New xorriso-dd-target option -trust_lsblk_udev

xorriso-dd-target/xorriso-dd-target

@@ -15,7 +15,7 @@
 # announces.
 
 xdt_print_version() {
-  echo "xorriso-dd-target , version 1.5.3 , 2020.01.08.204757"
+  echo "xorriso-dd-target , version 1.5.3 , 2020.02.12.145929"
 }
 
 
@@ -123,6 +123,10 @@ xdt_print_usage() {
   echo "                    If no filesystems are detected and the program"
   echo "                    has no superuser power, the device is not advised."
   echo "                    If -DO_WRITE is given, run umount and dd by sudo." 
+  echo " -trust_lsblk_udev  Suppress the reason no_fs_while_not_su- if lsblk"
+  echo "                    is linked with libudev.so. In this case it is very"
+  echo "                    likely that lsblk can retrieve FSTYPE even if"
+  echo "                    run by a non-priviledged user."
   echo " -image_file PATH   Set the path of the image file which shall be"
   echo "                    written to a device. Its size will be set as"
   echo "                    -min_size."
@@ -220,6 +224,7 @@ xdt_reset_job() {
   xdt_dummy_force=
   xdt_no_pacifier=
   xdt_do_plug_test=
+  xdt_trust_lsblk_udev=
 
   # Status
   xdt_sudo_cmd=
@@ -233,6 +238,7 @@ xdt_reset_job() {
 }
 
 ## Predict superuser power. Possibly enable sudo with lsblk -o FSTYPE and dd.
+## Also predict whether lsblk -o FSTYPE will bring results as non-root.
 xdt_predict_su_power() {
   if test "$(whoami)" = "root"
   then
@@ -251,6 +257,16 @@ xdt_predict_su_power() {
       return 11
     fi
   fi
+
+  # lsblk linked with libudev.so usually can obtain filesystem info
+  # without superuser powers.
+  if test -n "$xdt_trust_lsblk_udev"
+  then
+    if ldd "$xdt_lsblk_cmd" | grep '\tlibudev\.so' >/dev/null
+    then
+      xdt_lsblk_fs_wo_su=y
+    fi
+  fi
   return 0
 }
 
@@ -308,6 +324,9 @@ xdt_arg_interpreter() {
     elif test "X$xdt_i" = "X-look_for_iso"
     then
       xdt_look_for_iso=y
+    elif test "X$xdt_i" = "X-trust_lsblk_udev"
+    then
+      xdt_trust_lsblk_udev=y
     elif test "X$xdt_i" = "X-with_sudo"
     then
       xdt_with_sudo=y
@@ -604,7 +623,7 @@ xdt_list_devices() {
     # Decide whether the found filesystems look dispensible enough
     xdt_reasons="${xdt_reasons}${xdt_good_fs}${xdt_bad_fs}"
     if test "${xdt_bad_fs}${xdt_good_fs}" = "" \
-       && test -z "$xdt_have_su_power"
+       && test -z "$xdt_have_su_power" && test -z "$xdt_lsblk_fs_wo_su"
     then
       xdt_yucky=y
       xdt_reasons="${xdt_reasons}no_fs_while_not_su- "