Add libcuda.so symlink to CDI spec

This change adds a hook to create a libcuda.so symlink to
the CDI specification. This aligns the CDI spec behaviour
with the libnvidia-container implementation.

Signed-off-by: Evan Lezar <[email protected]>

Author: elezar

pkg/nvcdi/driver-nvml.go

@@ -32,6 +32,12 @@ import (
 	"github.com/NVIDIA/nvidia-container-toolkit/internal/lookup/root"
 )
 
+type driverVersionDiscoverer struct {
+	discover.Discover
+	nvidiaCDIHookPath string
+	version           string
+}
+
 // NewDriverDiscoverer creates a discoverer for the libraries and binaries associated with a driver installation.
 // The supplied NVML Library is used to query the expected driver version.
 func NewDriverDiscoverer(logger logger.Interface, driver *root.Driver, nvidiaCDIHookPath string, ldconfigPath string, nvmllib nvml.Interface) (discover.Discover, error) {
@@ -100,7 +106,11 @@ func NewDriverLibraryDiscoverer(logger logger.Interface, driver *root.Driver, nv
 	hooks, _ := discover.NewLDCacheUpdateHook(logger, libraries, nvidiaCDIHookPath, ldconfigPath)
 
 	d := discover.Merge(
-		libraries,
+		&driverVersionDiscoverer{
+			Discover:          libraries,
+			nvidiaCDIHookPath: nvidiaCDIHookPath,
+			version:           version,
+		},
 		hooks,
 	)
 
@@ -220,3 +230,37 @@ func getVersionLibs(logger logger.Interface, driver *root.Driver, version string
 
 	return relative, nil
 }
+
+func (d driverVersionDiscoverer) Hooks() ([]discover.Hook, error) {
+	mounts, err := d.Discover.Mounts()
+	if err != nil {
+		return nil, fmt.Errorf("failed to get library mounts: %v", err)
+	}
+
+	var links []string
+	for _, mount := range mounts {
+		dir, filename := filepath.Split(mount.Path)
+		// TODO: We should include the other libraries as is done here:
+		// https://github.com/NVIDIA/nvidia-container-toolkit/blob/79c59aeb7f59dd612793ac80a8d7022c554634bb/internal/platform-support/tegra/symlinks.go#L84-L97
+		if d.isDriverLibrary(filename, "libcuda.so") {
+			// create libcuda.so -> libcuda.so.1 symlink
+			links = append(links, fmt.Sprintf("%s::%s", "libcuda.so.1", filepath.Join(dir, "libcuda.so")))
+		}
+	}
+
+	if len(links) == 0 {
+		return nil, nil
+	}
+
+	hooks := discover.CreateCreateSymlinkHook(d.nvidiaCDIHookPath, links)
+
+	return hooks.Hooks()
+
+}
+
+// isDriverLibrary checks whether the specified filename is a specific driver library.
+func (d driverVersionDiscoverer) isDriverLibrary(filename string, libraryName string) bool {
+	pattern := libraryName + "." + d.version
+	match, _ := filepath.Match(pattern, filename)
+	return match
+}