1 #include <linux/sched.h>
2 #include <linux/slab.h>
3 #include <linux/pid_namespace.h>
9 static int proc_self_readlink(struct dentry *dentry, char __user *buffer,
12 struct pid_namespace *ns = dentry->d_sb->s_fs_info;
13 pid_t tgid = task_tgid_nr_ns(current, ns);
14 char tmp[PROC_NUMBUF];
17 sprintf(tmp, "%d", tgid);
18 return readlink_copy(buffer, buflen, tmp);
21 static const char *proc_self_get_link(struct dentry *dentry,
23 struct delayed_call *done)
25 struct pid_namespace *ns = inode->i_sb->s_fs_info;
26 pid_t tgid = task_tgid_nr_ns(current, ns);
30 * Not currently supported. Once we can inherit all of struct pid,
33 if (current->flags & PF_KTHREAD)
34 return ERR_PTR(-EOPNOTSUPP);
37 return ERR_PTR(-ENOENT);
38 /* 11 for max length of signed int in decimal + NULL term */
39 name = kmalloc(12, dentry ? GFP_KERNEL : GFP_ATOMIC);
41 return dentry ? ERR_PTR(-ENOMEM) : ERR_PTR(-ECHILD);
42 sprintf(name, "%d", tgid);
43 set_delayed_call(done, kfree_link, name);
47 static const struct inode_operations proc_self_inode_operations = {
48 .readlink = proc_self_readlink,
49 .get_link = proc_self_get_link,
52 static unsigned self_inum;
54 int proc_setup_self(struct super_block *s)
56 struct inode *root_inode = d_inode(s->s_root);
57 struct pid_namespace *ns = s->s_fs_info;
60 inode_lock(root_inode);
61 self = d_alloc_name(s->s_root, "self");
63 struct inode *inode = new_inode(s);
65 inode->i_ino = self_inum;
66 inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
67 inode->i_mode = S_IFLNK | S_IRWXUGO;
68 inode->i_uid = GLOBAL_ROOT_UID;
69 inode->i_gid = GLOBAL_ROOT_GID;
70 inode->i_op = &proc_self_inode_operations;
74 self = ERR_PTR(-ENOMEM);
77 self = ERR_PTR(-ENOMEM);
79 inode_unlock(root_inode);
81 pr_err("proc_fill_super: can't allocate /proc/self\n");
88 void __init proc_self_init(void)
90 proc_alloc_inum(&self_inum);