Hi everybody,
Today I noticed that GNU tar (git master) now supports XATTRs, ACLs
and SELINUX-Attributes. I am really pleased to read this in "git log".
Congratualtions for this improvement. The improvements do not break
star und redhat tar compatibility.
Having used Redhats patch for many years now (and an improved version
which I made), I am able to enumerate a few points that IMHO need
improvement:
(1) tar archive creation with "--numeric-owner" option:
In this case, users are expectiing that the archive does not contain
any symbolic owner name, so it can be extracted to an emoty hard disc
on a system bootet e. g. by a rescue cd from Redhat. Current sitation
is that ACLs still include the symbolic owner and not the numeric owner.
This is quite trivial to fix:
Replace all ocurences of "val = acl_to_text(acl, &len);" by "val =
acl_to_any_text(acl, 0, ',', (
numeric_owner_option?TEXT_NUMERIC_IDS:0));" and followed by
"len=strlen(val);" after the "if (!val)" error-handling.
Effect: Numeric owner is stored.
I'd like to note that this improvement is essential to me.
(2a) tar archive creation without "--numeric-owner" option:
In GNU tar 1.26, for every file the owner is stored both, symbolic and
numeric. I would expect that ACLs are stored in both ways, too. star
shows us how to do that:
star stores the numeric owner in a forth field of an acl: (e.g.
"u:msteinbo:rwx:500").
(2b) tar extract should use the 4th field (discussed in point 2) in
presence of "-numeric-owner".
This together with point (2) enabled users to restore an backup
created without numeric owner option on a clean hard disc without
passwd entries for the users (let's assume that /etc/passwd is
contained in the archive so the operation makes sense).
I'd like to mention that this point would increase star compatibility
a lot.
Optional (3): Do not store ACLs iff ACL contains just the normal user,
group and other permissions, i. .e. the ACL is an compatibility ACL.
What is your opinion on these points?
Greetings from Germany
Markus Steinborn
GNU gv maintainer
PS: "iff" is the usual abbreviation for "if and only if" and not a typo.