kdump: Basic iscsi target dump support (software initiator)

BZ: 822701

This patch implements basic software iscsi dump support. Complex iscsi
setups like ibft etc might not work.

iscsi self configuration logic is currenlty part of kdump module. At some
point of time I would like to see it in dracut iscsi module instead of
kdump module when iscsi and other subsystems become self configuration aware
for general boot.

This patch will require work for complex setups. Some of them are.

- IPV6 support
- IBFT support
- Parsing some more advanced parameters and passing to netroot option.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>

dracut-module-setup.sh

@@ -108,6 +108,132 @@ kdump_install_conf() {
     inst "/tmp/$$-kdump.conf" "/etc/kdump.conf"
 }
 
+kdump_iscsi_get_rec_val() {
+
+    local result
+
+    # The open-iscsi 742 release changed to using flat files in
+    # /var/lib/iscsi.
+
+    result=$(/sbin/iscsiadm --show -m session -r ${1} | grep "^${2} = ")
+    result=${result##* = }
+    echo $result
+}
+
+kdump_get_iscsi_initiator() {
+    local _initiator
+    local initiator_conf="/etc/iscsi/initiatorname.iscsi"
+
+    [ -f "$initiator_conf" ] || return 1
+
+    while read _initiator; do
+        [ -z "${_initiator%%#*}" ] && continue # Skip comment lines
+
+        case $_initiator in
+            InitiatorName=*)
+                initiator=${_initiator#InitiatorName=}
+                echo "rd.iscsi.initiator=${initiator}"
+                return 0;;
+            *) ;;
+        esac
+    done < ${initiator_conf}
+
+    return 1
+}
+
+# No ibft handling yet.
+kdump_setup_iscsi_device() {
+    local path=$1
+    local tgt_name; local tgt_ipaddr;
+    local username; local password; local userpwd_str;
+    local username_in; local password_in; local userpwd_in_str;
+    local netdev
+    local idev
+    local netroot_str ; local initiator_str;
+    local netroot_conf="${initdir}/etc/cmdline.d/50iscsi.conf"
+    local initiator_conf="/etc/iscsi/initiatorname.iscsi"
+
+    dinfo "Found iscsi component $1"
+
+    # Check once before getting explicit values, so we can output a decent
+    # error message.
+
+    if ! /sbin/iscsiadm -m session -r ${path} >/dev/null ; then
+        derror "Unable to find iscsi record for $path"
+        return 1
+    fi
+
+    tgt_name=$(kdump_iscsi_get_rec_val ${path} "node.name")
+    tgt_ipaddr=$(kdump_iscsi_get_rec_val ${path} "node.conn\[0\].address")
+
+    # get and set username and password details
+    username=$(kdump_iscsi_get_rec_val ${path} "node.session.auth.username")
+    [ "$username" == "<empty>" ] && username=""
+    password=$(kdump_iscsi_get_rec_val ${path} "node.session.auth.password")
+    [ "$password" == "<empty>" ] && password=""
+    username_in=$(kdump_iscsi_get_rec_val ${path} "node.session.auth.username_in")
+    [ -n "$username" ] && userpwd_str="$username:$password"
+
+    # get and set incoming username and password details
+    [ "$username_in" == "<empty>" ] && username_in=""
+    password_in=$(kdump_iscsi_get_rec_val ${path} "node.session.auth.password_in")
+    [ "$password_in" == "<empty>" ] && password_in=""
+
+    [ -n "$username_in" ] && userpwd_in_str=":$username_in:$password_in"
+
+    netdev=$(/sbin/ip route get to ${tgt_ipaddr} | \
+        sed 's|.*dev \(.*\).*|\1|g' | awk '{ print $1; exit }')
+
+    kdump_setup_netdev $netdev
+
+    # prepare netroot= command line
+    # FIXME: IPV6 addresses require explicit [] around $tgt_ipaddr
+    # FIXME: Do we need to parse and set other parameters like protocol, port
+    #        iscsi_iface_name, netdev_name, LUN etc.
+
+    netroot_str="netroot=iscsi:${userpwd_str}${userpwd_in_str}@$tgt_ipaddr::::$tgt_name"
+
+    [[ -f $netroot_conf ]] || touch $netroot_conf
+
+    # If netroot target does not exist already, append.
+    if ! grep -q $netroot_str $netroot_conf; then
+         echo $netroot_str >> $netroot_conf
+         dinfo "Appended $netroot_str to $netroot_conf"
+    fi
+
+    # Setup initator
+    initiator_str=$(kdump_get_iscsi_initiator)
+    [ $? -ne "0" ] && derror "Failed to get initiator name" && return 1
+
+    # If initiator details do not exist already, append.
+    if ! grep -q "$initiator_str" $netroot_conf; then
+         echo "$initiator_str" >> $netroot_conf
+         dinfo "Appended "$initiator_str" to $netroot_conf"
+    fi
+}
+
+kdump_check_iscsi_targets () {
+    # If our prerequisites are not met, fail anyways.
+    type -P iscsistart >/dev/null || return 1
+
+    kdump_check_setup_iscsi() (
+        local _dev
+        _dev=$(get_maj_min $1)
+
+        [[ -L /sys/dev/block/$_dev ]] || return
+        cd "$(readlink -f /sys/dev/block/$_dev)"
+        until [[ -d sys || -d iscsi_session ]]; do
+            cd ..
+        done
+        [[ -d iscsi_session ]] && kdump_setup_iscsi_device "$PWD"
+    )
+
+    [[ $hostonly ]] || [[ $mount_needs ]] && {
+        for_each_host_dev_fs kdump_check_setup_iscsi
+    }
+}
+
+
 install() {
     kdump_install_conf
     inst "$moddir/monitor_dd_progress" "/kdumpscripts/monitor_dd_progress"
@@ -119,4 +245,9 @@ install() {
     inst "/bin/cut" "/bin/cut"
     inst "/sbin/makedumpfile" "/sbin/makedumpfile"
     inst_hook pre-pivot 9999 "$moddir/kdump.sh"
+
+    # Check for all the devices and if any device is iscsi, bring up iscsi
+    # target. Ideally all this should be pushed into dracut iscsi module
+    # at some point of time.
+    kdump_check_iscsi_targets
 }