Files
claude-os/CMakeLists.txt
AI 3d5fb4c267 Add CPIO initial ramdisk with build infrastructure and parser (AI)
Build system changes:
- scripts/gen_initrd.sh packs all files from apps/ into a newc-format
  CPIO archive at build/isodir/boot/initrd.cpio.
- CMakeLists.txt adds 'initrd' target as ISO dependency. GRUB loads the
  archive as a Multiboot2 module via 'module2 /boot/initrd.cpio'.
- apps/README added as placeholder file for initial ramdisk content.

Kernel changes:
- kernel.c scans Multiboot2 tags for MULTIBOOT_TAG_TYPE_MODULE to find
  the initrd's physical address range, then passes it to cpio_init().
- cpio.c/h implements a parser for the SVR4/newc CPIO format:
  - cpio_init(): lists archive contents on startup
  - cpio_find(): look up a file by name (handles ./ prefix)
  - cpio_next(): iterate through all entries
  - cpio_count(): count files in archive
- The initrd lives in identity-mapped physical memory, so no additional
  mapping is needed to access it.

Verified in QEMU: GRUB loads the module at 0x0014A000, CPIO parser
finds the README file (38 bytes). All existing functionality (Ring 3
processes, syscalls) continues to work.
2026-02-23 12:16:24 +00:00

52 lines
2.0 KiB
CMake

cmake_minimum_required(VERSION 3.16)
project(ClaudeOS C ASM)
set(CMAKE_C_STANDARD 99)
# We are building a kernel, so we don't want standard libraries
set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -ffreestanding -m32 -fno-pie -fno-pic -fno-builtin -fno-stack-protector -mno-sse -mno-mmx -g -O2 -Wall -Wextra")
set(CMAKE_ASM_FLAGS "${CMAKE_ASM_FLAGS} -m32 -fno-pie -fno-pic")
set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -m32 -nostdlib -no-pie")
# Define build output directory
set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib)
set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib)
set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
add_subdirectory(src)
# Create output directories
file(MAKE_DIRECTORY ${CMAKE_SOURCE_DIR}/release)
file(MAKE_DIRECTORY ${CMAKE_BINARY_DIR}/isodir/boot/grub)
# Generate CPIO initial ramdisk from apps directory.
# All files in apps/ are packed into a newc-format CPIO archive.
set(INITRD_FILE ${CMAKE_BINARY_DIR}/isodir/boot/initrd.cpio)
add_custom_command(
OUTPUT ${INITRD_FILE}
COMMAND ${CMAKE_SOURCE_DIR}/scripts/gen_initrd.sh ${CMAKE_SOURCE_DIR}/apps ${INITRD_FILE}
DEPENDS ${CMAKE_SOURCE_DIR}/apps
COMMENT "Generating CPIO initial ramdisk"
)
add_custom_target(initrd DEPENDS ${INITRD_FILE})
# Create grub.cfg for ISO - includes module2 for the initrd
file(WRITE ${CMAKE_BINARY_DIR}/isodir/boot/grub/grub.cfg "set timeout=0\nset default=0\nsearch --set=root --file /boot/kernel.bin\nmenuentry \"ClaudeOS\" { multiboot2 /boot/kernel.bin\n module2 /boot/initrd.cpio }")
# ISO Generation
add_custom_target(iso ALL
COMMAND ${CMAKE_COMMAND} -E copy ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/kernel ${CMAKE_BINARY_DIR}/isodir/boot/kernel.bin
COMMAND grub-mkrescue -o ${CMAKE_SOURCE_DIR}/release/claude-os.iso ${CMAKE_BINARY_DIR}/isodir
DEPENDS kernel initrd
COMMENT "Generating bootable ISO image"
)
# Test target
add_custom_target(test_images
COMMAND sh ${CMAKE_SOURCE_DIR}/test_images.sh
DEPENDS iso
COMMENT "Testing generated images in QEMU"
WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
)