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Detect boot and EFI partitions in extract-image

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RHEL-9 base images are whole-disk images with the /boot/efi partition
correctly set up for EFI Secure Boot. This doesn't work with
extract-image because it only mounts the root partition, leaving
/boot/efi empty even though grub2-efi & shim packages are "installed".

This change mounts discovered partitions to mnt/boot, mnt/boot/efi so
all content can be extracted from the image.

Partition detection is done by reading block device attributes and
matching on Boot Loader Specification[1] UIDs or labels as observed in
supported base images.

[1] https://systemd.io/BOOT_LOADER_SPECIFICATION/
Change-Id: I8487002a18ae6ca98609ab68d92ae9173a2b864f
This commit is contained in:
Steve Baker 2022-02-22 14:02:29 +13:00
parent 4376f66407
commit 0630b3cb69
1 changed files with 70 additions and 12 deletions
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82
diskimage_builder/elements/sysprep/bin/extract-image
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@ -18,6 +18,12 @@ CACHED_TAR=$DIB_IMAGE_CACHE/$BASE_IMAGE_TAR
DIB_LOCAL_IMAGE=${DIB_LOCAL_IMAGE:-""}
TAR_LOCK=$CACHED_TAR.lock
# GPT GUIDs of interest.
# See https://en.wikipedia.org/wiki/GUID_Partition_Table#Partition_type_GUIDs
# also https://systemd.io/BOOT_LOADER_SPECIFICATION/
GUID_EFI="c12a7328-f81f-11d2-ba4b-00a0c93ec93b"
GUID_LINUX_BOOT="bc13c2ff-59e6-4262-a352-b275fd6f7172"
function extract_image() {
if [ -n "$DIB_OFFLINE" -a -f "$CACHED_TAR" ] ; then
echo "Not checking freshness of cached $CACHED_TAR."
@ -59,29 +65,68 @@ function extract_image() {
qemu-img convert -f qcow2 -O raw $CACHED_IMAGE $RAW_FILE
ROOT_PARTITION=p$(sudo kpartx -l $RAW_FILE | awk "/loop[0-9]+p/"|wc -l)
sudo udevadm settle
# kpartx fails if no /dev/loop* exists, "losetup -f" prints first unused
# loop device and creates it if it doesn't exist
sudo losetup -f
LOOPDEV_BASE=$(basename $(sudo losetup -f))
# add partition mappings
sudo kpartx -av $RAW_FILE
# XXX: Parsing stdout is dangerous, would like a better way to discover
# the device used for the image.
ROOT_LOOPDEV=$(sudo kpartx -av $RAW_FILE | \
awk "/loop[0-9]+$ROOT_PARTITION/ {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
if ! timeout 5 sh -c "while ! [ -e /dev/mapper/$ROOT_LOOPDEV ]; do sleep 1; done"; then
echo "Error: Could not find /dev/mapper/$ROOT_LOOPDEV"
if ! timeout 5 sh -c "while ! ls /dev/mapper/${LOOPDEV_BASE}p* ; do sleep 1; done"; then
echo "Error: Could not find any ${LOOPDEV_BASE} devices"
exit 1
fi
EACTION="sudo kpartx -d $RAW_FILE ; $EACTION"
trap "$EACTION" EXIT
ROOT_LOOPDEV=""
BOOT_LOOPDEV=""
EFI_LOOPDEV=""
LOOPDEVS=$(ls /dev/mapper/${LOOPDEV_BASE}p* | sort -r)
for LOOPDEV in ${LOOPDEVS}; do
lsblk --all --nodeps -P --output-all $LOOPDEV
fstype=$(lsblk --all --nodeps --noheadings --output FSTYPE $LOOPDEV)
label=$(lsblk --all --nodeps --noheadings --output LABEL $LOOPDEV)
part_type_name=$(lsblk --all --nodeps --noheadings --output PARTTYPENAME $LOOPDEV || echo "")
part_type=$(lsblk --all --nodeps --noheadings --output PARTTYPE $LOOPDEV)
if [ -z "${fstype}" ]; then
# Ignore block device with no filesystem type
continue
fi
# look for EFI partition to mount at /boot/efi either by GUID or
# label convention
if [ -z "$EFI_LOOPDEV" ]; then
if [[ ${part_type} == ${GUID_EFI} || ${part_type_name} == "EFI System" ]]; then
EFI_LOOPDEV=$LOOPDEV
continue
fi
fi
# look for EFI partition to mount at /boot/efi either by GUID or
# label convention.
if [ -z "$BOOT_LOOPDEV" ]; then
if [[ ${part_type} == ${GUID_LINUX_BOOT} || ${label} == "boot" ]]; then
BOOT_LOOPDEV=$LOOPDEV
continue
fi
fi
if [ -z "$ROOT_LOOPDEV" ]; then
ROOT_LOOPDEV=$LOOPDEV
continue
fi
done
mkdir $WORKING/mnt
if [ "xfs" = "$(sudo blkid -o value -s TYPE /dev/mapper/$ROOT_LOOPDEV)" ]; then
if [ "xfs" = "$(sudo blkid -o value -s TYPE $ROOT_LOOPDEV)" ]; then
# mount xfs with nouuid, just in case that uuid is already mounted
# use ro to avoid/workaround xfs uuid issues on older
# kernels with newer rhel images which seem to set
@ -93,10 +138,23 @@ function extract_image() {
MOUNTOPTS=""
fi
sudo mount $MOUNTOPTS /dev/mapper/$ROOT_LOOPDEV $WORKING/mnt
sudo mount $MOUNTOPTS $ROOT_LOOPDEV $WORKING/mnt
EACTION="sudo umount -f $WORKING/mnt ; $EACTION"
trap "$EACTION" EXIT
if [ ! -z "$BOOT_LOOPDEV" ]; then
# mount to /boot
sudo mount $BOOT_LOOPDEV $WORKING/mnt/boot
EACTION="sudo umount -f $BOOT_LOOPDEV ; $EACTION"
trap "$EACTION" EXIT
fi
if [ ! -z "$EFI_LOOPDEV" ]; then
# mount to /boot/efi
sudo mount $EFI_LOOPDEV $WORKING/mnt/boot/efi
EACTION="sudo umount -f $EFI_LOOPDEV ; $EACTION"
trap "$EACTION" EXIT
fi
# find out if chroot tar has full xattr support
if [ 0 == `sudo chroot $WORKING/mnt bin/tar --help | grep -c xattrs-exclude` ]; then
TAROPTS="--no-xattrs"