利用私有api操作ios文件系统

Mac OS X: MobileDevice.framework
Location: /System/Library/PrivateFrameworks/MobileDevice.framework
Export command: nm /System/Library/PrivateFrameworks/MobileDevice.framework/Versions/A/MobileDevice

参考：
http://theiphonewiki.com/wiki/MobileDevice_Library#Mac_OS_X:_MobileDevice.framework