History

Vincent Batts 516158dbfb *.go: linting project specific code the pointer to the pool may be useful, but holding on that until I get benchmarks of memory use to show the benefit. Signed-off-by: Vincent Batts <vbatts@hashbangbash.com>		2023-03-25 20:45:23 -04:00
..
testdata	tar/asm: failing test for lack of EOF nils	2016-09-26 13:39:03 -07:00
README.md	tar/asm: another thought on clobbered files	2015-02-25 16:53:31 -05:00
assemble.go	*.go: linting project specific code	2023-03-25 20:45:23 -04:00
assemble_test.go	tar/asm: failing test for lack of EOF nils	2016-09-26 13:39:03 -07:00
disassemble.go	tar: asm: store padding in chunks to avoid memory exhaustion	2017-11-08 02:34:56 +11:00
disassemble_test.go	*.go: linting project specific code	2023-03-25 20:45:23 -04:00
doc.go	*: golint and docs	2015-03-09 14:11:11 -04:00

README.md

asm

This library for assembly and disassembly of tar archives, facilitated by github.com/vbatts/tar-split/tar/storage.

Concerns

For completely safe assembly/disassembly, there will need to be a Content Addressable Storage (CAS) directory, that maps to a checksum in the storage.Entity of storage.FileType.

This is due to the fact that tar archives can allow multiple records for the same path, but the last one effectively wins. Even if the prior records had a different payload.

In this way, when assembling an archive from relative paths, if the archive has multiple entries for the same path, then all payloads read in from a relative path would be identical.

Thoughts

Have a look-aside directory or storage. This way when a clobbering record is encountered from the tar stream, then the payload of the prior/existing file is stored to the CAS. This way the clobbering record's file payload can be extracted, but we'll have preserved the payload needed to reassemble a precise tar archive.

clobbered/path/to/file.[0-N]

alternatively

We could just not support tar streams that have clobbering file paths. Appending records to the archive is not incredibly common, and doesn't happen by default for most implementations. Not supporting them wouldn't be a security concern either, as if it did occur, we would reassemble an archive that doesn't validate signature/checksum, so it shouldn't be trusted anyway.

Otherwise, this will allow us to defer support for appended files as a FUTURE FEATURE.