diskimage-builder/elements/redhat-common/bin/extract-image

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#!/bin/bash
# Intended to be called from the root.d cloud-image script as follows:
# $TMP_HOOKS_PATH/bin/extract-image $BASE_IMAGE_FILE $BASE_IMAGE_TAR $IMAGE_LOCATION $CACHED_IMAGE
set -eu
BASE_IMAGE_FILE=$1
BASE_IMAGE_TAR=$2
IMAGE_LOCATION=$3
CACHED_IMAGE=$4
CACHED_TAR=$DIB_IMAGE_CACHE/$BASE_IMAGE_TAR
DIB_LOCAL_IMAGE=${DIB_LOCAL_IMAGE:-""}
if [ -n "$DIB_OFFLINE" -a -f "$CACHED_TAR" ] ; then
echo "Not checking freshness of cached $CACHED_TAR."
else
if [ -z "$DIB_LOCAL_IMAGE" ]; then
echo "Fetching Base Image"
# There seems to be some bad Fedora mirrors returning http 404's for the cloud image.
# If the image fails to download due to a 404 we retry once.
set +e
$TMP_HOOKS_PATH/bin/cache-url $IMAGE_LOCATION $CACHED_IMAGE
RV=$?
set -e
if [ "$RV" == "44" ] ; then
$TMP_HOOKS_PATH/bin/cache-url $IMAGE_LOCATION $CACHED_IMAGE
elif [ "$RV" != "0" ] ; then
exit 1
fi
fi
if [ ! -f $CACHED_TAR -o \
$CACHED_IMAGE -nt $CACHED_TAR ] ; then
echo "Repacking base image as tarball."
WORKING=$(mktemp -d)
EACTION="rm -r $WORKING"
trap "$EACTION" EXIT
echo "Working in $WORKING"
RAW_FILE=$(basename $BASE_IMAGE_FILE)
RAW_FILE=${RAW_FILE#.qcow2}.raw
qemu-img convert -f qcow2 -O raw $CACHED_IMAGE $WORKING/$RAW_FILE
# WARNING: The mattdm image has the root filesystem on the second
# partition (p2). If he changes the image the MAGIC_BIT
# might also need to change.
# UPDATE to above warning alluding to Fedora18:
# F19 images have the rootfs partition on p1
MAGIC_BIT=p1
# kpartx fails if no /dev/loop* exists, "losetup -f" prints first unused
# loop device and creates it if it doesn't exist
sudo losetup -f
# XXX: Parsing stdout is dangerous, would like a better way to discover
# the device used for the image.
# NOTE: On F17 (parted-3.0-10.fc17.x86_64), partprobe of
# /dev/loop0 does not create /dev/loop0p2, while kpartx at
# least creates /dev/mapper/loop0p2.
LOOPDEV=$(sudo kpartx -av $WORKING/$RAW_FILE | awk "/loop[0-9]+$MAGIC_BIT/ {print \$3}")
if ! timeout 5 sh -c "while ! [ -e /dev/mapper/$LOOPDEV ]; do sleep 1; done"; then
echo "Error: Could not find /dev/mapper/$LOOPDEV"
exit 1
fi
EACTION="sudo kpartx -d $WORKING/$RAW_FILE;$EACTION"
trap "$EACTION" EXIT
mkdir $WORKING/mnt
sudo mount /dev/mapper/$LOOPDEV $WORKING/mnt
EACTION="sudo umount -f $WORKING/mnt;$EACTION"
trap "$EACTION" EXIT
# Chroot in so that we get the correct uid/gid
sudo chroot $WORKING/mnt bin/tar -cz . > $WORKING/tmp.tar
mv $WORKING/tmp.tar $CACHED_TAR
else
echo "Using cached tar from $CACHED_TAR"
fi
fi
# Extract the base image (use --numeric-owner to avoid UID/GID mismatch between
# image tarball and host OS e.g. when building Fedora image on an openSUSE host)
echo "Extracting base root image from $CACHED_TAR"
sudo tar -C $TARGET_ROOT --numeric-owner -xzf $CACHED_TAR
if [ -e "$TARGET_ROOT/lost+found" ]; then
sudo rmdir $TARGET_ROOT/lost+found
fi