#!/usr/bin/env bash
#
# This file is part of the KubeVirt project
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
# Copyright the KubeVirt Authors.
#
# Builds fake-pci/fake-iommu modules and loads them on the current Linux host.

set -e
set -o pipefail

SCRIPT_PATH=$(dirname "$(realpath "$0")")
VFIO_DIR="${SCRIPT_PATH}"

: "${FAKE_PCI_DEVICES:=8}"
: "${FAKE_IOMMU:=true}"

log() { echo "[setup-host-vfio-pci] $*"; }

fatal() {
    echo "FATAL: $*" >&2
    exit 1
}

validate_root() {
    [ "$(id -u)" -eq 0 ] || fatal "This script must be run as root"
}

if [[ "$(uname -s)" != "Linux" ]]; then
    fatal "synthetic vfio-pci host setup requires Linux."
fi

if [ ! -x "${VFIO_DIR}/setup-fake-pci-host.sh" ]; then
    fatal "${VFIO_DIR}/setup-fake-pci-host.sh not found"
fi

build_modules() {
    local kdir="/lib/modules/$(uname -r)/build"
    if [[ ! -d "${kdir}" ]]; then
        echo "ERROR: kernel headers not found at ${kdir}"
        echo "Install headers for the running kernel, then retry:"
        echo "  Debian/Ubuntu: sudo apt-get install \"linux-headers-$(uname -r)\""
        echo "  Fedora/RHEL:   sudo dnf install \"kernel-devel-$(uname -r)\""
        exit 1
    fi

    log "Cleaning and rebuilding fake-iommu + fake-pci for kernel $(uname -r)"
    make -C "${VFIO_DIR}/fake-iommu" clean
    make -C "${VFIO_DIR}/fake-pci" clean
    make -C "${VFIO_DIR}/fake-iommu"
    make -C "${VFIO_DIR}/fake-pci"
}

_run_fake_pci() {
    FAKE_PCI_DEVICES="${FAKE_PCI_DEVICES}" \
        FAKE_PCI_DOMAIN="${FAKE_PCI_DOMAIN:-}" \
        FAKE_PCI_VENDOR_ID="${FAKE_PCI_VENDOR_ID:-}" \
        FAKE_PCI_DEVICE_ID="${FAKE_PCI_DEVICE_ID:-}" \
        FAKE_IOMMU="${FAKE_IOMMU:-true}" \
        bash "${VFIO_DIR}/setup-fake-pci-host.sh" "$@"
}

ACTION="${1:-setup}"
validate_root

case "${ACTION}" in
    setup)
        build_modules
        _run_fake_pci cleanup
        _run_fake_pci setup
        _run_fake_pci bind-vfio
        ;;
    cleanup|status|bind-vfio)
        _run_fake_pci "${ACTION}"
        ;;
    *)
        echo "Usage: $0 [setup|cleanup|status|bind-vfio]"
        exit 1
        ;;
esac

log "Done (${ACTION})"