balena-supervisor/mount-partitions.sh
Michal Toman 0045928944 mount-partitions.sh: Add support for encrypted partitions
After a recent change enforcing all the partitions to be on the same
block device, encrypted partitions are no longer being detected
correctly. This is because the assumption that the parent block device
is a substring of the actually mounted block device does not work
for LUKS devices - the mount will either be /dev/mapper/luks-XXX
or /dev/dm-X while the parent device is still e.g. /dev/sda.

The usual balenaOS boot partition is also split in two - boot and efi.
The boot partition (mounted under /mnt/boot) is encrypted and the efi
partition (mounted under /mnt/efi) is not.

This patch generalizes the detection of the parent device so that
it works with both encrypted and unencrypted partitions.

Change-type: patch
Signed-off-by: Michal Toman <michalt@balena.io>
2023-05-03 16:29:16 +02:00

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#!/bin/sh
# Mounts boot, state, & data partitions from balenaOS.
# The container must be privileged for this to function correctly.
# Set overlayfs root mountpoint
export ROOT_MOUNTPOINT="/mnt/root"
# Set DBus system bus address for getting the current boot block device
export DBUS_SYSTEM_BUS_ADDRESS="${DBUS_SYSTEM_BUS_ADDRESS:-unix:path="${ROOT_MOUNTPOINT}"/run/dbus/system_bus_socket}"
# Get the block device from systemd
# The dbus-send command below should return something like:
# ```
# method return time=1680132905.878117 sender=:1.0 -> destination=:1.20155 serial=245193 reply_serial=2
# variant string "/dev/sda1"
# ```
# Usage: dbus_get_mount PARTITION
# Partition is only the label, e.g. boot, state, data
dbus_get_mount() {
part="$1"
result=$(dbus-send --system --print-reply \
--dest=org.freedesktop.systemd1 /org/freedesktop/systemd1/unit/mnt_2d${part}_2emount org.freedesktop.DBus.Properties.Get \
string:"org.freedesktop.systemd1.Mount" string:"What" | grep "string" | cut -d'"' -f2 2>&1)
# If the output doesn't match the /dev/* device regex, exit with an error
if [ "$(echo "${result}" | grep -E '^/dev/')" = "" ]; then
echo "ERROR: Could not determine ${part} device from dbus. Please launch Supervisor as a privileged container with DBus socket access."
exit 1
fi
echo "${result}"
}
# Get the current boot block device in case there are duplicate partition labels
# for `(balena|resin)-(boot|state|data)` found.
current_boot_block_device=""
if [ "${TEST}" != 1 ]; then
mnt_boot_mount=$(dbus_get_mount "boot")
mnt_boot_type=$(lsblk -no type "${mnt_boot_mount}")
# If the (resin|balena)-boot partition is encrypted, we need to have a look at the efi partition
if [ "${mnt_boot_type}" = "crypt" ]; then
boot_part=$(dbus_get_mount "efi")
else
boot_part="${mnt_boot_mount}"
fi
current_boot_block_device=$(lsblk -no pkname "${boot_part}")
if [ "${current_boot_block_device}" = "" ]; then
echo "ERROR: Could not determine boot device from lsblk. Please launch Supervisor as a privileged container."
exit 1
fi
fi
# Mounts a device to a path if it's not already mounted.
# Usage: do_mount DEVICE MOUNT_PATH
do_mount() {
device=$1
mount_path=$2
# Create the directory if it doesn't exist
mkdir -p "${mount_path}"
# Mount the device if it doesn't exist
if [ "$(mountpoint -n "${mount_path}" | awk '{ print $1 }')" != "${device}" ]; then
mount "${device}" "${mount_path}"
fi
}
# Find the devices for each balenaOS partition.
# Usage: setup_then_mount PARTITION MOUNT_PATH
# PARTITION should be one of boot, state, or data.
setup_then_mount() {
# If in test environment, pretend we've succeeded at mounting everything to their
# new mountpoints. We don't want to actually mount in a containerized test environment
# where the Supervisor is probably not running on a host that has the needed partitions.
if [ "${TEST}" = 1 ]; then
return 0
fi
partition_label=$1
target_path=$2
# Try FS label first and partition label as a fallback
for arg in label partlabel; do
kname=$(lsblk "/dev/${current_boot_block_device}" -nlo "kname,${arg}" | grep -E "(resin|balena)-${partition_label}" | awk '{print $1}')
device="/dev/${kname}"
if [ -b "${device}" ]; then
echo "INFO: Found device $device on current boot device $current_boot_block_device, using as mount for '(resin|balena)-${partition_label}'."
do_mount "${device}" "${target_path}"
return 0
fi
done
# If no devices were found, use legacy mountpoints.
echo "ERROR: Could not determine which partition to mount for label '(resin|balena)-${partition_label}'. Please make sure the Supervisor is running on a balenaOS device."
exit 1
}
# Set boot mountpoint
BOOT_MOUNTPOINT="/mnt/boot"
setup_then_mount "boot" "${BOOT_MOUNTPOINT}"
export BOOT_MOUNTPOINT
# Read from the os-release of boot partition instead of overlay
export HOST_OS_VERSION_PATH="${BOOT_MOUNTPOINT}/os-release"
# CONFIG_MOUNT_POINT is set to /boot/config.json in Dockerfile.template,
# but that's a legacy mount provided by host and we should override it.
export CONFIG_MOUNT_POINT="${BOOT_MOUNTPOINT}/config.json"
# Set state mountpoint
STATE_MOUNTPOINT="/mnt/state"
setup_then_mount "state" "${STATE_MOUNTPOINT}"
export STATE_MOUNTPOINT
# Set data mountpoint
DATA_MOUNTPOINT="/mnt/data"
setup_then_mount "data" "${DATA_MOUNTPOINT}"
export DATA_MOUNTPOINT
# Mount the Supervisor database directory to a more accessible & backwards compatible location.
# TODO: DB should be moved to a managed volume and mounted to /data in-container.
# Handle the case of such a Supervisor volume already existing.
# NOTE: After this PR, it should be good to remove the OS's /data/database.sqlite mount.
if [ ! -f /data/database.sqlite ] && [ "${TEST}" != 1 ]; then
mkdir -p "${DATA_MOUNTPOINT}/resin-data/balena-supervisor"
mount -o bind,shared "${DATA_MOUNTPOINT}"/resin-data/balena-supervisor /data
fi
export DATABASE_PATH="/data/database.sqlite"