Meta: Add script to build image with EXTLINUX bootloader

Author: https://github.com/DolphinChips
Commit: https://github.com/SerenityOS/serenity/commit/5d4f521c9d0
Pull-request: https://github.com/SerenityOS/serenity/pull/6946
Reviewed-by: https://github.com/linusg

Meta/build-image-extlinux.sh

@@ -0,0 +1,96 @@
+#!/bin/sh
+
+set -e
+
+die() {
+    echo "die: $*"
+    exit 1
+}
+
+if [ "$(id -u)" != 0 ]; then
+    exec sudo -E -- "$0" "$@" || die "this script needs to run as root"
+else
+    : "${SUDO_UID:=0}" "${SUDO_GID:=0}"
+fi
+
+for dir in "/usr/lib/syslinux" "/usr/share/syslinux"; do
+    if [ -d $dir ]; then
+        syslinux_dir=$dir
+        break
+    fi
+done
+if [ -z $syslinux_dir ]; then
+    echo "can't find syslinux directory"
+    exit 1
+fi
+
+disk_usage() {
+    du -sm "$1" | cut -f1
+}
+
+DISK_SIZE=$(($(disk_usage "$SERENITY_SOURCE_DIR/Base") + $(disk_usage Root) + 300))
+
+echo "setting up disk image..."
+dd if=/dev/zero of=extlinux_disk_image bs=1M count="${DISK_SIZE:-800}" status=none || die "couldn't create disk image"
+chown "$SUDO_UID":"$SUDO_GID" extlinux_disk_image || die "couldn't adjust permissions on disk image"
+echo "done"
+
+printf "creating loopback device... "
+dev=$(losetup --find --partscan --show extlinux_disk_image)
+if [ -z "$dev" ]; then
+    die "couldn't mount loopback device"
+fi
+echo "loopback device is at ${dev}"
+
+cleanup() {
+    if [ -d mnt ]; then
+        printf "unmounting filesystem... "
+        umount mnt || ( sleep 1 && sync && umount mnt )
+        rmdir mnt
+        echo "done"
+    fi
+
+    if [ -e "${dev}" ]; then
+        printf "cleaning up loopback device... "
+        losetup -d "${dev}"
+        echo "done"
+    fi
+}
+trap cleanup EXIT
+
+printf "creating partition table... "
+parted -s "${dev}" mklabel msdos mkpart primary ext2 32k 100% -a minimal set 1 boot on || die "couldn't partition disk"
+partition_number="p1"
+echo "done"
+
+printf "destroying old filesystem... "
+dd if=/dev/zero of="${dev}${partition_number}" bs=1M count=1 status=none || die "couldn't destroy old filesystem"
+echo "done"
+
+printf "creating new filesystem... "
+mke2fs -q -I 128 "${dev}${partition_number}" || die "couldn't create filesystem"
+echo "done"
+
+printf "mounting filesystem... "
+mkdir -p mnt
+mount "${dev}${partition_number}" mnt/ || die "couldn't mount filesystem"
+echo "done"
+
+script_path=$(cd -P -- "$(dirname -- "$0")" && pwd -P)
+"$script_path/build-root-filesystem.sh"
+
+if [ -z "$1" ]; then
+    extlinux_cfg="$SERENITY_SOURCE_DIR"/Meta/extlinux.conf
+else
+    extlinux_cfg=$1
+fi
+
+echo "installing extlinux with $extlinux_cfg..."
+mkdir -p mnt/boot/extlinux
+extlinux --install mnt/boot/extlinux
+cp "$extlinux_cfg" mnt/boot/extlinux/extlinux.conf
+for module in mboot.c32 menu.c32 libutil.c32 libcom32.c32; do
+    cp $syslinux_dir/$module mnt/boot/extlinux/
+done
+dd bs=440 count=1 conv=notrunc if=$syslinux_dir/mbr.bin of="$dev"
+echo "done"