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