Replace architecture-emulation-binaries with qemu-debootstrap

The architecture-emulation-binaries element does for a limited number
of architectures on Ubuntu exactly the same as `qemu-debootstrap`.
`qemu-debootstrap` comes in the qemu-user-static package that is
anyhow used when cross-building an image.

This patch replaces the complete architecture-emulation-binaries
element with a call to qemu-debootstrap.

Change-Id: Ib9667307bfd3ff7592444a2ec5b04aa5365a1872
Signed-off-by: Andreas Florath <andreas@florath.net>

diskimage_builder/elements/architecture-emulation-binaries/README.rst

@@ -1,24 +0,0 @@
-===============================
-architecture-emulation-binaries
-===============================
-
-This element enables execution for different architectures
-
-When building an image for an architecture that the host machine
-can not execute, we need to chroot into the image to execute code,
-and if the host architecture does not match, we need to emulate
-the instructions.
-
-This element does the following:
-
- * copies the binary file into chroot /usr/bin environment.
-   Binary file is chosen based on host architecture and
-   image architecture the user is trying to build.
-
-   If an image we are building for an architecture is not the host
-   architecture, install tools provided by qemu-user-static
-   (which needs to be installed) to allow us to run commands
-   inside the building image.
-
-   This is tested on amd64/i386 architecture to build armhf and arm64
-   ubuntu cloud images.

diskimage_builder/elements/architecture-emulation-binaries/cleanup.d/01-cleanbinary

@@ -1,12 +0,0 @@
-#!/bin/bash
-
-if [ ${DIB_DEBUG_TRACE:-1} -gt 0 ]; then
-    set -x
-fi
-set -eu
-set -o pipefail
-
-if [ -x "$TMP_MOUNT_PATH/tmp/clean_up_qemu_binary" ] ; then
-    "$TMP_MOUNT_PATH/tmp/clean_up_qemu_binary"
-    rm -rf "$TMP_MOUNT_PATH/tmp/clean_up_qemu_binary"
-fi

diskimage_builder/elements/architecture-emulation-binaries/extra-data.d/01-copy-binary

@@ -1,64 +0,0 @@
-#!/bin/bash
-
-if [ ${DIB_DEBUG_TRACE:-1} -gt 0 ]; then
-    set -x
-fi
-set -eu
-set -o pipefail
-
-function clean_up_arch_emulation {
-    cat <<EOF >$TMP_MOUNT_PATH/tmp/clean_up_qemu_binary
-#!/bin/bash
-
-set -eux
-set -o pipefail
-
-sudo rm -rf "${TMP_MOUNT_PATH}${1}"
-EOF
-
-    sudo chmod +x "$TMP_MOUNT_PATH/tmp/clean_up_qemu_binary"
-}
-
-function check_copy_file {
-    if [ -f "$1" ] ; then
-        if [ ! -f "${TMP_MOUNT_PATH}${1}" ]; then
-            sudo cp "$1" "$TMP_MOUNT_PATH/usr/bin"
-            clean_up_arch_emulation $1
-        fi
-    else
-        echo "qemu binary file not found."
-        exit 1
-    fi
-}
-
-function copy_binary {
-    echo "checking for architecture compatibility..."
-    img_arch=$2
-    if [[ "$host_arch" != "$img_arch" ]]; then
-        qemu_binary=$1
-        check_copy_file $qemu_binary
-    else
-        echo "Emulation not required for this host/image architecture combination"
-    fi
-}
-
-host_arch="$(uname -m)"
-
-case "$ARCH" in
-    "i386" | "amd64")
-        qemu_binary_file="/usr/bin/qemu-i386-static"
-        copy_binary $qemu_binary_file $ARCH
-    ;;
-    "armhf")
-        qemu_binary_file="/usr/bin/qemu-arm-static"
-        copy_binary $qemu_binary_file $ARCH
-    ;;
-    "arm64" | "aarch64")
-        qemu_binary_file="/usr/bin/qemu-aarch64-static"
-        copy_binary $qemu_binary_file $ARCH
-    ;;
-    *)
-        echo "architecture not supported"
-        exit 1
-    ;;
-esac

diskimage_builder/elements/debootstrap/root.d/08-debootstrap

@@ -34,6 +34,8 @@ DEBOOTSTRAP_TARBALL=$DIB_IMAGE_CACHE/debootstrap-${DISTRO_NAME}-${DIB_RELEASE}-$
 http_proxy=${http_proxy:-}
 no_proxy=${no_proxy:-}
 
+DEBOOTSTRAP_QEMU=""
+
 if [ -n "$DIB_OFFLINE" -o -n "${DIB_DEBIAN_USE_DEBOOTSTRAP_CACHE:-}" ] && [ -f $DEBOOTSTRAP_TARBALL ] ; then
     echo $DEBOOTSTRAP_TARBALL found in cache. Using.
     sudo tar -C $TARGET_ROOT --numeric-owner -xzf $DEBOOTSTRAP_TARBALL
@@ -47,7 +49,14 @@ else
     # Have to --include=python because of dib-run-parts
     # Have to --include=sudo for pre-install.d use of sudoers files
     # Have to --include=busybox because initramfs needs it
-    sudo sh -c "http_proxy=$http_proxy no_proxy=$no_proxy debootstrap --verbose \
+
+    if [ $(dpkg --print-architecture) != ${ARCH} ]; then
+        # Target architecture diffrent from host architecture:
+        # there is the need to call 'qemu-debootstrap'.
+        DEBOOTSTRAP_QEMU="qemu-"
+    fi
+
+    sudo sh -c "http_proxy=$http_proxy no_proxy=$no_proxy ${DEBOOTSTRAP_QEMU}debootstrap --verbose \
         --variant=minbase \
         --components=${DIB_DEBIAN_COMPONENTS} \
         --arch=${ARCH} \
@@ -64,7 +73,6 @@ else
     sudo rm -fr ${TARGET_ROOT}/etc/apt/sources.list \
         ${TARGET_ROOT}/etc/apt/sources.list.d
 
-
     echo Caching debootstrap result in $DEBOOTSTRAP_TARBALL
     if [ "${DIB_DEBOOTSTRAP_CACHE:-0}" != "0" ]; then
         sudo tar --numeric-owner -C $TARGET_ROOT -zcf $DEBOOTSTRAP_TARBALL --exclude='./tmp/*' .