From fb816880451696c1bdb72493b38a8c8778ac8fb9 Mon Sep 17 00:00:00 2001
From: John Ogness <john.ogness@linutronix.de>
Date: Fri, 26 Apr 2019 15:06:20 +0206
Subject: dd-multi.sh: add --keep-files

The first couple steps of the dd-multi.sh script is to:

1. make a sparse copy of the original image
2. loop mount the copy
3. unpack the layers to the loop mount
4. create a vmdk of the copy
5. copy the image and vmdk to the usb drives

If many USB drives need to be prepared at once, usually the
dd-multi.sh script will need to be called multiple times (due
to not enough USB-3 ports being available). However, there is
no need for steps 1-4 to run each time.

Add a --keep-files argument that will not delete the copy and vmdk
files on completion. The --keep-files argument also tells the
dd-multi.sh script to look for existing copy and vmdk files. If
they are found, they are used.

Signed-off-by: John Ogness <john.ogness@linutronix.de>
---
 lx-trainer-vm/dd-multi.sh | 64 +++++++++++++++++++++++++++++++++--------------
 1 file changed, 45 insertions(+), 19 deletions(-)

diff --git a/lx-trainer-vm/dd-multi.sh b/lx-trainer-vm/dd-multi.sh
index 78740f1..4dbaac7 100755
--- a/lx-trainer-vm/dd-multi.sh
+++ b/lx-trainer-vm/dd-multi.sh
@@ -13,6 +13,9 @@ usage_exit()
 	echo "example: copying image to devices: sde, sdf, sdg"
 	echo "$0 lx-trainer.img /dev/sde /dev/sdf /dev/sdg"
 	echo
+	echo "    use --keep-files to speed up multiple calls"
+	echo "    (so that vmdk and img can be re-used later)"
+	echo
 	exit 1
 }
 
@@ -48,11 +51,15 @@ SRC=""
 LAYERS=""
 DESTS=""
 
+KEEP_FILES=0
 for arg in $@; do
 	case $arg in
 	--layer=*)
 		LAYERS="$LAYERS `echo $arg | sed -e 's/^--layer=//'`"
 		;;
+	--keep-files)
+		KEEP_FILES=1
+		;;
 	--*)
 		echo "error: unknown option: $arg"
 		usage_exit
@@ -97,10 +104,7 @@ if [ "`env - /sbin/parted --script $SRC print | \
 fi
 
 SRC_FILE="${SRC}_copy.img"
-VMDK_FILE="${SRC}.vmdk"
-
-echo 'creating a sparse copy of the image'
-cp -a --sparse=always $SRC $SRC_FILE
+VMDK_FILE="${SRC_FILE}.vmdk"
 
 # setup temp directory for mountpoints
 TMP_ROOT="/tmp/dd-multi-`date +%s`.$$"
@@ -108,26 +112,41 @@ rm -rf $TMP_ROOT
 mkdir -p $TMP_ROOT
 echo "using directory $TMP_ROOT for mount points"
 
-if [ -n "$LAYERS" ]; then
-	LOOPDEV=`losetup --show -P -f $SRC_FILE`
-	LOOPPT="${LOOPDEV}p${ROOTPT}"
+if [ $KEEP_FILES -eq 1 -a -f $SRC_FILE ]; then
+	echo 'using existing prepared copy of the image'
+	if [ -n "$LAYERS" ]; then
+		echo '(SPECIFIED LAYERS WILL NOT BE RE-UNPACKED)'
+	fi
+else
+	echo 'creating a sparse copy of the image'
+	cp -a --sparse=always $SRC $SRC_FILE
 
-	mkdir -p ${TMP_ROOT}${LOOPPT}
-	mount $LOOPPT ${TMP_ROOT}${LOOPPT}
+	if [ -n "$LAYERS" ]; then
+		LOOPDEV=`losetup --show -P -f $SRC_FILE`
+		LOOPPT="${LOOPDEV}p${ROOTPT}"
 
-	for tarball in $LAYERS; do
-		echo "unpacking layer: $tarball"
-		tar -x -f $tarball --numeric-owner -C ${TMP_ROOT}${LOOPPT}
-	done
+		mkdir -p ${TMP_ROOT}${LOOPPT}
+		mount $LOOPPT ${TMP_ROOT}${LOOPPT}
 
-	sync
-	umount ${LOOPPT}
+		for tarball in $LAYERS; do
+			echo "unpacking layer: $tarball"
+			tar -x -f $tarball --numeric-owner \
+				-C ${TMP_ROOT}${LOOPPT}
+		done
 
-	losetup -d $LOOPDEV
+		sync
+		umount ${LOOPPT}
+
+		losetup -d $LOOPDEV
+	fi
 fi
 
-echo 'creating vmdk file'
-qemu-img convert -O vmdk $SRC_FILE $VMDK_FILE
+if [ $KEEP_FILES -eq 1 -a -f $VMDK_FILE ]; then
+	echo 'using existing prepared vmdk file'
+else
+	echo 'creating vmdk file'
+	qemu-img convert -O vmdk $SRC_FILE $VMDK_FILE
+fi
 
 # delete mbr's
 dd if=/dev/zero bs=10M count=1 2> /dev/null | tee $DESTS > /dev/null
@@ -181,6 +200,13 @@ for dest in $DESTS; do
 done
 
 # cleanup temp directory
-rm -rf $TMP_ROOT $VMDK_FILE $SRC_FILE
+rm -rf $TMP_ROOT
+if [ $KEEP_FILES -ne 1 ]; then
+	rm -f $VMDK_FILE $SRC_FILE
+else
+	echo "as requested, not removing:"
+	echo "     $VMDK_FILE"
+	echo "     $SRC_FILE"
+fi
 
 echo 'done, no errors'
-- 
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