#!/bin/sh
set -e

#
# udevd since 232-20 learned to generate stable interface names for network
# interfaces in kvm/qemu. However, existing machines upgrading will be using
# the ethX names instead. The most risk-averse action is to encode
# "persistent-net-rules" like rules to keep the ethX names on upgrades, since
# the interface names (ethX) may be in use not only in /etc/network/interfaces
# but in other configurations too (daemons, firewalls, etc).
#
# This is a one time action, and can be removed after the next stable & LTS
# releases. (~ May 2018)
#

rulesfile=/etc/udev/rules.d/70-persistent-net.rules

if [ `uname -m` != 's390x' ]
then
    exit 0
fi

if [ `systemd-detect-virt` != 'kvm' ]
then
    exit 0
fi

if [ -f $rulesfile ]
then
    exit 0
fi

for interface in /sys/class/net/eth*
do
    [ -d $interface ] || continue
    name=$(basename $interface)
    address=$(cat $interface/address)
    cat <<EOF >>$rulesfile
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="$address", KERNEL=="eth*", NAME="$name"
EOF
done