Rework memtest handling, incl. usage of latest available memtest file

If we try to copy the memtest86+.bin file as shipped with memtest86+
versions <=5.01-3.1, we either copy such an old file from the build
directory (grml_chroot), or if that doesn't exist (e.g. because the
memtest86+ package isn't installed), we might end up copying an old
memtest file from the build host system instead.

AS ${BUILD_OUTPUT}/boot/addons/memtest exists already then, we don't
update the file any longer (e.g. from a more recent memtest86+ package),
and therefore end up with an old and outdated memtest version in BIOS
boot, while EFI boot provides a more recent memtest version. This is
inconsistent and unexpected behavior.

So instead try to use the most recent version of memtest86* files first,
and only then fall back to the old memtest86+ <=5.01-3.1 file behavior.

While looking into this, I also noticed that until memtest86+ versions
<=6.10-2 it used to be named memtest86+x32.bin, while as of memtest86+
versions >=6.10-3 it's memtest86+ia32.bin instead. As we have version
6.10-4 in bookworm/stable and only pre-6 version 5.01-3.1 in e.g.
bullseye/oldstable, let's skip any backwards compatibility for
memtest86+x32.bin.

Furthermore while at it, drop duplicate execution of `copy_addon_file
memtest86+x64.bin /boot addons` and `copy_addon_file memtest86+x32.bin
/boot addons` to avoid ending up with further duplicate files on the
ISO. So related to #128, we now
ship /boot/addons/memtest on each of grml64 + grml32, and respectively
only /boot/addons/memtest86+x64.efi on grml64 only and
/boot/addons/memtest86+ia32.efi on grml32 only. To rename the files into
FAT16/8.3 compatible "/boot/addons/memtest", let's provide a proper
return code from within copy_addon_file() if we couldn't find any
matching file.

Related to #128

Closes: grml/grml#178

grml-live

@@ -327,6 +327,7 @@ copy_addon_file() {
   msg="Missing addon file: \"$1\""
   ewarn "$msg" ; eend 1
   log "copy_addon_file: $msg"
+  return 1
 }
 
 # replace placeholders in template files with actual information
@@ -1193,34 +1194,39 @@ if [ "$ARCH" = i386 ] || [ "$ARCH" = amd64 ] || [ "$ARCH" = arm64 ] ; then
         copy_addon_file ipxe.efi /usr/lib/ipxe addons
         copy_addon_file pci.ids /usr/share/misc addons
 
-        # memtest86+ <=5.01-3.1
-        copy_addon_file memtest86+.bin /boot addons
-        # make memtest filename FAT16/8.3 compatible
-        if [ -r "${BUILD_OUTPUT}/boot/addons/memtest86+.bin" ] ; then
-          mv "${BUILD_OUTPUT}/boot/addons/memtest86+.bin" \
-             "${BUILD_OUTPUT}/boot/addons/memtest"
-        fi
-
         # memtest86+ >=6.00-1
-        copy_addon_file memtest86+x32.bin /boot addons
-        copy_addon_file memtest86+x32.efi /boot addons
-        copy_addon_file memtest86+x64.bin /boot addons
-        copy_addon_file memtest86+x64.efi /boot addons
+        if [[ "$ARCH" == "amd64" ]] ; then
+          copy_addon_file memtest86+x64.efi /boot addons
+        elif [[ "$ARCH" == "i386" ]] ; then
+          copy_addon_file memtest86+ia32.efi /boot addons
+        fi
 
         # provide memtest86+ >=6.00-1 files as "memtest" file
         # for BIOS boot in isolinux/syslinux
         if ! [ -r "${BUILD_OUTPUT}/boot/addons/memtest" ] ; then
           if [[ "$ARCH" == "amd64" ]] ; then
-            copy_addon_file memtest86+x64.bin /boot addons
+            copy_addon_file memtest86+x64.bin /boot addons &&
+            # make memtest filename FAT16/8.3 compatible
             mv "${BUILD_OUTPUT}/boot/addons/memtest86+x64.bin" \
                "${BUILD_OUTPUT}/boot/addons/memtest"
           elif [[ "$ARCH" == "i386" ]] ; then
-            copy_addon_file memtest86+x32.bin /boot addons
-            mv "${BUILD_OUTPUT}/boot/addons/memtest86+x32.bin" \
+            copy_addon_file memtest86+ia32.bin /boot addons &&
+            # make memtest filename FAT16/8.3 compatible
+            mv "${BUILD_OUTPUT}/boot/addons/memtest86+ia32.bin" \
                "${BUILD_OUTPUT}/boot/addons/memtest"
           fi
         fi
 
+        # fallback: if we still don't have /boot/addons/memtest available, we
+        # might have an older memtest86+ version (<=5.01-3.1) which ships
+        # file "memtest86+.bin" instead
+        if ! [ -r "${BUILD_OUTPUT}/boot/addons/memtest" ] ; then
+          copy_addon_file memtest86+.bin /boot addons &&
+          # make memtest filename FAT16/8.3 compatible
+          mv "${BUILD_OUTPUT}/boot/addons/memtest86+.bin" \
+             "${BUILD_OUTPUT}/boot/addons/memtest"
+        fi
+
         # since syslinux(-common) v3:6.03~pre1+dfsg-4 the files are in a
         # different directory :(
         if [ -d "${CHROOT_OUTPUT}/usr/lib/syslinux/modules/bios/" ] ; then

templates/boot/grub/addons.cfg

@@ -14,9 +14,9 @@ if [ "${grub_platform}" == "efi" ] ; then
         }
       fi
     else # assume i386
-      if test -e /boot/addons/memtest86+x32.efi ; then
-        menuentry "Memory test (memtest86+x32.efi)" {
-          linuxefi /boot/addons/memtest86+x32.efi
+      if test -e /boot/addons/memtest86+ia32.efi ; then
+        menuentry "Memory test (memtest86+ia32.efi)" {
+          linuxefi /boot/addons/memtest86+ia32.efi
         }
       fi
     fi
@@ -39,10 +39,10 @@ if [ "${grub_platform}" != "efi" ] ; then
       }
     fi
   else  # assume i386
-    if test -e /boot/addons/memtest86+x32.bin ; then
-      menuentry "Memory test (memtest86+x32.bin)" {
+    if test -e /boot/addons/memtest86+ia32.bin ; then
+      menuentry "Memory test (memtest86+ia32.bin)" {
         insmod linux16
-        linux16 /boot/addons/memtest86+x32.bin
+        linux16 /boot/addons/memtest86+ia32.bin
       }
     elif test -e /boot/addons/memtest ; then # fallback to old memtest
       menuentry "Memory test (memtest86+)" {