add wrapper script to set umask on downstream images

Ref: 92c6e348cffd05ff4fd78c038f43877e7886ff85

Dockerfile

@@ -99,6 +99,7 @@ RUN \
 	/app \
 	/config \
 	/defaults && \
+ mv /usr/bin/with-contenv /usr/bin/with-contenvb && \
  echo "**** cleanup ****" && \
  apt-get clean && \
  rm -rf \

Dockerfile.aarch64

@@ -99,6 +99,7 @@ RUN \
 	/app \
 	/config \
 	/defaults && \
+ mv /usr/bin/with-contenv /usr/bin/with-contenvb && \
  echo "**** add qemu ****" && \
  curl -o \
  /usr/bin/qemu-aarch64-static -L \

Dockerfile.armhf

@@ -99,6 +99,7 @@ RUN \
 	/app \
 	/config \
 	/defaults && \
+ mv /usr/bin/with-contenv /usr/bin/with-contenvb && \
  echo "**** add qemu ****" && \
  curl -o \
  /usr/bin/qemu-arm-static -L \

root/usr/bin/with-contenv

+#! /bin/bash
+if [[ -f /var/run/s6/container_environment/UMASK ]] && [[ "$(pwdx $$)" =~ "/run/s6/services/" ]]; then
+  umask $(cat /var/run/s6/container_environment/UMASK)
+  exec /usr/bin/with-contenvb "$@"
+else
+  exec /usr/bin/with-contenvb "$@"
+fi