| | 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/magic.h> |
| | 17 | #include <linux/mount.h> |
| | 18 | #include <linux/init.h> |
| | 19 | #include <linux/user_namespace.h> |
| | 20 | |
| | 21 | #include "sysfs.h" |
| | 22 | |
| | 23 | static struct kernfs_root *sysfs_root; |
| | 24 | struct kernfs_node *sysfs_root_kn; |
| | 25 | |
| | 26 | static struct dentry *sysfs_mount(struct file_system_type *fs_type, |
| | 27 | int flags, const char *dev_name, void *data) |
| | 28 | { |
| | 29 | struct dentry *root; |
| | 30 | void *ns; |
| | 31 | bool new_sb; |
| | 32 | |
| | 33 | if (!(flags & MS_KERNMOUNT)) { |
| | 34 | if (!kobj_ns_current_may_mount(KOBJ_NS_TYPE_NET)) |
| | 35 | return ERR_PTR(-EPERM); |
| | 36 | } |
| | 37 | |
| | 38 | ns = kobj_ns_grab_current(KOBJ_NS_TYPE_NET); |
| | 39 | root = kernfs_mount_ns(fs_type, flags, sysfs_root, |
| | 40 | SYSFS_MAGIC, &new_sb, ns); |
| | 41 | if (IS_ERR(root) || !new_sb) |
| | 42 | kobj_ns_drop(KOBJ_NS_TYPE_NET, ns); |
| | 43 | else if (new_sb) |
| | 44 | /* Userspace would break if executables appear on sysfs */ |
| | 45 | root->d_sb->s_iflags |= SB_I_NOEXEC; |
| | 46 | |
| | 47 | return root; |
| | 48 | } |
| | 49 | |
| | 50 | static void sysfs_kill_sb(struct super_block *sb) |
| | 51 | { |
| | 52 | void *ns = (void *)kernfs_super_ns(sb); |
| | 53 | |
| | 54 | kernfs_kill_sb(sb); |
| | 55 | kobj_ns_drop(KOBJ_NS_TYPE_NET, ns); |
| | 56 | } |
| | 57 | |
| | 58 | static struct file_system_type sysfs_fs_type = { |
| | 59 | .name = "sysfs", |
| | 60 | .mount = sysfs_mount, |
| | 61 | .kill_sb = sysfs_kill_sb, |
| | 62 | .fs_flags = FS_USERNS_VISIBLE | FS_USERNS_MOUNT, |
| | 63 | }; |
| | 64 | |
| | 65 | int __init sysfs_init(void) |
| | 66 | { |
| | 67 | int err; |
| | 68 | |
| | 69 | sysfs_root = kernfs_create_root(NULL, KERNFS_ROOT_EXTRA_OPEN_PERM_CHECK, |
| | 70 | NULL); |
| | 71 | if (IS_ERR(sysfs_root)) |
| | 72 | return PTR_ERR(sysfs_root); |
| | 73 | |
| | 74 | sysfs_root_kn = sysfs_root->kn; |
| | 75 | |
| | 76 | err = register_filesystem(&sysfs_fs_type); |
| | 77 | if (err) { |
| | 78 | kernfs_destroy_root(sysfs_root); |
| | 79 | return err; |
| | 80 | } |
| | 81 | |
| | 82 | return 0; |
| | 83 | } |
projects / linux-2.6-block.git / blame_incremental