class File

def self.probe_stat_in(dir) #:nodoc:
  basename = [
    '.permissions_check',
    Thread.current.object_id,
    Process.pid,
    rand(1000000)
  ].join('.')
  file_name = join(dir, basename)
  FileUtils.touch(file_name)
  stat(file_name)
ensure
  FileUtils.rm_f(file_name) if file_name
end