_ContainerizationTar: Add new native tar reader/writer #474
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Swift does not have a native tar reader/writer, and we'd really like to avoid linking more (libarchive) libraries to vminitd if we can get away with it. For copying directories into/out of containers tar is fairly nice as it's a simple way to preserve everything you need to be able to reassemble the directory on the receiving end. Due to this, I decided to write a somewhat simple tar reader/writer solely for this purpose. Unfortunately, there's quite a lot of work to get vminitd/ to compile on macOS without the static linux SDK, so it was making unit testing these additions quite a pain, so for now the new work lives in _ContainerizationTar (where the underscore is trying to denote that this is rather experimental..). This change aims to add a simple tar reader and writer with support pax extended headers (for long file names and > 8 GiB files). Because its intended purpose is in a scenario where we own both the creator and ingestor, the reader does NOT handle every case, but it is good at unarchiving the archives the library has made :)
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Swift does not have a native tar reader/writer, and we'd really like to avoid linking more (libarchive) libraries to vminitd if we can get away with it. For copying directories into/out of containers tar is fairly nice as it's a simple way to preserve everything you need to be able to reassemble the directory on the receiving end. Due to this, I decided to write a somewhat simple tar reader/writer solely for this purpose. Unfortunately, there's quite a lot of work to get vminitd/ to compile on macOS without the static linux SDK, so it was making unit testing these additions quite a pain, so for now the new work lives in _ContainerizationTar (where the underscore is trying to denote that this is rather experimental..).
This change aims to add a simple tar reader and writer with support for pax extended headers (for long file names and > 8 GiB files). Because its intended purpose is in a scenario where we own both the creator and ingestor, the reader does NOT handle every case, but it is good at unarchiving the archives the library has made :)