From 8e6b57b38a4de34a271aefd45ed8fa87a9a49b00 Mon Sep 17 00:00:00 2001
From: Evan Lezar <elezar@nvidia.com>
Date: Tue, 14 Jan 2025 18:31:51 +0100
Subject: [PATCH] Remove watch option from create-dev-char-symlinks

This removes the untested watch option from the
nvidia-ctk system create-dev-char-symlinks command.

This also removes the direct dependency on fsnotify.

Signed-off-by: Evan Lezar <elezar@nvidia.com>
---
 .../create-dev-char-symlinks.go               | 89 +------------------
 go.mod                                        |  2 +-
 2 files changed, 3 insertions(+), 88 deletions(-)

diff --git a/cmd/nvidia-ctk/system/create-dev-char-symlinks/create-dev-char-symlinks.go b/cmd/nvidia-ctk/system/create-dev-char-symlinks/create-dev-char-symlinks.go
index 36794a61f..dff068eb4 100644
--- a/cmd/nvidia-ctk/system/create-dev-char-symlinks/create-dev-char-symlinks.go
+++ b/cmd/nvidia-ctk/system/create-dev-char-symlinks/create-dev-char-symlinks.go
@@ -19,12 +19,8 @@ package devchar
 import (
 	"fmt"
 	"os"
-	"os/signal"
 	"path/filepath"
-	"strings"
-	"syscall"
 
-	"github.com/fsnotify/fsnotify"
 	"github.com/urfave/cli/v2"
 
 	"github.com/NVIDIA/nvidia-container-toolkit/internal/logger"
@@ -44,7 +40,6 @@ type config struct {
 	devCharPath       string
 	driverRoot        string
 	dryRun            bool
-	watch             bool
 	createAll         bool
 	createDeviceNodes bool
 	loadKernelModules bool
@@ -89,13 +84,6 @@ func (m command) build() *cli.Command {
 			Destination: &cfg.driverRoot,
 			EnvVars:     []string{"NVIDIA_DRIVER_ROOT", "DRIVER_ROOT"},
 		},
-		&cli.BoolFlag{
-			Name:        "watch",
-			Usage:       "If set, the command will watch for changes to the driver root and recreate the symlinks when changes are detected.",
-			Value:       false,
-			Destination: &cfg.watch,
-			EnvVars:     []string{"WATCH"},
-		},
 		&cli.BoolFlag{
 			Name:        "create-all",
 			Usage:       "Create all possible /dev/char symlinks instead of limiting these to existing device nodes.",
@@ -127,7 +115,7 @@ func (m command) build() *cli.Command {
 }
 
 func (m command) validateFlags(r *cli.Context, cfg *config) error {
-	if cfg.createAll && cfg.watch {
+	if cfg.createAll {
 		return fmt.Errorf("create-all and watch are mutually exclusive")
 	}
 
@@ -145,19 +133,6 @@ func (m command) validateFlags(r *cli.Context, cfg *config) error {
 }
 
 func (m command) run(c *cli.Context, cfg *config) error {
-	var watcher *fsnotify.Watcher
-	var sigs chan os.Signal
-
-	if cfg.watch {
-		watcher, err := newFSWatcher(filepath.Join(cfg.driverRoot, "dev"))
-		if err != nil {
-			return fmt.Errorf("failed to create FS watcher: %v", err)
-		}
-		defer watcher.Close()
-
-		sigs = newOSWatcher(syscall.SIGHUP, syscall.SIGINT, syscall.SIGTERM, syscall.SIGQUIT)
-	}
-
 	l, err := NewSymlinkCreator(
 		WithLogger(m.logger),
 		WithDevCharPath(cfg.devCharPath),
@@ -171,47 +146,11 @@ func (m command) run(c *cli.Context, cfg *config) error {
 		return fmt.Errorf("failed to create symlink creator: %v", err)
 	}
 
-create:
 	err = l.CreateLinks()
 	if err != nil {
 		return fmt.Errorf("failed to create links: %v", err)
 	}
-	if !cfg.watch {
-		return nil
-	}
-	for {
-		select {
-
-		case event := <-watcher.Events:
-			deviceNode := filepath.Base(event.Name)
-			if !strings.HasPrefix(deviceNode, "nvidia") {
-				continue
-			}
-			if event.Has(fsnotify.Create) {
-				m.logger.Infof("%s created, restarting.", event.Name)
-				goto create
-			}
-			if event.Has(fsnotify.Remove) {
-				m.logger.Infof("%s removed. Ignoring", event.Name)
-
-			}
-
-		// Watch for any other fs errors and log them.
-		case err := <-watcher.Errors:
-			m.logger.Errorf("inotify: %s", err)
-
-		// React to signals
-		case s := <-sigs:
-			switch s {
-			case syscall.SIGHUP:
-				m.logger.Infof("Received SIGHUP, recreating symlinks.")
-				goto create
-			default:
-				m.logger.Infof("Received signal %q, shutting down.", s)
-				return nil
-			}
-		}
-	}
+	return nil
 }
 
 type linkCreator struct {
@@ -399,27 +338,3 @@ type deviceNode struct {
 func (d deviceNode) devCharName() string {
 	return fmt.Sprintf("%d:%d", d.major, d.minor)
 }
-
-func newFSWatcher(files ...string) (*fsnotify.Watcher, error) {
-	watcher, err := fsnotify.NewWatcher()
-	if err != nil {
-		return nil, err
-	}
-
-	for _, f := range files {
-		err = watcher.Add(f)
-		if err != nil {
-			watcher.Close()
-			return nil, err
-		}
-	}
-
-	return watcher, nil
-}
-
-func newOSWatcher(sigs ...os.Signal) chan os.Signal {
-	sigChan := make(chan os.Signal, 1)
-	signal.Notify(sigChan, sigs...)
-
-	return sigChan
-}
diff --git a/go.mod b/go.mod
index ac3686923..fe42e160f 100644
--- a/go.mod
+++ b/go.mod
@@ -5,7 +5,6 @@ go 1.20
 require (
 	github.com/NVIDIA/go-nvlib v0.6.1
 	github.com/NVIDIA/go-nvml v0.12.4-1
-	github.com/fsnotify/fsnotify v1.7.0
 	github.com/moby/sys/symlink v0.3.0
 	github.com/opencontainers/runtime-spec v1.2.0
 	github.com/pelletier/go-toml v1.9.5
@@ -21,6 +20,7 @@ require (
 require (
 	github.com/cpuguy83/go-md2man/v2 v2.0.4 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/fsnotify/fsnotify v1.7.0 // indirect
 	github.com/google/uuid v1.6.0 // indirect
 	github.com/hashicorp/errwrap v1.1.0 // indirect
 	github.com/kr/pretty v0.3.1 // indirect