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: