Copy cmd from container-config

This change copies the code from container-config/cmd to
tools/container. This allows the code to be built and
added to the container image without additional refactoring.

As the configuration utilities are incorporated into the cmds
of the nvidia-container-toolkit, the code will be moved from tools.

Files copied from:

383587f766

Signed-off-by: Evan Lezar <elezar@nvidia.com>

tools/container/toolkit/executable.go

@@ -0,0 +1,153 @@
+/**
+# Copyright (c) 2021, 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 main
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"sort"
+	"strings"
+
+	log "github.com/sirupsen/logrus"
+)
+
+type executableTarget struct {
+	dotfileName string
+	wrapperName string
+}
+
+type executable struct {
+	source   string
+	target   executableTarget
+	env      map[string]string
+	preLines []string
+	argLines []string
+}
+
+// install installs an executable component of the NVIDIA container toolkit. The source executable
+// is copied to a `.real` file and a wapper is created to set up the environment as required.
+func (e executable) install(destFolder string) (string, error) {
+	log.Infof("Installing executable '%v' to %v", e.source, destFolder)
+
+	dotfileName := e.dotfileName()
+
+	installedDotfileName, err := installFileToFolderWithName(destFolder, dotfileName, e.source)
+	if err != nil {
+		return "", fmt.Errorf("error installing file '%v' as '%v': %v", e.source, dotfileName, err)
+	}
+	log.Infof("Installed '%v'", installedDotfileName)
+
+	wrapperFilename, err := e.installWrapper(destFolder, installedDotfileName)
+	if err != nil {
+		return "", fmt.Errorf("error wrapping '%v': %v", installedDotfileName, err)
+	}
+	log.Infof("Installed wrapper '%v'", wrapperFilename)
+
+	return wrapperFilename, nil
+}
+
+func (e executable) dotfileName() string {
+	return e.target.dotfileName
+}
+
+func (e executable) wrapperName() string {
+	return e.target.wrapperName
+}
+
+func (e executable) installWrapper(destFolder string, dotfileName string) (string, error) {
+	wrapperPath := filepath.Join(destFolder, e.wrapperName())
+	wrapper, err := os.Create(wrapperPath)
+	if err != nil {
+		return "", fmt.Errorf("error creating executable wrapper: %v", err)
+	}
+	defer wrapper.Close()
+
+	err = e.writeWrapperTo(wrapper, destFolder, dotfileName)
+	if err != nil {
+		return "", fmt.Errorf("error writing wrapper contents: %v", err)
+	}
+
+	err = ensureExecutable(wrapperPath)
+	if err != nil {
+		return "", fmt.Errorf("error making wrapper executable: %v", err)
+	}
+	return wrapperPath, nil
+}
+
+func (e executable) writeWrapperTo(wrapper io.Writer, destFolder string, dotfileName string) error {
+	r := newReplacements(destDirPattern, destFolder)
+
+	// Add the shebang
+	fmt.Fprintln(wrapper, "#! /bin/sh")
+
+	// Add the preceding lines if any
+	for _, line := range e.preLines {
+		fmt.Fprintf(wrapper, "%s\n", r.apply(line))
+	}
+
+	// Update the path to include the destination folder
+	var env map[string]string
+	if e.env == nil {
+		env = make(map[string]string)
+	} else {
+		env = e.env
+	}
+
+	path, specified := env["PATH"]
+	if !specified {
+		path = "$PATH"
+	}
+	env["PATH"] = strings.Join([]string{destFolder, path}, ":")
+
+	var sortedEnvvars []string
+	for e := range env {
+		sortedEnvvars = append(sortedEnvvars, e)
+	}
+	sort.Strings(sortedEnvvars)
+
+	for _, e := range sortedEnvvars {
+		v := env[e]
+		fmt.Fprintf(wrapper, "%s=%s \\\n", e, r.apply(v))
+	}
+	// Add the call to the target executable
+	fmt.Fprintf(wrapper, "%s \\\n", dotfileName)
+
+	// Insert additional lines in the `arg` list
+	for _, line := range e.argLines {
+		fmt.Fprintf(wrapper, "\t%s \\\n", r.apply(line))
+	}
+	// Add the script arguments "$@"
+	fmt.Fprintln(wrapper, "\t\"$@\"")
+
+	return nil
+}
+
+// ensureExecutable is equivalent to running chmod +x on the specified file
+func ensureExecutable(path string) error {
+	info, err := os.Stat(path)
+	if err != nil {
+		return fmt.Errorf("error getting file info for '%v': %v", path, err)
+	}
+	executableMode := info.Mode() | 0111
+	err = os.Chmod(path, executableMode)
+	if err != nil {
+		return fmt.Errorf("error setting executable mode for '%v': %v", path, err)
+	}
+	return nil
+}