Add copy/paste support (#1520)

* add `vnc type` command to send string
* properly shift keys for `vnc type`
* send ClientCutText contents immediately
* add bidirectional copy/paste flag
* fix requirements in help for bi-directional copy/paste
* disable extended clipboard support in noVNC
* vnc: handle negative length for ClientCutText
* print playback errors on paste; handle special characters
* error out on launch if bidirectional-copy-paste set and requirements not met

cmd/minimega/external.go

@@ -25,6 +25,9 @@ var (
 	MIN_OVS     = []int{1, 11}
 	// MIN_KERNEL for Overlayfs
 	MIN_KERNEL = []int{3, 18}
+
+	// feature requirements
+	MIN_QEMU_COPY_PASTE = []int{6, 1}
 )
 
 // externalDependencies contains all the external programs that minimega
@@ -255,6 +258,22 @@ func checkVersion(name string, min []int, versionFn func() ([]int, error)) error
 	return nil
 }
 
+// checks that qemu has the chardev `required`
+func checkQemuChardev(required string) error {
+	out, err := processWrapper("kvm", "-chardev", "help")
+	if err != nil {
+		return fmt.Errorf("check qemu chardev failed: %v", err)
+	}
+
+	fields := strings.Split(out, "\n")
+	for _, f := range fields {
+		if strings.TrimSpace(f) == required {
+			return nil
+		}
+	}
+	return fmt.Errorf("qemu does not have required chardev: %v", required)
+}
+
 // lsModule returns true if the specified module is in the `lsmod` output
 func lsModule(s string) bool {
 	log.Info("checking for kernel module: %v", s)

cmd/minimega/kvm.go

@@ -189,6 +189,12 @@ type KVMConfig struct {
 	// socket at the path provided
 	TpmSocketPath string
 
+	// Enables bidirectional copy paste instead of basic pasting into VM.
+	// Requires QEMU 6.1+ compiled with qemu-vdagent chardev and for spice-vdagent to be installed on VM.
+	//
+	// Default: false
+	BidirectionalCopyPaste bool
+
 	// Add additional arguments to be passed to the QEMU instance. For example:
 	//
 	// 	vm config qemu-append -serial tcp:localhost:4001
@@ -546,6 +552,7 @@ func (vm *KVMConfig) String() string {
 	fmt.Fprintf(w, "Sockets:\t%v\n", vm.Sockets)
 	fmt.Fprintf(w, "VGA:\t%v\n", vm.Vga)
 	fmt.Fprintf(w, "Usb Use XHCI:\t%v\n", vm.UsbUseXHCI)
+	fmt.Fprintf(w, "Bidirectional Copy Paste:\t%v\n", vm.BidirectionalCopyPaste)
 	fmt.Fprintf(w, "TPM Socket: \t%v\n", vm.TpmSocketPath)
 	w.Flush()
 	fmt.Fprintln(&o)
@@ -772,6 +779,14 @@ func (vm *KvmVM) connectVNC() error {
 				for {
 					msg, err := vnc.ReadClientMessage(tee)
 					if err == nil {
+						// for cut text, send text immediately as string if not bi-directional
+						if cut, ok := msg.(*vnc.ClientCutText); ok && !vm.BidirectionalCopyPaste {
+							log.Info("sending text for ClientCutText: %s", cut.Text)
+							err = ns.Player.PlaybackString(vm.Name, vm.vncShim.Addr().String(), string(cut.Text))
+							if err != nil {
+								log.Warnln(err)
+							}
+						}
 						ns.Recorder.Route(vm.GetName(), msg)
 						continue
 					}
@@ -926,6 +941,17 @@ func (vm *KvmVM) launch() error {
 	var sErr bytes.Buffer
 
 	vmConfig := VMConfig{BaseConfig: vm.BaseConfig, KVMConfig: vm.KVMConfig}
+
+	// if using bidirectionalCopyPaste, error out if dependencies aren't met
+	if vmConfig.BidirectionalCopyPaste {
+		if err := checkVersion("qemu", MIN_QEMU_COPY_PASTE, qemuVersion); err != nil {
+			return fmt.Errorf("bidirectional-copy-paste not supported. Please disable: %v", err)
+		}
+		if err := checkQemuChardev("qemu-vdagent"); err != nil {
+			return fmt.Errorf("bidirectional-copy-paste not supported. Please disable: %v", err)
+		}
+	}
+
 	args := vmConfig.qemuArgs(vm.ID, vm.instancePath)
 	args = vmConfig.applyQemuOverrides(args)
 	log.Debug("final qemu args: %#v", args)
@@ -1475,6 +1501,15 @@ func (vm VMConfig) qemuArgs(id int, vmPath string) []string {
 		args = append(args, fmt.Sprintf("virtserialport,bus=virtio-serial%v.0,chardev=charvserialCC,id=charvserialCC,name=cc", virtioPort))
 	}
 
+	if vm.BidirectionalCopyPaste {
+		addVirtioDevice()
+
+		args = append(args, "-chardev")
+		args = append(args, "qemu-vdagent,id=vdagent,clipboard=on")
+		args = append(args, "-device")
+		args = append(args, fmt.Sprintf("virtserialport,bus=virtio-serial%v.0,chardev=vdagent,name=com.redhat.spice.0", virtioPort))
+	}
+
 	if vm.VirtioPorts != "" {
 		names := []string{}
 

cmd/minimega/vnc_cli.go

@@ -8,6 +8,7 @@ import (
 	"errors"
 	"fmt"
 	"path/filepath"
+	"strings"
 	"sync"
 
 	"github.com/sandia-minimega/minimega/v2/pkg/minicli"
@@ -64,6 +65,7 @@ below.
 #: This is an example of a vnc playback comment`,
 		Patterns: []string{
 			"vnc <play,> <vm target> <filename>",
+			"vnc <type,> <vm target> <str>...",
 			"vnc <stop,> <vm target>",
 			"vnc <pause,> <vm target>",
 			"vnc <continue,> <vm target>",
@@ -126,6 +128,8 @@ func cliVNCPlay(ns *Namespace, c *minicli.Command, resp *minicli.Response) error
 		switch {
 		case c.BoolArgs["play"]:
 			return true, ns.Player.Playback(id, rhost, fname)
+		case c.BoolArgs["type"]:
+			return true, ns.Player.PlaybackString(id, rhost, strings.Join(c.ListArgs["str"], " "))
 		case c.BoolArgs["stop"]:
 			return true, ns.Player.Stop(id)
 		case c.BoolArgs["inject"]:

internal/vnc/decode.go

@@ -54,6 +54,9 @@ func ReadClientMessage(r io.Reader) (interface{}, error) {
 		msg = msg2
 	case TypeClientCutText:
 		msg2 := &ClientCutText{_ClientCutText: *msg.(*_ClientCutText)}
+		if msg2.Length < 0 {
+			msg2.Length = -msg2.Length
+		}
 		msg2.Text = make([]uint8, msg2.Length)
 
 		err = binary.Read(r, binary.BigEndian, &msg2.Text)

internal/vnc/keysym.go

@@ -4,7 +4,10 @@
 
 package vnc
 
-import "fmt"
+import (
+	"fmt"
+	"unicode"
+)
 
 // Inverse of keysym.
 var keysymInverse = map[uint32]string{}
@@ -33,3 +36,23 @@ func xStringToKeysym(s string) (uint32, error) {
 
 	return uint32(0), fmt.Errorf("unknown key: `%s`", s)
 }
+
+func asciiCharToKeysymString(c rune) (string, error) {
+	// ascii 0x20 - 0x7E map directly to keysym values.
+	// manually shift cases for tab, nl, and cr
+	if c == 0x9 || c == 0xa || c == 0xd {
+		c += 0xff00
+	} else if c >= unicode.MaxASCII {
+		return "", fmt.Errorf("unknown non-ascii character: %U %c", c, c)
+	}
+	keysym, err := xKeysymToString(uint32(c))
+	if err != nil {
+		return "uint32(0)", fmt.Errorf("character has no keysym mapping: %c", c)
+	}
+	return keysym, nil
+}
+
+func requiresShift(s string) bool {
+	_, ok := shiftedKeysyms[s]
+	return ok
+}

internal/vnc/playback.go

@@ -209,10 +209,12 @@ func (p *playback) Stop() error {
 	defer p.Unlock()
 
 	if p.closed {
-		return errors.New("playback has already stopped")
+		log.Info("playback has already stopped for %v", p.ID)
+		return nil
 	}
 
 	close(p.signal)
+	close(p.done)
 	p.closed = true
 	log.Info("Finished playback on %v", p.ID)
 

internal/vnc/player.go

@@ -6,6 +6,7 @@ package vnc
 
 import (
 	"fmt"
+	"os"
 	"sync"
 
 	log "github.com/sandia-minimega/minimega/v2/pkg/minilog"
@@ -99,29 +100,71 @@ func (p *Player) reap() {
 // Creates a new VNC connection, the initial playback reader, and starts the
 // vnc playback
 func (p *Player) Playback(id, rhost, filename string) error {
+	_, err := p.playback(id, rhost, filename)
+	return err
+}
+
+func (p *Player) PlaybackString(id, rhost, str string) error {
+	if len(str) == 0 {
+		return nil
+	}
+
+	f, err := os.CreateTemp("", "mm_vnc_")
+	if err != nil {
+		return err
+	}
+
+	for _, char := range str {
+		keysym, err := asciiCharToKeysymString(char)
+		if err != nil {
+			return err
+		}
+		shift := requiresShift(keysym)
+		if shift {
+			f.WriteString("0:KeyEvent,true,Shift_L\n")
+		}
+		f.WriteString(fmt.Sprintf("0:KeyEvent,true,%s\n", keysym))
+		f.WriteString(fmt.Sprintf("0:KeyEvent,false,%s\n", keysym))
+		if shift {
+			f.WriteString("0:KeyEvent,false,Shift_L\n")
+		}
+	}
+	if err := f.Close(); err != nil {
+		return err
+	}
+
+	pb, err := p.playback(id, rhost, f.Name())
+
+	// remove file when playback is done
+	go func() {
+		<-pb.done
+		if err := os.Remove(f.Name()); err != nil {
+			log.Warn("Failed to delete temp file %s used for playback", f.Name())
+		}
+	}()
+
+	return err
+}
+
+func (p *Player) playback(id, rhost, filename string) (*playback, error) {
 	p.mu.Lock()
 	defer p.mu.Unlock()
-
 	// clear out any old playbacks
 	p.reap()
 
-	return p.playback(id, rhost, filename)
-}
-
-func (p *Player) playback(id, rhost, filename string) error {
 	// Is this playback already running?
 	if _, ok := p.m[id]; ok {
-		return fmt.Errorf("kb playback %v already playing", id)
+		return nil, fmt.Errorf("kb playback %v already playing", id)
 	}
 
 	pb, err := newPlayback(id, rhost)
 	if err != nil {
-		return err
+		return nil, err
 	}
 
 	p.m[pb.ID] = pb
 
-	return pb.Start(filename)
+	return pb, pb.Start(filename)
 }
 
 func (p *Player) Inject(id, rhost, s string) error {
@@ -157,7 +200,8 @@ func (p *Player) Inject(id, rhost, s string) error {
 	case *LoadFileEvent:
 		// This is an injected LoadFile event without a running playback. This is
 		// equivalent to starting a new vnc playback.
-		return p.playback(id, rhost, e.File)
+		_, err := p.playback(id, rhost, e.File)
+		return err
 	case *WaitForItEvent:
 		return fmt.Errorf("unhandled inject event for non-running playback: %T", e)
 	default:

internal/vnc/protocol.go

@@ -87,7 +87,7 @@ type PointerEvent struct {
 
 type _ClientCutText struct {
 	_      [3]byte // Padding
-	Length uint32  // Length of Text
+	Length int32   // Length of Text. Signed for extended pseudo-encoding
 }
 
 // See RFC 6143 Section 7.5.6
@@ -186,7 +186,7 @@ func (m *PointerEvent) Write(w io.Writer) error {
 
 func (m *ClientCutText) Write(w io.Writer) error {
 	// Ensure length is set correctly
-	m.Length = uint32(len(m.Text))
+	m.Length = int32(len(m.Text))
 
 	if err := writeMessage(w, TypeClientCutText, m._ClientCutText); err != nil {
 		return err