysfs_create_groups - given a directory kobject, create a bunch of attribute groups
202 * @kobj: The kobject to create the group on
203 * @groups: The attribute groups to create, NULL terminated
205 * This function creates a bunch of attribute groups. If an error occurs when
206 * creating a group, all previously created groups will be removed, unwinding
207 * everything back to the original state when this function was called.
208 * It will explicitly warn and error if any of the attribute files being
209 * created already exist.
211 * Returns 0 on success or error code from sysfs_create_group on failure.
213 int sysfs_create_groups(struct kobject *kobj,
214 const struct attribute_group **groups)
216 return internal_create_groups(kobj, 0, groups);
218 EXPORT_SYMBOL_GPL(sysfs_create_groups);
221 * sysfs_update_groups - given a directory kobject, create a bunch of attribute groups
222 * @kobj: The kobject to update the group on
223 * @groups: The attribute groups to update, NULL terminated
225 * This function update a bunch of attribute groups. If an error occurs when
226 * updating a group, all previously updated groups will be removed together
227 * with already existing (not updated) attributes.
229 * Returns 0 on success or error code from sysfs_update_group on failure.
231 int sysfs_update_groups(struct kobject *kobj,
232 const struct attribute_group **groups)
234 return internal_create_groups(kobj, 1, groups);
236 EXPORT_SYMBOL_GPL(sysfs_update_groups);
239 * sysfs_update_group - given a directory kobject, update an attribute group
240 * @kobj: The kobject to update the group on
241 * @grp: The attribute group to update
243 * This function updates an attribute group. Unlike
244 * sysfs_create_group(), it will explicitly not warn or error if any
245 * of the attribute files being created already exist. Furthermore,
246 * if the visibility of the files has changed through the is_visible()
247 * callback, it will update the permissions and add or remove the
248 * relevant files. Changing a group's name (subdirectory name under
249 * kobj's directory in sysfs) is not allowed.
251 * The primary use for this function is to call it after making a change
252 * that affects group visibility.
254 * Returns 0 on success or error code on failure.
256 int sysfs_update_group(struct kobject *kobj,
257 const struct attribute_group *grp)
259 return internal_create_group(kobj, 1, grp);
261 EXPORT_SYMBOL_GPL(sysfs_update_group);
264 * sysfs_remove_group: remove a group from a kobject
265 * @kobj: kobject to remove the group from
266 * @grp: group to remove
268 * This function removes a group of attributes from a kobject. The attributes
269 * previously have to have been created for this group, otherwise it will fail.
271 void sysfs_remove_group(struct kobject *kobj,
272 const struct attribute_group *grp)
274 struct kernfs_node *parent = kobj->sd;
275 struct kernfs_node *kn;
278 kn = kernfs_find_and_get(parent, grp->name);
280 WARN(!kn, KERN_WARNING
281 "sysfs group '%s' not found for kobject '%s'\n",
282 grp->name, kobject_name(kobj));
290 remove_files(kn, grp);
296 EXPORT_SYMBOL_GPL(sysfs_remove_group);
299 * sysfs_remove_groups - remove a list of groups
301 * @kobj: The kobject for the groups to be removed from
302 * @groups: NULL terminated list of groups to be removed
304 * If groups is not NULL, remove the specified groups from the kobject.
306 void sysfs_remove_groups(struct kobject *kobj,
307 const struct attribute_group **groups)
313 for (i = 0; groups[i]; i++)
314 sysfs_remove_group(kobj, groups[i]);
316 EXPORT_SYMBOL_GPL(sysfs_remove_groups);
319 * sysfs_merge_group - merge files into a pre-existing attribute group.
320 * @kobj: The kobject containing the group.
321 * @grp: The files to create and the attribute group they belong to.
323 * This function returns an error if the group doesn't exist or any of the
324 * files already exist in that group, in which case none of the new files
327 int sysfs_merge_group(struct kobject *kobj,
328 const struct attribute_group *grp)
330 struct kernfs_node *parent;
334 struct attribute *const *attr;
337 parent = kernfs_find_and_get(kobj->sd, grp->name);
341 kobject_get_ownership(kobj, &uid, &gid);
343 for ((i = 0, attr = grp->attrs); *attr && !error; (++i, ++attr))
344 error = sysfs_add_file_mode_ns(parent, *attr, (*attr)->mode,
348 kernfs_remove_by_name(parent, (*--attr)->name);
354 EXPORT_SYMBOL_GPL(sysfs_merge_group);
357 * sysfs_unmerge_group - remove files from a pre-existing attribute group.
358 * @kobj: The kobject containing the group.
359 * @grp: The files to remove and the attribute group they belong to.
361 void sysfs_unmerge_group(struct kobject *kobj,
362 const struct attribute_group *grp)
364 struct kernfs_node *parent;
365 struct attribute *const *attr;
367 parent = kernfs_find_and_get(kobj->sd, grp->name);
369 for (attr = grp->attrs; *attr; ++attr)
370 kernfs_remove_by_name(parent, (*attr)->name);
374 EXPORT_SYMBOL_GPL(sysfs_unmerge_group);
377 * sysfs_add_link_to_group - add a symlink to an attribute group.
378 * @kobj: The kobject containing the group.
379 * @group_name: The name of the group.
380 * @target: The target kobject of the symlink to create.
381 * @link_name: The name of the symlink to create.
383 int sysfs_add_link_to_group(struct kobject *kobj, const char *group_name,
384 struct kobject *target, const char *link_name)
386 struct kernfs_node *parent;
389 parent = kernfs_find_and_get(kobj->sd, group_name);
393 error = sysfs_create_link_sd(parent, target, link_name);
398 EXPORT_SYMBOL_GPL(sysfs_add_link_to_group);
401 * sysfs_remove_link_from_group - remove a symlink from an attribute group.
402 * @kobj: The kobject containing the group.
403 * @group_name: The name of the group.
404 * @link_name: The name of the symlink to remove.
406 void sysfs_remove_link_from_group(struct kobject *kobj, const char *group_name,
407 const char *link_name)
409 struct kernfs_node *parent;
411 parent = kernfs_find_and_get(kobj->sd, group_name);
413 kernfs_remove_by_name(parent, link_name);
417 EXPORT_SYMBOL_GPL(sysfs_remove_link_from_group);
420 * compat_only_sysfs_link_entry_to_kobj - add a symlink to a kobject pointing
421 * to a group or an attribute
422 * @kobj: The kobject containing the group.
423 * @target_kobj: The target kobject.
424 * @target_name: The name of the target group or attribute.
425 * @symlink_name: The name of the symlink file (target_name will be
426 * considered if symlink_name is NULL).
428 int compat_only_sysfs_link_entry_to_kobj(struct kobject *kobj,
429 struct kobject *target_kobj,
430 const char *target_name,
431 const char *symlink_name)
433 struct kernfs_node *target;
434 struct kernfs_node *entry;
435 struct kernfs_node *link;
438 * We don't own @target_kobj and it may be removed at any time.
439 * Synchronize using sysfs_symlink_target_lock. See sysfs_remove_dir()
442 spin_lock(&sysfs_symlink_target_lock);
443 target = target_kobj->sd;
446 spin_unlock(&sysfs_symlink_target_lock);
450 entry = kernfs_find_and_get(target, target_name);
457 symlink_name = target_name;
459 link = kernfs_create_link(kobj->sd, symlink_name, entry);
460 if (PTR_ERR(link) == -EEXIST)
461 sysfs_warn_dup(kobj->sd, symlink_name);
465 return PTR_ERR_OR_ZERO(link);
467 EXPORT_SYMBOL_GPL(compat_only_sysfs_link_entry_to_kobj);
469 static int sysfs_group_attrs_change_owner(struct kernfs_node *grp_kn,
470 const struct attribute_group *grp,
471 struct iattr *newattrs)
473 struct kernfs_node *kn;
477 struct attribute *const *attr;
479 for (attr = grp->attrs; *attr; attr++) {
480 kn = kernfs_find_and_get(grp_kn, (*attr)->name);
484 error = kernfs_setattr(kn, newattrs);
491 if (grp->bin_attrs) {
492 struct bin_attribute *const *bin_attr;
494 for (bin_attr = grp->bin_attrs; *bin_attr; bin_attr++) {
495 kn = kernfs_find_and_get(grp_kn, (*bin_attr)->attr.name);
499 error = kernfs_setattr(kn, newattrs);
510 * sysfs_group_change_owner - change owner of an attribute group.
511 * @kobj: The kobject containing the group.
512 * @grp: The attribute group.
513 * @kuid: new owner's kuid
514 * @kgid: new owner's kgid
516 * Returns 0 on success or error code on failure.
518 int sysfs_group_change_owner(struct kobject *kobj,
519 const struct attribute_group *grp, kuid_t kuid,
522 struct kernfs_node *grp_kn;
524 struct iattr newattrs = {
525 .ia_valid = ATTR_UID | ATTR_GID,
530 if (!kobj->state_in_sysfs)
534 grp_kn = kernfs_find_and_get(kobj->sd, grp->name);
536 kernfs_get(kobj->sd);
542 error = kernfs_setattr(grp_kn, &newattrs);
544 error = sysfs_group_attrs_change_owner(grp_kn, grp, &newattrs);
550 EXPORT_SYMBOL_GPL(sysfs_group_change_owner);
553 * sysfs_groups_change_owner - change owner of a set of attribute groups.
554 * @kobj: The kobject containing the groups.
555 * @groups: The attribute groups.
556 * @kuid: new owner's kuid
557 * @kgid: new owner's kgid
559 * Returns 0 on success or error code on failure.
561 int sysfs_groups_change_owner(struct kobject *kobj,
562 const struct attribute_group **groups,
563 kuid_t kuid, kgid_t kgid)
567 if (!kobj->state_in_sysfs)
573 for (i = 0; groups[i]; i++) {
574 error = sysfs_group_change_owner(kobj, groups[i], kuid, kgid);
581 EXPORT_SYMBOL_GPL(sysfs_groups_change_owner);