nc-restore: Fix potential dataloss when restoring backup (fixes #1417)

- nc-restore: Keep old data directory if present
- nc-restore: Temporarily move and restore user files during nc-restore

Signed-off-by: Tobias K <6317548+theCalcaholic@users.noreply.github.com>

bin/ncp/BACKUPS/nc-backup.sh

@@ -114,6 +114,7 @@ tar $compress_arg -cf "$destfile" \
     --exclude "nextcloud/data/*/files_versions/*" \
     --exclude "nextcloud/data/ncp-update-backups" \
     --exclude "nextcloud/data/__groupfolders" \
+    --exclude "nextcloud/.data_*" \
     -C $basedir nextcloud/ \
   || {
         echo "error generating backup"

bin/ncp/BACKUPS/nc-restore.sh

@@ -63,9 +63,31 @@ tar $compress_arg -xf "$BACKUPFILE" -C "$TMPDIR" || exit 1
 ## RESTORE FILES
 
 echo "restore files..."
+[[ -d "$NCDIR/data" ]] && {
+  DATA_BKP_DIR="$(mktemp -d -p "$NCDIR/.." nc-data-XXXXXX)"
+  mv -T "$NCDIR/data" "$DATA_BKP_DIR/"
+}
 rm -rf "$NCDIR"
 mv -T "$TMPDIR"/nextcloud "$NCDIR" || { echo "Error restoring base files"; exit 1; }
 
+if [[ -n "$DATA_BKP_DIR" ]]
+then
+  echo "Restoring $NCDIR/data..."
+  target="$NCDIR/data"
+  [[ -d "$target" ]] && target="$NCDIR/.data_$(date)"
+  mv -T "$DATA_BKP_DIR" "$target"
+else
+fi
+
+if [[ -n "$DATA_BKP_DIR" ]]
+then
+  echo "Restoring $NCDIR/data..."
+  target="$NCDIR/data"
+  [[ -d "$target" ]] && target="$NCDIR/.data_$(date)"
+  mv -T "$DATA_BKP_DIR" "$target"
+else
+fi
+
 # update NC database password to this instance
 sed -i "s|'dbpassword' =>.*|'dbpassword' => '$DBPASSWD',|" /var/www/nextcloud/config/config.php