Commit | Line | Data |
---|---|---|
e656d8a6 | 1 | #include <linux/sched.h> |
0d01ff25 | 2 | #include <linux/slab.h> |
021ada7d AV |
3 | #include <linux/pid_namespace.h> |
4 | #include "internal.h" | |
e656d8a6 EB |
5 | |
6 | /* | |
7 | * /proc/self: | |
8 | */ | |
9 | static int proc_self_readlink(struct dentry *dentry, char __user *buffer, | |
10 | int buflen) | |
11 | { | |
12 | struct pid_namespace *ns = dentry->d_sb->s_fs_info; | |
13 | pid_t tgid = task_tgid_nr_ns(current, ns); | |
14 | char tmp[PROC_NUMBUF]; | |
15 | if (!tgid) | |
16 | return -ENOENT; | |
17 | sprintf(tmp, "%d", tgid); | |
5d826c84 | 18 | return readlink_copy(buffer, buflen, tmp); |
e656d8a6 EB |
19 | } |
20 | ||
6b255391 AV |
21 | static const char *proc_self_get_link(struct dentry *dentry, |
22 | struct inode *inode, void **cookie) | |
e656d8a6 | 23 | { |
6b255391 | 24 | struct pid_namespace *ns = inode->i_sb->s_fs_info; |
e656d8a6 | 25 | pid_t tgid = task_tgid_nr_ns(current, ns); |
680baacb AV |
26 | char *name; |
27 | ||
28 | if (!tgid) | |
29 | return ERR_PTR(-ENOENT); | |
30 | /* 11 for max length of signed int in decimal + NULL term */ | |
1a384eaa AV |
31 | name = kmalloc(12, dentry ? GFP_KERNEL : GFP_ATOMIC); |
32 | if (unlikely(!name)) | |
33 | return dentry ? ERR_PTR(-ENOMEM) : ERR_PTR(-ECHILD); | |
680baacb AV |
34 | sprintf(name, "%d", tgid); |
35 | return *cookie = name; | |
e656d8a6 EB |
36 | } |
37 | ||
e656d8a6 EB |
38 | static const struct inode_operations proc_self_inode_operations = { |
39 | .readlink = proc_self_readlink, | |
6b255391 | 40 | .get_link = proc_self_get_link, |
87dc800b | 41 | .put_link = kfree_put_link, |
e656d8a6 EB |
42 | }; |
43 | ||
021ada7d AV |
44 | static unsigned self_inum; |
45 | ||
46 | int proc_setup_self(struct super_block *s) | |
e656d8a6 | 47 | { |
2b0143b5 | 48 | struct inode *root_inode = d_inode(s->s_root); |
021ada7d AV |
49 | struct pid_namespace *ns = s->s_fs_info; |
50 | struct dentry *self; | |
51 | ||
52 | mutex_lock(&root_inode->i_mutex); | |
53 | self = d_alloc_name(s->s_root, "self"); | |
54 | if (self) { | |
55 | struct inode *inode = new_inode_pseudo(s); | |
56 | if (inode) { | |
57 | inode->i_ino = self_inum; | |
58 | inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; | |
59 | inode->i_mode = S_IFLNK | S_IRWXUGO; | |
60 | inode->i_uid = GLOBAL_ROOT_UID; | |
61 | inode->i_gid = GLOBAL_ROOT_GID; | |
62 | inode->i_op = &proc_self_inode_operations; | |
63 | d_add(self, inode); | |
64 | } else { | |
65 | dput(self); | |
66 | self = ERR_PTR(-ENOMEM); | |
67 | } | |
68 | } else { | |
69 | self = ERR_PTR(-ENOMEM); | |
70 | } | |
71 | mutex_unlock(&root_inode->i_mutex); | |
72 | if (IS_ERR(self)) { | |
73 | pr_err("proc_fill_super: can't allocate /proc/self\n"); | |
74 | return PTR_ERR(self); | |
75 | } | |
76 | ns->proc_self = self; | |
77 | return 0; | |
78 | } | |
e656d8a6 | 79 | |
021ada7d AV |
80 | void __init proc_self_init(void) |
81 | { | |
82 | proc_alloc_inum(&self_inum); | |
e656d8a6 | 83 | } |