https://single9.net/2013/03/gmtp-ubuntu-%e7%84%a1%e6%b3%95%e9%80%a3%e4%b8%8aandroid-4-1%e7%9a%84%e6%89%8b%e6%a9%9f%ef%bc%9f%e8%a9%a6%e8%a9%a6%e9%80%99%e5%80%8b%e5%90%a7%ef%bc%81/