On Wed, Sep 30, 2009 at 11:01 PM, Tim Kientzle <[email protected]> wrote: > Michael D. Adams wrote: >> >> Running tar over the exact same file at two different time isn't >> producing the exact same tar file. >> >> I've tracked this down to the mtime field in the header that has >> typeflag=x. >> >> Questions: >> (1) Is this behavior in conformance with the POSIX-2001 spec? I >> haven't seen anywhere that says what the mtime field should be when >> there is an mtime extended header, but other tar/pax implementations >> just fill it with zeros. > > I don't think the POSIX spec says anything about this. > You should be able to avoid it, of course, by using > "ustar" format, which does not generate the 'x' entries.
Except that I was going to use the extended headers to store ACL information. But if push comes to shove I might just use your suggestion and leave out those ACLs so I can store it in "ustar" format. > I'm curious which "other tar/pax" implementations > you surveyed? Schilling's star uses the mtime of the file inside the tar (like you say that bsdtar does), but Schilling's spax uses zeros. (Version "1.5a75 (i386-redhat-linux-gnu)" on both.) Either behavior would be fine for my purposes. Only the way gnutar does it causes a problem. Michael D. Adams [email protected]
