From bc4e19aa48309acdc77e70bcff3afc6751fd9954 Mon Sep 17 00:00:00 2001
From: Evan Lezar <elezar@nvidia.com>
Date: Mon, 27 Nov 2023 11:17:55 +0100
Subject: [PATCH] Add --relative-to option to nvidia-ctk transform root

This change adds a --relative-to option to the nvidia-ctk transform root
command. This defaults to "host" maintaining the existing behaviour.

If --relative-to=container is specified, the root transform is applied to
container paths in the CDI specification instead of host paths.

Signed-off-by: Evan Lezar <elezar@nvidia.com>
---
 CHANGELOG.md                              |  1 +
 cmd/nvidia-ctk/cdi/transform/root/root.go | 32 ++++++++++++++++-------
 2 files changed, 24 insertions(+), 9 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4f7389e0..c4812fde 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,7 @@
 * Add support for injecting /dev/nvidia-nvswitch* devices if the NVIDIA_NVSWITCH=enabled envvar is specified.
 * Added support for `nvidia-ctk runtime configure --enable-cdi` for the `docker` runtime. Note that this requires Docker >= 25.
 * Fixed bug in `nvidia-ctk config` command when using `--set`. The types of applied config options are now applied correctly.
+* Add `--relative-to` option to `nvidia-ctk transform root` command. This controls whether the root transformation is applied to host or container paths.
 
 * [libnvidia-container] Fix device permission check when using cgroupv2 (fixes #227)
 
diff --git a/cmd/nvidia-ctk/cdi/transform/root/root.go b/cmd/nvidia-ctk/cdi/transform/root/root.go
index 8933a815..4de8d9c6 100644
--- a/cmd/nvidia-ctk/cdi/transform/root/root.go
+++ b/cmd/nvidia-ctk/cdi/transform/root/root.go
@@ -23,7 +23,7 @@ import (
 
 	"github.com/NVIDIA/nvidia-container-toolkit/internal/logger"
 	"github.com/NVIDIA/nvidia-container-toolkit/pkg/nvcdi/spec"
-	"github.com/NVIDIA/nvidia-container-toolkit/pkg/nvcdi/transform"
+	transformroot "github.com/NVIDIA/nvidia-container-toolkit/pkg/nvcdi/transform/root"
 	"github.com/urfave/cli/v2"
 	"tags.cncf.io/container-device-interface/pkg/cdi"
 )
@@ -39,8 +39,9 @@ type transformOptions struct {
 
 type options struct {
 	transformOptions
-	from string
-	to   string
+	from       string
+	to         string
+	relativeTo string
 }
 
 // NewCommand constructs a generate-cdi command with the specified logger
@@ -67,6 +68,11 @@ func (m command) build() *cli.Command {
 	}
 
 	c.Flags = []cli.Flag{
+		&cli.StringFlag{
+			Name:        "from",
+			Usage:       "specify the root to be transformed",
+			Destination: &opts.from,
+		},
 		&cli.StringFlag{
 			Name:        "input",
 			Usage:       "Specify the file to read the CDI specification from. If this is '-' the specification is read from STDIN",
@@ -79,9 +85,10 @@ func (m command) build() *cli.Command {
 			Destination: &opts.output,
 		},
 		&cli.StringFlag{
-			Name:        "from",
-			Usage:       "specify the root to be transformed",
-			Destination: &opts.from,
+			Name:        "relative-to",
+			Usage:       "specify whether the transform is relative to the host or to the container. One of [ host | container ]",
+			Value:       "host",
+			Destination: &opts.relativeTo,
 		},
 		&cli.StringFlag{
 			Name:        "to",
@@ -95,6 +102,12 @@ func (m command) build() *cli.Command {
 }
 
 func (m command) validateFlags(c *cli.Context, opts *options) error {
+	switch opts.relativeTo {
+	case "host":
+	case "container":
+	default:
+		return fmt.Errorf("invalid --relative-to value: %v", opts.relativeTo)
+	}
 	return nil
 }
 
@@ -104,9 +117,10 @@ func (m command) run(c *cli.Context, opts *options) error {
 		return fmt.Errorf("failed to load CDI specification: %w", err)
 	}
 
-	err = transform.NewHostRootTransformer(
-		opts.from,
-		opts.to,
+	err = transformroot.New(
+		transformroot.WithRoot(opts.from),
+		transformroot.WithTargetRoot(opts.to),
+		transformroot.WithRelativeTo(opts.relativeTo),
 	).Transform(spec.Raw())
 	if err != nil {
 		return fmt.Errorf("failed to transform CDI specification: %w", err)