rename docker-entrypoint to container-entrypoint

Signed-off-by: Claudius Heine <ch@denx.de>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>

container-entrypoint

@@ -0,0 +1,50 @@
+#!/bin/bash
+
+if mount | grep -q "on / type aufs"; then
+    cat <<EOF >&2
+WARNING: Generation of wic images will fail!
+
+Your docker host setup uses broken aufs as storage driver. Adjust the docker
+configuration to use a different driver (overlay, overlay2, devicemapper). You
+may also need to update the host distribution (e.g. Debian Jessie -> Stretch).
+
+EOF
+fi
+
+USER_ID=${USER_ID:-30000}
+GROUP_ID=${GROUP_ID:-30000}
+
+if [ $USER_ID == 0 ]; then
+	# We shall run everything as root
+	mkdir -p /builder
+
+	GOSU=""
+else
+	if ! grep -q "^builder:" /etc/group; then
+		groupadd -o --gid $GROUP_ID builder
+	fi
+	if ! id builder >/dev/null 2>&1; then
+		# Create a non-root user that will perform the actual build
+		useradd -o --uid $USER_ID --gid $GROUP_ID --create-home \
+			--home-dir /builder builder
+	fi
+
+	GOSU="gosu builder"
+fi
+
+if [ "$PWD" = / ]; then
+	cd /builder
+fi
+
+if [ -n "$1" ]; then
+	case "$1" in
+	build|shell|-*)
+		exec $GOSU kas "$@"
+		;;
+	*)
+		exec $GOSU "$@"
+		;;
+	esac
+else
+	exec $GOSU bash
+fi