//go:build linux

package system

import "syscall"

// overlayMagic is statfs's f_type for an overlay filesystem (OVERLAYFS_SUPER_MAGIC, linux/magic.h).
const overlayMagic = 0x794c7630

func statDev(path string) (uint64, bool) {
	var st syscall.Stat_t
	if err := syscall.Stat(path, &st); err != nil {
		return 0, false
	}
	return uint64(st.Dev), true
}

func isOverlayFS(path string) (isOverlay, ok bool) {
	var st syscall.Statfs_t
	if err := syscall.Statfs(path, &st); err != nil {
		return false, false
	}
	return int64(st.Type) == overlayMagic, true
}