cli: Add initial cli implementation.

- Add kata-runtime
- Add unit test
- Add Makefile to build cli

Fixes: #33

Signed-off-by: Julio Montes <julio.montes@intel.com>
Signed-off-by: James O. D. Hunt <james.o.hunt@intel.com>
Signed-off-by: Jose Carlos Venegas Munoz <jose.carlos.venegas.munoz@intel.com>

cli/utils.go

@@ -0,0 +1,207 @@
+// Copyright (c) 2017 Intel Corporation
+//
+// 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 (
+	"bytes"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+)
+
+const unknown = "<<unknown>>"
+
+// variables to allow tests to modify the values
+var (
+	procVersion = "/proc/version"
+	osRelease   = "/etc/os-release"
+
+	// Clear Linux has a different path (for stateless support)
+	osReleaseClr = "/usr/lib/os-release"
+)
+
+func fileExists(path string) bool {
+	if _, err := os.Stat(path); os.IsNotExist(err) {
+		return false
+	}
+
+	return true
+}
+
+func getFileContents(file string) (string, error) {
+	bytes, err := ioutil.ReadFile(file)
+	if err != nil {
+		return "", err
+	}
+
+	return string(bytes), nil
+}
+
+func getKernelVersion() (string, error) {
+	contents, err := getFileContents(procVersion)
+	if err != nil {
+		return "", err
+	}
+
+	fields := strings.Fields(contents)
+
+	if len(fields) < 3 {
+		return "", fmt.Errorf("unexpected contents in %v", procVersion)
+	}
+
+	version := fields[2]
+
+	return version, nil
+}
+
+// getDistroDetails returns the distributions name and version string.
+// If it is not possible to determine both values an error is
+// returned.
+func getDistroDetails() (name, version string, err error) {
+	files := []string{osRelease, osReleaseClr}
+
+	for _, file := range files {
+		contents, err := getFileContents(file)
+		if err != nil {
+			if os.IsNotExist(err) {
+				continue
+			}
+
+			return "", "", err
+		}
+
+		lines := strings.Split(contents, "\n")
+
+		for _, line := range lines {
+			if strings.HasPrefix(line, "NAME=") {
+				fields := strings.Split(line, "=")
+				name = strings.Trim(fields[1], `"`)
+			} else if strings.HasPrefix(line, "VERSION_ID=") {
+				fields := strings.Split(line, "=")
+				version = strings.Trim(fields[1], `"`)
+			}
+		}
+
+		if name != "" && version != "" {
+			return name, version, nil
+		}
+	}
+
+	return "", "", fmt.Errorf("failed to find expected fields in one of %v", files)
+}
+
+// getCPUDetails returns the vendor and model of the CPU.
+// If it is not possible to determine both values an error is
+// returned.
+func getCPUDetails() (vendor, model string, err error) {
+	cpuinfo, err := getCPUInfo(procCPUInfo)
+	if err != nil {
+		return "", "", err
+	}
+
+	lines := strings.Split(cpuinfo, "\n")
+
+	for _, line := range lines {
+		if strings.HasPrefix(line, "vendor_id") {
+			fields := strings.Split(line, ":")
+			if len(fields) > 1 {
+				vendor = strings.TrimSpace(fields[1])
+			}
+		} else if strings.HasPrefix(line, "model name") {
+			fields := strings.Split(line, ":")
+			if len(fields) > 1 {
+				model = strings.TrimSpace(fields[1])
+			}
+		}
+	}
+
+	if vendor != "" && model != "" {
+		return vendor, model, nil
+	}
+
+	return "", "", fmt.Errorf("failed to find expected fields in file %v", procCPUInfo)
+}
+
+// resolvePath returns the fully resolved and expanded value of the
+// specified path.
+func resolvePath(path string) (string, error) {
+	if path == "" {
+		return "", fmt.Errorf("path must be specified")
+	}
+
+	absolute, err := filepath.Abs(path)
+	if err != nil {
+		return "", err
+	}
+
+	resolved, err := filepath.EvalSymlinks(absolute)
+	if err != nil {
+		if os.IsNotExist(err) {
+			// Make the error clearer than the default
+			return "", fmt.Errorf("file %v does not exist", absolute)
+		}
+
+		return "", err
+	}
+
+	return resolved, nil
+}
+
+// runCommandFull returns the commands space-trimmed standard output and
+// error on success. Note that if the command fails, the requested output will
+// still be returned, along with an error.
+func runCommandFull(args []string, includeStderr bool) (string, error) {
+	cmd := exec.Command(args[0], args[1:]...)
+	var err error
+	var bytes []byte
+
+	if includeStderr {
+		bytes, err = cmd.CombinedOutput()
+	} else {
+		bytes, err = cmd.Output()
+	}
+
+	trimmed := strings.TrimSpace(string(bytes))
+
+	return trimmed, err
+}
+
+// runCommand returns the commands space-trimmed standard output on success
+func runCommand(args []string) (string, error) {
+	return runCommandFull(args, false)
+}
+
+// writeFile write data into specified file
+func writeFile(filePath string, data string, fileMode os.FileMode) error {
+	// Normally dir should not be empty, one case is that cgroup subsystem
+	// is not mounted, we will get empty dir, and we want it fail here.
+	if filePath == "" {
+		return fmt.Errorf("no such file for %s", filePath)
+	}
+
+	if err := ioutil.WriteFile(filePath, []byte(data), fileMode); err != nil {
+		return fmt.Errorf("failed to write %v to %v: %v", data, filePath, err)
+	}
+
+	return nil
+}
+
+// isEmptyString return if string is empty
+func isEmptyString(b []byte) bool {
+	return len(bytes.Trim(b, "\n")) == 0
+}