1
2#include <linux/sched.h>
3#include <linux/slab.h>
4#include <linux/pid_namespace.h>
5#include "internal.h"
6
7
8
9
10static const char *proc_thread_self_get_link(struct dentry *dentry,
11 struct inode *inode,
12 struct delayed_call *done)
13{
14 struct pid_namespace *ns = inode->i_sb->s_fs_info;
15 pid_t tgid = task_tgid_nr_ns(current, ns);
16 pid_t pid = task_pid_nr_ns(current, ns);
17 char *name;
18
19 if (!pid)
20 return ERR_PTR(-ENOENT);
21 name = kmalloc(PROC_NUMBUF + 6 + PROC_NUMBUF,
22 dentry ? GFP_KERNEL : GFP_ATOMIC);
23 if (unlikely(!name))
24 return dentry ? ERR_PTR(-ENOMEM) : ERR_PTR(-ECHILD);
25 sprintf(name, "%d/task/%d", tgid, pid);
26 set_delayed_call(done, kfree_link, name);
27 return name;
28}
29
30static const struct inode_operations proc_thread_self_inode_operations = {
31 .get_link = proc_thread_self_get_link,
32};
33
34static unsigned thread_self_inum;
35
36int proc_setup_thread_self(struct super_block *s)
37{
38 struct inode *root_inode = d_inode(s->s_root);
39 struct pid_namespace *ns = s->s_fs_info;
40 struct dentry *thread_self;
41
42 inode_lock(root_inode);
43 thread_self = d_alloc_name(s->s_root, "thread-self");
44 if (thread_self) {
45 struct inode *inode = new_inode_pseudo(s);
46 if (inode) {
47 inode->i_ino = thread_self_inum;
48 inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
49 inode->i_mode = S_IFLNK | S_IRWXUGO;
50 inode->i_uid = GLOBAL_ROOT_UID;
51 inode->i_gid = GLOBAL_ROOT_GID;
52 inode->i_op = &proc_thread_self_inode_operations;
53 d_add(thread_self, inode);
54 } else {
55 dput(thread_self);
56 thread_self = ERR_PTR(-ENOMEM);
57 }
58 } else {
59 thread_self = ERR_PTR(-ENOMEM);
60 }
61 inode_unlock(root_inode);
62 if (IS_ERR(thread_self)) {
63 pr_err("proc_fill_super: can't allocate /proc/thread_self\n");
64 return PTR_ERR(thread_self);
65 }
66 ns->proc_thread_self = thread_self;
67 return 0;
68}
69
70void __init proc_thread_self_init(void)
71{
72 proc_alloc_inum(&thread_self_inum);
73}
74
