#!/bin/bash

set -e

good_nodes=""

for i in $(invirt-getconf --ls iscsi.targets); do
    # Extract the portal to talk to
    portal_ip=$(invirt-getconf iscsi.targets.$i.ip)

    # Extract the interfaces we should talk to this portal
    # on. Unfortunately, we have to ask about all the interfaces
    # simultaneously, because iscsiadm deletes all existing mentions
    # of a portal when you run discovery again.
    ifaces=$(for j in $(invirt-getconf --ls iscsi.targets.$i.ifaces); do invirt-getconf iscsi.targets.$i.ifaces.$j; done)

    echo "Connecting to $portal_ip via $ifaces"

    # Use SendTargets to discover the available targets on the given portal.
    iscsiadm -m discovery -t st -p $portal_ip:3260 $(for iface in $ifaces; do echo -I $iface; done)

    # Because of protocol limitations (see
    # http://www.pdl.cmu.edu/mailinglists/ips/mail/msg05174.html), the
    # discovery attempt may have returned additional targets that are
    # unreachable via this interface/portal. Make a list of discovered
    # target, portal, interface combinations so we can later remove
    # extraneous ones.
    for iface in $ifaces; do
	good_nodes="$good_nodes "$(echo /etc/iscsi/nodes/*/$portal_ip,3260,1/$iface)
    done

    # If the discovery attempt did not log into the target, explicitly do so now.
    for iface in $ifaces; do
	iscsiadm -m node -p $portal_ip:3260 -I $iface -l
    done
done

# Find all the nodes we now know about that we weren't supposed to
bad_nodes=$(find /etc/iscsi/nodes -type f | grep -Fxvf <(echo "$good_nodes" | sed 's/ /\n/g'))
# and delete them.
echo "Removing "$(echo $bad_nodes | wc -w)" extraneous discovered targets"
for node in $bad_nodes; do
    echo "Removing $node"

    # Remove the node entry
    rm $node;

    # Remove the cached results of the discovery so iscsiadm doesn't
    # get confused
    find /etc/iscsi/send_targets -lname "${node%/*}" -delete
done