is_mount_point.go

package main

import (
	"path"
	"syscall"
)

// isMountPoint returns true if the given directory is a mountpoint
func isMountPoint(fileName string) (bool, error) {
	dir := path.Clean(fileName)
	if dir == "/" {
		return true, nil
	}
	var stDir, stParent syscall.Stat_t
	err := syscall.Stat(dir, &stDir)
	if err != nil {
		return false, err
	}
	err = syscall.Stat(path.Dir(dir), &stParent)
	if err != nil {
		return false, err
	}

	return stDir.Dev != stParent.Dev, nil
}