add script for extract & generate rootfs.cpio.gz

Change-Id: Ic33a2d54e584f66be29c62abc5715d4c545be129

scripts/build_rootfs.sh

@@ -0,0 +1,41 @@
+#!/bin/bash
+
+set -e
+
+function generate_rootfs()
+{
+    if [ -d rootfs ] ; then
+    	(cd rootfs; find . | fakeroot cpio -o -Hnewc | gzip > ../"$1")
+    else
+    	echo "rootfs not exist"
+    	exit 1
+    fi
+}
+
+function extract_rootfs()
+{
+    if [ -f "$1" ] ; then
+    	rm -rf rootfs && mkdir rootfs
+    	gzip -dc $1 | (cd rootfs; fakeroot cpio -i)
+    else
+    	echo "$1 not exist"
+    	exit 1
+    fi
+}
+
+if [ $# -ne 2 ]; then
+	echo -e "please input correct parameters"
+	echo -e "\t[build.sh -e rootf.cpio.gz] Extract the rootfs template to rootfs folder"
+	echo -e "\tthen make some changes in the rootfs folder"
+	echo -e "\t[build.sh -c rootf.cpio.gz] Generate the rootfs from the rootfs folder"
+	exit 1
+fi
+
+if [ "$1" = "-e" ] ; then
+	extract_rootfs $2
+elif [ "$1" = "-c" ] ; then
+	generate_rootfs $2
+else
+	echo "Argument is invalid!!!"
+	exit 1
+fi