[FFmpeg-devel] Why 'You can only build one library type at once on MinGW'?

Michael Niedermayer michaelni
Sat May 12 01:15:57 CEST 2007


Hi

On Sat, May 12, 2007 at 12:52:58AM +0300, Uoti Urpala wrote:
> On Fri, 2007-05-11 at 23:18 +0200, Michael Niedermayer wrote:
> > and yes your security critical libs can still be loaded at random addresses
> > security critical libs per definition are not 4gb large ...
> 
> It's usually not the libraries that are security critical but the
> processes using them. If you want to avoid known addresses then all
> libraries in the process should be randomized.

yes


> 
> > i hope even someone who doesnt understand how PIC works can see that it does
> > take the pointer "last" from the GOT and then dereferences it which is
> > double indirection
> > this happen because some wise text x86-ABI or ELF or whatever _requires_ it
> > IIRC
> 
> That depends on the visibility of the symbol. If you make the symbol
> static or hidden ("library-wide static") then it does not need
> indirection. Same for the less often used visibility values protected or
> internal.

if i do something non portable which will break some things ... yes iam
not disageeing

and to get this totally off topic disscussion a little back to ffmpeg, 
i wish i could get gcc to make all symbols which arent in a specific set
of headers "library-wide static" anyone knows a simple and clean trick
to do that?

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Let us carefully observe those good qualities wherein our enemies excel us
and endeavor to excel them, by avoiding what is faulty, and imitating what
is excellent in them. -- Plutarch
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