Re: [Bug-tar] [PATCH] Extended attribute support for tar

[Sergey Poznyakoff]

James Antill <address@hidden> wrote:

>  Hi, I've created support for creating/extracting SELinux/user/root
> xattrs in GNUtar. If you have some free time, I'd appreciate anyone
> looking over the patch and letting me know if anything needs to change
> for inclusion.

Thank you. After a quick glance it turns out the patch does need something
done before accepting for inclusion:

1. All xattrs-specific stuff should be concentrated in one source module
   instead of being scattered around 7 source files;
2. Proper autoconf machinery should be added to detect the presence of
   the special calls it uses (fgetfilecon, flistxattr and a lot of
   others) and disable it if any of them is not available;
3. I don't see any reason to create a second (prefix) table in
   xheader.c, I'd prefer to expand the functionality of the main table
   instead;
4. The patch is based on 1.15.90 version, current CVS version has moved
   ahead since then (in particular, xheader.c was changed), so it would
   be advisable to base it on the CVS head.

>  Known "issues":
[...] 
> 6. Not entirely sure what to do when SELinux/xattr's aren't supported
> when doing the extraction ... atm. tar just ignores it.

That's right.

> 7. Currently tar defaults to not doing anything when creating an
> archive, so you need to pass --xattrs or --selinux to get all xattrs or
> just SELinux context information in the archive.

That's OK as well.

> 8. AIUI star only includes the headers when using it's special exustar
> format, the patch I've done for GNUtar just includes it on the else
> clause of:
> 
>   if (archive_format == V7_FORMAT || numeric_owner_option)
> 
> ...which probably needs to be just the former test, or maybe limited to
> certain formats?

It should be limited to POSIX.1-2001 format only (POSIX_FORMAT). 

Regards,
Sergey