Hi Andre,
On Fri, 2012-04-20 at 10:35 +0800, Andre Fischer wrote:
> Thanks Michael for your analysis.
No problem :-) hope it helps.
> I dont't think that copying the files is a problem. After all we are
> already unzipping the zlib tar ball to a location of our choosing. Why
> should copying some of the files to yet another location change
> anything ?
Copying these files, obscures the fact that unzip.c and another file (I
forget which) come from contrib/minizip and not the normal, well
understood main zlib source, which people are used to having
well-understood and sane licensing.
> They are not part of the source package and the binary packages will
> contain the resulting zlib library anyway, regardless of the location
> of any of its source files. But, of course, I am not a laywer.
Of course ! the resulting zlib binary will contained a compiled version
of zlib/contrib/minizip/unzip.c - as I see it anyhow - not for Linux,
but for Windows and Mac. And naturally neither of us are lawyers :-)
> Regarding the license issue:
> I agree that the licensing may appear to be confusing because the
> LICENSE file referenced in unzip.c is missing.
Quite, the question is, what did that file contain ? and/or where is
it ?
> But if you look closely
> at the text, it says that the license text is also included in zip.h,
> and that file exists and contains the same license text that is also
> listed in MiniZip64_info.txt (in the same directory.) That license is
...
> This text is contained in main/LICENSE at around line 2017. I see no
> problem with this.
It seems highly unclear to me; the contrib code is ( I assume ) dropped
in from a separate project / location. The unzip.c header reads:
https://github.com/madler/zlib/blob/master/contrib/minizip/unzip.c#L16
[snip]
Decryption code comes from crypt.c by Info-ZIP but has been
...
See the accompanying file LICENSE, version 2000-Apr-09 or later
(the contents of which are also included in zip.h) for terms of use.
If, for some reason, all these files are missing, the Info-ZIP license
also may be found at: ftp://ftp.info-zip.org/pub/infozip/license.html
[/snip]
There is no LICENSE file in this directory, nor in the minizip
distribution itself ;-) Interestingly api.c also claims to be api.h, and
there is plenty of scope for obsolete / un-audited statements there.
Presumably this is why it lives in contrib/
As we agree, this is somewhat confusing; however - given that
confusion, we have a handy link to the infozip license embedded, and the
ftp link (to an HTML page!) still resolves, and produces a page
containing:
"This is version 2009-Jan-02 of the Info-ZIP license."
which seems similar to the versioning of the (now gone) file referred
to in the unzip.c file (right?). There are a number of other conditions
there:
ftp://ftp.info-zip.org/pub/infozip/license.html
My suspicion is that, perhaps, that code was copied from infozip's
package, whose download I just hunted down for you here:
http://sourceforge.net/projects/infozip/develop
Which contains a LICENSE file and a different zip.h reference.
Sadly I don't have more time to dig into this for you guys. Of course,
with luck it's not an issue; it's certainly a rather convoluted one, and
it's only for some rather unclear / small pieces of unzip.c.
All the best,
Michael.
--
[email protected] <><, Pseudo Engineer, itinerant idiot
