[PATCH 3/3] scripts/start_vm: Deduplicate start_qemu

[Henning Schild <henning.schild@siemens.com>]

Instead of echoing what we are about to execute, switch the shell to
verbose mode. But only toggle "x" if it was not seet already.

This simplifies the script and future changes will only have to touch
one spot.

Signed-off-by: Henning Schild <henning.schild@siemens.com>
---
 scripts/start_vm | 22 ++++++----------------
 1 file changed, 6 insertions(+), 16 deletions(-)

diff --git a/scripts/start_vm b/scripts/start_vm
index 4cb05ae..26274be 100755
--- a/scripts/start_vm
+++ b/scripts/start_vm
@@ -17,22 +17,11 @@ bb2sh() {
 }
 
 start_qemu() {
-    root1=`echo $QEMU_ROOTFS_DEV \
-        | sed 's,##ROOTFS_IMAGE##,$IMAGE_DIR/'"$ROOTFS_IMAGE"','`
-    echo -e "IMAGE_DIR=$IMAGE_DIR; \\\\\n\
-qemu-system-$QEMU_ARCH \\\\\n\
-    -m 1024M \\\\\n\
-    -M $QEMU_MACHINE \\\\\n\
-    $QCPU\\\\\n\
-    -nographic \\\\\n\
-    -kernel \$QKERNEL \\\\\n\
-    -initrd \$QINITRD \\\\\n\
-    -append \"console=$MACHINE_SERIAL root=/dev/$ROOTFS_DEV rw\" \\\\\n\
-    $EXTRA_ARGS \\\\\n\
-    $root1"
-
-    root2=`echo $QEMU_ROOTFS_DEV \
+    root=`echo $QEMU_ROOTFS_DEV \
         | sed 's,##ROOTFS_IMAGE##,'$IMAGE_DIR/$ROOTFS_IMAGE','`
+    local had_x
+    echo $- | grep -q x && had_x=1 || had_x=0
+    [ $had_x -eq 0 ] && set -x
     qemu-system-$QEMU_ARCH \
 	-m 1024M \
 	-M $QEMU_MACHINE \
@@ -42,7 +31,8 @@ qemu-system-$QEMU_ARCH \\\\\n\
 	-initrd $QINITRD \
 	-append "console=$MACHINE_SERIAL root=/dev/$ROOTFS_DEV rw" \
 	$EXTRA_ARGS \
-	$root2
+	$root
+    [ $had_x -eq 0 ] && set +x
 }
 
 show_help() {
-- 
2.16.1