internal/modifier/gated.go

/**
# Copyright (c) 2022, NVIDIA CORPORATION.  All rights reserved.
#
# 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.
**/

package modifier

import (
	"fmt"

	"github.com/NVIDIA/nvidia-container-toolkit/internal/config"
	"github.com/NVIDIA/nvidia-container-toolkit/internal/config/image"
	"github.com/NVIDIA/nvidia-container-toolkit/internal/discover"
	"github.com/NVIDIA/nvidia-container-toolkit/internal/logger"
	"github.com/NVIDIA/nvidia-container-toolkit/internal/lookup/root"
	"github.com/NVIDIA/nvidia-container-toolkit/internal/oci"
)

// NewFeatureGatedModifier creates the modifiers for optional features.
// These include:
//
//	NVIDIA_GDS=enabled
//	NVIDIA_MOFED=enabled
//	NVIDIA_NVSWITCH=enabled
//	NVIDIA_GDRCOPY=enabled
//
// If not devices are selected, no changes are made.
func NewFeatureGatedModifier(logger logger.Interface, cfg *config.Config, image image.CUDA, driver *root.Driver) (oci.SpecModifier, error) {
	if devices := image.VisibleDevicesFromEnvVar(); len(devices) == 0 {
		logger.Infof("No modification required; no devices requested")
		return nil, nil
	}

	var discoverers []discover.Discover

	driverRoot := cfg.NVIDIAContainerCLIConfig.Root
	devRoot := cfg.NVIDIAContainerCLIConfig.Root

	if image.Getenv("NVIDIA_GDS") == "enabled" {
		d, err := discover.NewGDSDiscoverer(logger, driverRoot, devRoot)
		if err != nil {
			return nil, fmt.Errorf("failed to construct discoverer for GDS devices: %w", err)
		}
		discoverers = append(discoverers, d)
	}

	if image.Getenv("NVIDIA_MOFED") == "enabled" {
		d, err := discover.NewMOFEDDiscoverer(logger, devRoot)
		if err != nil {
			return nil, fmt.Errorf("failed to construct discoverer for MOFED devices: %w", err)
		}
		discoverers = append(discoverers, d)
	}

	if image.Getenv("NVIDIA_NVSWITCH") == "enabled" {
		d, err := discover.NewNvSwitchDiscoverer(logger, devRoot)
		if err != nil {
			return nil, fmt.Errorf("failed to construct discoverer for NVSWITCH devices: %w", err)
		}
		discoverers = append(discoverers, d)
	}

	if image.Getenv("NVIDIA_GDRCOPY") == "enabled" {
		d, err := discover.NewGDRCopyDiscoverer(logger, devRoot)
		if err != nil {
			return nil, fmt.Errorf("failed to construct discoverer for GDRCopy devices: %w", err)
		}
		discoverers = append(discoverers, d)
	}

	// If the feature flag has explicitly been toggled, we don't make any modification.
	if !cfg.Features.DisableCUDACompatLibHook.IsEnabled() {
		cudaCompatDiscoverer, err := getCudaCompatModeDiscoverer(logger, cfg, driver)
		if err != nil {
			return nil, fmt.Errorf("failed to construct CUDA Compat discoverer: %w", err)
		}
		discoverers = append(discoverers, cudaCompatDiscoverer)
	}

	return NewModifierFromDiscoverer(logger, discover.Merge(discoverers...))
}

func getCudaCompatModeDiscoverer(logger logger.Interface, cfg *config.Config, driver *root.Driver) (discover.Discover, error) {
	// For legacy mode, we only include the enable-cuda-compat hook if cuda-compat-mode is set to hook.
	if cfg.NVIDIAContainerRuntimeConfig.Mode == "legacy" && cfg.NVIDIAContainerRuntimeConfig.Modes.Legacy.CUDACompatMode != config.CUDACompatModeHook {
		return nil, nil
	}

	compatLibHookDiscoverer := discover.NewCUDACompatHookDiscoverer(logger, cfg.NVIDIACTKConfig.Path, driver)
	// For non-legacy modes we return the hook as is. These modes *should* already include the update-ldcache hook.
	if cfg.NVIDIAContainerRuntimeConfig.Mode != "legacy" {
		return compatLibHookDiscoverer, nil
	}

	// For legacy mode, we also need to inject a hook to update the LDCache
	// after we have modifed the configuration.
	ldcacheUpdateHookDiscoverer, err := discover.NewLDCacheUpdateHook(
		logger,
		discover.None{},
		cfg.NVIDIACTKConfig.Path,
		"",
	)
	if err != nil {
		return nil, fmt.Errorf("failed to construct ldcache update discoverer: %w", err)
	}

	return discover.Merge(compatLibHookDiscoverer, ldcacheUpdateHookDiscoverer), nil
}