Qos: Code explanation

mechanism

qosmngr/files/etc/init.d/qos

@@ -13,7 +13,88 @@ PROG=/usr/sbin/qosmngr
 . /lib/functions.sh
 include /lib/qos
 
+comparator() {
+	awk '
+		function find_duplicate_config() {
+			#Eradicate leading zeros
+			c = substr(c, 2)
+
+			if(c) {
+				#Process first file
+				if(FNR == NR) {
+				      qoscs[++count] = c
+				}
+				#Process second file and find the difference
+				else {
+					for(count in qoscs) {
+						if(qoscs[count] == c) {
+							qosds[count] = 1
+							break
+						}
+					}
+				}
+			}
+			c = ""
+		}
+
+		#Find the last config of the first file
+		!fls && NR != FNR {
+			#Eradicate leading zeros
+			c = substr(c, 2)
+			qoscs[++count] = c
+			fls = 1
+		}
+
+		#Match config section and  find duplicate config
+		/^config/ && c { find_duplicate_config() }
+
+		#Match the line starts with letters and aggregate the config section
+		/^\s*[a-z]/ {
+			sub("^\\s*", "")
+			c = c "\n" $0
+		}
+
+		#Identify the difference between the two files at the end
+		END {
+			find_duplicate_config()
+
+			#Loop through the config section in the first file and find the difference
+			for(count in qoscs) {
+				if(!(count in qosds)) {
+				       print qoscs[count] "\n"
+				}
+			}
+		}' $1 $2 > $3
+}
+
+#function to handle a policer section
+qos_reload_handler() {
+	qos_mechanism_handler() {
+		config_get cfgtype "$1" TYPE
+
+		if [ "$cfgtype" == "shaper" ]; then
+        		reload_qos $cfgtype
+       		elif [ "$cfgtype" == "classify" ]; then
+        		reload_qos $cfgtype
+       		elif [ "$cfgtype" == "policer" ]; then
+        		reload_qos $cfgtype
+       		elif [ "$cfgtype" == "queue" ]; then
+			restart
+		fi
+
+	}
+
+        config_load "/tmp/qos_config_diff"
+	config_foreach qos_mechanism_handler
+}
+
+
 start_service() {
+	if [ ! -f "/tmp/qos_config" ]; then
+		touch /tmp/qos_config
+		cp /etc/config/qos /tmp/qos_config
+	fi
+
 	if [ -f "/etc/config/qos" ]; then
 		reload_qos
 		procd_open_instance qosmngr
@@ -37,3 +118,15 @@ restart() {
 	setup_qos
 	start
 }
+
+reload_service()
+{
+	if [[ -f "/etc/config/qos"  && -f "/tmp/qos_config" ]]; then
+		comparator /etc/config/qos /tmp/qos_config /tmp/qos_config_diff
+		cp /etc/config/qos /tmp/qos_config
+		if [[ ! -z "/tmp/qos_config_diff" ]]; then
+       			qos_reload_handler
+		fi
+	fi
+}
+