Re: [PATCH] usertools/pmdinfo: remove dependency to ldd

[Olivier Matz <olivier.matz@6wind.com>]

Hi Robin,

On Thu, Oct 13, 2022 at 03:41:25PM +0200, Robin Jarry wrote:
> Some environments (buildroot) do not have the ldd utility installed by
> default. However, ldd is often only a wrapper shell script that actually
> checks that the arguments are valid ELF files and executes them with
> the LD_TRACE_LOADED_OBJECTS=1 variable set in the environment.
> 
> Since ld.so is the actual ELF interpreter which is loaded first when
> executing a program, executing any dynamic ELF program/library with that
> variable set will cause all dependent dynamic libraries to be printed
> and ld.so will exit before even running main.
> 
> Excerpt from ld.so(7) man page:
> 
>   LD_TRACE_LOADED_OBJECTS
>     If set (to any value), causes the program to list its dynamic
>     dependencies, as if run by ldd(1), instead of running normally.
> 
> Change dpdk-pmdinfo.py to actually "execute" the files provided on the
> command line with LD_TRACE_LOADED_OBJECTS=1 set. Ensure that the files
> are valid dynamically executable ELF programs to avoid obscure and
> confusing errors.
> 
> Reported-by: Olivier Matz <olivier.matz@6wind.com>
> Signed-off-by: Robin Jarry <rjarry@redhat.com>

Tested on buildroot without ldd.

Reviewed-by: Olivier Matz <olivier.matz@6wind.com>