summaryrefslogtreecommitdiffstats
path: root/fs/sysfs/group.c
blob: fe611949a7f7419f789dbb8b4335b76d03e9fab9 (plain) (blame)
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
/*
 * 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;
	int i;

	for (i = 0, attr = grp->attrs; *attr; i++, attr++)
		sysfs_hash_and_remove(dir_sd, (*attr)->name);
}

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

	for (i = 0, attr = grp->attrs; *attr && !error; i++, attr++) {
		mode_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, (*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);
	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->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, create an attribute group
 * @kobj:	The kobject to create the group on
 * @grp:	The attribute group to create
 *
 * 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, 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);
}


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