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 (bin_attr = grp->bin_attrs; *bin_attr; bin_attr++) {
77			if (update)
78				kernfs_remove_by_name(parent,
79						(*bin_attr)->attr.name);
80			error = sysfs_add_file_mode_ns(parent,
81					&(*bin_attr)->attr, true,
82					(*bin_attr)->attr.mode, NULL);
83			if (error)
84				break;
85		}
86		if (error)
87			remove_files(parent, grp);
88	}
89exit:
90	return error;
91}
92
93
94static int internal_create_group(struct kobject *kobj, int update,
95				 const struct attribute_group *grp)
96{
97	struct kernfs_node *kn;
98	int error;
99
100	BUG_ON(!kobj || (!update && !kobj->sd));
101
102	/* Updates may happen before the object has been instantiated */
103	if (unlikely(update && !kobj->sd))
104		return -EINVAL;
105	if (!grp->attrs && !grp->bin_attrs) {
106		WARN(1, "sysfs: (bin_)attrs not set by subsystem for group: %s/%s\n",
107			kobj->name, grp->name ?: "");
108		return -EINVAL;
109	}
110	if (grp->name) {
111		kn = kernfs_create_dir(kobj->sd, grp->name,
112				       S_IRWXU | S_IRUGO | S_IXUGO, kobj);
113		if (IS_ERR(kn)) {
114			if (PTR_ERR(kn) == -EEXIST)
115				sysfs_warn_dup(kobj->sd, grp->name);
116			return PTR_ERR(kn);
117		}
118	} else
119		kn = kobj->sd;
120	kernfs_get(kn);
121	error = create_files(kn, kobj, grp, update);
122	if (error) {
123		if (grp->name)
124			kernfs_remove(kn);
125	}
126	kernfs_put(kn);
127	return error;
128}
129
130/**
131 * sysfs_create_group - given a directory kobject, create an attribute group
132 * @kobj:	The kobject to create the group on
133 * @grp:	The attribute group to create
134 *
135 * This function creates a group for the first time.  It will explicitly
136 * warn and error if any of the attribute files being created already exist.
137 *
138 * Returns 0 on success or error.
139 */
140int sysfs_create_group(struct kobject *kobj,
141		       const struct attribute_group *grp)
142{
143	return internal_create_group(kobj, 0, grp);
144}
145EXPORT_SYMBOL_GPL(sysfs_create_group);
146
147/**
148 * sysfs_create_groups - given a directory kobject, create a bunch of attribute groups
149 * @kobj:	The kobject to create the group on
150 * @groups:	The attribute groups to create, NULL terminated
151 *
152 * This function creates a bunch of attribute groups.  If an error occurs when
153 * creating a group, all previously created groups will be removed, unwinding
154 * everything back to the original state when this function was called.
155 * It will explicitly warn and error if any of the attribute files being
156 * created already exist.
157 *
158 * Returns 0 on success or error code from sysfs_create_group on error.
159 */
160int sysfs_create_groups(struct kobject *kobj,
161			const struct attribute_group **groups)
162{
163	int error = 0;
164	int i;
165
166	if (!groups)
167		return 0;
168
169	for (i = 0; groups[i]; i++) {
170		error = sysfs_create_group(kobj, groups[i]);
171		if (error) {
172			while (--i >= 0)
173				sysfs_remove_group(kobj, groups[i]);
174			break;
175		}
176	}
177	return error;
178}
179EXPORT_SYMBOL_GPL(sysfs_create_groups);
180
181/**
182 * sysfs_update_group - given a directory kobject, update an attribute group
183 * @kobj:	The kobject to update the group on
184 * @grp:	The attribute group to update
185 *
186 * This function updates an attribute group.  Unlike
187 * sysfs_create_group(), it will explicitly not warn or error if any
188 * of the attribute files being created already exist.  Furthermore,
189 * if the visibility of the files has changed through the is_visible()
190 * callback, it will update the permissions and add or remove the
191 * relevant files.
192 *
193 * The primary use for this function is to call it after making a change
194 * that affects group visibility.
195 *
196 * Returns 0 on success or error.
197 */
198int sysfs_update_group(struct kobject *kobj,
199		       const struct attribute_group *grp)
200{
201	return internal_create_group(kobj, 1, grp);
202}
203EXPORT_SYMBOL_GPL(sysfs_update_group);
204
205/**
206 * sysfs_remove_group: remove a group from a kobject
207 * @kobj:	kobject to remove the group from
208 * @grp:	group to remove
209 *
210 * This function removes a group of attributes from a kobject.  The attributes
211 * previously have to have been created for this group, otherwise it will fail.
212 */
213void sysfs_remove_group(struct kobject *kobj,
214			const struct attribute_group *grp)
215{
216	struct kernfs_node *parent = kobj->sd;
217	struct kernfs_node *kn;
218
219	if (grp->name) {
220		kn = kernfs_find_and_get(parent, grp->name);
221		if (!kn) {
222			WARN(!kn, KERN_WARNING
223			     "sysfs group %p not found for kobject '%s'\n",
224			     grp, kobject_name(kobj));
225			return;
226		}
227	} else {
228		kn = parent;
229		kernfs_get(kn);
230	}
231
232	remove_files(kn, grp);
233	if (grp->name)
234		kernfs_remove(kn);
235
236	kernfs_put(kn);
237}
238EXPORT_SYMBOL_GPL(sysfs_remove_group);
239
240/**
241 * sysfs_remove_groups - remove a list of groups
242 *
243 * @kobj:	The kobject for the groups to be removed from
244 * @groups:	NULL terminated list of groups to be removed
245 *
246 * If groups is not NULL, remove the specified groups from the kobject.
247 */
248void sysfs_remove_groups(struct kobject *kobj,
249			 const struct attribute_group **groups)
250{
251	int i;
252
253	if (!groups)
254		return;
255	for (i = 0; groups[i]; i++)
256		sysfs_remove_group(kobj, groups[i]);
257}
258EXPORT_SYMBOL_GPL(sysfs_remove_groups);
259
260/**
261 * sysfs_merge_group - merge files into a pre-existing attribute group.
262 * @kobj:	The kobject containing the group.
263 * @grp:	The files to create and the attribute group they belong to.
264 *
265 * This function returns an error if the group doesn't exist or any of the
266 * files already exist in that group, in which case none of the new files
267 * are created.
268 */
269int sysfs_merge_group(struct kobject *kobj,
270		       const struct attribute_group *grp)
271{
272	struct kernfs_node *parent;
273	int error = 0;
274	struct attribute *const *attr;
275	int i;
276
277	parent = kernfs_find_and_get(kobj->sd, grp->name);
278	if (!parent)
279		return -ENOENT;
280
281	for ((i = 0, attr = grp->attrs); *attr && !error; (++i, ++attr))
282		error = sysfs_add_file(parent, *attr, false);
283	if (error) {
284		while (--i >= 0)
285			kernfs_remove_by_name(parent, (*--attr)->name);
286	}
287	kernfs_put(parent);
288
289	return error;
290}
291EXPORT_SYMBOL_GPL(sysfs_merge_group);
292
293/**
294 * sysfs_unmerge_group - remove files from a pre-existing attribute group.
295 * @kobj:	The kobject containing the group.
296 * @grp:	The files to remove and the attribute group they belong to.
297 */
298void sysfs_unmerge_group(struct kobject *kobj,
299		       const struct attribute_group *grp)
300{
301	struct kernfs_node *parent;
302	struct attribute *const *attr;
303
304	parent = kernfs_find_and_get(kobj->sd, grp->name);
305	if (parent) {
306		for (attr = grp->attrs; *attr; ++attr)
307			kernfs_remove_by_name(parent, (*attr)->name);
308		kernfs_put(parent);
309	}
310}
311EXPORT_SYMBOL_GPL(sysfs_unmerge_group);
312
313/**
314 * sysfs_add_link_to_group - add a symlink to an attribute group.
315 * @kobj:	The kobject containing the group.
316 * @group_name:	The name of the group.
317 * @target:	The target kobject of the symlink to create.
318 * @link_name:	The name of the symlink to create.
319 */
320int sysfs_add_link_to_group(struct kobject *kobj, const char *group_name,
321			    struct kobject *target, const char *link_name)
322{
323	struct kernfs_node *parent;
324	int error = 0;
325
326	parent = kernfs_find_and_get(kobj->sd, group_name);
327	if (!parent)
328		return -ENOENT;
329
330	error = sysfs_create_link_sd(parent, target, link_name);
331	kernfs_put(parent);
332
333	return error;
334}
335EXPORT_SYMBOL_GPL(sysfs_add_link_to_group);
336
337/**
338 * sysfs_remove_link_from_group - remove a symlink from an attribute group.
339 * @kobj:	The kobject containing the group.
340 * @group_name:	The name of the group.
341 * @link_name:	The name of the symlink to remove.
342 */
343void sysfs_remove_link_from_group(struct kobject *kobj, const char *group_name,
344				  const char *link_name)
345{
346	struct kernfs_node *parent;
347
348	parent = kernfs_find_and_get(kobj->sd, group_name);
349	if (parent) {
350		kernfs_remove_by_name(parent, link_name);
351		kernfs_put(parent);
352	}
353}
354EXPORT_SYMBOL_GPL(sysfs_remove_link_from_group);
355