Bundle unicode.pf2 in a squashfs memdisk attached to the signed EFI binary

[jak@debian.org: Replace the previous fat memdisk with the squashfs
 one Ubuntu uses which produces much smaller binaries]

debian/build-efi-images

@@ -43,16 +43,6 @@ cleanup () {
 }
 trap cleanup EXIT HUP INT QUIT TERM
 
-# Return the number of 1KiB blocks needed to store a file in the
-# memdisk, with an extra block for the directory entry
-rounded_size () {
-    BLOCK_SIZE=1024
-    size=$(stat -c %s $1)
-    rounded=$(( ( ($size + $BLOCK_SIZE - 1) / $BLOCK_SIZE) + 1))
-    echo "Adding $rounded blocks to memdisk for $1" >&2
-    echo $rounded
-}
-
 rm -rf "$outdir"
 mkdir -p "$outdir"
 
@@ -62,7 +52,8 @@ workdir="$(mktemp -d build-efi-images.XXXXXX)"
 echo 'normal (memdisk)/grub.cfg' >"$workdir/grub-bootstrap.cfg"
 
 # Skeleton configuration file which finds the real boot disk.
-cat >"$workdir/grub.cfg" <<EOF
+mkdir "$workdir/memdisk-cd"
+cat >"$workdir/memdisk-cd/grub.cfg" <<EOF
 if [ -z "\$prefix" -o ! -e "\$prefix" ]; then
 	if ! search --file --set=root /.disk/info; then
 		search --file --set=root /.disk/mini-info
@@ -78,7 +69,8 @@ else
 fi
 EOF
 
-cat >"$workdir/grub-netboot.cfg" <<EOF
+mkdir "$workdir/memdisk-netboot"
+cat >"$workdir/memdisk-netboot/grub.cfg" <<EOF
 if [ -e \$prefix/$platform/grub.cfg ]; then
 	source \$prefix/$platform/grub.cfg
 elif [ -e \$prefix/grub.cfg-$deb_arch ]; then
@@ -88,33 +80,16 @@ else
 fi
 EOF
 
-# Calculate the size of the embedded filesystem needed
-FATFS_SIZE=64 # 64KiB for the embedded grub.cfg and the metadata
-
-# Only copy in unicode.pf2 for now, we don't want the binary images
-# too large
-FONTS=$grub_core/../unicode.pf2
-for FONT in $FONTS; do
-    FATFS_SIZE=$(($FATFS_SIZE + $(rounded_size $FONT)))
-done
+mkdir -p "$workdir/memdisk/fonts"
 
-mkfs.msdos -C "$workdir/memdisk.fat" $FATFS_SIZE
-mcopy -i "$workdir/memdisk.fat" "$workdir/grub.cfg" ::grub.cfg
-mmd -i "$workdir/memdisk.fat" ::fonts
-for FONT in $FONTS; do
-    mcopy -i "$workdir/memdisk.fat" "$FONT" ::fonts/$(basename $FONT)
+for name in "memdisk" "memdisk-cd" "memdisk-netboot"; do
+        mkdir -p "$workdir/$name/fonts"
+        cp "$grub_core/../unicode.pf2" "$workdir/$name/fonts"
 done
-# Let's show what's here so we have it in build logs
-mdir -/ -i "$workdir/memdisk.fat"
 
-mkfs.msdos -C "$workdir/memdisk-netboot.fat" $FATFS_SIZE
-mcopy -i "$workdir/memdisk-netboot.fat" "$workdir/grub-netboot.cfg" ::grub.cfg
-mmd -i "$workdir/memdisk-netboot.fat" ::fonts
-for FONT in $FONTS; do
-    mcopy -i "$workdir/memdisk-netboot.fat" "$FONT" ::fonts/$(basename $FONT)
-done
-# Let's show what's here so we have it in build logs
-mdir -/ -i "$workdir/memdisk.fat"
+mksquashfs "$workdir/memdisk-cd" "$workdir/memdisk-cd.squashfs" -comp xz
+mksquashfs "$workdir/memdisk-netboot" "$workdir/memdisk-netboot.squashfs" -comp xz
+mksquashfs "$workdir/memdisk" "$workdir/memdisk.squashfs" -comp xz
 
 CD_MODULES="
 	all_video
@@ -235,7 +210,7 @@ echo "Including modules $CD_MODULES in $outdir/gcd$efi_name.efi"
     -o "$outdir/gcd$efi_name.efi" \
     -c "$workdir/grub-bootstrap.cfg" \
     -d "$grub_core" \
-    -m "$workdir/memdisk.fat" \
+    -m "$workdir/memdisk-cd.squashfs" \
     -p /boot/grub \
     --sbat "$sbat_csv" \
     $CD_MODULES
@@ -245,9 +220,8 @@ echo "Including modules $GRUB_MODULES in $outdir/grub$efi_name.efi"
 "$grub_mkimage" \
     -O "$platform" \
     -o "$outdir/grub$efi_name.efi" \
-    -c "$workdir/grub-bootstrap.cfg" \
     -d "$grub_core" \
-    -m "$workdir/memdisk.fat" \
+    -m "$workdir/memdisk.squashfs" \
     -p "/EFI/$efi_vendor" \
     --sbat "$sbat_csv" \
     $GRUB_MODULES
@@ -259,7 +233,7 @@ echo "Including modules $NET_MODULES in $outdir/grubnet$efi_name.efi"
     -o "$outdir/grubnet$efi_name.efi" \
     -c "$workdir/grub-bootstrap.cfg" \
     -d "$grub_core" \
-    -m "$workdir/memdisk-netboot.fat" \
+    -m "$workdir/memdisk-netboot.squashfs" \
     -p /grub \
     --sbat "$sbat_csv" \
     $NET_MODULES
@@ -273,7 +247,7 @@ echo "Including modules $NET_MODULES in $outdir/grubnet$efi_name-installer.efi"
     -o "$outdir/grubnet$efi_name-installer.efi" \
     -c "$workdir/grub-bootstrap.cfg" \
     -d "$grub_core" \
-    -m "$workdir/memdisk-netboot.fat" \
+    -m "$workdir/memdisk-netboot.squashfs" \
     -p "/${efi_vendor}-installer/$deb_arch/grub" \
     --sbat "$sbat_csv" \
     $NET_MODULES

debian/control

@@ -28,7 +28,7 @@ Build-Depends: debhelper-compat (= 13),
  liblzma-dev,
  liblzo2-dev,
  dosfstools [any-i386 any-amd64 any-arm64],
- mtools [any-i386 any-amd64 any-arm64],
+ squashfs-tools [any-i386 any-amd64 any-arm64],
  wamerican,
  libparted-dev [any-powerpc any-ppc64 any-ppc64el],
  pkg-config,