[Ns-developers] user-space code integration update

[Mathieu Lacage]

On Thu, 2008-08-07 at 13:25 +0100, Gustavo Carneiro wrote:
> 
> 
> 2008/8/6 Mathieu Lacage <mathieu.lacage at sophia.inria.fr>
>         hi,
>         
>         Recently, I resumed work on the ns-3-simu branch with a focus
>         towards
>         helping liu merge his code back into ns-3 and starting to port
>         quagga.
>         The biggest change in http://code.nsnam.org/mathieu/ns-3-simu
>         is that I
>         added support for loading in memory unmodified executables
>         with an elf
>         loader and running them over ns-3. This is implemented in the
>         src/process/elf-loader.h|cc files through a bunch of tricks to
>         force the
>         libc elf loader to load the same binary multiple times in
>         memory.
>         
>         I also added a lot of code to the libc replacement and have
>         gotten
>         sufficiently far to run the example programs in
>         examples/process.cc and
>         examples/process-udp-server.cc and
>         examples/process-udp-client.cc.
> 
> For replacing many libc functions (e.g. it works for socket
> functions), you can also use LD_PRELOAD to replace weak symbols.  I
> was wondering, what led you down this more complicated path instead?

because not all symbols are weak and because we don't want to replace
the libc used by ns-3: we want to replace the libc used only by the
simulated programs.

Mathieu