[Pkg-openmpi-maintainers] Bug#839387: package builds crashing under fakeroot

[Christian Seiler]

On 10/03/2016 04:50 PM, Alastair McKinstry wrote:
> In OpenMPI 2.0, Michael Banck discovered that some of the packages that
> failed were doing so as openmpi no longer works under fakeroot.
> 
> Upstream (Gilles Gouaillaerdet) point out:
> 
>     from |validate_cred| in
>     |opal/mca/pmix/pmix112/pmix/src/sec/pmix_native.c|
> 
>     |getsockopt (peer->sd, SOL_SOCKET, SO_PEERCRED, &ucred, &crlen);|
> 
>     my understanding is that |fakeroot| tricks the processes into
>     believing they are ran as |root|,
>     as such, |orted| expects a connection from |root| (e.g. |ucred.uid|
>     is |0|)
>     /* in singleton mode, an |orted| is fork&exec'ed under the hood */
> 
>     but |fakeroot| cannot trick |getsockopt|, which returns the user
>     (non zero)
> 
> So its a legitimate tightening of credential-checking in pmix. However
> it causes problems for us running tests under binary-arch.

If the tests themselves don't need root (fakeroot is required for
Debian's build infrastructure), you could just remove the fakeroot
libraries from LD_PRELOAD.

Example script (save as e.g. debian/nofakeroot, make it executable,
call the tests via debian/nofakeroot command in debian/rules):

#!/bin/sh

filter_fakeroot() {
  oldifs="$IFS"
  IFS=":"
  s=
  set -- $LD_PRELOAD
  for lib in "$@" ; do
    if [ x"$lib" = x"${lib%libfakeroot-*}" ] ; then
      printf "%s%s" "$s" "$lib"
      s=:
    fi
  done
  IFS="$OLDIFS"
}

export LD_PRELOAD="$(filter_fakeroot)"
exec "$@"

Regards,
Christian