From 10bd29265b3aebf149bc5e93e91462732c9240de Mon Sep 17 00:00:00 2001
From: Simon Kelley <simon@thekelleys.org.uk>
Date: Fri, 27 Sep 2013 21:07:30 +0100
Subject: [PATCH] macscript: create file if it doesn't exist.

---
 contrib/mactable/macscript | 34 ++++++++++++++++++++--------------
 1 file changed, 20 insertions(+), 14 deletions(-)

diff --git a/contrib/mactable/macscript b/contrib/mactable/macscript
index 8d807c5..44a4477 100755
--- a/contrib/mactable/macscript
+++ b/contrib/mactable/macscript
@@ -11,20 +11,26 @@ action="$1"
 mac="$2"   # IPv4
 ip="$3"
 
-if [  -n "$DNSMASQ_IAID" ]; then
-  if [ -z "$DNSMASQ_MAC" -a "$action" = "old" ]; then
-       # MAC not known by dnsmasq, probably due to restart.
-       exit 0;
-  fi
-  mac="$DNSMASQ_MAC"   # IPv6
+# ensure it always exists.
+
+if [ ! -f "$STATUS_FILE" ]; then
+  touch "$STATUS_FILE"
 fi
 
-if [ "$action" = "add" -o "$action" = "old" -o "$action" = "del" ]; then
-  if [ -f "$STATUS_FILE" ]; then
-    sed "/^${ip//./\.} / d" "$STATUS_FILE" > "$STATUS_FILE".new
-  fi
-  if [ "$action" = "add" -o "$action" = "old" ]; then
-    echo "$ip $mac" >> "$STATUS_FILE".new
-  fi
-  mv  "$STATUS_FILE".new "$STATUS_FILE" # atomic update.
+if [  -n "$DNSMASQ_IAID" ]; then
+    mac="$DNSMASQ_MAC"   # IPv6
+fi
+
+# worry about an add or old action when the MAC address is not known:
+# leave any old one in place in that case.
+
+if [ "$action" = "add" -o "$action" = "old" -o "$action" = "del" ]; then
+  if [ -n "$mac" -o "$action" = "del" ]; then
+    sed "/^${ip//./\.} / d" "$STATUS_FILE" > "$STATUS_FILE".new
+  
+    if [ "$action" = "add" -o "$action" = "old" ]; then
+       echo "$ip $mac" >> "$STATUS_FILE".new
+    fi
+    mv  "$STATUS_FILE".new "$STATUS_FILE" # atomic update.
+  fi
 fi