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44 lines
1.5 KiB
Markdown
44 lines
1.5 KiB
Markdown
asm
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===
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This library for assembly and disassembly of tar archives, facilitated by
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`github.com/vbatts/tar-split/tar/storage`.
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Concerns
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--------
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For completely safe assembly/disassembly, there will need to be a Content
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Addressable Storage (CAS) directory, that maps to a checksum in the
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`storage.Entity` of `storage.FileType`.
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This is due to the fact that tar archives _can_ allow multiple records for the
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same path, but the last one effectively wins. Even if the prior records had a
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different payload.
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In this way, when assembling an archive from relative paths, if the archive has
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multiple entries for the same path, then all payloads read in from a relative
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path would be identical.
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Thoughts
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--------
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Have a look-aside directory or storage. This way when a clobbering record is
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encountered from the tar stream, then the payload of the prior/existing file is
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stored to the CAS. This way the clobbering record's file payload can be
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extracted, but we'll have preserved the payload needed to reassemble a precise
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tar archive.
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clobbered/path/to/file.[0-N]
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*alternatively*
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We could just _not_ support tar streams that have clobbering file paths.
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Appending records to the archive is not incredibly common, and doesn't happen
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by default for most implementations. Not supporting them wouldn't be a
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security concern either, as if it did occur, we would reassemble an archive
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that doesn't validate signature/checksum, so it shouldn't be trusted anyway.
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Otherwise, this will allow us to defer support for appended files as a FUTURE FEATURE.
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