CompressedTarReader returns a tar reader from the supplied (optionally compressed) tarball stream.

DetectCompression detects compression from a file name.

DetectCompressionFile detects the compression type of a file and returns the tar arguments needed to unpack the file, compression type (in the form of a file extension), and the command needed to decompress the file to an uncompressed tarball.

ExtractWithFds runs extractor process under specifc AppArmor profile.

Unpack extracts image from archive.

RunWrapper is an optional function that's used to wrap rsync, useful for confinement like AppArmor.