Re: [Acl-devel] [Bug-tar] gtar's ACL support is still unusable

[Joerg Schilling]

Because of that missimplementaion in GNU tar, I reworked the star.4 man page
and added information on when the additional numeric values may be omitted and 
how the ACL entries are restored:

...
          If the user name or group name field is numeric because
          the related user has no entry in the passwd/group data-
          base at the time the archive is created, the additional
          numeric field may be omitted.

          This  is  an   example   of   the   format   used   for
          SCHILY.acl.access  (a space has been inserted after the
          equal sign and lines are broken [marked with '\' ]  for
          readability, additional fields in bold):

          SCHILY.acl.access= user::rwx,user:lisa:r-x:502, \
                             group::r-x,group:toolies:rwx:102, \
                             mask::rwx,other::r--x

          If and only if the user ID 502 and group ID 102 have no
          passwd/group  entry,  our  example acl entry looks this
          way:

          SCHILY.acl.access= user::rwx,user:502:r-x, \
                             group::r-x,group:102:rwx:, \
                             mask::rwx,other::r--x

          The added numerical  user  and  group  identifiers  are
          essential  when  restoring  a  system completely from a
          backup, as initially  the  name-to-identifier  mappings
          may  not be available, and then file ownership restora-
          tion would not work.

          When the archive is unpacked and the  ACL  entries  for
          the  files  are  restored, first the additional numeric
          fields are removed and an attempt is  made  to  restore
          the  resulting  ACL  data.   If that fails, the numeric
          fields are extracted and  the  related  user  name  and
          group  name  fields are replaced by the numeric fields,
          before the ACL restore is retried.
...

Jörg

-- 
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