tidy script init (4/4) - top level cmd "auto redirect" handling

Partial fix for #952919

Gbp-Dch: Short
Closes: #952919

functions/init.sh

@@ -29,3 +29,24 @@ Init_config_data ()
 	Read_conffiles $(Common_config_files)
 	Set_defaults
 }
+
+Maybe_auto_redirect ()
+{
+	local TYPE="${1}"; shift
+
+	case "${TYPE}" in
+		clean|config|build)
+			;;
+		*)
+			Echo_error "Unknown auto redirect type"
+			exit 1
+			;;
+	esac
+
+	local AUTO_SCRIPT="auto/${TYPE}"
+	if [ -x "${AUTO_SCRIPT}" ]; then
+		Echo_message "Executing ${AUTO_SCRIPT} script."
+		./"${AUTO_SCRIPT}" "${@}"
+		exit ${?}
+	fi
+}

scripts/build/build

@@ -17,16 +17,10 @@ set -e
 Auto_build_config
 
 # Redirecting to auto script if required
-if [ "${1}" != "noauto" ] && [ -x auto/build ]
-then
-	Echo_message "Executing auto/build script."
-	./auto/build "${@}"
-	exit ${?}
-fi
-
-if [ "${1}" = "noauto" ]
-then
+if [ "${1}" = "noauto" ]; then
 	shift
+else
+	Maybe_auto_redirect build
 fi
 
 # Setting static variables

scripts/build/clean

@@ -14,16 +14,10 @@ set -e
 [ -e "${LIVE_BUILD}/scripts/build.sh" ] && . "${LIVE_BUILD}/scripts/build.sh" || . /usr/lib/live/build.sh
 
 # Redirecting to auto script if required
-if [ "${1}" != "noauto" ] && [ -x auto/clean ]
-then
-	Echo_message "Executing auto/clean script."
-	./auto/clean "${@}"
-	exit ${?}
-fi
-
-if [ "${1}" = "noauto" ]
-then
+if [ "${1}" = "noauto" ]; then
 	shift
+else
+	Maybe_auto_redirect clean
 fi
 
 # Setting static variables

scripts/build/config

@@ -883,16 +883,10 @@ then
 fi
 
 # Redirecting to auto script if required
-if [ "${1}" != "noauto" ] && [ -x auto/config ]
-then
-	Echo_message "Executing auto/config script."
-	./auto/config "${@}"
-	exit ${?}
-fi
-
-if [ "${1}" = "noauto" ]
-then
+if [ "${1}" = "noauto" ]; then
 	shift
+else
+	Maybe_auto_redirect config
 fi
 
 # Reading system configuration