include/uapi/linux/nsfs.h

#ifndef __LINUX_NSFS_H
#define __LINUX_NSFS_H

#include <linux/ioctl.h>

#define NSIO	0xb7

/* Returns a file descriptor that refers to an owning user namespace */
#define NS_GET_USERNS	_IO(NSIO, 0x1)
/* Returns a file descriptor that refers to a parent namespace */
#define NS_GET_PARENT	_IO(NSIO, 0x2)

#endif /* __LINUX_NSFS_H */