Add create-soname-symlinks hook

This change adds a create-soname-symlinks hook that can be used to ensure
that the soname symlinks for injected libraries exist in a container.

This is done by calling ldconfig -n -N for the folders containing the injected
libraries.

This also ensures that libcuda.so is present in the ldcache when the update-ldcache
hook is run.

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

cmd/nvidia-cdi-hook/commands/commands.go

@@ -20,6 +20,7 @@ import (
 	"github.com/urfave/cli/v2"
 
 	"github.com/NVIDIA/nvidia-container-toolkit/cmd/nvidia-cdi-hook/chmod"
+	soname "github.com/NVIDIA/nvidia-container-toolkit/cmd/nvidia-cdi-hook/create-soname-symlinks"
 	symlinks "github.com/NVIDIA/nvidia-container-toolkit/cmd/nvidia-cdi-hook/create-symlinks"
 	"github.com/NVIDIA/nvidia-container-toolkit/cmd/nvidia-cdi-hook/cudacompat"
 	ldcache "github.com/NVIDIA/nvidia-container-toolkit/cmd/nvidia-cdi-hook/update-ldcache"
@@ -34,5 +35,6 @@ func New(logger logger.Interface) []*cli.Command {
 		symlinks.NewCommand(logger),
 		chmod.NewCommand(logger),
 		cudacompat.NewCommand(logger),
+		soname.NewCommand(logger),
 	}
 }

cmd/nvidia-cdi-hook/create-soname-symlinks/soname-symlinks.go

@@ -0,0 +1,132 @@
+/**
+# Copyright (c) 2025, 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 soname
+
+import (
+	"errors"
+	"fmt"
+	"path/filepath"
+
+	"github.com/urfave/cli/v2"
+
+	"github.com/NVIDIA/nvidia-container-toolkit/internal/config"
+	"github.com/NVIDIA/nvidia-container-toolkit/internal/logger"
+	"github.com/NVIDIA/nvidia-container-toolkit/internal/oci"
+	safeexec "github.com/NVIDIA/nvidia-container-toolkit/internal/safe-exec"
+)
+
+type command struct {
+	logger logger.Interface
+	safeexec.Execer
+}
+
+type options struct {
+	folders       cli.StringSlice
+	ldconfigPath  string
+	containerSpec string
+}
+
+// NewCommand constructs an create-soname-symlinks command with the specified logger
+func NewCommand(logger logger.Interface) *cli.Command {
+	c := command{
+		logger: logger,
+		Execer: safeexec.New(logger),
+	}
+	return c.build()
+}
+
+// build the create-soname-symlinks command
+func (m command) build() *cli.Command {
+	cfg := options{}
+
+	// Create the 'create-soname-symlinks' command
+	c := cli.Command{
+		Name:  "create-soname-symlinks",
+		Usage: "Create soname symlinks for the specified folders using ldconfig -n -N",
+		Before: func(c *cli.Context) error {
+			return m.validateFlags(c, &cfg)
+		},
+		Action: func(c *cli.Context) error {
+			return m.run(c, &cfg)
+		},
+	}
+
+	c.Flags = []cli.Flag{
+		&cli.StringSliceFlag{
+			Name:        "folder",
+			Usage:       "Specify a folder to search for shared libraries for which soname symlinks need to be created",
+			Destination: &cfg.folders,
+		},
+		&cli.StringFlag{
+			Name:        "ldconfig-path",
+			Usage:       "Specify the path to the ldconfig program",
+			Destination: &cfg.ldconfigPath,
+			Value:       "/sbin/ldconfig",
+		},
+		&cli.StringFlag{
+			Name:        "container-spec",
+			Usage:       "Specify the path to the OCI container spec. If empty or '-' the spec will be read from STDIN",
+			Destination: &cfg.containerSpec,
+		},
+	}
+
+	return &c
+}
+
+func (m command) validateFlags(c *cli.Context, cfg *options) error {
+	if cfg.ldconfigPath == "" {
+		return errors.New("ldconfig-path must be specified")
+	}
+	return nil
+}
+
+func (m command) run(c *cli.Context, cfg *options) error {
+	s, err := oci.LoadContainerState(cfg.containerSpec)
+	if err != nil {
+		return fmt.Errorf("failed to load container state: %v", err)
+	}
+
+	containerRoot, err := s.GetContainerRootDirPath()
+	if err != nil {
+		return fmt.Errorf("failed to determined container root: %v", err)
+	}
+	if containerRoot == "" {
+		m.logger.Warningf("No container root detected")
+		return nil
+	}
+
+	dirs := cfg.folders.Value()
+	if len(dirs) == 0 {
+		return nil
+	}
+
+	ldconfigPath := config.ResolveLDConfigPathOnHost(cfg.ldconfigPath)
+	args := []string{filepath.Base(ldconfigPath)}
+
+	args = append(args,
+		// Specify the containerRoot to use.
+		"-r", string(containerRoot),
+		// Specify -n to only process the specified folders.
+		"-n",
+		// Explicitly disable updating the LDCache.
+		"-N",
+	)
+	// Explicitly specific the directories to add.
+	args = append(args, dirs...)
+
+	return m.Exec(ldconfigPath, args, nil)
+}

cmd/nvidia-ctk-installer/container/toolkit/toolkit_test.go

@@ -95,6 +95,13 @@ containerEdits:
     - create-symlinks
     - --link
     - libcuda.so.1::/lib/x86_64-linux-gnu/libcuda.so
+  - hookName: createContainer
+    path: {{ .toolkitRoot }}/nvidia-cdi-hook
+    args:
+    - nvidia-cdi-hook
+    - create-soname-symlinks
+    - --folder
+    - /lib/x86_64-linux-gnu
   - hookName: createContainer
     path: {{ .toolkitRoot }}/nvidia-cdi-hook
     args:

cmd/nvidia-ctk/cdi/generate/generate_test.go

@@ -97,6 +97,13 @@ containerEdits:
     - nvidia-cdi-hook
     - enable-cuda-compat
     - --host-driver-version=999.88.77
+  - hookName: createContainer
+    path: /usr/bin/nvidia-cdi-hook
+    args:
+    - nvidia-cdi-hook
+    - create-soname-symlinks
+    - --folder
+    - /lib/x86_64-linux-gnu
   - hookName: createContainer
     path: /usr/bin/nvidia-cdi-hook
     args:

internal/discover/ldconfig.go

@@ -50,16 +50,16 @@ func (d ldconfig) Hooks() ([]Hook, error) {
 	if err != nil {
 		return nil, fmt.Errorf("failed to discover mounts for ldcache update: %v", err)
 	}
-	h := CreateLDCacheUpdateHook(
+	hooks := CreateLDCacheUpdateHooks(
 		d.nvidiaCDIHookPath,
 		d.ldconfigPath,
 		getLibraryPaths(mounts),
 	)
-	return []Hook{h}, nil
+	return hooks, nil
 }
 
-// CreateLDCacheUpdateHook locates the NVIDIA Container Toolkit CLI and creates a hook for updating the LD Cache
+// CreateLDCacheUpdateHooks locates the NVIDIA Container Toolkit CLI and creates a hook for updating the LD Cache
-func CreateLDCacheUpdateHook(executable string, ldconfig string, libraries []string) Hook {
+func CreateLDCacheUpdateHooks(executable string, ldconfig string, libraries []string) []Hook {
 	var args []string
 
 	if ldconfig != "" {
@@ -70,13 +70,20 @@ func CreateLDCacheUpdateHook(executable string, ldconfig string, libraries []str
 		args = append(args, "--folder", f)
 	}
 
-	hook := CreateNvidiaCDIHook(
+	hooks := []Hook{
-		executable,
+		CreateNvidiaCDIHook(
-		"update-ldcache",
+			executable,
-		args...,
+			"create-soname-symlinks",
-	)
+			args...,
+		),
+		CreateNvidiaCDIHook(
+			executable,
+			"update-ldcache",
+			args...,
+		),
+	}
 
-	return hook
+	return hooks
 }
 
 // getLibraryPaths extracts the library dirs from the specified mounts

internal/discover/ldconfig_test.go

@@ -38,11 +38,22 @@ func TestLDCacheUpdateHook(t *testing.T) {
 		mounts        []Mount
 		mountError    error
 		expectedError error
-		expectedArgs  []string
+		expectedHooks []Hook
 	}{
 		{
-			description:  "empty mounts",
+			description: "empty mounts",
-			expectedArgs: []string{"nvidia-cdi-hook", "update-ldcache"},
+			expectedHooks: []Hook{
+				{
+					Lifecycle: "createContainer",
+					Path:      testNvidiaCDIHookPath,
+					Args:      []string{"nvidia-cdi-hook", "create-soname-symlinks"},
+				},
+				{
+					Lifecycle: "createContainer",
+					Path:      testNvidiaCDIHookPath,
+					Args:      []string{"nvidia-cdi-hook", "update-ldcache"},
+				},
+			},
 		},
 		{
 			description:   "mount error",
@@ -65,7 +76,18 @@ func TestLDCacheUpdateHook(t *testing.T) {
 					Path: "/usr/local/lib/libbar.so",
 				},
 			},
-			expectedArgs: []string{"nvidia-cdi-hook", "update-ldcache", "--folder", "/usr/local/lib", "--folder", "/usr/local/libother"},
+			expectedHooks: []Hook{
+				{
+					Lifecycle: "createContainer",
+					Path:      testNvidiaCDIHookPath,
+					Args:      []string{"nvidia-cdi-hook", "create-soname-symlinks", "--folder", "/usr/local/lib", "--folder", "/usr/local/libother"},
+				},
+				{
+					Lifecycle: "createContainer",
+					Path:      testNvidiaCDIHookPath,
+					Args:      []string{"nvidia-cdi-hook", "update-ldcache", "--folder", "/usr/local/lib", "--folder", "/usr/local/libother"},
+				},
+			},
 		},
 		{
 			description: "host paths are ignored",
@@ -75,12 +97,34 @@ func TestLDCacheUpdateHook(t *testing.T) {
 					Path:     "/usr/local/lib/libfoo.so",
 				},
 			},
-			expectedArgs: []string{"nvidia-cdi-hook", "update-ldcache", "--folder", "/usr/local/lib"},
+			expectedHooks: []Hook{
+				{
+					Lifecycle: "createContainer",
+					Path:      testNvidiaCDIHookPath,
+					Args:      []string{"nvidia-cdi-hook", "create-soname-symlinks", "--folder", "/usr/local/lib"},
+				},
+				{
+					Lifecycle: "createContainer",
+					Path:      testNvidiaCDIHookPath,
+					Args:      []string{"nvidia-cdi-hook", "update-ldcache", "--folder", "/usr/local/lib"},
+				},
+			},
 		},
 		{
 			description:  "explicit ldconfig path is passed",
 			ldconfigPath: testLdconfigPath,
-			expectedArgs: []string{"nvidia-cdi-hook", "update-ldcache", "--ldconfig-path", testLdconfigPath},
+			expectedHooks: []Hook{
+				{
+					Lifecycle: "createContainer",
+					Path:      testNvidiaCDIHookPath,
+					Args:      []string{"nvidia-cdi-hook", "create-soname-symlinks", "--ldconfig-path", testLdconfigPath},
+				},
+				{
+					Lifecycle: "createContainer",
+					Path:      testNvidiaCDIHookPath,
+					Args:      []string{"nvidia-cdi-hook", "update-ldcache", "--ldconfig-path", testLdconfigPath},
+				},
+			},
 		},
 	}
 
@@ -91,12 +135,6 @@ func TestLDCacheUpdateHook(t *testing.T) {
 					return tc.mounts, tc.mountError
 				},
 			}
-			expectedHook := Hook{
-				Path:      testNvidiaCDIHookPath,
-				Args:      tc.expectedArgs,
-				Lifecycle: "createContainer",
-			}
-
 			d, err := NewLDCacheUpdateHook(logger, mountMock, testNvidiaCDIHookPath, tc.ldconfigPath)
 			require.NoError(t, err)
 
@@ -110,9 +148,7 @@ func TestLDCacheUpdateHook(t *testing.T) {
 			}
 
 			require.NoError(t, err)
-			require.Len(t, hooks, 1)
+			require.EqualValues(t, tc.expectedHooks, hooks)
-
-			require.EqualValues(t, hooks[0], expectedHook)
 
 			devices, err := d.Devices()
 			require.NoError(t, err)

tests/e2e/nvidia-container-toolkit_test.go

@@ -215,4 +215,26 @@ var _ = Describe("docker", Ordered, ContinueOnFailure, func() {
 			Expect(ldconfigOut).To(ContainSubstring("/usr/lib64"))
 		})
 	})
+
+	When("A container is run using CDI", Ordered, func() {
+		BeforeAll(func(ctx context.Context) {
+			_, _, err := r.Run("docker pull ubuntu")
+			Expect(err).ToNot(HaveOccurred())
+		})
+
+		It("should include libcuda.so in the ldcache", func(ctx context.Context) {
+			ldcacheOutput, _, err := r.Run("docker run --rm -i --runtime=nvidia -e NVIDIA_VISIBLE_DEVICES=runtime.nvidia.com/gpu=all ubuntu bash -c \"ldconfig -p | grep 'libcuda.so'\"")
+			Expect(err).ToNot(HaveOccurred())
+			Expect(ldcacheOutput).ToNot(BeEmpty())
+
+			ldcacheLines := strings.Split(ldcacheOutput, "\n")
+			var libs []string
+			for _, line := range ldcacheLines {
+				parts := strings.SplitN(line, " (", 2)
+				libs = append(libs, strings.TrimSpace(parts[0]))
+			}
+
+			Expect(libs).To(ContainElements([]string{"libcuda.so", "libcuda.so.1"}))
+		})
+	})
 })