On Oct 4, 2012, at 8:45 AM, Joerg Schilling wrote: > Tim Kientzle <[email protected]> wrote: > >> >> On Oct 3, 2012, at 5:01 AM, Pavel Raiskup wrote: >> >>>> FWIW, both star and bsdtar support xattrs on Linux. >>>> >>>> It would be nice if GNU tar were compatible with those existing >>>> implementations. >>> >>> Thanks Tim, yes -- xattr-patched GNU tar would be unable to extract >>> extended attributes from archives created by BSD tar now. In BSD tar >>> pax headers you are using base64 encoding for xattr values *but* in >>> different namespace --> so it will be very easy to allow GNU tar unpack >>> also BSD tar archives. I missed that fact and I'll address that later. >> >> Thanks! >> >> bsdtar also URL encodes the xattr name when building the pax property >> name. This ensures the final key will be entirely ASCII (and hence will >> not cause any problems with readers that expect all keys to be valid UTF-8). >> >> I can point you to the code in libarchive that handles this if you want >> a detailed reference. (The code is BSD-licensed; you're welcome >> to copy it if you wish.) > > Mmm, is bsdtar incompatible to star? > > Do you have a documentation for your format?
https://github.com/libarchive/libarchive/wiki/TarExtendedAttributes As mentioned there, I'm also missing documentation for star's xattr format. In particular, I'm not clear how it handles non-ASCII bytes in the attributes name. I would appreciate help extending this documentation. I've also tried to collect information about other tar extensions. Tim
