blob: e58a31e8fb2a186aaa2d3dee62811f090e2ade57 [file] [log] [blame]
Eric W. Biederman00978752014-07-31 03:10:50 -07001#include <linux/sched.h>
Eric W. Biederman00978752014-07-31 03:10:50 -07002#include <linux/slab.h>
3#include <linux/pid_namespace.h>
4#include "internal.h"
5
6/*
7 * /proc/thread_self:
8 */
9static 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
Al Viro6b255392015-11-17 10:20:54 -050022static const char *proc_thread_self_get_link(struct dentry *dentry,
Al Virofceef392015-12-29 15:58:39 -050023 struct inode *inode,
24 struct delayed_call *done)
Eric W. Biederman00978752014-07-31 03:10:50 -070025{
Al Viro6b255392015-11-17 10:20:54 -050026 struct pid_namespace *ns = inode->i_sb->s_fs_info;
Eric W. Biederman00978752014-07-31 03:10:50 -070027 pid_t tgid = task_tgid_nr_ns(current, ns);
28 pid_t pid = task_pid_nr_ns(current, ns);
Al Viro680baac2015-05-02 13:32:22 -040029 char *name;
30
31 if (!pid)
32 return ERR_PTR(-ENOENT);
Al Viro1a384ea2015-11-17 10:58:42 -050033 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);
Al Viro680baac2015-05-02 13:32:22 -040037 sprintf(name, "%d/task/%d", tgid, pid);
Al Virofceef392015-12-29 15:58:39 -050038 set_delayed_call(done, kfree_link, name);
39 return name;
Eric W. Biederman00978752014-07-31 03:10:50 -070040}
41
42static const struct inode_operations proc_thread_self_inode_operations = {
43 .readlink = proc_thread_self_readlink,
Al Viro6b255392015-11-17 10:20:54 -050044 .get_link = proc_thread_self_get_link,
Eric W. Biederman00978752014-07-31 03:10:50 -070045};
46
47static unsigned thread_self_inum;
48
49int proc_setup_thread_self(struct super_block *s)
50{
David Howells2b0143b2015-03-17 22:25:59 +000051 struct inode *root_inode = d_inode(s->s_root);
Eric W. Biederman00978752014-07-31 03:10:50 -070052 struct pid_namespace *ns = s->s_fs_info;
53 struct dentry *thread_self;
54
Al Viro59551022016-01-22 15:40:57 -050055 inode_lock(root_inode);
Eric W. Biederman00978752014-07-31 03:10:50 -070056 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 }
Al Viro59551022016-01-22 15:40:57 -050074 inode_unlock(root_inode);
Eric W. Biederman00978752014-07-31 03:10:50 -070075 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
83void __init proc_thread_self_init(void)
84{
85 proc_alloc_inum(&thread_self_inum);
86}