Support adding DHCP interfaces one at a time.

Refactors dhcp-all-interfaces.sh so that if an optional
INTERFACE argument (the first argument) is passed to the script
it only inspects that single interface. If no argument is
passed then the previous default behaviour is used which
causes all interfaces to be inspected.

To avoid a collision with the previous $1 we move to using
$FLOCKED for the exec flock command which runs on distributions
using ENI.

Also sets PATH so that the commands within the script
can all be found if it isn't set properly (/sbin/ip, /bin/cat, etc.)

This is a move towards using udev rules to add these types
of interfaces automatically.

Change-Id: I3ec8fd2cc2071bfc6943c744ca619e31b71146fc

elements/dhcp-all-interfaces/install.d/50-dhcp-all-interfaces

@@ -9,6 +9,5 @@ DIB_INIT_SYSTEM=$(dib-init-system)
 if [ "$DIB_INIT_SYSTEM" == "upstart" ]; then
     install -D -g root -o root -m 0755 ${SCRIPTDIR}/dhcp-all-interfaces.conf /etc/init/dhcp-all-interfaces.conf
 elif [ "$DIB_INIT_SYSTEM" == "systemd" ]; then
-    install -D -g root -o root -m 0755 ${SCRIPTDIR}/dhcp-all-interfaces.service /usr/lib/systemd/system/dhcp-all-interfaces.service
-    systemctl enable dhcp-all-interfaces.service
+    install -D -g root -o root -m 0644 ${SCRIPTDIR}/udev.rules /etc/udev/rules.d/99-dhcp-all-interfaces.rules
 fi

elements/dhcp-all-interfaces/install.d/dhcp-all-interfaces.service

@@ -1,14 +0,0 @@
-[Unit]
-Description=DHCP All Interfaces Service
-Wants=local-fs.target systemd-udev-settle.service
-After=local-fs.target systemd-udev-settle.service
-Before=network.service
-
-[Service]
-Type=oneshot
-ExecStart=/usr/local/sbin/dhcp-all-interfaces.sh
-RemainAfterExit=yes
-
-[Install]
-WantedBy=multi-user.target
-Alias=dhcp-all-interfaces.service

elements/dhcp-all-interfaces/install.d/dhcp-all-interfaces.sh

@@ -1,7 +1,10 @@
 #!/bin/bash
 
+INTERFACE=${1:-} #optional, if not specified configure all available interfaces
 ENI_FILE="/etc/network/interfaces"
 
+PATH=/sbin:$PATH
+
 if [ -d "/etc/network" ]; then
     CONF_TYPE="eni"
 elif [ -d "/etc/sysconfig/network-scripts/" ]; then
@@ -13,9 +16,9 @@ fi
 
 if [ "$CONF_TYPE" == "eni" ]; then
     # Serialize runs so that we don't miss hot-add interfaces
-    FLOCK=${1:-}
-    if [ -z "$FLOCK" ] ; then
-        exec flock -x $ENI_FILE $0 flocked
+    FLOCKED=${FLOCKED:-}
+    if [ -z "$FLOCKED" ] ; then
+        FLOCKED=true exec flock -x $ENI_FILE $0
     fi
 fi
 
@@ -63,16 +66,17 @@ function config_exists() {
     fi
 }
 
-for interface in $(ls /sys/class/net | grep -v ^lo$) ; do
-  MAC_ADDR_TYPE="$(cat /sys/class/net/${interface}/addr_assign_type)"
+function inspect_interface() {
+  local interface=$1
+  local mac_addr_type="$(cat /sys/class/net/${interface}/addr_assign_type)"
 
   echo -n "Inspecting interface: $interface..."
   if config_exists $interface; then
     echo "Has config, skipping."
-  elif [ "$MAC_ADDR_TYPE" != "0" ]; then
+  elif [ "$mac_addr_type" != "0" ]; then
     echo "Device has generated MAC, skipping."
-   else
-    ip link set dev $interface up >/dev/null 2>&1
+  else
+    ip link set dev $interface up &>/dev/null
     HAS_LINK="$(get_if_link $interface)"
 
     TRIES=10
@@ -91,4 +95,13 @@ for interface in $(ls /sys/class/net | grep -v ^lo$) ; do
       disable_interface "$interface"
     fi
   fi
-done
+
+}
+
+if [ -n "$INTERFACE" ]; then
+    inspect_interface $INTERFACE
+else
+    for iface in $(ls /sys/class/net | grep -v ^lo$); do
+        inspect_interface $iface
+    done
+fi

elements/dhcp-all-interfaces/install.d/udev.rules

@@ -0,0 +1 @@
+SUBSYSTEM=="net", ACTION=="add", RUN+="/usr/local/sbin/dhcp-all-interfaces.sh $name", RUN+="/sbin/ifup $name"