path: root/recipes-containers/vcontainer/vcontainer-initramfs-create.inc

# SPDX-FileCopyrightText: Copyright (C) 2025 Bruce Ashfield
#
# SPDX-License-Identifier: MIT
#
# vcontainer-initramfs-create.inc
# ===========================================================================
# Shared code for building QEMU boot blobs (vdkr/vpdmn)
# ===========================================================================
#
# This .inc file contains common code for building boot blobs.
# Individual recipes (vdkr-initramfs-create, vpdmn-initramfs-create)
# set VCONTAINER_RUNTIME and include this file.
#
# Required variables from including recipe:
#   VCONTAINER_RUNTIME - "vdkr" or "vpdmn"
#
# Boot flow:
#   QEMU boots kernel + tiny initramfs
#   -> preinit mounts rootfs.img from /dev/vda
#   -> switch_root into rootfs.img
#   -> ${VCONTAINER_RUNTIME}-init.sh runs
#
# ===========================================================================

HOMEPAGE = "https://git.yoctoproject.org/meta-virtualization/"
LICENSE = "MIT"
LIC_FILES_CHKSUM = "file://${COMMON_LICENSE_DIR}/MIT;md5=0835ade698e0bcf8506ecda2f7b4f302"

inherit deploy

# Not built by default - user must explicitly request via bitbake or vcontainer-native
EXCLUDE_FROM_WORLD = "1"

# Need squashfs-tools-native for unsquashfs to extract files from rootfs.img
DEPENDS = "squashfs-tools-native"

# Always rebuild - no sstate caching for this recipe
# This ensures source file changes (like init scripts in the rootfs) are picked up
SSTATE_SKIP_CREATION = "1"
do_compile[nostamp] = "1"
do_deploy[nostamp] = "1"

# Only populate native sysroot, skip target sysroot to avoid libgcc conflicts
INHIBIT_DEFAULT_DEPS = "1"

# Dependencies:
# 1. The multiconfig rootfs image from same vruntime-* multiconfig
# 2. The kernel from main build (not multiconfig)
#
# Use regular depends for rootfs-image since both recipes are in the same multiconfig
# Use mcdepends for kernel since it's from the main (default) config
do_compile[depends] = "${VCONTAINER_RUNTIME}-rootfs-image:do_image_complete"
do_compile[mcdepends] = "mc:${VCONTAINER_MULTICONFIG}::virtual/kernel:do_deploy"

# Preinit is shared between vdkr and vpdmn
SRC_URI = "file://vdkr-preinit.sh"

S = "${UNPACKDIR}"
B = "${WORKDIR}/build"

def get_kernel_image_name(d):
    arch = d.getVar('TARGET_ARCH')
    if arch == 'aarch64':
        return 'Image'
    elif arch in ['x86_64', 'i686', 'i586']:
        return 'bzImage'
    elif arch == 'arm':
        return 'zImage'
    return 'Image'

def get_multiconfig_name(d):
    arch = d.getVar('TARGET_ARCH')
    if arch == 'aarch64':
        return 'vruntime-aarch64'
    elif arch in ['x86_64', 'i686', 'i586']:
        return 'vruntime-x86-64'
    return 'vruntime-aarch64'

def get_blob_arch(d):
    """Map TARGET_ARCH to vrunner blob architecture (aarch64 or x86_64)"""
    arch = d.getVar('TARGET_ARCH')
    if arch == 'aarch64':
        return 'aarch64'
    elif arch in ['x86_64', 'i686', 'i586']:
        return 'x86_64'
    return 'aarch64'

KERNEL_IMAGETYPE_INITRAMFS = "${@get_kernel_image_name(d)}"
VCONTAINER_MULTICONFIG = "${@get_multiconfig_name(d)}"
BLOB_ARCH = "${@get_blob_arch(d)}"

# Path to the multiconfig build output
VCONTAINER_MC_DEPLOY = "${TOPDIR}/tmp-${VCONTAINER_MULTICONFIG}/deploy/images/${MACHINE}"

do_compile() {
    mkdir -p ${B}

    # =========================================================================
    # PART 1: BUILD TINY INITRAMFS (just for switch_root)
    # =========================================================================
    INITRAMFS_DIR="${B}/initramfs"
    rm -rf ${INITRAMFS_DIR}
    mkdir -p ${INITRAMFS_DIR}/bin
    mkdir -p ${INITRAMFS_DIR}/proc
    mkdir -p ${INITRAMFS_DIR}/sys
    mkdir -p ${INITRAMFS_DIR}/dev
    mkdir -p ${INITRAMFS_DIR}/mnt/root

    bbnote "Building tiny initramfs for switch_root..."

    # Extract busybox from the multiconfig rootfs image (squashfs)
    MC_TMPDIR="${TOPDIR}/tmp-${VCONTAINER_MULTICONFIG}"
    ROOTFS_SRC="${MC_TMPDIR}/deploy/images/${MACHINE}/${VCONTAINER_RUNTIME}-rootfs-image-${MACHINE}.rootfs.squashfs"

    if [ ! -f "${ROOTFS_SRC}" ]; then
        bbfatal "Rootfs image not found at ${ROOTFS_SRC}. Build it first with: bitbake mc:${VCONTAINER_MULTICONFIG}:${VCONTAINER_RUNTIME}-rootfs-image"
    fi

    # Extract busybox from rootfs using unsquashfs
    # In usrmerge layouts, busybox is at usr/bin/busybox
    BUSYBOX_PATH="usr/bin/busybox"
    EXTRACT_DIR="${B}/squashfs-extract"

    bbnote "Extracting busybox from $BUSYBOX_PATH"
    # Try native sysroot first, fall back to system unsquashfs
    UNSQUASHFS="${WORKDIR}/recipe-sysroot-native/usr/bin/unsquashfs"
    if [ ! -x "$UNSQUASHFS" ]; then
        UNSQUASHFS="/usr/bin/unsquashfs"
    fi
    if [ ! -x "$UNSQUASHFS" ]; then
        bbfatal "unsquashfs not found in native sysroot or at /usr/bin/unsquashfs"
    fi
    bbnote "Using unsquashfs: $UNSQUASHFS"

    rm -rf "${EXTRACT_DIR}"
    $UNSQUASHFS -d "${EXTRACT_DIR}" "${ROOTFS_SRC}" "$BUSYBOX_PATH"

    if [ ! -f "${EXTRACT_DIR}/${BUSYBOX_PATH}" ]; then
        bbfatal "Failed to extract busybox from rootfs image"
    fi
    cp "${EXTRACT_DIR}/${BUSYBOX_PATH}" "${INITRAMFS_DIR}/bin/busybox"
    chmod +x ${INITRAMFS_DIR}/bin/busybox

    # Create minimal symlinks
    cd ${INITRAMFS_DIR}/bin
    for cmd in sh mount umount mkdir ls cat echo sleep switch_root reboot; do
        ln -sf busybox $cmd 2>/dev/null || true
    done
    cd -

    # Install preinit script as /init
    cp ${S}/vdkr-preinit.sh ${INITRAMFS_DIR}/init
    chmod +x ${INITRAMFS_DIR}/init

    # Create tiny initramfs cpio
    bbnote "Creating tiny initramfs cpio archive..."
    cd ${INITRAMFS_DIR}
    find . | cpio -o -H newc 2>/dev/null | gzip -9 > ${B}/initramfs.cpio.gz
    cd -

    INITRAMFS_SIZE=$(stat -c%s ${B}/initramfs.cpio.gz)
    bbnote "Tiny initramfs created: ${INITRAMFS_SIZE} bytes ($(expr ${INITRAMFS_SIZE} / 1024)KB)"

    # =========================================================================
    # PART 2: COPY ROOTFS FROM MULTICONFIG BUILD
    # =========================================================================
    bbnote "Looking for multiconfig rootfs at: ${MC_TMPDIR}/deploy/images/${MACHINE}"

    # ROOTFS_SRC already set above when extracting busybox
    cp "${ROOTFS_SRC}" ${B}/rootfs.img
    ROOTFS_SIZE=$(stat -c%s ${B}/rootfs.img)
    bbnote "Rootfs image copied: ${ROOTFS_SIZE} bytes ($(expr ${ROOTFS_SIZE} / 1024 / 1024)MB)"

    # =========================================================================
    # PART 3: COPY KERNEL
    # =========================================================================
    bbnote "Copying kernel image..."
    KERNEL_FILE="${DEPLOY_DIR_IMAGE}/${KERNEL_IMAGETYPE_INITRAMFS}"
    if [ -f "${KERNEL_FILE}" ]; then
        cp "${KERNEL_FILE}" ${B}/kernel
        KERNEL_SIZE=$(stat -c%s ${B}/kernel)
        bbnote "Kernel copied: ${KERNEL_SIZE} bytes ($(expr ${KERNEL_SIZE} / 1024 / 1024)MB)"
    else
        bbwarn "Kernel not found at ${KERNEL_FILE}"
    fi
}

do_install[noexec] = "1"
do_package[noexec] = "1"
do_packagedata[noexec] = "1"
do_package_write_rpm[noexec] = "1"
do_package_write_ipk[noexec] = "1"
do_package_write_deb[noexec] = "1"
do_populate_sysroot[noexec] = "1"

do_deploy() {
    # Deploy to ${VCONTAINER_RUNTIME}/<arch> subdirectory
    install -d ${DEPLOYDIR}/${VCONTAINER_RUNTIME}/${BLOB_ARCH}

    if [ -f ${B}/initramfs.cpio.gz ]; then
        install -m 0644 ${B}/initramfs.cpio.gz ${DEPLOYDIR}/${VCONTAINER_RUNTIME}/${BLOB_ARCH}/
        bbnote "Deployed initramfs.cpio.gz to ${VCONTAINER_RUNTIME}/${BLOB_ARCH}/"
    fi

    if [ -f ${B}/rootfs.img ]; then
        install -m 0644 ${B}/rootfs.img ${DEPLOYDIR}/${VCONTAINER_RUNTIME}/${BLOB_ARCH}/
        bbnote "Deployed rootfs.img to ${VCONTAINER_RUNTIME}/${BLOB_ARCH}/"
    fi

    if [ -f ${B}/kernel ]; then
        install -m 0644 ${B}/kernel ${DEPLOYDIR}/${VCONTAINER_RUNTIME}/${BLOB_ARCH}/${KERNEL_IMAGETYPE_INITRAMFS}
        bbnote "Deployed kernel as ${VCONTAINER_RUNTIME}/${BLOB_ARCH}/${KERNEL_IMAGETYPE_INITRAMFS}"
    fi

    cat > ${DEPLOYDIR}/${VCONTAINER_RUNTIME}/${BLOB_ARCH}/README << EOF
${VCONTAINER_RUNTIME} Boot Blobs
==================

Built for: ${TARGET_ARCH}
Machine: ${MACHINE}
Multiconfig: ${VCONTAINER_MULTICONFIG}
Date: $(date)

Files:
  ${KERNEL_IMAGETYPE_INITRAMFS}  - Kernel image for QEMU
  initramfs.cpio.gz              - Tiny initramfs (switch_root only)
  rootfs.img                     - Root filesystem with container tools

Boot flow:
  QEMU boots kernel + initramfs
  -> preinit mounts rootfs.img from /dev/vda
  -> switch_root into rootfs.img
  -> ${VCONTAINER_RUNTIME}-init.sh runs container commands
EOF
}

addtask deploy after do_compile before do_build