1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/cache.h>
3 #include <linux/sched.h>
4 #include <linux/slab.h>
5 #include <linux/pid_namespace.h>
11 static const char *proc_thread_self_get_link(struct dentry *dentry,
13 struct delayed_call *done)
15 struct pid_namespace *ns = proc_pid_ns(inode->i_sb);
16 pid_t tgid = task_tgid_nr_ns(current, ns);
17 pid_t pid = task_pid_nr_ns(current, ns);
21 * Not currently supported. Once we can inherit all of struct pid,
24 if (current->flags & PF_IO_WORKER)
25 return ERR_PTR(-EOPNOTSUPP);
28 return ERR_PTR(-ENOENT);
29 name = kmalloc(10 + 6 + 10 + 1, dentry ? GFP_KERNEL : GFP_ATOMIC);
31 return dentry ? ERR_PTR(-ENOMEM) : ERR_PTR(-ECHILD);
32 sprintf(name, "%u/task/%u", tgid, pid);
33 set_delayed_call(done, kfree_link, name);
37 static const struct inode_operations proc_thread_self_inode_operations = {
38 .get_link = proc_thread_self_get_link,
41 static unsigned thread_self_inum __ro_after_init;
43 int proc_setup_thread_self(struct super_block *s)
45 struct inode *root_inode = d_inode(s->s_root);
46 struct proc_fs_info *fs_info = proc_sb_info(s);
47 struct dentry *thread_self;
50 inode_lock(root_inode);
51 thread_self = d_alloc_name(s->s_root, "thread-self");
53 struct inode *inode = new_inode(s);
55 inode->i_ino = thread_self_inum;
56 inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
57 inode->i_mode = S_IFLNK | S_IRWXUGO;
58 inode->i_uid = GLOBAL_ROOT_UID;
59 inode->i_gid = GLOBAL_ROOT_GID;
60 inode->i_op = &proc_thread_self_inode_operations;
61 d_add(thread_self, inode);
67 inode_unlock(root_inode);
70 pr_err("proc_fill_super: can't allocate /proc/thread-self\n");
72 fs_info->proc_thread_self = thread_self;
77 void __init proc_thread_self_init(void)
79 proc_alloc_inum(&thread_self_inum);