OSX Lion: gnutar restore bad

[greno]

Hi,
Today I needed to use gnutar to create a tarball on my Mac-mini w/Lion.

It tarred up what I wanted and I checked the tarball and all the files and directories showed the proper owner and group.

Eg:

# gnutar tvzf /tmp/tarball.tgz
gnutar: Removing leading `/' from member names-rw-r--r-- root/wheel        0 2011-05-25 13:27 Users/.localized

-rwxr-xr-x me/staff        228 2012-05-03 22:48 /Users/._me
drwxr-xr-x me/staff          0 2012-05-03 22:48 Users/me/
drwxrwxrwt root/wheel        0 2012-05-03 20:54 Users/Shared/
-rw-r--r-- root/wheel        0 2011-05-25 13:27 Users/Shared/.localized
-rwxrwxrwx me/wheel         82 2012-05-03 20:55 /Users/Shared/._SC Info
drwxrwxrwx me/wheel          0 2012-05-03 20:55 Users/Shared/SC Info/
-rw------- me/staff       2036 2012-05-04 16:13 Users/me/.bash_history
-rw------- me/staff          3 2012-05-02 14:39 Users/me/.CFUserTextEncoding
-rw-r--r-- me/staff         82 2012-05-03 16:38 /Users/me/._.DS_Store
-rw-r--r-- me/staff      15364 2012-05-03 16:38 Users/me/.DS_Store
-rw------- me/staff         42 2012-05-03 22:48 Users/me/.lesshst
drwx------ me/staff          0 2012-05-02 18:30 Users/me/.ssh/
drwx------ me/staff          0 2012-05-03 23:28 Users/me/.Trash/
-rwx------ me/staff        228 2012-05-03 23:28 /Users/me/._Desktop
drwx------ me/staff          0 2012-05-03 23:28 Users/me/Desktop/
-rwx------ me/staff        228 2012-05-02 21:06 /Users/me/._Documents
drwx------ me/staff          0 2012-05-02 21:06 Users/me/Documents/
-rwx------ me/staff        228 2012-05-03 16:37 /Users/me/._Downloads
drwx------ me/staff          0 2012-05-03 16:37 Users/me/Downloads/
-rwx------ me/staff        228 2012-05-03 20:55 /Users/me/._Library
drwx------ me/staff          0 2012-05-03 20:55 Users/me/Library/

I tried restoring this tarball under /tmp just to check it. And all the files and directories are restored owned by "_unknown _unknown".

Eg:

# ls -lR
total 0
drwxr-xr-x  5 _unknown  _unknown  170 May  2 14:39 Users

./Users:
total 0
-rw-r--r--   1 _unknown  _unknown    0 May 25  2011 .localized
drwxrwxrwt   4 _unknown  _unknown  136 May  4 17:53 Shared
drwxr-xr-x+ 16 _unknown  _unknown  544 May  4 17:53 me

./Users/Shared:
total 0
-rw-r--r--  1 _unknown  _unknown   0 May 25  2011 .localized
drwxrwxrwx@ 2 _unknown  _unknown  68 May  3 20:55 SC Info

./Users/Shared/SC Info:

./Users/me:
total 56
-rw-------   1 _unknown  _unknown      3 May  2 14:39 .CFUserTextEncoding
-rw-r--r--@  1 _unknown  _unknown  15364 May  3 16:38 .DS_Store
drwx------   6 _unknown  _unknown    204 May  4 17:53 .Trash
-rw-------   1 _unknown  _unknown   2036 May  4 16:13 .bash_history
-rw-------   1 _unknown  _unknown     42 May  3 22:48 .lesshst
drwx------   3 _unknown  _unknown    102 May  4 17:53 .ssh
drwx------+  4 _unknown  _unknown    136 May  4 17:53 Desktop
drwx------+  6 _unknown  _unknown    204 May  4 17:53 Documents
drwx------+  8 _unknown  _unknown    272 May  4 17:53 Downloads
drwx------@ 36 _unknown  _unknown   1224 May  4 17:53 Library
drwx------+  3 _unknown  _unknown    102 May  4 17:53 Movies
drwx------+  4 _unknown  _unknown    136 May  4 17:53 Music
drwx------+  5 _unknown  _unknown    170 May  4 17:53 Pictures
drwxr-xr-x+  5 _unknown  _unknown    170 May  4 17:53 Public

# gnutar czf /tmp/tarball.tgz <dir> is how I created it

# gnutar xzf /tmp/tarball.tgz is how I restored from it.

Is there some flags I need to give osx gnutar to get it to restore the proper ownership?

.

 

[maflynn]

Why not use OSX's tar utility?

 

[greno]

Why not use OSX's tar utility?

Because I have a whole set of tools written using gnutar that I brought over to the Mac from my Linux boxes. All I need is for OSX gnutar to actually work as intended and everything is fine. It appears there is some problem with OSX gnutar however.

.

 

[greno]

A big problem I can see right away is that OSX gnutar is storing the extended file information inside the archive in "absolute" format. That is WITH the leading '/'. **That is wrong**.

Eg:

gnutar: Removing leading `/' from member names

-rw-r--r-- root/wheel        0 2011-05-25 13:27 Users/.localized
-rwxr-xr-x me/staff        228 2012-05-03 22:48 /Users/._me        [B]<<<===[/B]
drwxr-xr-x me/staff          0 2012-05-03 22:48 Users/me/

Default behavior of gnutar as you can see from the informational header is to remove all leading '/' unless the archive was specifically created with -P / --absolute-names flag.

So that is a bug.

Whatever changes Apple made to gnutar to support its extended file attributes were not done completely correctly.

So your choices are either create an absolute archive and always use it to restore to the exact same position.

gnutar Pcf tarball.tar /dir /dir /dir  # forward slashes; must be extracted from '/' directory.

Or always make sure that you archive everything relatively. Even if you are working from / (root) directory.

cd /; gnutar cf tarball.tar  dir dir dir  # no forward slashes

What you cannot do is create an archive using absolute file references and then extract it to another place.

gnutar cf tarball.tar /dir /dir /dir  # forward slashes; now cannot be extracted to any other location.

.