extra bytes in zip archive when used with logrotate

[Oleg Goldshmidt]

shimi <linux-il at shimi.net> writes:

> On Mon, Aug 6, 2012 at 5:35 PM, Oleg Goldshmidt <pub at goldshmidt.org> wrote:
>
>                $ unzip -l file.log.zip
>      Archive:  file.log.zip
>      warning [file.log.zip]:  16 extra bytes at beginning or within
>      zipfile
>        (attempting to process anyway)
>        Length      Date    Time    Name
>      ---------  ---------- -----   ----
>          71992  08-06-2012 16:05   zipit.10182
>      ---------                     -------
>          71992                     1 file
>
>      and the archive cannot be opened:
>
> Maybe I missed it, but, what _are_ the first 16 bytes? Anything
> interesting? It sounds like something is sent to the zip that is not
> supposed to be sent there, e.g. redirect from stderr, like a notice
> going there. Any chance those 16 bytes are human readable ASCII?

Hmm... It never occurred to me to check because the warning does not
say that the extra bytes are at the beginning - it says "at beginning
or within". This seems to be consistent with the unzip code that
outputs the warning when some combination of offsets does not look
right (maybe I missed something but it didnt look like the beginning
of the file was specificlly checked).

I will only regain access to the test system on Wednesday - will od or
similar then.

Thanks,

-- 
Oleg Goldshmidt | pub at goldshmidt.org