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
|
/*
* fs/sysfs/symlink.c - sysfs symlink implementation
*
* Copyright (c) 2001-3 Patrick Mochel
* Copyright (c) 2007 SUSE Linux Products GmbH
* Copyright (c) 2007 Tejun Heo <teheo@suse.de>
*
* This file is released under the GPLv2.
*
* Please see Documentation/filesystems/sysfs.txt for more information.
*/
#include <linux/fs.h>
#include <linux/module.h>
#include <linux/kobject.h>
#include <linux/mutex.h>
#include <linux/security.h>
#include "sysfs.h"
static int sysfs_do_create_link_sd(struct sysfs_dirent *parent_sd,
struct kobject *target,
const char *name, int warn)
{
struct sysfs_dirent *sd, *target_sd = NULL;
BUG_ON(!name || !parent_sd);
/*
* We don't own @target and it may be removed at any time.
* Synchronize using sysfs_symlink_target_lock. See
* sysfs_remove_dir() for details.
*/
spin_lock(&sysfs_symlink_target_lock);
if (target->sd) {
target_sd = target->sd;
kernfs_get(target_sd);
}
spin_unlock(&sysfs_symlink_target_lock);
if (!target_sd)
return -ENOENT;
sd = kernfs_create_link(parent_sd, name, target_sd);
kernfs_put(target_sd);
if (!IS_ERR(sd))
return 0;
if (warn && PTR_ERR(sd) == -EEXIST)
sysfs_warn_dup(parent_sd, name);
return PTR_ERR(sd);
}
/**
* sysfs_create_link_sd - create symlink to a given object.
* @sd: directory we're creating the link in.
* @target: object we're pointing to.
* @name: name of the symlink.
*/
int sysfs_create_link_sd(struct sysfs_dirent *sd, struct kobject *target,
const char *name)
{
return sysfs_do_create_link_sd(sd, target, name, 1);
}
static int sysfs_do_create_link(struct kobject *kobj, struct kobject *target,
const char *name, int warn)
{
struct sysfs_dirent *parent_sd = NULL;
if (!kobj)
parent_sd = sysfs_root_sd;
else
parent_sd = kobj->sd;
if (!parent_sd)
return -EFAULT;
return sysfs_do_create_link_sd(parent_sd, target, name, warn);
}
/**
* sysfs_create_link - create symlink between two objects.
* @kobj: object whose directory we're creating the link in.
* @target: object we're pointing to.
* @name: name of the symlink.
*/
int sysfs_create_link(struct kobject *kobj, struct kobject *target,
const char *name)
{
return sysfs_do_create_link(kobj, target, name, 1);
}
EXPORT_SYMBOL_GPL(sysfs_create_link);
/**
* sysfs_create_link_nowarn - create symlink between two objects.
* @kobj: object whose directory we're creating the link in.
* @target: object we're pointing to.
* @name: name of the symlink.
*
* This function does the same as sysfs_create_link(), but it
* doesn't warn if the link already exists.
*/
int sysfs_create_link_nowarn(struct kobject *kobj, struct kobject *target,
const char *name)
{
return sysfs_do_create_link(kobj, target, name, 0);
}
/**
* sysfs_delete_link - remove symlink in object's directory.
* @kobj: object we're acting for.
* @targ: object we're pointing to.
* @name: name of the symlink to remove.
*
* Unlike sysfs_remove_link sysfs_delete_link has enough information
* to successfully delete symlinks in tagged directories.
*/
void sysfs_delete_link(struct kobject *kobj, struct kobject *targ,
const char *name)
{
const void *ns = NULL;
/*
* We don't own @target and it may be removed at any time.
* Synchronize using sysfs_symlink_target_lock. See
* sysfs_remove_dir() for details.
*/
spin_lock(&sysfs_symlink_target_lock);
if (targ->sd && (kobj->sd->s_flags & SYSFS_FLAG_NS))
ns = targ->sd->s_ns;
spin_unlock(&sysfs_symlink_target_lock);
kernfs_remove_by_name_ns(kobj->sd, name, ns);
}
/**
* sysfs_remove_link - remove symlink in object's directory.
* @kobj: object we're acting for.
* @name: name of the symlink to remove.
*/
void sysfs_remove_link(struct kobject *kobj, const char *name)
{
struct sysfs_dirent *parent_sd = NULL;
if (!kobj)
parent_sd = sysfs_root_sd;
else
parent_sd = kobj->sd;
kernfs_remove_by_name(parent_sd, name);
}
EXPORT_SYMBOL_GPL(sysfs_remove_link);
/**
* sysfs_rename_link_ns - rename symlink in object's directory.
* @kobj: object we're acting for.
* @targ: object we're pointing to.
* @old: previous name of the symlink.
* @new: new name of the symlink.
* @new_ns: new namespace of the symlink.
*
* A helper function for the common rename symlink idiom.
*/
int sysfs_rename_link_ns(struct kobject *kobj, struct kobject *targ,
const char *old, const char *new, const void *new_ns)
{
struct sysfs_dirent *parent_sd, *sd = NULL;
const void *old_ns = NULL;
int result;
if (!kobj)
parent_sd = sysfs_root_sd;
else
parent_sd = kobj->sd;
if (targ->sd)
old_ns = targ->sd->s_ns;
result = -ENOENT;
sd = kernfs_find_and_get_ns(parent_sd, old, old_ns);
if (!sd)
goto out;
result = -EINVAL;
if (sysfs_type(sd) != SYSFS_KOBJ_LINK)
goto out;
if (sd->s_symlink.target_sd->priv != targ)
goto out;
result = kernfs_rename_ns(sd, parent_sd, new, new_ns);
out:
kernfs_put(sd);
return result;
}
EXPORT_SYMBOL_GPL(sysfs_rename_link_ns);
|
