[PATCH RFC 10/10] hotplug/Linux: add iscsi block hotplug script

[Roger Pau Monne <roger.pau@citrix.com>]

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

Authentication parameters, including the password are passed as
parameters to iscsiadm, which is not recommended because other users
of the system can see them. This parameters could also be set by
editing a corresponding file directly, but the location of this file
seems to be different depending on the distribution used.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
---
 tools/hotplug/Linux/Makefile    |    1 +
 tools/hotplug/Linux/block-iscsi |  254 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 255 insertions(+), 0 deletions(-)
 create mode 100644 tools/hotplug/Linux/block-iscsi

diff --git a/tools/hotplug/Linux/Makefile b/tools/hotplug/Linux/Makefile
index 0605559..98c7738 100644
--- a/tools/hotplug/Linux/Makefile
+++ b/tools/hotplug/Linux/Makefile
@@ -21,6 +21,7 @@ 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 0000000..ddb96c5
--- /dev/null
+++ b/tools/hotplug/Linux/block-iscsi
@@ -0,0 +1,254 @@
+#!/bin/sh
+#
+# 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.
+
+remove_label()
+{
+    echo $1 | sed "s/^\("$2"\)//"
+}
+
+check_tools()
+{
+    if ! type iscsiadm > /dev/null 2>&1; then
+        echo "Unable to find iscsiadm tool"
+        return 1
+    fi
+    if [ "$multipath" = "y" ] && ! type multipath > /dev/null 2>&1; then
+        echo "Unable to find multipath"
+        return 1
+    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 "$1" | tr "," "\n")
+    do
+        if [ -n "$password" ]; then
+            password="$password,$param"
+            continue
+        fi
+        case $param in
+        iqn=*)
+            iqn=$(remove_label $param "iqn=")
+            ;;
+        portal=*)
+            portal=$(remove_label $param "portal=")
+            ;;
+        auth_method=*)
+            auth_method=$(remove_label $param "auth_method=")
+            ;;
+        user=*)
+            user=$(remove_label $param "user=")
+            ;;
+        multipath=*)
+            multipath=$(remove_label $param "multipath=")
+            ;;
+        password=*)
+            password=$(remove_label $param "password=")
+            ;;
+        esac
+    done
+    if [ -z "$iqn" ] || [ -z "$portal" ]; then
+        echo "iqn= and portal= are required parameters"
+        return 1
+    fi
+    if [ "$multipath" != "y" ] && [ "$multipath" != "n" ]; then
+        echo "multipath valid values are y and n, $multipath not a valid value"
+        return 1
+    fi
+    return 0
+}
+
+# Outputs the block device major:minor
+device_major_minor()
+{
+    stat -L -c %t:%T "$1"
+}
+
+# Sets $dev to point to the device associated with the value in iqn
+find_device()
+{
+    while [ ! -e /dev/disk/by-path/*"$iqn"-lun-0 ]; do
+        sleep 0.1
+    done
+    sddev=$(readlink -f /dev/disk/by-path/*"$iqn"-lun-0)
+    if [ ! -b "$sddev" ]; then
+        echo "Unable to find attached device path"
+        return 1
+    fi
+    if [ "$multipath" = "y" ]; then
+        mdev=$(multipath -ll "$sddev" | head -1 | awk '{ print $1}')
+        if [ ! -b /dev/mapper/"$mdev" ]; then
+            echo "Unable to find attached device multipath"
+            return 1
+        fi
+        dev="/dev/mapper/$mdev"
+    else
+        dev="$sddev"
+    fi
+    return 0
+}
+
+# Attaches the target $iqn in $portal and sets $dev to point to the
+# multipath device
+attach()
+{
+    iscsiadm -m node --targetname "$iqn" -p "$portal" --login > /dev/null 2>&1
+    if [ $? -ne 0 ]; then
+        echo "Unable to connect to target"
+        return 1
+    fi
+    find_device
+    if [ $? -ne 0 ]; then
+        echo "Unable to find iSCSI device"
+        return 1
+    fi
+    return 0
+}
+
+# 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"
+    if [ $? -eq 0 ]; then
+        echo "Device already opened"
+        return 1
+    fi
+    # Discover portal targets
+    iscsiadm -m discovery -t st -p $portal 2>&1 | grep -q "$iqn"
+    if [ $? -ne 0 ]; then
+        echo "No matching target iqn found"
+        return 1
+    fi
+    # Set auth method if necessary
+    if [ -n "$auth_method" ] || [ -n "$user" ] || [ -n "$password" ]; then
+        iscsiadm -m node --targetname "$iqn" -p "$portal" --op=update --name \
+            node.session.auth.authmethod --value="$auth_method" \
+            > /dev/null 2>&1 && \
+        iscsiadm -m node --targetname "$iqn" -p "$portal" --op=update --name \
+            node.session.auth.username --value="$user" \
+            > /dev/null 2>&1 && \
+        iscsiadm -m node --targetname "$iqn" -p "$portal" --op=update --name \
+            node.session.auth.password --value="$password" \
+            > /dev/null 2>&1
+        if [ $? -ne 0 ]; then
+            echo "Unable to set authentication parameters"
+            return 1
+        fi
+    fi
+    return 0
+}
+
+# Attaches the device and writes xenstore backend entries to connect
+# the device
+add()
+{
+    localattach
+    if [ $? -ne 0 ]; then
+        echo "Failed to attach device"
+        return 1
+    fi
+    mm=$(device_major_minor "$dev")
+    xenstore-write "$BACKEND_PATH/physical-device" "$mm"
+    xenstore-write "$BACKEND_PATH/params" "$dev"
+    return 0
+}
+
+# Disconnects the device
+remove()
+{
+    find_device
+    if [ $? -ne 0 ]; then
+        echo "Unable to find device"
+        return 1
+    fi
+    iscsiadm -m node --targetname "$iqn" -p "$portal" --logout > /dev/null 2>&1
+    if [ $? -ne 0 ]; then
+        echo "Unable to disconnect target"
+        return 1
+    fi
+    return 0
+}
+
+# Removes the auth params set by prepare
+unprepare()
+{
+    if [ -n "$auth_method" ] || [ -n "$user" ] || [ -n "$password" ]; then
+        iscsiadm -m node --targetname "$iqn" -p "$portal" --op=delete --name \
+            node.session.auth.authmethod > /dev/null 2>&1
+        iscsiadm -m node --targetname "$iqn" -p "$portal" --op=delete --name \
+            node.session.auth.username > /dev/null 2>&1
+        iscsiadm -m node --targetname "$iqn" -p "$portal" --op=delete --name \
+            node.session.auth.password > /dev/null 2>&1
+    fi
+}
+
+# Attaches the device to the current domain, and writes the resulting
+# block device to xenstore
+localattach()
+{
+    attach
+    if [ $? -ne 0 ]; then
+        echo "Failed to attach device"
+        return 1
+    fi
+    xenstore-write "$HOTPLUG_PATH/pdev" "$dev"
+    return 0
+}
+
+command=$1
+target=$(xenstore-read $HOTPLUG_PATH/params)
+
+if [ -z "$target" ]; then
+    echo "No information about the target"
+    exit 1
+fi
+
+check_tools || exit 1
+
+parse_target "$target"
+
+case $command in
+prepare)
+    prepare
+    exit $?
+    ;;
+add)
+    add
+    exit $?
+    ;;
+remove)
+    remove
+    exit $?
+    ;;
+unprepare)
+    unprepare
+    exit $?
+    ;;
+localattach)
+    localattach
+    exit $?
+    ;;
+localdetach)
+    remove
+    exit $?
+    ;;
+esac
-- 
1.7.7.5 (Apple Git-26)


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