Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1/*
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.
11 */
12
13#define DEBUG
14
15#include <linux/fs.h>
16#include <linux/mount.h>
17#include <linux/init.h>
18#include <linux/user_namespace.h>
19
20#include "sysfs.h"
21
22static struct kernfs_root *sysfs_root;
23struct kernfs_node *sysfs_root_kn;
24
25static struct dentry *sysfs_mount(struct file_system_type *fs_type,
26 int flags, const char *dev_name, void *data)
27{
28 struct dentry *root;
29 void *ns;
30
31 if (!(flags & MS_KERNMOUNT)) {
32 if (!capable(CAP_SYS_ADMIN) && !fs_fully_visible(fs_type))
33 return ERR_PTR(-EPERM);
34
35 if (!kobj_ns_current_may_mount(KOBJ_NS_TYPE_NET))
36 return ERR_PTR(-EPERM);
37 }
38
39 ns = kobj_ns_grab_current(KOBJ_NS_TYPE_NET);
40 root = kernfs_mount_ns(fs_type, flags, sysfs_root, ns);
41 if (IS_ERR(root))
42 kobj_ns_drop(KOBJ_NS_TYPE_NET, ns);
43 return root;
44}
45
46static void sysfs_kill_sb(struct super_block *sb)
47{
48 void *ns = (void *)kernfs_super_ns(sb);
49
50 kernfs_kill_sb(sb);
51 kobj_ns_drop(KOBJ_NS_TYPE_NET, ns);
52}
53
54static struct file_system_type sysfs_fs_type = {
55 .name = "sysfs",
56 .mount = sysfs_mount,
57 .kill_sb = sysfs_kill_sb,
58 .fs_flags = FS_USERNS_MOUNT,
59};
60
61int __init sysfs_init(void)
62{
63 int err;
64
65 sysfs_root = kernfs_create_root(NULL, NULL);
66 if (IS_ERR(sysfs_root))
67 return PTR_ERR(sysfs_root);
68
69 sysfs_root_kn = sysfs_root->kn;
70
71 err = register_filesystem(&sysfs_fs_type);
72 if (err) {
73 kernfs_destroy_root(sysfs_root);
74 return err;
75 }
76
77 return 0;
78}