Merge branch 'fix-executable-locator' into 'main'

Fix location of executables in PATH

See merge request nvidia/container-toolkit/container-toolkit!148

cmd/nvidia-container-toolkit/main.go

@@ -6,21 +6,20 @@ import (
 	"log"
 	"os"
 	"os/exec"
-	"path"
 	"path/filepath"
 	"runtime"
 	"runtime/debug"
 	"strconv"
 	"strings"
 	"syscall"
+
+	"github.com/NVIDIA/nvidia-container-toolkit/internal/lookup"
 )
 
 var (
 	debugflag  = flag.Bool("debug", false, "enable debug output")
 	forceflag  = flag.Bool("force", false, "force execution of prestart hook in experimental mode")
 	configflag = flag.String("config", "", "configuration file")
-
-	defaultPATH = []string{"/usr/local/sbin", "/usr/local/bin", "/usr/sbin", "/usr/bin", "/sbin", "/bin"}
 )
 
 func exit() {
@@ -36,28 +35,16 @@ func exit() {
 	os.Exit(0)
 }
 
-func getPATH(config CLIConfig) string {
-	dirs := filepath.SplitList(os.Getenv("PATH"))
-	// directories from the hook environment have higher precedence
-	dirs = append(dirs, defaultPATH...)
-
-	if config.Root != nil {
-		rootDirs := []string{}
-		for _, dir := range dirs {
-			rootDirs = append(rootDirs, path.Join(*config.Root, dir))
-		}
-		// directories with the root prefix have higher precedence
-		dirs = append(rootDirs, dirs...)
-	}
-	return strings.Join(dirs, ":")
-}
-
 func getCLIPath(config CLIConfig) string {
 	if config.Path != nil {
 		return *config.Path
 	}
 
-	if err := os.Setenv("PATH", getPATH(config)); err != nil {
+	var root string
+	if config.Root != nil {
+		root = *config.Root
+	}
+	if err := os.Setenv("PATH", lookup.GetPath(root)); err != nil {
 		log.Panicln("couldn't set PATH variable:", err)
 	}
 

internal/lookup/executable.go

@@ -25,24 +25,13 @@ import (
 	log "github.com/sirupsen/logrus"
 )
 
-const (
-	envPath = "PATH"
-)
-
-var defaultPaths = []string{"/usr/local/sbin", "/usr/local/bin", "/usr/sbin", "/usr/bin", "/sbin", "/bin"}
-
 type executable struct {
 	file
 }
 
 // NewExecutableLocator creates a locator to fine executable files in the path. A logger can also be specified.
 func NewExecutableLocator(logger *log.Logger, root string) Locator {
-	pathEnv := os.Getenv(envPath)
-	paths := filepath.SplitList(pathEnv)
-
-	if root != "" {
-		paths = append(paths, defaultPaths...)
-	}
+	paths := GetPaths(root)
 
 	var prefixes []string
 	for _, dir := range paths {

internal/lookup/path.go

@@ -0,0 +1,69 @@
+/**
+# Copyright (c) 2022, 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 lookup
+
+import (
+	"os"
+	"path"
+	"path/filepath"
+	"strings"
+)
+
+const (
+	envPath = "PATH"
+)
+
+var (
+	defaultPATH = []string{"/usr/local/sbin", "/usr/local/bin", "/usr/sbin", "/usr/bin", "/sbin", "/bin"}
+)
+
+// GetPaths returns a list of paths for a specified root. These are constructed from the
+// PATH environment variable, a default path list, and the supplied root.
+func GetPaths(root string) []string {
+	dirs := filepath.SplitList(os.Getenv(envPath))
+
+	inDirs := make(map[string]bool)
+	for _, d := range dirs {
+		inDirs[d] = true
+	}
+
+	// directories from the environment have higher precedence
+	for _, d := range defaultPATH {
+		if inDirs[d] {
+			// We don't add paths that are already included
+			continue
+		}
+		dirs = append(dirs, d)
+	}
+
+	if root != "" && root != "/" {
+		rootDirs := []string{}
+		for _, dir := range dirs {
+			rootDirs = append(rootDirs, path.Join(root, dir))
+		}
+		// directories with the root prefix have higher precedence
+		dirs = append(rootDirs, dirs...)
+	}
+
+	return dirs
+}
+
+// GetPath returns a colon-separated path value that can be used to set the PATH
+// environment variable
+func GetPath(root string) string {
+	return strings.Join(GetPaths(root), ":")
+}

internal/oci/runtime_low_level.go

@@ -18,8 +18,8 @@ package oci
 
 import (
 	"fmt"
-	"os/exec"
 
+	"github.com/NVIDIA/nvidia-container-toolkit/internal/lookup"
 	log "github.com/sirupsen/logrus"
 )
 
@@ -43,14 +43,15 @@ func findRuntime(logger *log.Logger, candidates []string) (string, error) {
 		return "", fmt.Errorf("at least one runtime candidate must be specified")
 	}
 
+	locator := lookup.NewExecutableLocator(logger, "/")
 	for _, candidate := range candidates {
 		logger.Debugf("Looking for runtime binary '%v'", candidate)
-		runcPath, err := exec.LookPath(candidate)
-		if err == nil {
-			logger.Debugf("Found runtime binary '%v'", runcPath)
-			return runcPath, nil
+		targets, err := locator.Locate(candidate)
+		if err == nil && len(targets) > 0 {
+			logger.Debugf("Found runtime binary '%v'", targets)
+			return targets[0], nil
 		}
-		logger.Debugf("Runtime binary '%v' not found: %v", candidate, err)
+		logger.Debugf("Runtime binary '%v' not found: %v (targets=%v)", candidate, err, targets)
 	}
 
 	return "", fmt.Errorf("no runtime binary found from candidate list: %v", candidates)