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Commit | Line | Data |
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0097875b | 1 | #include <linux/sched.h> |
0097875b EB |
2 | #include <linux/slab.h> |
3 | #include <linux/pid_namespace.h> | |
4 | #include "internal.h" | |
5 | ||
6 | /* | |
7 | * /proc/thread_self: | |
8 | */ | |
9 | static int proc_thread_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 | pid_t pid = task_pid_nr_ns(current, ns); | |
15 | char tmp[PROC_NUMBUF + 6 + PROC_NUMBUF]; | |
16 | if (!pid) | |
17 | return -ENOENT; | |
18 | sprintf(tmp, "%d/task/%d", tgid, pid); | |
19 | return readlink_copy(buffer, buflen, tmp); | |
20 | } | |
21 | ||
6b255391 AV |
22 | static const char *proc_thread_self_get_link(struct dentry *dentry, |
23 | struct inode *inode, void **cookie) | |
0097875b | 24 | { |
6b255391 | 25 | struct pid_namespace *ns = inode->i_sb->s_fs_info; |
0097875b EB |
26 | pid_t tgid = task_tgid_nr_ns(current, ns); |
27 | pid_t pid = task_pid_nr_ns(current, ns); | |
680baacb AV |
28 | char *name; |
29 | ||
30 | if (!pid) | |
31 | return ERR_PTR(-ENOENT); | |
1a384eaa AV |
32 | name = kmalloc(PROC_NUMBUF + 6 + PROC_NUMBUF, |
33 | dentry ? GFP_KERNEL : GFP_ATOMIC); | |
34 | if (unlikely(!name)) | |
35 | return dentry ? ERR_PTR(-ENOMEM) : ERR_PTR(-ECHILD); | |
680baacb AV |
36 | sprintf(name, "%d/task/%d", tgid, pid); |
37 | return *cookie = name; | |
0097875b EB |
38 | } |
39 | ||
40 | static const struct inode_operations proc_thread_self_inode_operations = { | |
41 | .readlink = proc_thread_self_readlink, | |
6b255391 | 42 | .get_link = proc_thread_self_get_link, |
0097875b EB |
43 | .put_link = kfree_put_link, |
44 | }; | |
45 | ||
46 | static unsigned thread_self_inum; | |
47 | ||
48 | int proc_setup_thread_self(struct super_block *s) | |
49 | { | |
2b0143b5 | 50 | struct inode *root_inode = d_inode(s->s_root); |
0097875b EB |
51 | struct pid_namespace *ns = s->s_fs_info; |
52 | struct dentry *thread_self; | |
53 | ||
54 | mutex_lock(&root_inode->i_mutex); | |
55 | thread_self = d_alloc_name(s->s_root, "thread-self"); | |
56 | if (thread_self) { | |
57 | struct inode *inode = new_inode_pseudo(s); | |
58 | if (inode) { | |
59 | inode->i_ino = thread_self_inum; | |
60 | inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; | |
61 | inode->i_mode = S_IFLNK | S_IRWXUGO; | |
62 | inode->i_uid = GLOBAL_ROOT_UID; | |
63 | inode->i_gid = GLOBAL_ROOT_GID; | |
64 | inode->i_op = &proc_thread_self_inode_operations; | |
65 | d_add(thread_self, inode); | |
66 | } else { | |
67 | dput(thread_self); | |
68 | thread_self = ERR_PTR(-ENOMEM); | |
69 | } | |
70 | } else { | |
71 | thread_self = ERR_PTR(-ENOMEM); | |
72 | } | |
73 | mutex_unlock(&root_inode->i_mutex); | |
74 | if (IS_ERR(thread_self)) { | |
75 | pr_err("proc_fill_super: can't allocate /proc/thread_self\n"); | |
76 | return PTR_ERR(thread_self); | |
77 | } | |
78 | ns->proc_thread_self = thread_self; | |
79 | return 0; | |
80 | } | |
81 | ||
82 | void __init proc_thread_self_init(void) | |
83 | { | |
84 | proc_alloc_inum(&thread_self_inum); | |
85 | } |