1#include <linux/sched.h>
2#include <linux/slab.h>
3#include <linux/pid_namespace.h>
4#include "internal.h"
5
6
7
8
9static const char *proc_thread_self_get_link(struct dentry *dentry,
10 struct inode *inode,
11 struct delayed_call *done)
12{
13 struct pid_namespace *ns = inode->i_sb->s_fs_info;
14 pid_t tgid = task_tgid_nr_ns(current, ns);
15 pid_t pid = task_pid_nr_ns(current, ns);
16 char *name;
17
18 if (!pid)
19 return ERR_PTR(-ENOENT);
20 name = kmalloc(PROC_NUMBUF + 6 + PROC_NUMBUF,
21 dentry ? GFP_KERNEL : GFP_ATOMIC);
22 if (unlikely(!name))
23 return dentry ? ERR_PTR(-ENOMEM) : ERR_PTR(-ECHILD);
24 sprintf(name, "%d/task/%d", tgid, pid);
25 set_delayed_call(done, kfree_link, name);
26 return name;
27}
28
29static const struct inode_operations proc_thread_self_inode_operations = {
30 .get_link = proc_thread_self_get_link,
31};
32
33static unsigned thread_self_inum;
34
35int proc_setup_thread_self(struct super_block *s)
36{
37 struct inode *root_inode = d_inode(s->s_root);
38 struct pid_namespace *ns = s->s_fs_info;
39 struct dentry *thread_self;
40
41 inode_lock(root_inode);
42 thread_self = d_alloc_name(s->s_root, "thread-self");
43 if (thread_self) {
44 struct inode *inode = new_inode_pseudo(s);
45 if (inode) {
46 inode->i_ino = thread_self_inum;
47 inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
48 inode->i_mode = S_IFLNK | S_IRWXUGO;
49 inode->i_uid = GLOBAL_ROOT_UID;
50 inode->i_gid = GLOBAL_ROOT_GID;
51 inode->i_op = &proc_thread_self_inode_operations;
52 d_add(thread_self, inode);
53 } else {
54 dput(thread_self);
55 thread_self = ERR_PTR(-ENOMEM);
56 }
57 } else {
58 thread_self = ERR_PTR(-ENOMEM);
59 }
60 inode_unlock(root_inode);
61 if (IS_ERR(thread_self)) {
62 pr_err("proc_fill_super: can't allocate /proc/thread_self\n");
63 return PTR_ERR(thread_self);
64 }
65 ns->proc_thread_self = thread_self;
66 return 0;
67}
68
69void __init proc_thread_self_init(void)
70{
71 proc_alloc_inum(&thread_self_inum);
72}
73
