Add result file support in helper

Helper always outputs the result to the second serial port (ttyS1).

helper/common.sh

@@ -27,8 +27,7 @@
 # those of the authors and should not be interpreted as representing official
 # policies, either expressed or implied, of GRNET S.A.
 
-OUTPUT=/dev/ttyS0
-RESULT=/dev/ttyS2
+RESULT=/dev/ttyS1
 FLOPPY_DEV=/dev/fd0
 
 PATH=/sbin:/bin:/usr/sbin:/usr/bin:/usr/local/sbin:/usr/local/bin
@@ -40,7 +39,7 @@ RESIZE2FS=resize2fs
 CLEANUP=( )
 
 log_error() {
-    echo "$@" >&2
+    echo "ERROR: $@" | tee $RESULT >&2
     exit 1
 }
 
@@ -119,7 +118,4 @@ cleanup() {
 
 trap cleanup EXIT
 
-# Redirect stdout and stderr
-exec &> $OUTPUT
-
 # vim: set sta sts=4 shiftwidth=4 sw=4 et ai :

helper/rc.local.in

@@ -70,6 +70,8 @@ fi
 echo "Execute all snf-image tasks...." 
 $RUN_PARTS -v --exit-on-error "/usr/lib/snf-image/tasks"
 
+echo "SUCCESS" > $RESULT
+
 cleanup
 trap - EXIT