busybox tar cannot unpack this file

Joakim Tjernlund joakim.tjernlund at transmode.se
Thu Apr 23 09:11:43 UTC 2015


On Thu, 2015-04-23 at 01:17 +0100, Hin-Tak Leung wrote:
> You don't know much about tar, tgz and gzip, do you?

I am no expert but I do know something, enough to hack on bb gzip:
  http://git.busybox.net/busybox/commit/?id=0866b369003fbf81f8f35eb15360a628b3f3aa9a

> 
> $curl 'https://share.transmode.com/data/public/72b153.php?dl=true' > /tmp/1
> $file /tmp/1
> /tmp/1: gzip compressed data, last modified: Mon Mar 30 12:14:03 2015, from Unix
> 
> The correct way to process your file is:
> 
> curl 'https://share.transmode.com/data/public/72b153.php?dl=true' | gzip -dc | tar -xf - 
> 
> I think you meant to do (you are missing the z option in tar):
> gzip -dc  rootfs.old.tgz | tar -tf - > /tmp/fff
> or
> tar -ztf rootfs.old.tgz > /tmp/ttt

These days you don't have to specify z, tar detects it automatically.
but to be clear busybox tar ztf rootfs.old.tgz gives the same error.

I do need you to confirm that you used busybox tar, not gnu tar in above test? 

> 
> BTW, I think you should have warned that it is nearly 500MB in size.

Yeah, slipped my mind. The file need to be > 500 MB the error to occur.

 Jocke

> 
> --------------------------------------------
> On Thu, 23/4/15, Joakim Tjernlund <joakim.tjernlund at transmode.se> wrote:
> 
>  https://share.transmode.com/data/public/72b153.php
>  
>  busybox tar -tf rootfs.old.tgz > /tmp/ttt
>  tar: warning: skipping header 'S'
>  tar: invalid tar magic
>  
>  File is generated on ppc32 with GNU tar and unpacking is on
>  amd64
>  
>  busybox on ppc32 CAN unpack it so I guess this an endian or
>  32 vs 64 bits problem.
>  
>  BusyBox v1.23.1 
>  tar (GNU tar) 1.27.1
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