1#!/bin/sh
2#
3# This script illustrates the sequence of operations in configfs to
4# create a very simple LIO iSCSI target with a file or block device
5# backstore.
6#
7# (C) Copyright 2014 Christophe Vu-Brugier <cvubrugier@fastmail.fm>
8#
9
10print_usage() {
11    cat <<EOF
12Usage: $(basename $0) [-p PORTAL] DEVICE|FILE
13Export a block device or a file as an iSCSI target with a single LUN
14EOF
15}
16
17die() {
18    echo $1
19    exit 1
20}
21
22while getopts "hp:" arg; do
23    case $arg in
24        h) print_usage; exit 0;;
25        p) PORTAL=${OPTARG};;
26    esac
27done
28shift $(($OPTIND - 1))
29
30DEVICE=$1
31[ -n "$DEVICE" ] || die "Missing device or file argument"
32[ -b $DEVICE -o -f $DEVICE ] || die "Invalid device or file: ${DEVICE}"
33IQN="iqn.2003-01.org.linux-iscsi.$(hostname):$(basename $DEVICE)"
34[ -n "$PORTAL" ] || PORTAL="0.0.0.0:3260"
35
36CONFIGFS=/sys/kernel/config
37CORE_DIR=$CONFIGFS/target/core
38ISCSI_DIR=$CONFIGFS/target/iscsi
39
40# Load the target modules and mount the config file system
41lsmod | grep -q configfs || modprobe configfs
42lsmod | grep -q target_core_mod || modprobe target_core_mod
43mount | grep -q ^configfs || mount -t configfs none $CONFIGFS
44mkdir -p $ISCSI_DIR
45
46# Create a backstore
47if [ -b $DEVICE ]; then
48    BACKSTORE_DIR=$CORE_DIR/iblock_0/data
49    mkdir -p $BACKSTORE_DIR
50    echo "udev_path=${DEVICE}" > $BACKSTORE_DIR/control
51else
52    BACKSTORE_DIR=$CORE_DIR/fileio_0/data
53    mkdir -p $BACKSTORE_DIR
54    DEVICE_SIZE=$(du -b $DEVICE | cut -f1)
55    echo "fd_dev_name=${DEVICE}" > $BACKSTORE_DIR/control
56    echo "fd_dev_size=${DEVICE_SIZE}" > $BACKSTORE_DIR/control
57    echo 1 > $BACKSTORE_DIR/attrib/emulate_write_cache
58fi
59echo 1 > $BACKSTORE_DIR/enable
60
61# Create an iSCSI target and a target portal group (TPG)
62mkdir $ISCSI_DIR/$IQN
63mkdir $ISCSI_DIR/$IQN/tpgt_1/
64
65# Create a LUN
66mkdir $ISCSI_DIR/$IQN/tpgt_1/lun/lun_0
67ln -s $BACKSTORE_DIR $ISCSI_DIR/$IQN/tpgt_1/lun/lun_0/data
68echo 1 > $ISCSI_DIR/$IQN/tpgt_1/enable
69
70# Create a network portal
71mkdir $ISCSI_DIR/$IQN/tpgt_1/np/$PORTAL
72
73# Disable authentication
74echo 0 > $ISCSI_DIR/$IQN/tpgt_1/attrib/authentication
75echo 1 > $ISCSI_DIR/$IQN/tpgt_1/attrib/generate_node_acls
76
77# Allow write access for non authenticated initiators
78echo 0 > $ISCSI_DIR/$IQN/tpgt_1/attrib/demo_mode_write_protect
79
80echo "Target ${IQN}, portal ${PORTAL} has been created"
81