Merge "Support adding DHCP interfaces one at a time."

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=/bin:/sbin:$PATH
+
 if [ -d "/etc/network" ]; then
     CONF_TYPE="eni"
 elif [ -d "/etc/sysconfig/network-scripts/" ]; then
@@ -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