Re: [Bug-tar] xattr support on Linux

[Pavel Raiskup]

On Tue, 2012-10-09 at 21:31 -0700, Tim Kientzle wrote:
> On Oct 9, 2012, at 12:57 AM, Pavel Raiskup wrote:
>
>> On Mon, 2012-10-08 at 15:24 -0700, Paul Eggert wrote:
>>> On 10/08/2012 08:52 AM, Pavel Raiskup wrote:
>>>> we are not able to store/restore extended attributes containing '='
>>>> character in the keyword properly - same situation in star as our patch
>>>> uses the same approach.
>>>
>>> Can't we fix this by URL-encoding '=' and '%' when creating the tar file
>>> and URL-decoding when extracting?  It sounds easy, but it's not done
>>> by that patch, so what am I missing?
>>
>> Yes, that seems to be OK solution.  I'll prepare patch today and I'll post
>> it in the xattr-proposal thread.
>
> bsdtar also URL-encodes any characters that
> aren't printable ASCII.
>
> This avoids any problems if a reader expects
> the key name to be valid UTF-8.

Tim, what problems you mean?  I expected that tar implementations are
searching for '0x3d' byte as a splitting point between KEY and VALUE.
And all '=' characters in KEY are URL-encoded -> no ambiguity.

As proposed simplified encoding transforms only '%' and '=' characters,
GNU tar may never transform the string from UTF-8 valid to non-UTF-8
string?

Pavel