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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 | 22 | static const char *proc_thread_self_get_link(struct dentry *dentry, |
fceef393 AV |
23 | struct inode *inode, |
24 | struct delayed_call *done) | |
0097875b | 25 | { |
6b255391 | 26 | struct pid_namespace *ns = inode->i_sb->s_fs_info; |
0097875b EB |
27 | pid_t tgid = task_tgid_nr_ns(current, ns); |
28 | pid_t pid = task_pid_nr_ns(current, ns); | |
680baacb AV |
29 | char *name; |
30 | ||
31 | if (!pid) | |
32 | return ERR_PTR(-ENOENT); | |
1a384eaa AV |
33 | name = kmalloc(PROC_NUMBUF + 6 + PROC_NUMBUF, |
34 | dentry ? GFP_KERNEL : GFP_ATOMIC); | |
35 | if (unlikely(!name)) | |
36 | return dentry ? ERR_PTR(-ENOMEM) : ERR_PTR(-ECHILD); | |
680baacb | 37 | sprintf(name, "%d/task/%d", tgid, pid); |
fceef393 AV |
38 | set_delayed_call(done, kfree_link, name); |
39 | return name; | |
0097875b EB |
40 | } |
41 | ||
42 | static const struct inode_operations proc_thread_self_inode_operations = { | |
43 | .readlink = proc_thread_self_readlink, | |
6b255391 | 44 | .get_link = proc_thread_self_get_link, |
0097875b EB |
45 | }; |
46 | ||
47 | static unsigned thread_self_inum; | |
48 | ||
49 | int proc_setup_thread_self(struct super_block *s) | |
50 | { | |
2b0143b5 | 51 | struct inode *root_inode = d_inode(s->s_root); |
0097875b EB |
52 | struct pid_namespace *ns = s->s_fs_info; |
53 | struct dentry *thread_self; | |
54 | ||
5955102c | 55 | inode_lock(root_inode); |
0097875b EB |
56 | thread_self = d_alloc_name(s->s_root, "thread-self"); |
57 | if (thread_self) { | |
58 | struct inode *inode = new_inode_pseudo(s); | |
59 | if (inode) { | |
60 | inode->i_ino = thread_self_inum; | |
61 | inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; | |
62 | inode->i_mode = S_IFLNK | S_IRWXUGO; | |
63 | inode->i_uid = GLOBAL_ROOT_UID; | |
64 | inode->i_gid = GLOBAL_ROOT_GID; | |
65 | inode->i_op = &proc_thread_self_inode_operations; | |
66 | d_add(thread_self, inode); | |
67 | } else { | |
68 | dput(thread_self); | |
69 | thread_self = ERR_PTR(-ENOMEM); | |
70 | } | |
71 | } else { | |
72 | thread_self = ERR_PTR(-ENOMEM); | |
73 | } | |
5955102c | 74 | inode_unlock(root_inode); |
0097875b EB |
75 | if (IS_ERR(thread_self)) { |
76 | pr_err("proc_fill_super: can't allocate /proc/thread_self\n"); | |
77 | return PTR_ERR(thread_self); | |
78 | } | |
79 | ns->proc_thread_self = thread_self; | |
80 | return 0; | |
81 | } | |
82 | ||
83 | void __init proc_thread_self_init(void) | |
84 | { | |
85 | proc_alloc_inum(&thread_self_inum); | |
86 | } |