Add a script to convert the docker into chroot

The docker image will be exported into a tar archive
containing the chroot directory

Issue-ID: OOM-1551
Change-Id: I8709ffd59156243e42bebbaf03838120149d47b0
Signed-off-by: Petr Ospalý <p.ospaly@partner.samsung.com>

diff --git a/ansible/docker/create_docker_chroot.sh b/ansible/docker/create_docker_chroot.sh
new file mode 100755 (executable)
index 0000000..f8e256d
--- /dev/null
+++ b/ansible/docker/create_docker_chroot.sh
@@ -0,0 +1,220 @@
+#!/bin/sh
+
+#   COPYRIGHT NOTICE STARTS HERE
+
+#   Copyright 2018 © Samsung Electronics Co., Ltd.
+#
+#   Licensed under the Apache License, Version 2.0 (the "License");
+#   you may not use this file except in compliance with the License.
+#   You may obtain a copy of the License at
+#
+#       http://www.apache.org/licenses/LICENSE-2.0
+#
+#   Unless required by applicable law or agreed to in writing, software
+#   distributed under the License is distributed on an "AS IS" BASIS,
+#   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#   See the License for the specific language governing permissions and
+#   limitations under the License.
+
+#   COPYRIGHT NOTICE ENDS HERE
+
+
+set -e
+
+CMD=$(basename "$0")
+
+help()
+{
+    echo "
+NAME:
+    ${CMD} - create a chroot directory from docker image
+
+DESCRIPTION:
+    It will export docker image into a directory capable of chrooting.
+    It needs and will run these commands (requires docker service):
+        docker create
+        docker export
+
+USAGE:
+    ${CMD} [-h|--help|help]
+        This help
+
+    ${CMD} convert <docker-name> <name-of-directory>
+
+        It will convert docker image into directory - no chroot yet.
+        The name of the docker image must be imported already (not a file):
+            docker image ls
+
+        The directory will be created and so this command will fail if some
+        directory or a file of this name (filepath) already exists!
+        There is another script run_chroot.sh with which you can do chroot
+        on this newly created directory - so it is expected that this
+        directory is kept clean and as it is.
+        If you don't care about this feature (run_chroot.sh) and you know
+        what are you doing, then do necessary mounts and execute:
+            chroot <name-of-directory>/chroot /bin/sh -l
+"
+}
+
+#
+# PLEASE DON'T TOUCH ME
+#
+
+# readme file for run_chroot.sh
+readme()
+{
+    md_codequote='```'
+
+cat > "$CHROOT_METADIR"/README.md <<EOF
+# RUN CHROOT COMMAND
+
+# usage:
+
+${md_codequote}
+run_chroot.sh help
+${md_codequote}
+
+**Don't modify insides of this directory (where this README.md lies).**
+
+The structure is needed as it is.
+
+If you wish to just run chroot by yourself, you can do:
+${md_codequote}
+chroot ./chroot /bin/sh -l
+${md_codequote}
+
+# requirements:
+
+* root privileges
+* docker service
+
+# directory structure:
+${md_codequote}
+   README.md
+   chroot/
+   .overlay
+   .workdir
+   .merged
+${md_codequote}
+EOF
+}
+
+# arg: <docker-name>
+check_docker_image()
+{
+    image="$1"
+    match=$(docker image ls --no-trunc -q "$image" | wc -l)
+
+    case $match in
+        0)
+            echo ERROR: "Docker image does not exist: ${DOCKER_IMAGE}" >&2
+            exit 1
+            ;;
+        1)
+            :
+            ;;
+        *)
+            echo ERROR: "Multiple results for this docker name: ${DOCKER_IMAGE}" >&2
+            exit 1
+            ;;
+    esac
+
+    return 0
+}
+
+cleanup()
+{
+    if [ -n "$DOCKER_CONTAINER" ] ; then
+        echo INFO: "Delete the export container: ${DOCKER_CONTAINER}" >&2
+        if ! docker rm "$DOCKER_CONTAINER" > /dev/null ; then
+            echo ERROR: "Failed to delete: ${DOCKER_CONTAINER}" >&2
+        fi
+    fi
+}
+
+on_exit()
+{
+    set +e
+    cleanup
+}
+
+action=nil
+case "$1" in
+    ''|-h|--help|help)
+        help
+        exit 0
+        ;;
+    convert)
+        action=convert
+        DOCKER_IMAGE="$2"
+        CHROOT_METADIR="$3"
+        ;;
+    *)
+        echo ERROR: "Bad usage" >&2
+        help >&2
+        exit 1
+        ;;
+esac
+
+
+case "$action" in
+    ''|nil)
+        echo ERROR: "Nothing to do - missing command" >&2
+        help >&2
+        exit 1
+        ;;
+    convert)
+        if [ -z "$DOCKER_IMAGE" ] || [ -z "$CHROOT_METADIR" ] ; then
+            echo ERROR: "Missing argument" >&2
+            help >&2
+            exit 1
+        fi
+
+        if [ -e "$CHROOT_METADIR" ] ; then
+            echo ERROR: "Filepath already exists: ${CHROOT_METADIR}" >&2
+            echo ERROR: "Please rename it, remove it or use different name" >&2
+            echo ERROR: "I need my working directory empty, thanks" >&2
+            exit 1
+        fi
+
+        # check if docker image is there
+        check_docker_image "$DOCKER_IMAGE"
+
+        # we must be root
+        if [ "$(id -u)" -ne 0 ] ; then
+            echo ERROR: "I need root privileges and you are not root: $(id -nu)" >&2
+            exit 1
+        fi
+
+        # making sure that CHROOT_METADIR is absolute path
+        CHROOT_METADIR=$(readlink -f "$CHROOT_METADIR")
+
+        # set trap
+        trap on_exit INT QUIT TERM EXIT
+
+        # making readme
+        mkdir -p "$CHROOT_METADIR"/
+        readme
+
+        # create container
+        DOCKER_CONTAINER=$(docker create "$DOCKER_IMAGE")
+        if [ -z "$DOCKER_CONTAINER" ] ; then
+            echo ERROR: "I could not create a container from: ${DOCKER_IMAGE}" >&2
+            exit 1
+        fi
+
+        # unpacking of image
+        mkdir -p "$CHROOT_METADIR"/chroot
+        echo INFO: "Export started - it can take a while to finish..." >&2
+        if ! docker export "$DOCKER_CONTAINER" | tar -C "$CHROOT_METADIR"/chroot -xf - ; then
+            echo ERROR: "Unpacking failed - permissions?" >&2
+            exit 1
+        else
+            echo INFO: "Export success: $CHROOT_METADIR/chroot" >&2
+            echo INFO: "Checkout the README file: $CHROOT_METADIR/README.md" >&2
+        fi
+        ;;
+esac
+
+exit 0
+