Wharfie

#!/bin/bash
#
# We are running inside of Qemu and use the block devices to
# exchange large amounts of files. Our build jobs are long-term
# jobs, so we just copy the whole data forth and back. While we
# are keeping timestamps and we keep old files inside of a cache
# partition.
#
# We expect the following layout of our block devices, as they
# are passed to Qemu at the command line:
#
# - sda: This is the root partition of the system (read-only for us)
# - sdb: This is also a real partition, which is used for caching
# - sdc: This is our input tar archive (no real partition, so it can't be mounted)
# - sdd: This is our output tar archive. Itself it might contain multiple archives.
#
# Note the drawback of this solution is, that we have maximum limits
# for input and output packets. But those limits can be fully influenced
# by the caller, why it seems acceptable anyway.
#

echo "#########################################################"
echo "# Wharfie started"
echo "#########################################################"

sleep 10;

echo "#########################################################"

# setup network
dhclient eth0

echo "#########################################################"


# enable binfmt for all supported architectures
update-binfmts --enable qemu-arm
update-binfmts --enable qemu-armeb
update-binfmts --enable qemu-ppc
echo "#########################################################"

# mount the cache folder to /build and change into it
[ ! -d /build ] && mkdir /build
mount /dev/sdb1 /build &&
    cd /build &&
    
    # untar the input into the build folder
    tar -xpf /dev/sdc &&
    
    # run make in the build folder
    make WHARFIE_MK=wharfie.mk &&

    # pack everything, except some fix excludes to output
    tar --exclude='*.piling.tar' --exclude='debian_version.mk' --exclude='debian_toolchain.tar' --exclude='debian_toolchain_env.sh' -cf /dev/sdd .

# shut the VM down
sync
shutdown -P now