• Joe Tsai's avatar
    archive/tar: use best effort at writing USTAR header · c991d2ab
    Joe Tsai authored
    Prior to this change, if the Writer needed to use the PAX format, it would
    output a USTAR header with an empty name. This should be okay since the PAX
    specification dictates that the PAX record for "path" should override the
    semantic meaning of any of the old USTAR fields.
    
    Unfortunately, the implementation of tar on OpenBSD 6.1 is too strict with
    their handling of PAX files such that they check for the validity of this
    bogus field even though the PAX header is present.
    
    To allow Go's Writer output be parsible by OpenBSD's tar utility,
    we write a best-effort (ASCII-only and truncated) version of the original
    file name. Note that this still fails in some edge-cases (for example,
    a Chinese filename containing all non-ASCII characters). OpenBSD should really
    relax their checking, as you honestly can't always expect a sensible path
    to be generated when USTAR cannot handle the original path.
    
    Fixes #20707
    
    Change-Id: Id7d77349023d2152d7291d582cd050b6681760e4
    Reviewed-on: https://go-review.googlesource.com/46914
    Run-TryBot: Joe Tsai <thebrokentoaster@gmail.com>
    TryBot-Result: Gobot Gobot <gobot@golang.org>
    Reviewed-by: 's avatarIan Lance Taylor <iant@golang.org>
    c991d2ab