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Commit | Line | Data |
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1da177e4 | 1 | /* |
6d66f5cd TH |
2 | * fs/sysfs/symlink.c - operations for initializing and mounting sysfs |
3 | * | |
4 | * Copyright (c) 2001-3 Patrick Mochel | |
5 | * Copyright (c) 2007 SUSE Linux Products GmbH | |
6 | * Copyright (c) 2007 Tejun Heo <teheo@suse.de> | |
7 | * | |
8 | * This file is released under the GPLv2. | |
9 | * | |
10 | * Please see Documentation/filesystems/sysfs.txt for more information. | |
1da177e4 LT |
11 | */ |
12 | ||
6b8fbde4 | 13 | #define DEBUG |
1da177e4 LT |
14 | |
15 | #include <linux/fs.h> | |
16 | #include <linux/mount.h> | |
1da177e4 | 17 | #include <linux/init.h> |
87a8ebd6 | 18 | #include <linux/user_namespace.h> |
1da177e4 LT |
19 | |
20 | #include "sysfs.h" | |
21 | ||
ba7443bc | 22 | static struct kernfs_root *sysfs_root; |
324a56e1 | 23 | struct kernfs_node *sysfs_root_kn; |
061447a4 | 24 | |
d0e46f88 AV |
25 | static struct dentry *sysfs_mount(struct file_system_type *fs_type, |
26 | int flags, const char *dev_name, void *data) | |
1da177e4 | 27 | { |
4b93dc9b TH |
28 | struct dentry *root; |
29 | void *ns; | |
fed95bab | 30 | bool new_sb; |
9e7fdd25 | 31 | |
7dc5dbc8 EB |
32 | if (!(flags & MS_KERNMOUNT)) { |
33 | if (!capable(CAP_SYS_ADMIN) && !fs_fully_visible(fs_type)) | |
34 | return ERR_PTR(-EPERM); | |
35 | ||
c84a3b27 TH |
36 | if (!kobj_ns_current_may_mount(KOBJ_NS_TYPE_NET)) |
37 | return ERR_PTR(-EPERM); | |
7dc5dbc8 | 38 | } |
87a8ebd6 | 39 | |
4b93dc9b | 40 | ns = kobj_ns_grab_current(KOBJ_NS_TYPE_NET); |
fed95bab LZ |
41 | root = kernfs_mount_ns(fs_type, flags, sysfs_root, &new_sb, ns); |
42 | if (IS_ERR(root) || !new_sb) | |
4b93dc9b TH |
43 | kobj_ns_drop(KOBJ_NS_TYPE_NET, ns); |
44 | return root; | |
45 | } | |
46 | ||
9e7fdd25 | 47 | static void sysfs_kill_sb(struct super_block *sb) |
4b93dc9b | 48 | { |
a7560a01 TH |
49 | void *ns = (void *)kernfs_super_ns(sb); |
50 | ||
4b93dc9b | 51 | kernfs_kill_sb(sb); |
a7560a01 | 52 | kobj_ns_drop(KOBJ_NS_TYPE_NET, ns); |
4b93dc9b TH |
53 | } |
54 | ||
1da177e4 LT |
55 | static struct file_system_type sysfs_fs_type = { |
56 | .name = "sysfs", | |
d0e46f88 | 57 | .mount = sysfs_mount, |
9e7fdd25 | 58 | .kill_sb = sysfs_kill_sb, |
4f326c00 | 59 | .fs_flags = FS_USERNS_MOUNT, |
1da177e4 LT |
60 | }; |
61 | ||
4b93dc9b TH |
62 | int __init sysfs_init(void) |
63 | { | |
64 | int err; | |
e0bf68dd | 65 | |
555724a8 TH |
66 | sysfs_root = kernfs_create_root(NULL, KERNFS_ROOT_EXTRA_OPEN_PERM_CHECK, |
67 | NULL); | |
4b93dc9b TH |
68 | if (IS_ERR(sysfs_root)) |
69 | return PTR_ERR(sysfs_root); | |
70 | ||
324a56e1 | 71 | sysfs_root_kn = sysfs_root->kn; |
ba7443bc | 72 | |
1da177e4 | 73 | err = register_filesystem(&sysfs_fs_type); |
4b93dc9b TH |
74 | if (err) { |
75 | kernfs_destroy_root(sysfs_root); | |
76 | return err; | |
77 | } | |
9e30cc95 TH |
78 | |
79 | return 0; | |
1da177e4 | 80 | } |