Re: support for translators in tar

[Thomas Bushnell, BSG]

Marcus Brinkmann <Marcus.Brinkmann@ruhr-uni-bochum.de> writes:

> There is one complication.  Symlinks, device files, fifos and
> similar are also implemented as translators.  However, I'd expect
> that a symlink together with the --do-not-dereference-translators
> option will not store a /hurd/symlink translator, but a symlink.
> So, the translator handling code will recognize the couple of
> special translators and coerce them into archive entries compatible
> to traditional Unix systems.

The translator handling code certainly needs to detect the special
cases and DTRT.  

The normal tar behavior, which should do nothing special for
translators, but should handle symlinks specially, is to use lstat as
it does now.  lstat (on the Hurd) does a file lookup with the O_NOLINK
flag.  

For the special --do-not-dereference-translators mode, you want
basically exactly the same thing for the lookup, except use
O_NOTRANS.  Then you have to check to see if there is a translator,
and if there is, see if it's one of the special well-known translators
(and turn them into the appropriate standard special archive entry
type).