runtime: add debug console service

Add `kata-runtime exec` to enter guest OS
through shell started by agent

Fixes: #245

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

src/runtime/cli/config-generated.go.in

@@ -39,6 +39,7 @@ var version = "@VERSION@"
 // project-specific command names
 var envCmd = fmt.Sprintf("%s-env", projectPrefix)
 var checkCmd = fmt.Sprintf("%s-check", projectPrefix)
+var execCmd = "exec"
 
 // project-specific option names
 var configFilePathOption = fmt.Sprintf("%s-config", projectPrefix)

src/runtime/cli/kata-exec.go

@@ -0,0 +1,208 @@
+// Copyright (c) 2017-2019 Intel Corporation
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+
+package main
+
+import (
+	"fmt"
+	"io"
+	"io/ioutil"
+	"net"
+	"net/http"
+	"net/url"
+	"os"
+	"strings"
+
+	"sync"
+	"time"
+
+	"github.com/containerd/console"
+	"github.com/kata-containers/kata-containers/src/runtime/pkg/katautils"
+	clientUtils "github.com/kata-containers/kata-containers/src/runtime/virtcontainers/pkg/agent/protocols/client"
+	"github.com/pkg/errors"
+	"github.com/urfave/cli"
+)
+
+const (
+
+	// The buffer size used to specify the buffer for IO streams copy
+	bufSize = 32 << 10
+
+	defaultTimeout = 3 * time.Second
+)
+
+var (
+	bufPool = sync.Pool{
+		New: func() interface{} {
+			buffer := make([]byte, bufSize)
+			return &buffer
+		},
+	}
+)
+
+var kataExecCLICommand = cli.Command{
+	Name:  execCmd,
+	Usage: "Enter into guest by debug console",
+	Flags: []cli.Flag{
+		cli.StringFlag{
+			Name:  "monitor-addr",
+			Usage: "Kata monitor listen address.",
+		},
+		cli.Uint64Flag{
+			Name:  "debug-port",
+			Usage: "Port that debug console is listening on.",
+		},
+	},
+	Action: func(context *cli.Context) error {
+		ctx, err := cliContextToContext(context)
+		if err != nil {
+			return err
+		}
+		span, _ := katautils.Trace(ctx, "exec")
+		defer span.Finish()
+
+		endPoint := context.String("monitor-addr")
+		if endPoint == "" {
+			endPoint = "http://localhost:8090"
+		}
+
+		port := context.Uint64("debug-port")
+		if port == 0 {
+			port = 1026
+		}
+
+		sandboxID := context.Args().Get(0)
+		if sandboxID == "" {
+			return fmt.Errorf("SandboxID not found")
+		}
+
+		conn, err := getConn(endPoint, sandboxID, port)
+		if err != nil {
+			return err
+		}
+		defer conn.Close()
+
+		con := console.Current()
+		defer con.Reset()
+
+		if err := con.SetRaw(); err != nil {
+			return err
+		}
+
+		iostream := &iostream{
+			conn:   conn,
+			exitch: make(chan struct{}),
+			closed: false,
+		}
+
+		ioCopy(iostream, con)
+
+		<-iostream.exitch
+		return nil
+	},
+}
+
+func ioCopy(stream *iostream, con console.Console) {
+	var wg sync.WaitGroup
+
+	// stdin
+	go func() {
+		p := bufPool.Get().(*[]byte)
+		defer bufPool.Put(p)
+		io.CopyBuffer(stream, con, *p)
+	}()
+
+	// stdout
+	wg.Add(1)
+	go func() {
+		p := bufPool.Get().(*[]byte)
+		defer bufPool.Put(p)
+		io.CopyBuffer(os.Stdout, stream, *p)
+		wg.Done()
+	}()
+
+	wg.Wait()
+	close(stream.exitch)
+}
+
+type iostream struct {
+	conn   net.Conn
+	exitch chan struct{}
+	closed bool
+}
+
+func (s *iostream) Write(data []byte) (n int, err error) {
+	if s.closed {
+		return 0, errors.New("stream closed")
+	}
+	return s.conn.Write(data)
+}
+
+func (s *iostream) Close() error {
+	if s.closed {
+		return errors.New("stream closed")
+	}
+
+	err := s.conn.Close()
+	if err == nil {
+		s.closed = true
+	}
+
+	return err
+}
+
+func (s *iostream) Read(data []byte) (n int, err error) {
+	if s.closed {
+		return 0, errors.New("stream closed")
+	}
+
+	return s.conn.Read(data)
+}
+
+func getConn(endPoint, sandboxID string, port uint64) (net.Conn, error) {
+	shimURL := fmt.Sprintf("%s/agent-url?sandbox=%s", endPoint, sandboxID)
+	resp, err := http.Get(shimURL)
+	if err != nil {
+		return nil, err
+	}
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("Failed to get %s: %d", shimURL, resp.StatusCode)
+	}
+
+	defer resp.Body.Close()
+	data, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return nil, err
+	}
+
+	sock := strings.TrimSuffix(string(data), "\n")
+	addr, err := url.Parse(sock)
+	if err != nil {
+		return nil, err
+	}
+
+	// validate more
+	switch addr.Scheme {
+	case clientUtils.VSockSocketScheme:
+		// vsock://31513974:1024
+		shimAddr := clientUtils.VSockSocketScheme + ":" + addr.Host
+		shimAddr = strings.Replace(shimAddr, ":1024", fmt.Sprintf(":%d", port), -1)
+		return clientUtils.VsockDialer(shimAddr, defaultTimeout)
+
+	case clientUtils.HybridVSockScheme:
+		// addr: hvsock:///run/vc/firecracker/340b412c97bf1375cdda56bfa8f18c8a/root/kata.hvsock:1024
+		hvsocket := strings.Split(addr.Path, ":")
+		if len(hvsocket) != 2 {
+			return nil, fmt.Errorf("Invalid hybrid vsock scheme: %s", sock)
+		}
+
+		// hvsock:///run/vc/firecracker/340b412c97bf1375cdda56bfa8f18c8a/root/kata.hvsock
+		shimAddr := fmt.Sprintf("%s:%s:%d", clientUtils.HybridVSockScheme, hvsocket[0], port)
+		return clientUtils.HybridVSockDialer(shimAddr, defaultTimeout)
+	}
+
+	return nil, fmt.Errorf("schema %s not found", addr.Scheme)
+}

src/runtime/cli/kata-monitor/main.go

@@ -36,6 +36,7 @@ func main() {
 	m := http.NewServeMux()
 	m.Handle("/metrics", http.HandlerFunc(km.ProcessMetricsRequest))
 	m.Handle("/sandboxes", http.HandlerFunc(km.ListSandboxes))
+	m.Handle("/agent-url", http.HandlerFunc(km.GetAgentURL))
 
 	// for debug shim process
 	m.Handle("/debug/vars", http.HandlerFunc(km.ExpvarHandler))

src/runtime/cli/main.go

@@ -125,6 +125,7 @@ var runtimeCommands = []cli.Command{
 	// Kata Containers specific extensions
 	kataCheckCLICommand,
 	kataEnvCLICommand,
+	kataExecCLICommand,
 	factoryCLICommand,
 }