#include <linux/sched.h>#include <linux/slab.h>#include <linux/pid_namespace.h>#include "internal.h" /* * /proc/thread_self: */static int proc_thread_self_readlink(struct dentry *dentry, char __user *buffer,			      int buflen){	struct pid_namespace *ns = dentry->d_sb->s_fs_info;	pid_t tgid = task_tgid_nr_ns(current, ns);	pid_t pid = task_pid_nr_ns(current, ns);	char tmp[PROC_NUMBUF + 6 + PROC_NUMBUF];	if (!pid)		return -ENOENT;	sprintf(tmp, "%d/task/%d", tgid, pid);	return readlink_copy(buffer, buflen, tmp);} static const char *proc_thread_self_follow_link(struct dentry *dentry, void **cookie){	struct pid_namespace *ns = dentry->d_sb->s_fs_info;	pid_t tgid = task_tgid_nr_ns(current, ns);	pid_t pid = task_pid_nr_ns(current, ns);	char *name; 	if (!pid)		return ERR_PTR(-ENOENT);	name = kmalloc(PROC_NUMBUF + 6 + PROC_NUMBUF, GFP_KERNEL);	if (!name)		return ERR_PTR(-ENOMEM);	sprintf(name, "%d/task/%d", tgid, pid);	return *cookie = name;} static const struct inode_operations proc_thread_self_inode_operations = {	.readlink	= proc_thread_self_readlink,	.follow_link	= proc_thread_self_follow_link,	.put_link	= kfree_put_link,}; static unsigned thread_self_inum; int proc_setup_thread_self(struct super_block *s){	struct inode *root_inode = d_inode(s->s_root);	struct pid_namespace *ns = s->s_fs_info;	struct dentry *thread_self; 	mutex_lock(&root_inode->i_mutex);	thread_self = d_alloc_name(s->s_root, "thread-self");	if (thread_self) {		struct inode *inode = new_inode_pseudo(s);		if (inode) {			inode->i_ino = thread_self_inum;			inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;			inode->i_mode = S_IFLNK | S_IRWXUGO;			inode->i_uid = GLOBAL_ROOT_UID;			inode->i_gid = GLOBAL_ROOT_GID;			inode->i_op = &proc_thread_self_inode_operations;			d_add(thread_self, inode);		} else {			dput(thread_self);			thread_self = ERR_PTR(-ENOMEM);		}	} else {		thread_self = ERR_PTR(-ENOMEM);	}	mutex_unlock(&root_inode->i_mutex);	if (IS_ERR(thread_self)) {		pr_err("proc_fill_super: can't allocate /proc/thread_self\n");		return PTR_ERR(thread_self);	}	ns->proc_thread_self = thread_self;	return 0;} void __init proc_thread_self_init(void){	proc_alloc_inum(&thread_self_inum);}