[oneimage] Check if graph service address got from dhcp is valid url (#324)

* [oneimage] Check if graph service address got from dhcp is valid url

Author: taoyl-ms

files/image_config/updategraph/updategraph

@@ -29,9 +29,14 @@ if [ "$src" = "dhcp" ]; then
 
     HOSTNAME=`hostname -s`
     GRAPH_URL=`sonic-cfggen -t /tmp/dhcp_graph_url -a "{\"hostname\": \"$HOSTNAME\"}"`
+    URL_REGEX='^(https?|ftp|file)://[-A-Za-z0-9\+&@#/%?=~_|!:,.;]*[-A-Za-z0-9\+&@#/%=~_|]$'
+    if [[ ! $GRAPH_URL =~ $URL_REGEX ]]; then
+        echo "\"$GRAPH_URL\" is not a valid url. Skipping graph update."
+        exit 0
+    fi
     if [ "$dhcp_as_static" = "true" ]; then
-        sed -i "/src=d/d" /etc/sonic/updategraph.conf
-        echo "src=$GRAPH_URL" >> /etc/sonic/updategraph.conf
+        sed -i "/src=/d" /etc/sonic/updategraph.conf
+        echo "src=\"$GRAPH_URL\"" >> /etc/sonic/updategraph.conf
     fi
 else
     GRAPH_URL=$src