diskimage-builder/elements/ubuntu-core/root.d/10-cache-ubuntu-image
Pino Toscano f35aace69f Use shorter temporary file names for kpartx
The loopback handling in the Linux kernel limits the filenames of
files associated to loopback devices, see also linux/loop.h.
This is reflected also on userspace, as kpartx will silently do nothing
(exiting with 0) when requesting to remove a filename longer than 64
characters, as that name will obviously not match the truncated
filename. The result of this is that, when extracting qcow2 images for
the first time, if the qcow2 filename is long enough then the loopback
device will not be removed, remaining as stale in the host.

As a workaround, use a temporary file name when convering a qcow2 image
to raw, instead of using the base name of the qcow2 file.
While this still will not fix the issue when manually using a long
temporary directory (e.g. TMP_DIR=/very/long/etc...), at least should
avoid it in other cases.

Change-Id: Ibf46cd313a9d89412c0e1068fa0993be6c5a29db
2015-04-21 10:36:33 +02:00

86 lines
3.5 KiB
Bash
Executable File

#!/bin/bash
# These are useful, or at worst not harmful, for all images we build.
if [ ${DIB_DEBUG_TRACE:-0} -gt 0 ]; then
set -x
fi
set -eu
set -o pipefail
[ -n "$ARCH" ]
[ -n "$TARGET_ROOT" ]
shopt -s extglob
DIB_CLOUD_IMAGES=${DIB_CLOUD_IMAGES:-http://cdimage.ubuntu.com/ubuntu-core/preview}
DIB_RELEASE=${DIB_RELEASE:-alpha-01}
BASE_IMAGE_FILE=${BASE_IMAGE_FILE:-ubuntu-core-$DIB_RELEASE.img}
BASE_IMAGE_TAR=$DIB_RELEASE-ubuntu-core.tgz
SHA256SUMS=${SHA256SUMS:-$DIB_CLOUD_IMAGES/SHA256SUMS}
CACHED_FILE=$DIB_IMAGE_CACHE/$BASE_IMAGE_FILE
CACHED_TAR=$DIB_IMAGE_CACHE/$BASE_IMAGE_TAR
CACHED_SUMS=$DIB_IMAGE_CACHE/SHA256SUMS.ubuntu-core.$DIB_RELEASE
if [ -n "$DIB_OFFLINE" -a -f "$CACHED_TAR" ] ; then
echo "Not checking freshness of cached $CACHED_TAR"
else
echo "Fetching Base Image"
$TMP_HOOKS_PATH/bin/cache-url $SHA256SUMS $CACHED_SUMS
$TMP_HOOKS_PATH/bin/cache-url $DIB_CLOUD_IMAGES/$BASE_IMAGE_FILE $CACHED_FILE
pushd $DIB_IMAGE_CACHE
if ! grep "$BASE_IMAGE_FILE" $CACHED_SUMS | sha256sum --check - ; then
# It is likely that an upstream http(s) proxy has given us a skewed
# result - either a cached SHA file or a cached image. Use cache-busting
# to get (as long as caches are compliant...) fresh files.
# Try the sha256sum first, just in case that is the stale one (avoiding
# downloading the larger image), and then if the sums still fail retry
# the image.
$TMP_HOOKS_PATH/bin/cache-url -f $SHA256SUMS $CACHED_SUMS
if ! grep "$BASE_IMAGE_FILE" $CACHED_SUMS | sha256sum --check - ; then
$TMP_HOOKS_PATH/bin/cache-url -f \
$DIB_CLOUD_IMAGES/$BASE_IMAGE_FILE $CACHED_FILE
grep "$BASE_IMAGE_FILE" $CACHED_SUMS | sha256sum --check -
fi
fi
popd
if [ ! -f $CACHED_TAR -o \
$DIB_IMAGE_CACHE/$BASE_IMAGE_FILE -nt $CACHED_TAR ] ; then
echo "Repacking base image as tarball."
WORKING=$(mktemp -d)
EACTION="rm -r $WORKING"
trap "$EACTION" EXIT
RAW_FILE=$(mktemp --tmpdir=$WORKING XXXXXX.raw)
qemu-img convert -f qcow2 -O raw $CACHED_FILE $RAW_FILE
MAGIC_BIT=p1
# NOTE: On RHEL, partprobe of /dev/loop0 does not create /dev/loop0p2,
# while kpartx at least creates /dev/mapper/loop0p2.
LOOPDEV=$(sudo kpartx -av $RAW_FILE | awk "/loop[0-9]+$MAGIC_BIT/ {print \$3}")
# If running inside Docker, make our nodes manually, because udev will not be working.
if [ -f /.dockerenv ]; then
sudo dmsetup --noudevsync mknodes
fi
export LOOPDEV=$LOOPDEV
echo "Loop device is set to: $LOOPDEV"
if ! timeout 5 sh -c "while ! [ -e /dev/mapper/$LOOPDEV ]; do sleep 1; done"; then
echo "Error: Could not find /dev/mapper/$LOOPDEV"
exit 1
fi
EACTION="sudo kpartx -d $RAW_FILE;$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 $DIB_IMAGE_CACHE/$BASE_IMAGE_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 Ubuntu image on an openSUSE host)
sudo tar -C $TARGET_ROOT --numeric-owner -xzf $DIB_IMAGE_CACHE/$BASE_IMAGE_TAR