Commit | Line | Data |
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e656d8a6 EB |
1 | #include <linux/sched.h> |
2 | #include <linux/namei.h> | |
0d01ff25 | 3 | #include <linux/slab.h> |
021ada7d AV |
4 | #include <linux/pid_namespace.h> |
5 | #include "internal.h" | |
e656d8a6 EB |
6 | |
7 | /* | |
8 | * /proc/self: | |
9 | */ | |
10 | static int proc_self_readlink(struct dentry *dentry, char __user *buffer, | |
11 | int buflen) | |
12 | { | |
13 | struct pid_namespace *ns = dentry->d_sb->s_fs_info; | |
14 | pid_t tgid = task_tgid_nr_ns(current, ns); | |
15 | char tmp[PROC_NUMBUF]; | |
16 | if (!tgid) | |
17 | return -ENOENT; | |
18 | sprintf(tmp, "%d", tgid); | |
19 | return vfs_readlink(dentry,buffer,buflen,tmp); | |
20 | } | |
21 | ||
22 | static void *proc_self_follow_link(struct dentry *dentry, struct nameidata *nd) | |
23 | { | |
24 | struct pid_namespace *ns = dentry->d_sb->s_fs_info; | |
25 | pid_t tgid = task_tgid_nr_ns(current, ns); | |
26 | char *name = ERR_PTR(-ENOENT); | |
27 | if (tgid) { | |
28 | /* 11 for max length of signed int in decimal + NULL term */ | |
29 | name = kmalloc(12, GFP_KERNEL); | |
30 | if (!name) | |
31 | name = ERR_PTR(-ENOMEM); | |
32 | else | |
33 | sprintf(name, "%d", tgid); | |
34 | } | |
35 | nd_set_link(nd, name); | |
36 | return NULL; | |
37 | } | |
38 | ||
39 | static void proc_self_put_link(struct dentry *dentry, struct nameidata *nd, | |
40 | void *cookie) | |
41 | { | |
42 | char *s = nd_get_link(nd); | |
43 | if (!IS_ERR(s)) | |
44 | kfree(s); | |
45 | } | |
46 | ||
47 | static const struct inode_operations proc_self_inode_operations = { | |
48 | .readlink = proc_self_readlink, | |
49 | .follow_link = proc_self_follow_link, | |
50 | .put_link = proc_self_put_link, | |
51 | }; | |
52 | ||
021ada7d AV |
53 | static unsigned self_inum; |
54 | ||
55 | int proc_setup_self(struct super_block *s) | |
e656d8a6 | 56 | { |
021ada7d AV |
57 | struct inode *root_inode = s->s_root->d_inode; |
58 | struct pid_namespace *ns = s->s_fs_info; | |
59 | struct dentry *self; | |
60 | ||
61 | mutex_lock(&root_inode->i_mutex); | |
62 | self = d_alloc_name(s->s_root, "self"); | |
63 | if (self) { | |
64 | struct inode *inode = new_inode_pseudo(s); | |
65 | if (inode) { | |
66 | inode->i_ino = self_inum; | |
67 | inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; | |
68 | inode->i_mode = S_IFLNK | S_IRWXUGO; | |
69 | inode->i_uid = GLOBAL_ROOT_UID; | |
70 | inode->i_gid = GLOBAL_ROOT_GID; | |
71 | inode->i_op = &proc_self_inode_operations; | |
72 | d_add(self, inode); | |
73 | } else { | |
74 | dput(self); | |
75 | self = ERR_PTR(-ENOMEM); | |
76 | } | |
77 | } else { | |
78 | self = ERR_PTR(-ENOMEM); | |
79 | } | |
80 | mutex_unlock(&root_inode->i_mutex); | |
81 | if (IS_ERR(self)) { | |
82 | pr_err("proc_fill_super: can't allocate /proc/self\n"); | |
83 | return PTR_ERR(self); | |
84 | } | |
85 | ns->proc_self = self; | |
86 | return 0; | |
87 | } | |
e656d8a6 | 88 | |
021ada7d AV |
89 | void __init proc_self_init(void) |
90 | { | |
91 | proc_alloc_inum(&self_inum); | |
e656d8a6 | 92 | } |