Immediately bail out on errors when generating the ISO fails

For example when the file system is (close to) full and trying to
generate the ISO, the $MKISOFS command line fails with exit code 32, but
we continue to operate on the ISO filename with the isohybrid related
actions and might overwrite the ISO by resetting it.

diff --git a/grml-live b/grml-live
index 3a8c8e7..beee3c8 100755 (executable)
--- a/grml-live
+++ b/grml-live
@@ -1589,9 +1589,19 @@ else
       eend $?
 
       log "$MKISOFS -V '${GRML_NAME} ${VERSION}' -publisher 'grml-live | grml.org' -l -r -J $BOOT_ARGS $EFI_ARGS -no-pad -o ${ISO_OUTPUT}/${ISO_NAME} ."
+      einfo "Generating ISO file..."
       $MKISOFS -V "${GRML_NAME} ${VERSION}" -publisher 'grml-live | grml.org' \
               -l -r -J $BOOT_ARGS $EFI_ARGS -no-pad \
               -o "${ISO_OUTPUT}/${ISO_NAME}" . ; RC=$?
+      eend $RC
+
+      # do not continue on errors, otherwise we might generate/overwrite the ISO with dd if=... stuff
+      if [ "$RC" != 0 ] ; then
+        log    "Error: critical error while generating ISO [exit code ${RC}]. Exiting."
+        eerror "Error: critical error while generating ISO [exit code ${RC}]. Exiting." ; eend 1
+        bailout $RC
+      fi
+
       # both of these need core.img there, so it’s easier to write it here
       if [ "$BOOT_METHOD" = "grub2" ] || [ "$HYBRID_METHOD" = "grub2" ]; then
          # must be <= 30720 bytes