#!/bin/sh
#
# Copyright 2020 -- Evilham <contact@evilham.com>
# This is BSD licensed as it's based on BSD-licensed code
#
# We could have used e.g. something like:
# - https://git.sr.ht/~sircmpwn/builds.sr.ht/tree/master/images/freebsd/genimg
#
# But we actually do want to compile the kernel, so that the IPv6-only images
# are different and don't support INET.

# Explode if something goes wrong
set -e

# What are we building?
# These are the only configuration options.
# They default to current environment.
# RELEASE: should be 'CURRENT' for current or 'X.Y' Defaults to 'CURRENT'.
# ARCH: probably amd64 for DCL
# VMFORMATS: defaults to qcow2, can also be raw. See man mkimg.
# OPENNEBULA_CONTEXT_VERSION: For DCL's OpenNebula that'd be 5.10.0 (default)
# OPENNEBULA_CONTEXT_REVISION: Defaults to 1.
RELEASE=${RELEASE:-CURRENT}
if [ "${RELEASE}" == "CURRENT" ]; then
        SRCBRANCH="master"
else
        SRCBRANCH="releng/${RELEASE}"
fi
ARCH=${ARCH:-amd64}
VMFORMATS=${VMFORMATS:-qcow2}
OPENNEBULA_CONTEXT_VERSION=${OPENNEBULA_CONTEXT_VERSION:-5.10.0}
OPENNEBULA_CONTEXT_REVISION=${OPENNEBULA_CONTEXT_REVISION:-1}

# Didn't see a need to make these configurable.
CHROOTDIR="/scratch"
SRCDIR="${CHROOTDIR}/usr/src"
OUR_DIR="$(realpath $(dirname "${0}"))"
OUR_SRCCONF="${SRCDIR}/release/src.conf"
OUR_RELEASE_CONF="${SRCDIR}/release/release.conf"
# Shorthand for the package file name.
OPENNEBULA_CONTEXT="one-context-${OPENNEBULA_CONTEXT_VERSION}_${OPENNEBULA_CONTEXT_REVISION}.txz"

setup_sources() {
        # Let's use git, we might need to install it
        if ! which git 2>&1 > /dev/null; then
                pkg install -y git
        fi

        if [ ! -d "$(dirname ${SRCDIR})" ]; then
                mkdir -p "$(dirname ${SRCDIR})"
        fi

        # Checkout needed branch
        if [ ! -d "${SRCDIR}" ]; then
                git clone "https://github.com/freebsd/freebsd" \
                        --branch "${SRCBRANCH}" "${SRCDIR}"
        else
                GIT_CMD="git -C ${SRCDIR}"
                ${GIT_CMD} clean -df
                ${GIT_CMD} reset --hard
                ${GIT_CMD} fetch
                ${GIT_CMD} checkout "${SRCBRANCH}"
                ${GIT_CMD} pull
        fi

        # Add settings for IPv6-only kernel
        cat > "${SRCDIR}/sys/${ARCH}/conf/GENERIC-IPV6ONLY" << EOF
include GENERIC
ident GENERIC-IPV6ONLY
makeoptions MKMODULESENV+="WITHOUT_INET_SUPPORT="
nooptions INET
nodevice gre
EOF
        # Fix vmimage.subr to install custom package and fix other things
        cat >> "${SRCDIR}/release/tools/vmimage.subr" << EOF
vm_extra_install_ports() {
        # Make sure we install the opennbula context package
        cp "/${OPENNEBULA_CONTEXT}" "\${DESTDIR}/tmp/${OPENNEBULA_CONTEXT}"
        chroot \${DESTDIR} \${EMULATOR} env ASSUME_ALWAYS_YES=yes \\
                /usr/sbin/pkg add '/tmp/${OPENNEBULA_CONTEXT}'

        # Now make sure the system has better defaults
        cat >> "\${DESTDIR}/etc/rc.conf" << eof
# Update to latest patch on first boot
firstboot_freebsd_update_enable="YES"
# Enable OpenNebula's service.
one_context_enable="YES"
# Enable SSH for customers
sshd_enable="YES"
# Clear tmp on boot
clear_tmp_enable="YES"
# Disable sendmail by default
sendmail_enable="NONE"
# Disable crash dumps
dumpdev="NO"
eof
        # Enable root access with SSH key.
        # It is user's responsibility to further secure their system.
        sed -i '' -E \
            's/(^#[ ]*|^)PermitRootLogin .*/PermitRootLogin without-password/' \
            "\${DESTDIR}/etc/ssh/sshd_config"
}
EOF
        # Skip building iso images
        rm "${SRCDIR}/release/${ARCH}/mkisoimages.sh"
        # This is a hack to not build the memstick
        cat > "${SRCDIR}/release/${ARCH}/make-memstick.sh" <<EOF
# Create an empty file, else checksums fail
touch "\${2}" || true
EOF
}

setup_our_env() {
        # Required by META_MODE to build faster next time
        # This saves a lot of time when e.g. compiling GENERIC and GENERIC-IPV6ONLY
        if ! kldstat | grep -q filemon; then
                kldload filemon
        fi
}

gen_releaseconf() {
        cat << EOF
#!/bin/sh
#
# Based off FreeBSD's release/release.conf.sample
#

# This redefines the prototype defined in release.sh.
# At this stage, the build chroot exists.
buildenv_setup() {
  # Ensure META_MODE is on
  echo "WITH_META_MODE=yes" > \${CHROOTDIR}/etc/src-env.conf
}

## Set the directory within which the release will be built.
CHROOTDIR="${CHROOTDIR}"

## Set to override the default target architecture and kernel
TARGET="${ARCH}"
TARGET_ARCH="${ARCH}"
KERNEL="${KERNEL_CONFIG}"

## Set to specify a custom make.conf and/or src.conf
SRC_CONF="${OUR_SRCCONF}"

# Since these are VMs, users should add other components if they want to.
NODOC=YES
NOPORTS=YES
NOSRC=YES

# We manage sources manually
SRC_UPDATE_SKIP=YES

## Set to pass additional flags to make(1) for the build chroot setup, such
## as TARGET/TARGET_ARCH.
# This was necessary for "cross-compiling"
CHROOT_MAKEENV="MK_LLVM_TARGET_X86=yes"

WITH_VMIMAGES=YES

# VM image size, see man 1 truncate
VMSIZE="10G"

# List of disk image formats, see man mkgimg.
VMFORMATS="${VMFORMATS}"

# These variables have to be exported because they are needed in subprocesses.
export NOSWAP=YES
# Custom ports
# - firstboot-freebsd-update helps us not have to create an image for each
#   patch level. We still will have to do it for each minor version update.
# - bash is apparently needed for one-context
export VM_EXTRA_PACKAGES="firstboot-freebsd-update bash"
EOF
}

_do_run_release() {
        . "${SRCDIR}/release/release.sh"
}
run_release() {
        _do_run_release -c "${OUR_RELEASE_CONF}"
}


build_image() {
        # Generate configuration
        echo "${2}" > "${OUR_SRCCONF}"
        KERNEL_CONFIG="${1}"
        gen_releaseconf > "${OUR_RELEASE_CONF}"
        # Be paranoid about files and stuff
        sync
        # Continue with the release script
        run_release
        # Be paranoid about files and stuff
        sync

        mv "${CHROOTDIR}/R/vmimages" "${OUR_DIR}/FreeBSD-${RELEASE}-${1}"

        # Be paranoid about files and stuff
        sync
}

our_main() {
        case "$1" in
                --dualstack)
                        BUILD_DUALSTACK=yes
                        ;;
                --ipv6only)
                        BUILD_IPV6ONLY=yes
                        ;;
                *)
                        cat << EOF
Run with --dualstack or --ipv6only depending on the image you want.
EOF
                        exit 1
                        ;;
        esac
        setup_sources
        setup_our_env
        # Fetch OpenNebula's context package
        fetch "https://github.com/OpenNebula/addon-context-linux/releases/download/v${OPENNEBULA_CONTEXT_VERSION}/${OPENNEBULA_CONTEXT}" \
                -o "${CHROOTDIR}/${OPENNEBULA_CONTEXT}"
        # Do run
        if [ -n "${BUILD_DUALSTACK}" ]; then
                build_image "GENERIC"
        fi
        if [ -n "${BUILD_IPV6ONLY}" ]; then
                build_image "GENERIC-IPV6ONLY" "$(cat << EOF
WITHOUT_INET=yes
WITHOUT_INET_SUPPORT=yes
EOF
)"
        fi

        cat << EOF

*************** DONE ***************
You will find the images under "${OUR_DIR}".
************************************
EOF
}

our_main "${@}"