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
|
/*
* fs/sysfs/dir.c - sysfs core and dir operation 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.
*/
#undef DEBUG
#include <linux/fs.h>
#include <linux/kobject.h>
#include <linux/slab.h>
#include "sysfs.h"
DEFINE_SPINLOCK(sysfs_symlink_target_lock);
void sysfs_warn_dup(struct kernfs_node *parent, const char *name)
{
char *buf;
buf = kzalloc(PATH_MAX, GFP_KERNEL);
if (buf)
kernfs_path(parent, buf, PATH_MAX);
WARN(1, KERN_WARNING "sysfs: cannot create duplicate filename '%s/%s'\n",
buf, name);
kfree(buf);
}
/**
* sysfs_create_dir_ns - create a directory for an object with a namespace tag
* @kobj: object we're creating directory for
* @ns: the namespace tag to use
*/
int sysfs_create_dir_ns(struct kobject *kobj, const void *ns)
{
struct kernfs_node *parent, *kn;
BUG_ON(!kobj);
if (kobj->parent)
parent = kobj->parent->sd;
else
parent = sysfs_root_kn;
if (!parent)
return -ENOENT;
kn = kernfs_create_dir_ns(parent, kobject_name(kobj),
S_IRWXU | S_IRUGO | S_IXUGO, kobj, ns);
if (IS_ERR(kn)) {
if (PTR_ERR(kn) == -EEXIST)
sysfs_warn_dup(parent, kobject_name(kobj));
return PTR_ERR(kn);
}
kobj->sd = kn;
return 0;
}
/**
* sysfs_remove_dir - remove an object's directory.
* @kobj: object.
*
* The only thing special about this is that we remove any files in
* the directory before we remove the directory, and we've inlined
* what used to be sysfs_rmdir() below, instead of calling separately.
*/
void sysfs_remove_dir(struct kobject *kobj)
{
struct kernfs_node *kn = kobj->sd;
/*
* In general, kboject owner is responsible for ensuring removal
* doesn't race with other operations and sysfs doesn't provide any
* protection; however, when @kobj is used as a symlink target, the
* symlinking entity usually doesn't own @kobj and thus has no
* control over removal. @kobj->sd may be removed anytime
* and symlink code may end up dereferencing an already freed node.
*
* sysfs_symlink_target_lock synchronizes @kobj->sd
* disassociation against symlink operations so that symlink code
* can safely dereference @kobj->sd.
*/
spin_lock(&sysfs_symlink_target_lock);
kobj->sd = NULL;
spin_unlock(&sysfs_symlink_target_lock);
if (kn) {
WARN_ON_ONCE(kernfs_type(kn) != KERNFS_DIR);
kernfs_remove(kn);
}
}
int sysfs_rename_dir_ns(struct kobject *kobj, const char *new_name,
const void *new_ns)
{
struct kernfs_node *parent;
int ret;
parent = kernfs_get_parent(kobj->sd);
ret = kernfs_rename_ns(kobj->sd, parent, new_name, new_ns);
kernfs_put(parent);
return ret;
}
int sysfs_move_dir_ns(struct kobject *kobj, struct kobject *new_parent_kobj,
const void *new_ns)
{
struct kernfs_node *kn = kobj->sd;
struct kernfs_node *new_parent;
new_parent = new_parent_kobj && new_parent_kobj->sd ?
new_parent_kobj->sd : sysfs_root_kn;
return kernfs_rename_ns(kn, new_parent, kn->name, new_ns);
}
/**
* sysfs_create_mount_point - create an always empty directory
* @parent_kobj: kobject that will contain this always empty directory
* @name: The name of the always empty directory to add
*/
int sysfs_create_mount_point(struct kobject *parent_kobj, const char *name)
{
struct kernfs_node *kn, *parent = parent_kobj->sd;
kn = kernfs_create_empty_dir(parent, name);
if (IS_ERR(kn)) {
if (PTR_ERR(kn) == -EEXIST)
sysfs_warn_dup(parent, name);
return PTR_ERR(kn);
}
return 0;
}
EXPORT_SYMBOL_GPL(sysfs_create_mount_point);
/**
* sysfs_remove_mount_point - remove an always empty directory.
* @parent_kobj: kobject that will contain this always empty directory
* @name: The name of the always empty directory to remove
*
*/
void sysfs_remove_mount_point(struct kobject *parent_kobj, const char *name)
{
struct kernfs_node *parent = parent_kobj->sd;
kernfs_remove_by_name_ns(parent, name, NULL);
}
EXPORT_SYMBOL_GPL(sysfs_remove_mount_point);
|
