runtime: add geust memory dump

When guest panic, dump guest kernel memory to host filesystem.
And also includes:
- hypervisor config
- hypervisor version
- and state of sandbox

Fixes: #1012

Signed-off-by: bin liu <bin@hyper.sh>

src/runtime/pkg/utils/utils.go

@@ -1,4 +1,4 @@
-// Copyright (c) 2020 Ant Financial
+// Copyright (c) 2020 Ant Group
 //
 // SPDX-License-Identifier: Apache-2.0
 //
@@ -6,7 +6,11 @@
 package utils
 
 import (
+	"fmt"
 	"net/http"
+	"os"
+	"os/exec"
+	"path/filepath"
 	"strings"
 )
 
@@ -31,3 +35,48 @@ func GzipAccepted(header http.Header) bool {
 func String2Pointer(s string) *string {
 	return &s
 }
+
+// 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)
+}
+
+// EnsureDir check if a directory exist, if not then create it
+func EnsureDir(path string, mode os.FileMode) error {
+	if !filepath.IsAbs(path) {
+		return fmt.Errorf("Not an absolute path: %s", path)
+	}
+
+	if fi, err := os.Stat(path); err != nil {
+		if os.IsNotExist(err) {
+			if err = os.MkdirAll(path, mode); err != nil {
+				return err
+			}
+		} else {
+			return err
+		}
+	} else if !fi.IsDir() {
+		return fmt.Errorf("Not a directory: %s", path)
+	}
+
+	return nil
+}