summaryrefslogtreecommitdiffstats
path: root/fs/sysfs/group.c
blob: e5719c6095c3de13114a684c03d274cc2ff0dea2 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
/*
 * fs/sysfs/group.c - Operations for adding/removing multiple files at once.
 *
 * Copyright (c) 2003 Patrick Mochel
 * Copyright (c) 2003 Open Source Development Lab
 *
 * This file is released undert the GPL v2. 
 *
 */

#include <linux/kobject.h>
#include <linux/module.h>
#include <linux/dcache.h>
#include <linux/namei.h>
#include <linux/err.h>
#include "sysfs.h"


static void remove_files(struct sysfs_dirent *dir_sd, struct kobject *kobj,
			 const struct attribute_group *grp)
{
	struct attribute *const* attr;
	struct bin_attribute *const* bin_attr;

	if (grp->attrs)
		for (attr = grp->attrs; *attr; attr++)
			sysfs_hash_and_remove(dir_sd, NULL, (*attr)->name);
	if (grp->bin_attrs)
		for (bin_attr = grp->bin_attrs; *bin_attr; bin_attr++)
			sysfs_remove_bin_file(kobj, *bin_attr);
}

static int create_files(struct sysfs_dirent *dir_sd, struct kobject *kobj,
			const struct attribute_group *grp, int update)
{
	struct attribute *const* attr;
	struct bin_attribute *const* bin_attr;
	int error = 0, i;

	if (grp->attrs) {
		for (i = 0, attr = grp->attrs; *attr && !error; i++, attr++) {
			umode_t mode = 0;

			/*
			 * In update mode, we're changing the permissions or
			 * visibility.  Do this by first removing then
			 * re-adding (if required) the file.
			 */
			if (update)
				sysfs_hash_and_remove(dir_sd, NULL,
						      (*attr)->name);
			if (grp->is_visible) {
				mode = grp->is_visible(kobj, *attr, i);
				if (!mode)
					continue;
			}
			error = sysfs_add_file_mode(dir_sd, *attr,
						    SYSFS_KOBJ_ATTR,
						    (*attr)->mode | mode);
			if (unlikely(error))
				break;
		}
		if (error) {
			remove_files(dir_sd, kobj, grp);
			goto exit;
		}
	}

	if (grp->bin_attrs) {
		for (bin_attr = grp->bin_attrs; *bin_attr; bin_attr++) {
			if (update)
				sysfs_remove_bin_file(kobj, *bin_attr);
			error = sysfs_create_bin_file(kobj, *bin_attr);
			if (error)
				break;
		}
		if (error)
			remove_files(dir_sd, kobj, grp);
	}
exit:
	return error;
}


static int internal_create_group(struct kobject *kobj, int update,
				 const struct attribute_group *grp)
{
	struct sysfs_dirent *sd;
	int error;

	BUG_ON(!kobj || (!update && !kobj->sd));

	/* Updates may happen before the object has been instantiated */
	if (unlikely(update && !kobj->sd))
		return -EINVAL;
	if (!grp->attrs) {
		WARN(1, "sysfs: attrs not set by subsystem for group: %s/%s\n",
			kobj->name, grp->name ? "" : grp->name);
		return -EINVAL;
	}
	if (grp->name) {
		error = sysfs_create_subdir(kobj, grp->name, &sd);
		if (error)
			return error;
	} else
		sd = kobj->sd;
	sysfs_get(sd);
	error = create_files(sd, kobj, grp, update);
	if (error) {
		if (grp->name)
			sysfs_remove_subdir(sd);
	}
	sysfs_put(sd);
	return error;
}

/**
 * sysfs_create_group - given a directory kobject, create an attribute group
 * @kobj:	The kobject to create the group on
 * @grp:	The attribute group to create
 *
 * This function creates a group for the first time.  It will explicitly
 * warn and error if any of the attribute files being created already exist.
 *
 * Returns 0 on success or error.
 */
int sysfs_create_group(struct kobject *kobj,
		       const struct attribute_group *grp)
{
	return internal_create_group(kobj, 0, grp);
}

/**
 * sysfs_update_group - given a directory kobject, update an attribute group
 * @kobj:	The kobject to update the group on
 * @grp:	The attribute group to update
 *
 * This function updates an attribute group.  Unlike
 * sysfs_create_group(), it will explicitly not warn or error if any
 * of the attribute files being created already exist.  Furthermore,
 * if the visibility of the files has changed through the is_visible()
 * callback, it will update the permissions and add or remove the
 * relevant files.
 *
 * The primary use for this function is to call it after making a change
 * that affects group visibility.
 *
 * Returns 0 on success or error.
 */
int sysfs_update_group(struct kobject *kobj,
		       const struct attribute_group *grp)
{
	return internal_create_group(kobj, 1, grp);
}



void sysfs_remove_group(struct kobject * kobj, 
			const struct attribute_group * grp)
{
	struct sysfs_dirent *dir_sd = kobj->sd;
	struct sysfs_dirent *sd;

	if (grp->name) {
		sd = sysfs_get_dirent(dir_sd, NULL, grp->name);
		if (!sd) {
			WARN(!sd, KERN_WARNING "sysfs group %p not found for "
				"kobject '%s'\n", grp, kobject_name(kobj));
			return;
		}
	} else
		sd = sysfs_get(dir_sd);

	remove_files(sd, kobj, grp);
	if (grp->name)
		sysfs_remove_subdir(sd);

	sysfs_put(sd);
}

/**
 * sysfs_merge_group - merge files into a pre-existing attribute group.
 * @kobj:	The kobject containing the group.
 * @grp:	The files to create and the attribute group they belong to.
 *
 * This function returns an error if the group doesn't exist or any of the
 * files already exist in that group, in which case none of the new files
 * are created.
 */
int sysfs_merge_group(struct kobject *kobj,
		       const struct attribute_group *grp)
{
	struct sysfs_dirent *dir_sd;
	int error = 0;
	struct attribute *const *attr;
	int i;

	dir_sd = sysfs_get_dirent(kobj->sd, NULL, grp->name);
	if (!dir_sd)
		return -ENOENT;

	for ((i = 0, attr = grp->attrs); *attr && !error; (++i, ++attr))
		error = sysfs_add_file(dir_sd, *attr, SYSFS_KOBJ_ATTR);
	if (error) {
		while (--i >= 0)
			sysfs_hash_and_remove(dir_sd, NULL, (*--attr)->name);
	}
	sysfs_put(dir_sd);

	return error;
}
EXPORT_SYMBOL_GPL(sysfs_merge_group);

/**
 * sysfs_unmerge_group - remove files from a pre-existing attribute group.
 * @kobj:	The kobject containing the group.
 * @grp:	The files to remove and the attribute group they belong to.
 */
void sysfs_unmerge_group(struct kobject *kobj,
		       const struct attribute_group *grp)
{
	struct sysfs_dirent *dir_sd;
	struct attribute *const *attr;

	dir_sd = sysfs_get_dirent(kobj->sd, NULL, grp->name);
	if (dir_sd) {
		for (attr = grp->attrs; *attr; ++attr)
			sysfs_hash_and_remove(dir_sd, NULL, (*attr)->name);
		sysfs_put(dir_sd);
	}
}
EXPORT_SYMBOL_GPL(sysfs_unmerge_group);

/**
 * sysfs_add_link_to_group - add a symlink to an attribute group.
 * @kobj:	The kobject containing the group.
 * @group_name:	The name of the group.
 * @target:	The target kobject of the symlink to create.
 * @link_name:	The name of the symlink to create.
 */
int sysfs_add_link_to_group(struct kobject *kobj, const char *group_name,
			    struct kobject *target, const char *link_name)
{
	struct sysfs_dirent *dir_sd;
	int error = 0;

	dir_sd = sysfs_get_dirent(kobj->sd, NULL, group_name);
	if (!dir_sd)
		return -ENOENT;

	error = sysfs_create_link_sd(dir_sd, target, link_name);
	sysfs_put(dir_sd);

	return error;
}
EXPORT_SYMBOL_GPL(sysfs_add_link_to_group);

/**
 * sysfs_remove_link_from_group - remove a symlink from an attribute group.
 * @kobj:	The kobject containing the group.
 * @group_name:	The name of the group.
 * @link_name:	The name of the symlink to remove.
 */
void sysfs_remove_link_from_group(struct kobject *kobj, const char *group_name,
				  const char *link_name)
{
	struct sysfs_dirent *dir_sd;

	dir_sd = sysfs_get_dirent(kobj->sd, NULL, group_name);
	if (dir_sd) {
		sysfs_hash_and_remove(dir_sd, NULL, link_name);
		sysfs_put(dir_sd);
	}
}
EXPORT_SYMBOL_GPL(sysfs_remove_link_from_group);

EXPORT_SYMBOL_GPL(sysfs_create_group);
EXPORT_SYMBOL_GPL(sysfs_update_group);
EXPORT_SYMBOL_GPL(sysfs_remove_group);