Re: forestalling GNU incompatibility - proposal for binary relative dynamic linking

[Marcus Meissner <meissner at suse dot de>]

On Tue, Jan 25, 2005 at 11:56:06AM -0800, Edward Peschko wrote:
> On Mon, Jan 24, 2005 at 10:34:10PM -0800, Dan Kegel wrote:
> > Edward Peschko wrote:
> > >After spending *two weeks* on various ways of building glibc, 
> > >I'm convinced that the gnu/linux toolchain is in great danger of 
> > >losing interoperability.
> > >
> > >The main problem is that the glibc's supplied with each commercial 
> > >system are *heavily* patched. My Suse 9.2 system has a rpm for 
> > >glibc with fifty patches.  Fifty patches! 
> > >
> > >Fifty patches which make the SuSE glibc binarily incompatible 
> > >with the redhat, and so on.  And everything is incompatible
> > >with the vanilla flavor.
> > 
> > I can sympathize with you.  I've spent several months
> > of my life building gcc and glibc.  (That's why I wrote
> > http://kegel.com/crosstool, so fewer people would ever have to go
> > through that hell.)
> > 
> > But fifty patches doesn't neccessarily mean binary incompatibility.
> > http://kegel.com/crosstool/crosstool-0.28-rc37/patches/glibc-2.3.2/
> > contains about 45 patches, but as far as I know, none of them
> > cause incompatibilities; most are neccessary to get glibc-2.3.2
> > to *build*.
> 
> Well, that might be the case with your fifty patches, but it sure
> isn't the case with mine..

We try to be binary compatible with upstream glibc.
 
> I build glibc out of the box, ie: no patches on a SuSE machine, same
> version as the OS (glibc-2.3.3), using latest gcc(gcc-3.4.3)
>  get segmentation faults every time when I try to run it against 
> system binaries. I set LD_LIBRARY_PATH back, and the segfaults go away. 

Very likely you did something wrong, building glibc is not for
the faint at heart.

Without more exact debug information we cannot say.

> Second - as far as the LSB standard is concerned, migrating to it 
> from incompatible glibc's is a trick in itself; you need to support 
> the legacy applications whilst you are migrating.  

> And hence to facilitate supporting the LSB it makes a lot of sense 
> to be able to support 2 incompatible libcs on the same machine at the 
> same time.

The SUSE included glibcs are LSB compliant, so there is no need to
migrate away from them.
 
> But there doesn't seem to be a good way to do this.  The best solution 
> someone has come up with so far is run stuff chrooted, which isn't 
> really a solution at all, because it doesn't allow for interoperability.

Just create your own Linux distribution.

Ciao, Marcus

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