Update Validator for /usr/bin symlink

Signed-off-by: Arjun <agadiyar@nvidia.com>

Author: JunAr7112

cmd/nvidia-validator/main.go

@@ -31,6 +31,7 @@ import (
 	"github.com/NVIDIA/go-nvlib/pkg/nvmdev"
 	"github.com/NVIDIA/go-nvlib/pkg/nvpci"
 	devchar "github.com/NVIDIA/nvidia-container-toolkit/cmd/nvidia-ctk/system/create-dev-char-symlinks"
+	"github.com/moby/sys/symlink"
 	log "github.com/sirupsen/logrus"
 	"github.com/stretchr/testify/assert/yaml"
 	cli "github.com/urfave/cli/v3"
@@ -135,6 +136,7 @@ var (
 	hostRootFlag                  string
 	driverInstallDirFlag          string
 	driverInstallDirCtrPathFlag   string
+	hostRootCtrPath               = "/host"
 )
 
 // defaultGPUWorkloadConfig is "vm-passthrough" unless
@@ -742,22 +744,43 @@ func isDriverManagedByOperator(ctx context.Context) (bool, error) {
 	return false, nil
 }
 
+func resolveHostNvidiaSMIPath() (string, error) {
+	nvidiaSMIPath, err := symlink.FollowSymlinkInScope(filepath.Join(hostRootCtrPath, "usr/bin/nvidia-smi"), hostRootCtrPath)
+	if err != nil {
+		return "", fmt.Errorf("failed to resolve 'nvidia-smi' path on the host: %w", err)
+	}
+
+	fileInfo, err := os.Lstat(nvidiaSMIPath)
+	if err != nil {
+		return "", fmt.Errorf("no 'nvidia-smi' file present on the host: %w", err)
+	}
+	if fileInfo.Size() == 0 {
+		return "", fmt.Errorf("empty 'nvidia-smi' file found on the host")
+	}
+
+	return nvidiaSMIPath, nil
+}
+
+func hostDriverValidationCommand() (string, []string, error) {
+	if _, err := resolveHostNvidiaSMIPath(); err != nil {
+		return "", nil, err
+	}
+
+	return "chroot", []string{hostRootCtrPath, "nvidia-smi"}, nil
+}
+
 func validateHostDriver(silent bool) error {
 	log.Info("Attempting to validate a pre-installed driver on the host")
-	if fileInfo, err := os.Lstat(filepath.Join("/host", wslNvidiaSMIPath)); err == nil && fileInfo.Size() != 0 {
+	if fileInfo, err := os.Lstat(filepath.Join(hostRootCtrPath, wslNvidiaSMIPath)); err == nil && fileInfo.Size() != 0 {
 		log.Infof("WSL2 system detected, assuming driver is pre-installed")
 		disableDevCharSymlinkCreation = true
 		return nil
 	}
-	fileInfo, err := os.Lstat("/host/usr/bin/nvidia-smi")
+
+	command, args, err := hostDriverValidationCommand()
 	if err != nil {
-		return fmt.Errorf("no 'nvidia-smi' file present on the host: %w", err)
-	}
-	if fileInfo.Size() == 0 {
-		return fmt.Errorf("empty 'nvidia-smi' file found on the host")
+		return err
 	}
-	command := "chroot"
-	args := []string{"/host", "nvidia-smi"}
 
 	return runCommand(command, args, silent)
 }
@@ -1747,17 +1770,21 @@ func (v *VGPUManager) validate() error {
 	return nil
 }
 
-func (v *VGPUManager) runValidation(silent bool) (hostDriver bool, err error) {
-	// invoke validation command
+func vGPUManagerValidationCommand() (bool, string, []string) {
 	command := "chroot"
 	args := []string{"/run/nvidia/driver", "nvidia-smi"}
 
-	// check if driver is pre-installed on the host and use host path for validation
-	if _, err := os.Lstat("/host/usr/bin/nvidia-smi"); err == nil {
-		args = []string{"/host", "nvidia-smi"}
-		hostDriver = true
+	if _, err := resolveHostNvidiaSMIPath(); err == nil {
+		return true, command, []string{hostRootCtrPath, "nvidia-smi"}
 	}
 
+	return false, command, args
+}
+
+func (v *VGPUManager) runValidation(silent bool) (hostDriver bool, err error) {
+	// invoke validation command
+	hostDriver, command, args := vGPUManagerValidationCommand()
+
 	if withWaitFlag {
 		return hostDriver, runCommandWithWait(command, args, sleepIntervalSecondsFlag, silent)
 	}

cmd/nvidia-validator/main_test.go

@@ -19,9 +19,58 @@ package main
 import (
 	"context"
 	"os"
+	"path/filepath"
+	"reflect"
 	"testing"
 )
 
+func Test_validateHostDriverWithAbsoluteUsrBinSymlink(t *testing.T) {
+	hostRoot := t.TempDir()
+
+	targetDir := filepath.Join(hostRoot, "run/current-system/sw/bin")
+	if err := os.MkdirAll(targetDir, 0755); err != nil {
+		t.Fatalf("failed to create target directory: %v", err)
+	}
+	if err := os.WriteFile(filepath.Join(targetDir, "nvidia-smi"), []byte("fake nvidia-smi"), 0755); err != nil {
+		t.Fatalf("failed to create nvidia-smi: %v", err)
+	}
+
+	usrDir := filepath.Join(hostRoot, "usr")
+	if err := os.MkdirAll(usrDir, 0755); err != nil {
+		t.Fatalf("failed to create usr directory: %v", err)
+	}
+	if err := os.Symlink("/run/current-system/sw/bin", filepath.Join(usrDir, "bin")); err != nil {
+		t.Fatalf("failed to create usr/bin symlink: %v", err)
+	}
+
+	originalHostRootCtrPath := hostRootCtrPath
+	hostRootCtrPath = hostRoot
+	defer func() { hostRootCtrPath = originalHostRootCtrPath }()
+
+	command, args, err := hostDriverValidationCommand()
+	if err != nil {
+		t.Fatalf("hostDriverValidationCommand() unexpected error: %v", err)
+	}
+	if command != "chroot" {
+		t.Fatalf("command = %q, want %q", command, "chroot")
+	}
+	wantArgs := []string{hostRoot, "nvidia-smi"}
+	if !reflect.DeepEqual(args, wantArgs) {
+		t.Fatalf("args = %v, want %v", args, wantArgs)
+	}
+
+	hostDriver, command, args := vGPUManagerValidationCommand()
+	if !hostDriver {
+		t.Fatal("vGPUManagerValidationCommand() did not detect host driver")
+	}
+	if command != "chroot" {
+		t.Fatalf("command = %q, want %q", command, "chroot")
+	}
+	if !reflect.DeepEqual(args, wantArgs) {
+		t.Fatalf("args = %v, want %v", args, wantArgs)
+	}
+}
+
 func Test_isValidComponent(t *testing.T) {
 	tests := []struct {
 		name      string

go.mod

@@ -11,6 +11,7 @@ require (
 	github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc
 	github.com/go-logr/logr v1.4.3
 	github.com/go-logr/zapr v1.3.0
+	github.com/moby/sys/symlink v0.3.0
 	github.com/onsi/ginkgo/v2 v2.28.3
 	github.com/onsi/gomega v1.40.0
 	github.com/openshift/api v0.0.0-20260213204242-d34f11c515b3

go.sum

@@ -148,6 +148,8 @@ github.com/mitchellh/reflectwalk v1.0.2 h1:G2LzWKi524PWgd3mLHV8Y5k7s6XUvT0Gef6zx
 github.com/mitchellh/reflectwalk v1.0.2/go.mod h1:mSTlrgnPZtwu0c4WaC2kGObEpuNDbx0jmZXqmk4esnw=
 github.com/moby/term v0.5.2 h1:6qk3FJAFDs6i/q3W/pQ97SX192qKfZgGjCQqfCJkgzQ=
 github.com/moby/term v0.5.2/go.mod h1:d3djjFCrjnB+fl8NJux+EJzu0msscUP+f8it8hPkFLc=
+github.com/moby/sys/symlink v0.3.0 h1:GZX89mEZ9u53f97npBy4Rc3vJKj7JBDj/PN2I22GrNU=
+github.com/moby/sys/symlink v0.3.0/go.mod h1:3eNdhduHmYPcgsJtZXW1W4XUJdZGBIkttZ8xKqPUJq0=
 github.com/modern-go/concurrent v0.0.0-20180228061459-e0a39a4cb421/go.mod h1:6dJC0mAP4ikYIbvyc7fijjWJddQyLn8Ig3JB5CqoB9Q=
 github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd h1:TRLaZ9cD/w8PVh93nsPXa1VrQ6jlwL5oN8l14QlcNfg=
 github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd/go.mod h1:6dJC0mAP4ikYIbvyc7fijjWJddQyLn8Ig3JB5CqoB9Q=