[fpc-pascal] FPC static linking of zlib

[Michael Van Canneyt]

On Tue, 13 Apr 2010, Matthias Klumpp wrote:

> On Tue, 13 Apr 2010 22:00:58 +0200, Micha Nelissen <micha at neli.hopto.org>
> wrote:
>> Matthias Klumpp wrote:
>>> If you build the package using lazbuild, lintian (the Debian policy
>>> checker
>>> tool) throws an error described here:
>>>  http://lintian.debian.org/tags/embedded-zlib.html
>>
>> paszlib is a pascal implementation of compression. How is that check
>> performed? Maybe it triggers on some specific function name?
> I'll ask someone.
>
>> I'm not sure if some version of zlib was translated to pascal; therefore
>> having the same security issues, or if it was written from scratch, so
>> that it won't have those security issues?
> Not sure...
> I should say that WinFF and easyMp3Gain do not use any ZLib function, so
> ZLib should not be in the binary.

When I use ldd to get the library dependencies, I get the following list of libraries:

home: >ldd bin/easymp3gain
         linux-vdso.so.1 =>  (0x00007fff17fff000)
         libX11.so.6 => /usr/lib/libX11.so.6 (0x00007f6de8258000)
         libgdk_pixbuf-2.0.so.0 => /usr/lib/libgdk_pixbuf-2.0.so.0 (0x00007f6de803c000)
         libgtk-x11-2.0.so.0 => /usr/lib/libgtk-x11-2.0.so.0 (0x00007f6de7a31000)
         libgdk-x11-2.0.so.0 => /usr/lib/libgdk-x11-2.0.so.0 (0x00007f6de7785000)
         libgobject-2.0.so.0 => /usr/lib/libgobject-2.0.so.0 (0x00007f6de753e000)
         libglib-2.0.so.0 => /lib/libglib-2.0.so.0 (0x00007f6de7277000)
         libgthread-2.0.so.0 => /usr/lib/libgthread-2.0.so.0 (0x00007f6de7072000)
         libgmodule-2.0.so.0 => /usr/lib/libgmodule-2.0.so.0 (0x00007f6de6e6e000)
         libpango-1.0.so.0 => /usr/lib/libpango-1.0.so.0 (0x00007f6de6c25000)
         libpthread.so.0 => /lib/libpthread.so.0 (0x00007f6de6a09000)
         libatk-1.0.so.0 => /usr/lib/libatk-1.0.so.0 (0x00007f6de67e9000)
         libcairo.so.2 => /usr/lib/libcairo.so.2 (0x00007f6de6566000)
         libdl.so.2 => /lib/libdl.so.2 (0x00007f6de6362000)
         libc.so.6 => /lib/libc.so.6 (0x00007f6de5ff3000)
         libxcb.so.1 => /usr/lib/libxcb.so.1 (0x00007f6de5dd7000)
         libgio-2.0.so.0 => /usr/lib/libgio-2.0.so.0 (0x00007f6de5b2d000)
         libm.so.6 => /lib/libm.so.6 (0x00007f6de58a9000)
         libpangocairo-1.0.so.0 => /usr/lib/libpangocairo-1.0.so.0 (0x00007f6de569d000)
         libXcomposite.so.1 => /usr/lib/libXcomposite.so.1 (0x00007f6de549a000)
         libXdamage.so.1 => /usr/lib/libXdamage.so.1 (0x00007f6de5298000)
         libXfixes.so.3 => /usr/lib/libXfixes.so.3 (0x00007f6de5092000)
         libpangoft2-1.0.so.0 => /usr/lib/libpangoft2-1.0.so.0 (0x00007f6de4e69000)
         libfreetype.so.6 => /usr/lib/libfreetype.so.6 (0x00007f6de4be4000)
         libfontconfig.so.1 => /usr/lib/libfontconfig.so.1 (0x00007f6de49b2000)
         libXext.so.6 => /usr/lib/libXext.so.6 (0x00007f6de47a0000)
         libXrender.so.1 => /usr/lib/libXrender.so.1 (0x00007f6de4596000)
         libXinerama.so.1 => /usr/lib/libXinerama.so.1 (0x00007f6de4394000)
         libXi.so.6 => /usr/lib/libXi.so.6 (0x00007f6de4189000)
         libXrandr.so.2 => /usr/lib/libXrandr.so.2 (0x00007f6de3f80000)
         libXcursor.so.1 => /usr/lib/libXcursor.so.1 (0x00007f6de3d76000)
         libpcre.so.3 => /lib/libpcre.so.3 (0x00007f6de3b48000)
         librt.so.1 => /lib/librt.so.1 (0x00007f6de3940000)
         /lib64/ld-linux-x86-64.so.2 (0x00007f6de858e000)
         libpixman-1.so.0 => /usr/lib/libpixman-1.so.0 (0x00007f6de36fb000)
         libdirectfb-1.2.so.0 => /usr/lib/libdirectfb-1.2.so.0 (0x00007f6de3470000)
         libfusion-1.2.so.0 => /usr/lib/libfusion-1.2.so.0 (0x00007f6de3266000)
         libdirect-1.2.so.0 => /usr/lib/libdirect-1.2.so.0 (0x00007f6de304b000)
         libpng12.so.0 => /usr/lib/libpng12.so.0 (0x00007f6de2e25000)
         libxcb-render-util.so.0 => /usr/lib/libxcb-render-util.so.0 (0x00007f6de2c21000)
         libxcb-render.so.0 => /usr/lib/libxcb-render.so.0 (0x00007f6de2a18000)
         libz.so.1 => /lib/libz.so.1 (0x00007f6de2801000)
         libXau.so.6 => /usr/lib/libXau.so.6 (0x00007f6de25fe000)
         libXdmcp.so.6 => /usr/lib/libXdmcp.so.6 (0x00007f6de23f9000)
         libresolv.so.2 => /lib/libresolv.so.2 (0x00007f6de21e0000)
         libselinux.so.1 => /lib/libselinux.so.1 (0x00007f6de1fc2000)
         libexpat.so.1 => /lib/libexpat.so.1 (0x00007f6de1d99000)

As you can see, it uses libz (or zlib) but dynamically, probably through some library dependency.

So I have no idea why they think it is linked statically. I searched the sources, but found
no direct dependency on paszlib or zlib, but there is an indirect dependency, because the paszlib
units are used. I think the jpeg and png support are the cause of this.

If you add the -s option to the compiler command line, in the link.res file that is then
generated when compiling, you can see that the paszlib unit is used.

Maybe they look for a function name (as suggested by Micha). In that case you should make
clear that zlib is not linked statically, but that paszlib simply contains a function with 
the same name.

Michael.