- dir: the directory to prepare
- packagesource: sources list
- logFile: Name of the file the messages from apt-get should be written to.
- returnCmd: Set to true, if the apt command should be returned or to false to execute it in this function.
- arch: Architecture to get package infos for.
- sourceName: The name of the package source list
- hardTryUpdate: Set to true, if the apt-get update should be run until it succeeds
- : Error text on error or empty string on success.