Re: [PATCH 0/2] support numeric owner/group tar image format

["Peter A. Bigot" <pab@pabigot.com>]

On 11/03/2014 08:55 AM, Mark Hatle wrote:
> On 11/2/14, 4:48 AM, Peter A. Bigot wrote:
>> A classic approach to building SD card images with varying rootfs sizes
>> is to create the filesystem and unpack a tar rootfs image onto it.  When
>> done outside pseudo the encoded user and group names from the tar file
>> are converted to identifiers using host files, which often result in
>> incorrect assignment for common names like messagebus and ntp.
>>
>> A solution is to create the rootfs archive using the numeric values
>> obtained from the target /etc files under pseudo, rather than the
>> corresponding names.  This series provides this function as a new image
>> file format "nug.tar".
>>
>> Peter A. Bigot (2):
>>    image_types.bbclass: whitespace and reorder
>>    image_types.bbclass: add tar --numeric-owner support
>>
>>   meta/classes/image_types.bbclass | 18 +++++++++++++++++-
>>   1 file changed, 17 insertions(+), 1 deletion(-)
>>
>
> I think this is incorrect.
>
> The current tar archives contain both the uname/gname -and- uid/gid.  
> When you extract, if you pass --numeric-owner it will switch from name 
> to number.  (At least it has whenever I've done it.)  The default 
> though is to use the uname/gname.

You're correct; both are stored per: 
http://www.gnu.org/software/tar/manual/html_node/Standard.html

This should probably be publicized more widely, since when the issue 
came up recently I wasn't the only one who discovered the hand-generated 
images had the wrong uid/gid values for non-root files.  Unnecessarily, 
as it turns out: adding --numeric-owner to the unpack does solve the 
problem.

Thanks.  I'll archive both patches in patchwork (the first is still 
valid, but is now unmotivated).

Peter