scripts/contrib/ddimage: replace blacklist with mount check

The blacklist, whilst previously useful for safety, is now becoming
obsolete - on my current system, the main storage is at /dev/nvme* and
if I plug in a USB stick it shows up as /dev/sdb which was previously
blacklisted. To make this more flexible, remove the blacklist and
instead check if the specified device is mounted, has a partition
that is mounted, or is otherwise in use according to the kernel, and
show an appropriate error and quit if so.

To make this robust, also ensure we handle where the specified device is
a symlink to another device.

Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

diff --git a/scripts/contrib/ddimage b/scripts/contrib/ddimage
index 01ff4318514a971d9522458158b2b4dfbc1d03c2..a7dc5f7487bee23f3c17f28eab28032972b4e3ac 100755 (executable)
--- a/scripts/contrib/ddimage
+++ b/scripts/contrib/ddimage
@@ -3,10 +3,6 @@
 # SPDX-License-Identifier: GPL-2.0-only
 #
 
-# Default to avoiding the first two disks on typical Linux and Mac OS installs
-# Better safe than sorry :-)
-BLACKLIST_DEVICES="/dev/sda /dev/sdb /dev/disk1 /dev/disk2"
-
 # 1MB blocksize
 BLOCKSIZE=1048576
 
@@ -32,7 +28,6 @@ image_details() {
 }
 
 device_details() {
-       DEV=$1
        BLOCK_SIZE=512
 
        echo "Device details"
@@ -45,7 +40,13 @@ device_details() {
        fi
 
        # Default / Linux information collection
-       echo "  device: $DEVICE"
+       ACTUAL_DEVICE=`readlink -f $DEVICE`
+       DEV=`basename $ACTUAL_DEVICE`
+       if [ "$ACTUAL_DEVICE" != "$DEVICE" ] ; then
+               echo "  device: $DEVICE -> $ACTUAL_DEVICE"
+       else
+               echo "  device: $DEVICE"
+       fi
        if [ -f "/sys/class/block/$DEV/device/vendor" ]; then
                echo "  vendor: $(cat /sys/class/block/$DEV/device/vendor)"
        else
@@ -64,6 +65,49 @@ device_details() {
        echo ""
 }
 
+check_mount_device() {
+       if cat /proc/self/mounts | awk '{ print $1 }' | grep /dev/ | grep -q -E "^$1$" ; then
+               return 0
+       fi
+       return 1
+}
+
+is_mounted() {
+       if [ "$(uname)" = "Darwin" ]; then
+               if df | awk '{ print $1 }' | grep /dev/ | grep -q -E "^$1(s[0-9]+)?$" ; then
+                       return 0
+               fi
+       else
+               if check_mount_device $1 ; then
+                       return 0
+               fi
+               DEV=`basename $1`
+               if [ -d /sys/class/block/$DEV/ ] ; then
+                       PARENT_BLKDEV=`basename $(readlink -f "/sys/class/block/$DEV/..")`
+                       if [ "$PARENT_BLKDEV" != "block" ] ; then
+                               if check_mount_device $PARENT_BLKDEV ; then
+                                       return 0
+                               fi
+                       fi
+                       for CHILD_BLKDEV in `find /sys/class/block/$DEV/ -mindepth  1 -maxdepth 1 -name "$DEV*" -type d`
+                       do
+                               if check_mount_device /dev/`basename $CHILD_BLKDEV` ; then
+                                       return 0
+                               fi
+                       done
+               fi
+       fi
+       return 1
+}
+
+is_inuse() {
+       HOLDERS_DIR="/sys/class/block/`basename $1`/holders"
+       if [ -d $HOLDERS_DIR ] && [ `ls -A $HOLDERS_DIR` ] ; then
+               return 0
+       fi
+       return 1
+}
+
 if [ $# -ne 2 ]; then
        usage
        exit 1
@@ -78,13 +122,23 @@ if [ ! -e "$IMAGE" ]; then
        exit 1
 fi
 
+if [ "$(uname)" = "Darwin" ]; then
+       # readlink doesn't support -f on MacOS, just assume it isn't a symlink
+       ACTUAL_DEVICE=$DEVICE
+else
+       ACTUAL_DEVICE=`readlink -f $DEVICE`
+fi
+if is_mounted $ACTUAL_DEVICE ; then
+       echo "ERROR: Device $DEVICE is currently mounted - check if this is the right device, and unmount it first if so"
+       device_details
+       exit 1
+fi
+if is_inuse $ACTUAL_DEVICE ; then
+       echo "ERROR: Device $DEVICE is currently in use (possibly part of LVM) - check if this is the right device!"
+       device_details
+       exit 1
+fi
 
-for i in ${BLACKLIST_DEVICES}; do
-       if [ "$i" = "$DEVICE" ]; then
-               echo "ERROR: Device $DEVICE is blacklisted"
-               exit 1
-       fi
-done
 
 if [ ! -w "$DEVICE" ]; then
        echo "ERROR: Device $DEVICE does not exist or is not writable"
@@ -93,7 +147,7 @@ if [ ! -w "$DEVICE" ]; then
 fi
 
 image_details $IMAGE
-device_details $(basename $DEVICE)
+device_details
 
 printf "Write $IMAGE to $DEVICE [y/N]? "
 read RESPONSE