#!/bin/bash
# ============================================================================
# DarkForge Linux — Phase 0, Chapter 5: Linux API Headers
# ============================================================================
# Purpose:  Install the Linux kernel API headers into the target sysroot.
#           These headers define the kernel-userspace interface that glibc
#           needs to compile against. We use kernel 6.19.8 to match our
#           target kernel version.
# Inputs:   ${LFS}/sources/linux-6.19.8.tar.xz
# Outputs:  Kernel headers in ${LFS}/usr/include/
# Assumes:  Running as 'lfs' user
# Ref:      LFS 13.0 §5.4
# ============================================================================

set -euo pipefail
source "${LFS}/sources/darkforge-env.sh"

PACKAGE="linux"
VERSION="6.19.8"
SRCDIR="${LFS}/sources"

echo "=== Installing ${PACKAGE}-${VERSION} API Headers ==="

cd "${SRCDIR}"
tar -xf "${PACKAGE}-${VERSION}.tar.xz"
cd "${PACKAGE}-${VERSION}"

# Clean any stale files or configurations
make mrproper

# Generate the sanitized kernel headers
# The 'headers' target produces userspace-safe versions of kernel headers
make headers

# Remove non-header files from the generated output
find usr/include -type f ! -name '*.h' -delete

# Install headers to target sysroot
cp -rv usr/include "${LFS}/usr"

# Cleanup
cd "${SRCDIR}"
rm -rf "${PACKAGE}-${VERSION}"

echo "=== ${PACKAGE}-${VERSION} API Headers installed ==="