Meta: Add a script for building UEFI disk images

This script is mostly based on build-image-grub-uefi.sh.
Compared to that script, it doesn't use GRUB and works for all
architectures.

The generated disk image works with removable media.

CMakeLists.txt

@@ -77,6 +77,12 @@ add_custom_target(qemu-image
     USES_TERMINAL
 )
 
+add_custom_target(uefi-image
+    COMMAND "${CMAKE_COMMAND}" -E env "SERENITY_SOURCE_DIR=${SerenityOS_SOURCE_DIR}" "SERENITY_ARCH=${SERENITY_ARCH}" "SERENITY_TOOLCHAIN=${CMAKE_CXX_COMPILER_ID}" "LLVM_VERSION=${CMAKE_CXX_COMPILER_VERSION}" "${SerenityOS_SOURCE_DIR}/Meta/build-image-uefi.sh"
+    BYPRODUCTS ${CMAKE_BINARY_DIR}/uefi_disk_image
+    USES_TERMINAL
+)
+
 if("${SERENITY_ARCH}" STREQUAL "x86_64")
     add_custom_target(grub-image
         COMMAND "${CMAKE_COMMAND}" -E env "SERENITY_SOURCE_DIR=${SerenityOS_SOURCE_DIR}" "SERENITY_ARCH=${SERENITY_ARCH}" "SERENITY_TOOLCHAIN=${CMAKE_CXX_COMPILER_ID}" "LLVM_VERSION=${CMAKE_CXX_COMPILER_VERSION}" "${SerenityOS_SOURCE_DIR}/Meta/build-image-grub.sh"

Meta/build-image-uefi.sh

@@ -0,0 +1,104 @@
+#!/usr/bin/env bash
+
+set -e
+
+script_path=$(cd -P -- "$(dirname -- "$0")" && pwd -P)
+
+. "${script_path}/shell_include.sh"
+
+if [ "$(id -u)" != 0 ]; then
+    set +e
+    ${SUDO} -- "${SHELL}" -c "\"$0\" $* || exit 42"
+    case $? in
+        1)
+            die "this script needs to run as root"
+            ;;
+        42)
+            exit 1
+            ;;
+        *)
+            exit 0
+            ;;
+    esac
+else
+    : "${SUDO_UID:=0}" "${SUDO_GID:=0}"
+fi
+
+DISK_SIZE=$(($(disk_usage "$SERENITY_SOURCE_DIR/Base") + $(disk_usage Root) + 512 + 300))
+
+printf "setting up disk image... "
+dd if=/dev/zero of=uefi_disk_image bs=1M count="${DISK_SIZE}" status=none || die "couldn't create disk image"
+chown "$SUDO_UID":"$SUDO_GID" uefi_disk_image || die "couldn't adjust permissions on disk image"
+echo "done"
+
+printf "creating loopback device... "
+dev=$(losetup --find --partscan --show uefi_disk_image)
+if [ -z "$dev" ]; then
+    die "couldn't mount loopback device"
+fi
+echo "loopback device is at ${dev}"
+
+cleanup() {
+    if [ -d esp ]; then
+        printf "unmounting EFI system partition... "
+        umount esp || ( sleep 1 && sync && umount esp )
+        rmdir esp
+        echo "done"
+    fi
+
+    if [ -d mnt ]; then
+        printf "unmounting root filesystem... "
+        umount mnt || ( sleep 1 && sync && umount mnt )
+        rmdir mnt
+        echo "done"
+    fi
+
+    if [ -e "${dev}" ]; then
+        printf "cleaning up loopback device... "
+        losetup -d "${dev}"
+        echo "done"
+    fi
+}
+trap cleanup EXIT
+
+printf "creating partition table... "
+parted -s "${dev}" mklabel gpt mkpart EFI fat32 0% 512MB mkpart SerenityOS ext2 512MB 100% set 1 esp on || die "couldn't partition disk"
+echo "done"
+
+printf "creating new filesystems... "
+mkfs.vfat -F 32 -n EFI "${dev}p1" >/dev/null || die "couldn't create EFI system partition filesystem"
+mke2fs -q -L SerenityOS "${dev}p2" || die "couldn't create root filesystem"
+echo "done"
+
+printf "mounting filesystems... "
+mkdir -p esp
+mount "${dev}p1" esp || die "couldn't mount EFI system partition"
+mkdir -p mnt
+mount "${dev}p2" mnt || die "couldn't mount root filesystem"
+echo "done"
+
+"$script_path/build-root-filesystem.sh"
+
+case $SERENITY_ARCH in
+    aarch64)
+        BOOT_FILE_NAME=BOOTAA64.EFI
+        ;;
+    riscv64)
+        BOOT_FILE_NAME=BOOTRISCV64.EFI
+        ;;
+    x86_64)
+        BOOT_FILE_NAME=BOOTX64.EFI
+        ;;
+    *)
+        die "unknown architecture: $SERENITY_ARCH"
+        ;;
+esac
+
+root_uuid=$(blkid -o export "${dev}p2" | grep ^PARTUUID | cut -d= -f2)
+
+cat <<EOF >esp/cmdline.txt
+root=PARTUUID:${root_uuid}
+EOF
+
+mkdir -p esp/EFI/BOOT
+cp mnt/boot/Kernel.efi esp/EFI/BOOT/$BOOT_FILE_NAME