hotplug/Linux: add iscsi block hotplug script

This hotplug script has been tested with IET and NetBSD iSCSI targets,
without authentication.

This hotplug script will only work with PV guests not using pygrub.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>

2 files changed, 155 insertions, 0 deletions

diff --git a/tools/hotplug/Linux/Makefile b/tools/hotplug/Linux/Makefile
index 99bf87f418..8b0d7f4dda 100644
--- a/tools/hotplug/Linux/Makefile
+++ b/tools/hotplug/Linux/Makefile
@@ -22,6 +22,7 @@ XEN_SCRIPTS += blktap
 XEN_SCRIPTS += xen-hotplug-cleanup
 XEN_SCRIPTS += external-device-migrate
 XEN_SCRIPTS += vscsi
+XEN_SCRIPTS += block-iscsi
 XEN_SCRIPT_DATA = xen-script-common.sh locking.sh logging.sh
 XEN_SCRIPT_DATA += xen-hotplug-common.sh xen-network-common.sh vif-common.sh
 XEN_SCRIPT_DATA += block-common.sh
diff --git a/tools/hotplug/Linux/block-iscsi b/tools/hotplug/Linux/block-iscsi
new file mode 100644
index 0000000000..8e36852832
--- /dev/null
+++ b/tools/hotplug/Linux/block-iscsi
@@ -0,0 +1,154 @@
+#!/bin/bash -e
+#
+# Open-iSCSI Xen block device hotplug script
+#
+# Author Roger Pau Monné <roger.pau@citrix.com>
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License as published
+# by the Free Software Foundation; version 2.1 only. with the special
+# exception on linking described in file LICENSE.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# Usage:
+#
+# Target should be specified using the following syntax:
+#
+# script=block-iscsi,vdev=xvda,target=iqn=<iqn>,portal=<portal IP>
+#
+# Portal address must be in IP format.
+#
+
+dir=$(dirname "$0")
+. "$dir/block-common.sh"
+
+remove_label()
+{
+    echo $1 | sed "s/^\("$2"\)//"
+}
+
+check_tools()
+{
+    if ! command -v iscsiadm > /dev/null 2>&1; then
+        fatal "Unable to find iscsiadm tool"
+    fi
+    if [ "$multipath" = "y" ] && ! command -v multipath > /dev/null 2>&1; then
+        fatal "Unable to find multipath"
+    fi
+}
+
+# Sets the following global variables based on the params field passed in as
+# a parameter: iqn, portal, auth_method, user, multipath, password
+parse_target()
+{
+    # set multipath default value
+    multipath="n"
+    for param in $(echo "$1" | tr "," "\n")
+    do
+        case $param in
+        iqn=*)
+            iqn=$(remove_label $param "iqn=")
+            ;;
+        portal=*)
+            portal=$(remove_label $param "portal=")
+            ;;
+        multipath=*)
+            multipath=$(remove_label $param "multipath=")
+            ;;
+        esac
+    done
+    if [ -z "$iqn" ] || [ -z "$portal" ]; then
+        fatal "iqn= and portal= are required parameters"
+    fi
+    if [ "$multipath" != "y" ] && [ "$multipath" != "n" ]; then
+        fatal "multipath valid values are y and n, $multipath not a valid value"
+    fi
+}
+
+# Sets $dev to point to the device associated with the value in iqn
+find_device()
+{
+    count=0
+    while [ ! -e /dev/disk/by-path/*"$iqn"-lun-0 ]; do
+        sleep 0.1
+        count=`expr $count + 1`
+        if [ count = 100 ]; then
+            # 10s timeout while waiting for iSCSI disk to settle
+            fatal "timeout waiting for iSCSI disk to settle"
+        fi
+    done
+    sddev=$(readlink -f /dev/disk/by-path/*"$iqn"-lun-0 || true)
+    if [ ! -b "$sddev" ]; then
+        fatal "Unable to find attached device path"
+    fi
+    if [ "$multipath" = "y" ]; then
+        mdev=$(multipath -ll "$sddev" | head -1 | awk '{ print $1}')
+        if [ ! -b /dev/mapper/"$mdev" ]; then
+            fatal "Unable to find attached device multipath"
+        fi
+        dev="/dev/mapper/$mdev"
+    else
+        dev="$sddev"
+    fi
+}
+
+# Attaches the target $iqn in $portal and sets $dev to point to the
+# multipath device
+attach()
+{
+    do_or_die iscsiadm -m node --targetname "$iqn" -p "$portal" --login > /dev/null
+    find_device
+}
+
+# Discovers targets in $portal and checks that $iqn is one of those targets
+# Also sets the auth parameters to attach the device
+prepare()
+{
+    # Check if target is already opened
+    iscsiadm -m session 2>&1 | grep -q "$iqn" && fatal "Device already opened"
+    # Discover portal targets
+    iscsiadm -m discovery -t st -p $portal 2>&1 | grep -q "$iqn" || \
+        fatal "No matching target iqn found"
+}
+
+# Attaches the device and writes xenstore backend entries to connect
+# the device
+add()
+{
+    attach
+    write_dev $dev
+}
+
+# Disconnects the device
+remove()
+{
+    find_device
+    do_or_die iscsiadm -m node --targetname "$iqn" -p "$portal" --logout > /dev/null
+}
+
+command=$1
+target=$(xenstore-read $XENBUS_PATH/params || true)
+if [ -z "$target" ]; then
+    fatal "No information about the target"
+fi
+
+parse_target "$target"
+
+check_tools || exit 1
+
+case $command in
+add)
+    prepare
+    add
+    ;;
+remove)
+    remove
+    ;;
+*)
+    exit 1
+    ;;
+esac