tools/create-image.sh: support for foreign architectures

Also update sy-env to be able to build the root image inside.

Signed-off-by: Alexander Egorenkov <Alexander.Egorenkov@ibm.com>

2 files changed, 50 insertions, 1 deletions

diff --git a/tools/create-image.sh b/tools/create-image.sh
index 0967b4c37..b702b75ab 100755
--- a/tools/create-image.sh
+++ b/tools/create-image.sh
@@ -16,6 +16,7 @@ if [ -z ${ADD_PACKAGE+x} ]; then
 fi
 
 # Variables affected by options
+ARCH=$(uname -m)
 RELEASE=stretch
 FEATURE=minimal
 SEEK=2047
@@ -25,6 +26,7 @@ PERF=false
 display_help() {
     echo "Usage: $0 [option...] " >&2
     echo
+    echo "   -a, --arch                 Set architecture"
     echo "   -d, --distribution         Set on which debian distribution to create"
     echo "   -f, --feature              Check what packages to install in the image, options are minimal, full"
     echo "   -s, --size                 Image size (MB), default 2048 (2G)"
@@ -43,6 +45,10 @@ while true; do
             display_help
             exit 0
             ;;
+        -a | --arch)
+	    ARCH=$2
+            shift 2
+            ;;
         -d | --distribution)
 	    RELEASE=$2
             shift 2
@@ -69,6 +75,20 @@ while true; do
     esac
 done
 
+# Foreign architecture
+if [ $ARCH != $(uname -m) ]; then
+    # Check for according qemu static binary
+    if ! which qemu-$ARCH-static; then
+        echo "Please install qemu static binary for architecture $ARCH (package 'qemu-user-static' on Debian/Ubuntu/Fedora)"
+        exit 1
+    fi
+    # Check for according binfmt entry
+    if [ ! -r /proc/sys/fs/binfmt_misc/qemu-$ARCH ]; then
+        echo "binfmt entry /proc/sys/fs/binfmt_misc/qemu-$ARCH does not exist"
+        exit 1
+    fi
+fi
+
 # Double check KERNEL when PERF is enabled
 if [ $PERF = "true" ] && [ -z ${KERNEL+x} ]; then
     echo "Please set KERNEL environment variable when PERF is enabled"
@@ -83,7 +103,21 @@ fi
 sudo rm -rf $DIR
 sudo mkdir -p $DIR
 sudo chmod 0755 $DIR
-sudo debootstrap --include=$PREINSTALL_PKGS --components=main,contrib,non-free $RELEASE $DIR
+
+# 1. debootstrap stage
+
+DEBOOTSTRAP_PARAMS="--include=$PREINSTALL_PKGS --components=main,contrib,non-free $RELEASE $DIR"
+if [ $ARCH != $(uname -m) ]; then
+    DEBOOTSTRAP_PARAMS="--arch=$ARCH --foreign $DEBOOTSTRAP_PARAMS"
+fi
+sudo debootstrap $DEBOOTSTRAP_PARAMS
+
+# 2. debootstrap stage: only necessary if target != host architecture
+
+if [ $ARCH != $(uname -m) ]; then
+    sudo cp $(which qemu-$ARCH-static) $DIR/$(which qemu-$ARCH-static)
+    sudo chroot $DIR /bin/bash -c "/debootstrap/debootstrap --second-stage"
+fi
 
 # Set some defaults and enable promtless ssh to the machine for root.
 sudo sed -i '/^root/ { s/:x:/::/ }' $DIR/etc/passwd
diff --git a/tools/docker/big-env/Dockerfile b/tools/docker/big-env/Dockerfile
index ec225ed7c..a940cfb5e 100644
--- a/tools/docker/big-env/Dockerfile
+++ b/tools/docker/big-env/Dockerfile
@@ -24,6 +24,21 @@ FROM gcr.io/syzkaller/env
 # NetBSD toolchain can be re-built with:
 # ./build.sh -j72 -m amd64 -U -T ../tools tools
 # ./build.sh -j72 -m amd64 -U -T ../tools -D ../dest distribution
+#
+# To build root image run:
+#	docker run -it --rm --privileged --device /dev/loop0 gcr.io/syzkaller/big-env
+#	mount binfmt_misc -t binfmt_misc /proc/sys/fs/binfmt_misc
+#	create-image.sh -a s390x -d buster
+
+RUN dpkg --add-architecture i386 && \
+	apt-get update && \
+	DEBIAN_FRONTEND=noninteractive apt-get install -y -q --no-install-recommends \
+	# required to build root images.
+	debootstrap ssh-tools qemu-user-static \
+	&& \
+	apt-get -y autoremove && \
+	apt-get clean autoclean && \
+	rm -rf /var/lib/apt/lists/{apt,dpkg,cache,log} /tmp/* /var/tmp/*
 
 RUN curl https://storage.googleapis.com/syzkaller/fuchsia-toolchain.tar.gz | tar -C /syzkaller -xz
 RUN curl https://storage.googleapis.com/syzkaller/netbsd-toolchain.tar.gz | tar -C /syzkaller -xz