Refactor structure.

1 files changed, 42 insertions, 0 deletions

diff --git a/builder/dnbd3-qcow2-rootfs/hooks/pre-mount/prepare-root-partition.sh b/builder/dnbd3-qcow2-rootfs/hooks/pre-mount/prepare-root-partition.sh
new file mode 100755
index 00000000..8b5ea48e
--- /dev/null
+++ b/builder/dnbd3-qcow2-rootfs/hooks/pre-mount/prepare-root-partition.sh
@@ -0,0 +1,42 @@
+function create_partition_via_offset() {
+    local device="$1"
+    local nameOrUUID="$2"
+    local loopDevice=$(losetup -f)
+
+    local sectorSize=$(blockdev --getbsz $device)
+    local partitionInfo=$(partx --raw --noheadings --output START,NAME,UUID /dev/nbd0 2>/dev/null| grep $nameOrUUID)
+    local offsetSectors=$(echo $partitionInfo | cut -d' ' -f1)
+    if [ -z "$offsetSectors" ]; then
+        warn "could not find partition with label/uuid '$nameOrUUID' on device $device"
+        return 1
+    fi
+    #warn $(($offsetSectors*512)) # could overflow on 32bit systems
+    local offsetBytes=$(echo $| awk -v x=$offsetSectors -v y=$sectorSize '{print x * y}')
+
+    # test if mount works directly (problem with btrfs device id)
+    #mount -v -o loop,offset=$offsetBytes $device $mountPoint
+    losetup -v -o $offsetBytes $loopDevice $device
+    echo $loopDevice
+}
+
+# Close previous connections to be able to run this script many times.
+dnbd3-client --device /dev/dnbd0 --close && \
+dnbd3-client --host gateway --image archLinux.qcow2 --device /dev/dnbd0 && \
+qemu-nbd --connect=/dev/nbd0 /dev/dnbd0 --read-only && \
+local read_only_partition="$(create_partition_via_offset /dev/nbd0 system)" && \
+# Make read-only partition writable.
+# TODO implement persistent available indicator.
+if true; then
+    local writable_device="/dev/ram0" && \
+    mknod --mode 660 "$writable_device" b 1 1 && \
+    chown root.disk "$writable_device"
+else
+    # Use next free loop device.
+    local writable_device="$(losetup -f)" && \
+    dd if=/dev/zero of=persistent_storage.img bs=1k count=1000 && \
+    losetup "$writable_device" persistent_storage.img
+fi
+local size="$(blockdev --getsz "$read_only_partition")" && \
+local writable_partition_name="root" && \
+dmsetup create "$writable_partition_name" --table \
+    "0 $partion_size snapshot $read_only_partition $writable_device N 1"