Add a script for setting up the metad NIC for Xen

The script does the bare minimum required to set up the interface during
instance creation. The rest of the process is carried out by the ifup-os
script.
Signed-off-by: Petr Pudlak <pudlak@google.com>
Reviewed-by: Helga Velroyen <helgav@google.com>

.gitignore

@@ -123,6 +123,7 @@
 /tools/users-setup
 /tools/vcluster-setup
 /tools/vif-ganeti
+/tools/vif-ganeti-metad
 /tools/net-common
 /tools/node-cleanup
 /tools/node-daemon-setup

Makefile.am

@@ -295,6 +295,7 @@ CLEANFILES = \
 	tools/kvm-ifup-os \
 	tools/xen-ifup-os \
 	tools/vif-ganeti \
+	tools/vif-ganeti-metad \
 	tools/net-common \
 	tools/users-setup \
 	tools/vcluster-setup \
@@ -1324,6 +1325,7 @@ myexeclib_SCRIPTS = \
 	tools/kvm-ifup-os \
 	tools/xen-ifup-os \
 	tools/vif-ganeti \
+	tools/vif-ganeti-metad \
 	tools/net-common \
 	$(HS_MYEXECLIB_PROGS)
 
@@ -1363,6 +1365,7 @@ EXTRA_DIST = \
 	tools/kvm-ifup.in \
 	tools/ifup-os.in \
 	tools/vif-ganeti.in \
+	tools/vif-ganeti-metad.in \
 	tools/net-common.in \
 	tools/vcluster-setup.in \
 	$(docinput) \
@@ -1877,6 +1880,10 @@ tools/vif-ganeti: tools/vif-ganeti.in $(REPLACE_VARS_SED)
 	sed -f $(REPLACE_VARS_SED) < $< > $@
 	chmod +x $@
 
+tools/vif-ganeti-metad: tools/vif-ganeti-metad.in $(REPLACE_VARS_SED)
+	sed -f $(REPLACE_VARS_SED) < $< > $@
+	chmod +x $@
+
 tools/net-common: tools/net-common.in $(REPLACE_VARS_SED)
 	sed -f $(REPLACE_VARS_SED) < $< > $@
 	chmod +x $@

lib/pathutils.py

@@ -69,6 +69,8 @@ XEN_CONSOLE_WRAPPER = _constants.PKGLIBDIR + "/tools/xen-console-wrapper"
 CFGUPGRADE = _constants.PKGLIBDIR + "/tools/cfgupgrade"
 POST_UPGRADE = _constants.PKGLIBDIR + "/tools/post-upgrade"
 ENSURE_DIRS = _constants.PKGLIBDIR + "/ensure-dirs"
+# Script to configure the metadata virtual network interface with Xen
+XEN_VIF_METAD_SETUP = _constants.PKGLIBDIR + "/vif-ganeti-metad"
 ETC_HOSTS = vcluster.ETC_HOSTS
 
 # Top-level paths

tools/vif-ganeti-metad.in

+#!/bin/sh
+#
+
+# Copyright (C) 2014 Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+# 1. Redistributions of source code must retain the above copyright notice,
+# this list of conditions and the following disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright
+# notice, this list of conditions and the following disclaimer in the
+# documentation and/or other materials provided with the distribution.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+# IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+# TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+# PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
+# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+# EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+# PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+# PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+# LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+# NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+# This Xen vif setup script does the bare minimum required to set up the
+# interface during instance creation. The rest of the process is carried out by
+# the ifup-os script.
+
+set -e
+
+xenstore_read() {
+  if ! xenstore-read "$XENBUS_PATH/$1" 2>/dev/null ; then
+    echo "$2"
+  fi
+}
+
+xenstore_write() {
+  xenstore-write "$XENBUS_PATH/$1" "$2"
+}
+
+log() {
+  local level="$1" ; shift
+  logger -p daemon."${level}" -t "$0" -- "$@"
+}
+
+: "${XENBUS_PATH:?}" "${vif:?}"
+
+vifname=$(xenstore_read "vifname" "")
+if [ -n "$vifname" ] ; then
+  if [ "$1" = "online" ] && ! ip link show "$vifname" >/dev/null >&2 ; then
+    log debug "Renaming interface ${vif} to ${vifname}"
+    ip link set "$vif" name "$vifname"
+  fi
+  vif="$vifname"
+fi
+
+case "$1" in
+  online)
+    # Tell Xen we're connected
+    xenstore_write "hotplug-status" "connected"
+    ;;
+  offline)
+    ifconfig "$vif" down || true
+    ;;
+esac