[PATCH] docker: Add binfmt-support for Isar cross-building

[Jan Kiszka <jan.kiszka@siemens.com>]

From: Jan Kiszka <jan.kiszka@siemens.com>

Additionally requires to run the container with --privileged - not nice but
unavoidable right now, see also
https://groups.google.com/forum/#!topic/isar-users/Un75m49InjY

Also note that running containers with different binfmt settings
concurrently will cause troubles. Same for the case that the host
requires deviating settings. Use carefully.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
---

Clearly no long-term solution, but as long as we need binfmt and want to
use Docker at least as packaging helper (not for isolation), this is
required.

 Dockerfile.isar | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/Dockerfile.isar b/Dockerfile.isar
index 0119720..ea644b4 100644
--- a/Dockerfile.isar
+++ b/Dockerfile.isar
@@ -10,7 +10,7 @@ RUN apt-get update && \
     apt-get install -y -f --no-install-recommends --target-release jessie \
             autoconf automake gdisk libtool bash-completion \
             sudo grub2 grub-efi-amd64-bin grub-efi-ia32-bin qemu-user-static \
-            reprepro python3 && \
+            reprepro python3 binfmt-support && \
     apt-get install -y -f --no-install-recommends --target-release jessie-backports \
             e2fsprogs && \
     apt-get install -y -f --no-install-recommends --target-release stretch \
@@ -20,3 +20,5 @@ RUN apt-get update && \
 
 RUN echo "builder ALL=NOPASSWD: ALL" > /etc/sudoers.d/builder-nopasswd && \
     chmod 660 /etc/sudoers.d/builder-nopasswd
+
+RUN sed -i "s|#!/bin/bash|\0\n\nupdate-binfmts --enable|" /kas/docker-entrypoint
-- 
2.12.3