Use functional options to construct runtime mode resolver

Signed-off-by: Evan Lezar <elezar@nvidia.com>

cmd/nvidia-container-runtime-hook/container_config.go

@@ -242,7 +242,14 @@ func (hookConfig *hookConfig) getNvidiaConfig(image image.CUDA, privileged bool)
 	}
 }
 
-func (hookConfig *hookConfig) getContainerConfig() (config containerConfig) {
+func (hookConfig *hookConfig) getContainerConfig() (config *containerConfig) {
+	hookConfig.Lock()
+	defer hookConfig.Unlock()
+
+	if hookConfig.containerConfig != nil {
+		return hookConfig.containerConfig
+	}
+
 	var h HookState
 	d := json.NewDecoder(os.Stdin)
 	if err := d.Decode(&h); err != nil {
@@ -271,10 +278,13 @@ func (hookConfig *hookConfig) getContainerConfig() (config containerConfig) {
 		log.Panicln(err)
 	}
 
-	return containerConfig{
+	cc := containerConfig{
 		Pid:    h.Pid,
 		Rootfs: s.Root.Path,
 		Image:  i,
 		Nvidia: hookConfig.getNvidiaConfig(i, privileged),
 	}
+	hookConfig.containerConfig = &cc
+
+	return hookConfig.containerConfig
 }

cmd/nvidia-container-runtime-hook/container_config_test.go

@@ -487,7 +487,7 @@ func TestGetNvidiaConfig(t *testing.T) {
 				hookCfg := tc.hookConfig
 				if hookCfg == nil {
 					defaultConfig, _ := config.GetDefault()
-					hookCfg = &hookConfig{defaultConfig}
+					hookCfg = &hookConfig{Config: defaultConfig}
 				}
 				cfg = hookCfg.getNvidiaConfig(image, tc.privileged)
 			}

cmd/nvidia-container-runtime-hook/hook_config.go

@@ -7,9 +7,11 @@ import (
 	"path"
 	"reflect"
 	"strings"
+	"sync"
 
 	"github.com/NVIDIA/nvidia-container-toolkit/internal/config"
 	"github.com/NVIDIA/nvidia-container-toolkit/internal/config/image"
+	"github.com/NVIDIA/nvidia-container-toolkit/internal/info"
 )
 
 const (
@@ -20,7 +22,9 @@ const (
 // hookConfig wraps the toolkit config.
 // This allows for functions to be defined on the local type.
 type hookConfig struct {
+	sync.Mutex
 	*config.Config
+	containerConfig *containerConfig
 }
 
 // loadConfig loads the required paths for the hook config.
@@ -55,7 +59,7 @@ func getHookConfig() (*hookConfig, error) {
 	if err != nil {
 		return nil, fmt.Errorf("failed to load config: %v", err)
 	}
-	config := &hookConfig{cfg}
+	config := &hookConfig{Config: cfg}
 
 	allSupportedDriverCapabilities := image.SupportedDriverCapabilities
 	if config.SupportedDriverCapabilities == "all" {
@@ -73,8 +77,8 @@ func getHookConfig() (*hookConfig, error) {
 
 // getConfigOption returns the toml config option associated with the
 // specified struct field.
-func (c hookConfig) getConfigOption(fieldName string) string {
-	t := reflect.TypeOf(c)
+func (c *hookConfig) getConfigOption(fieldName string) string {
+	t := reflect.TypeOf(&c)
 	f, ok := t.FieldByName(fieldName)
 	if !ok {
 		return fieldName
@@ -127,3 +131,20 @@ func (c *hookConfig) nvidiaContainerCliCUDACompatModeFlags() []string {
 	}
 	return []string{flag}
 }
+
+func (c *hookConfig) assertModeIsLegacy() error {
+	if c.NVIDIAContainerRuntimeHookConfig.SkipModeDetection {
+		return nil
+	}
+
+	mr := info.NewRuntimeModeResolver(
+		info.WithLogger(&logInterceptor{}),
+		info.WithImage(&c.containerConfig.Image),
+	)
+
+	mode := mr.ResolveRuntimeMode(c.NVIDIAContainerRuntimeConfig.Mode)
+	if mode == "legacy" {
+		return nil
+	}
+	return fmt.Errorf("invoking the NVIDIA Container Runtime Hook directly (e.g. specifying the docker --gpus flag) is not supported. Please use the NVIDIA Container Runtime (e.g. specify the --runtime=nvidia flag) instead")
+}

cmd/nvidia-container-runtime-hook/hook_config_test.go

@@ -90,10 +90,10 @@ func TestGetHookConfig(t *testing.T) {
 				}
 			}
 
-			var cfg hookConfig
+			var cfg *hookConfig
 			getHookConfig := func() {
 				c, _ := getHookConfig()
-				cfg = *c
+				cfg = c
 			}
 
 			if tc.expectedPanic {

cmd/nvidia-container-runtime-hook/main.go

@@ -55,7 +55,7 @@ func getCLIPath(config config.ContainerCLIConfig) string {
 }
 
 // getRootfsPath returns an absolute path. We don't need to resolve symlinks for now.
-func getRootfsPath(config containerConfig) string {
+func getRootfsPath(config *containerConfig) string {
 	rootfs, err := filepath.Abs(config.Rootfs)
 	if err != nil {
 		log.Panicln(err)
@@ -82,8 +82,8 @@ func doPrestart() {
 		return
 	}
 
-	if !hook.NVIDIAContainerRuntimeHookConfig.SkipModeDetection && info.ResolveAutoMode(&logInterceptor{}, hook.NVIDIAContainerRuntimeConfig.Mode, container.Image) != "legacy" {
-		log.Panicln("invoking the NVIDIA Container Runtime Hook directly (e.g. specifying the docker --gpus flag) is not supported. Please use the NVIDIA Container Runtime (e.g. specify the --runtime=nvidia flag) instead.")
+	if err := hook.assertModeIsLegacy(); err != nil {
+		log.Panicf("%v", err)
 	}
 
 	rootfs := getRootfsPath(container)