RE: git archive setting user and group

["Jason Pyeron" <jpyeron@pdinc.us>]

> From: Junio C Hamano
> Sent: Friday, January 22, 2021 5:29 PM
> 
> René Scharfe <l.s.r@web.de> writes:
> 
> > Am 22.01.21 um 21:40 schrieb Jason Pyeron:
> > ...
> >>         xsnprintf(header->uid, sizeof(header->uid), "%07o", 0);
> >>         xsnprintf(header->gid, sizeof(header->gid), "%07o", 0);
> >>         strlcpy(header->uname, "root", sizeof(header->uname));
> >>         strlcpy(header->gname, "root", sizeof(header->gname));
> >
> > Adding support for using a custom user and group should be easy.  Is
> > this just a cosmetic thing?  Regular users would ignore the user info in
> > the archive, and root should not be used for extracting, and on systems
> > that don't have a logwatch user this wouldn't make a difference anyway,
> > right?
> 
> I am not particularly interested in cosmetics, but it probably is OK
> to make uname/gname overridable.  I do not see any point in uid/gid
> numeric values overridable, though.  Just like user names and group

Interesting. So logwatch(0) vs logwatch(1100) ? I guess it is as good as any value, but tar never uses 0.

On a system without the logwatch user/group tar behaves as follows:

$ tar czf /tmp/logwatch.tgz --owner=logwatch --group=logwatch .

$ tar tvzf /tmp/logwatch.tgz | head -n 1
drwxrwxr-x logwatch/logwatch 0 2020-03-14 15:01 ./

$ tar tvzf /tmp/logwatch.tgz --numeric-owner | head -n 1
drwxrwxr-x 1049681/1049088   0 2020-03-14 15:01 ./

$ id
uid=1049681(myuser) gid=1049088(mygroup) groups=no one cares...

but when the user / group is known...

$ tar czf /tmp/logwatch.tgz --owner=Guest --group=Users .

$ tar tvzf /tmp/logwatch.tgz | head -n 1
drwxrwxr-x Guest/Users       0 2020-03-14 15:01 ./

$ tar tvzf /tmp/logwatch.tgz --numeric-owner | head -n 1
drwxrwxr-x 1049077/545       0 2020-03-14 15:01 ./

$ getent passwd Guest | cut -f 3 -d :
1049077

$ getent group Users | cut -f 3 -d :
545


> names do not name the same user and group on every machine, uid/gid
> are even less so.
> 
>