Add Python FAT32 tool and GRUB ESP install script

fat_tool.py provides zero-dependency FAT32 manipulation (ls, mkdir, cp-in, cp-out) using only Python stdlib struct/os. install-grub.sh uses it to extract the existing Redox bootloader from ESP, install GRUB as the primary boot manager, and set up the chainload configuration. Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent) Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>
2026-04-17 21:04:53 +01:00
parent ee761276de
commit 7d0d703b0b
2 changed files with 747 additions and 0 deletions
@@ -0,0 +1,121 @@
+#!/bin/bash
+# install-grub.sh — Install GRUB bootloader into a Red Bear OS disk image
+#
+# Boot sequence after installation:
+#   UEFI firmware → GRUB (menu) → chainload Redox bootloader → kernel → Red Bear OS
+#
+# Usage:
+#   ./local/scripts/install-grub.sh <harddrive.img>
+#   ./local/scripts/install-grub.sh build/x86_64/harddrive.img
+#
+# Prerequisites:
+#   - GRUB recipe built: make r.grub
+#   - ESP partition >= 8 MiB (set efi_partition_size = 16 in config)
+#   - Python 3 (for fat_tool.py — no mtools needed)
+
+set -euo pipefail
+
+IMAGE="${1:?Usage: $0 <harddrive.img>}"
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+REPO_ROOT="$(cd "${SCRIPT_DIR}/../.." && pwd)"
+
+ESP_LBA=2048
+ESP_SECTOR_SIZE=512
+ESP_OFFSET=$((ESP_LBA * ESP_SECTOR_SIZE))
+
+FAT_TOOL="${SCRIPT_DIR}/fat_tool.py"
+ESP="${IMAGE}@${ESP_OFFSET}"
+
+if [ ! -f "${IMAGE}" ]; then
+    echo "ERROR: Image file not found: ${IMAGE}" >&2
+    exit 1
+fi
+
+if ! command -v python3 &>/dev/null; then
+    echo "ERROR: python3 not found" >&2
+    exit 1
+fi
+
+GRUB_EFI=""
+GRUB_CFG=""
+
+# Search in recipe stage directory (cookbook stores output here)
+for f in $(find "${REPO_ROOT}/local/recipes/core/grub/target" -path "*/stage/usr/lib/boot/grub.efi" 2>/dev/null); do
+    GRUB_EFI="${f}"
+    break
+done
+
+for f in $(find "${REPO_ROOT}/local/recipes/core/grub/target" -path "*/stage/usr/lib/boot/grub.cfg" 2>/dev/null); do
+    GRUB_CFG="${f}"
+    break
+done
+
+# Fallback: search repo extracted packages
+if [ -z "${GRUB_EFI}" ]; then
+    for f in $(find "${REPO_ROOT}/repo" -path "*/grub/*/usr/lib/boot/grub.efi" 2>/dev/null); do
+        GRUB_EFI="${f}"
+        break
+    done
+fi
+
+if [ -z "${GRUB_CFG}" ]; then
+    for f in $(find "${REPO_ROOT}/repo" -path "*/grub/*/usr/lib/boot/grub.cfg" 2>/dev/null); do
+        GRUB_CFG="${f}"
+        break
+    done
+fi
+
+if [ -z "${GRUB_CFG}" ] && [ -f "${REPO_ROOT}/local/recipes/core/grub/grub.cfg" ]; then
+    GRUB_CFG="${REPO_ROOT}/local/recipes/core/grub/grub.cfg"
+fi
+
+if [ -z "${GRUB_EFI}" ]; then
+    echo "ERROR: Cannot find grub.efi in recipe output." >&2
+    echo "Build GRUB first: make r.grub" >&2
+    exit 1
+fi
+
+if [ -z "${GRUB_CFG}" ]; then
+    echo "ERROR: Cannot find grub.cfg" >&2
+    exit 1
+fi
+
+echo "GRUB Installation"
+echo "  Image:    ${IMAGE}"
+echo "  ESP:      offset ${ESP_OFFSET} bytes (LBA ${ESP_LBA})"
+echo "  GRUB EFI: ${GRUB_EFI}"
+echo "  GRUB CFG: ${GRUB_CFG}"
+echo ""
+
+echo "Current ESP contents:"
+python3 "${FAT_TOOL}" ls "${IMAGE}" "${ESP_OFFSET}" /
+echo ""
+
+REDBEAR_TMP=$(mktemp)
+trap 'rm -f "${REDBEAR_TMP}"' EXIT
+
+echo "Extracting Redox bootloader from ESP..."
+python3 "${FAT_TOOL}" cp-out "${IMAGE}" "${ESP_OFFSET}" "EFI/BOOT/BOOTX64.EFI" "${REDBEAR_TMP}"
+REDBEAR_SIZE=$(stat -c%s "${REDBEAR_TMP}")
+echo "  Redox bootloader: ${REDBEAR_SIZE} bytes"
+
+echo "Creating EFI/REDBEAR directory..."
+python3 "${FAT_TOOL}" mkdir "${IMAGE}" "${ESP_OFFSET}" "EFI/REDBEAR" 2>/dev/null || true
+
+echo "Installing Redox bootloader to EFI/REDBEAR/redbear.efi..."
+python3 "${FAT_TOOL}" cp-in "${IMAGE}" "${ESP_OFFSET}" "${REDBEAR_TMP}" "EFI/REDBEAR/redbear.efi"
+
+GRUB_SIZE=$(stat -c%s "${GRUB_EFI}")
+echo "Installing GRUB (${GRUB_SIZE} bytes) as EFI/BOOT/BOOTX64.EFI..."
+python3 "${FAT_TOOL}" cp-in "${IMAGE}" "${ESP_OFFSET}" "${GRUB_EFI}" "EFI/BOOT/BOOTX64.EFI"
+
+echo "Installing grub.cfg to EFI/BOOT/grub.cfg..."
+python3 "${FAT_TOOL}" cp-in "${IMAGE}" "${ESP_OFFSET}" "${GRUB_CFG}" "EFI/BOOT/grub.cfg"
+
+echo ""
+echo "Final ESP contents:"
+python3 "${FAT_TOOL}" ls "${IMAGE}" "${ESP_OFFSET}" /
+echo ""
+echo "Installation complete. Boot sequence: UEFI -> GRUB (5s timeout) -> Redox bootloader -> kernel"
+echo "Test with: make qemu"
+echo "Revert:    make all CONFIG_NAME=<your-config>  (rebuild without GRUB)"