1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
|
package virtwriter
import (
"bufio"
"encoding/binary"
"encoding/json"
"io"
"github.com/pkg/errors"
"k8s.io/client-go/tools/remotecommand"
)
// SocketDest is the "key" to where IO should go on the varlink
// multiplexed socket
type SocketDest int
const (
// ToStdout indicates traffic should go stdout
ToStdout SocketDest = iota
// ToStdin indicates traffic came from stdin
ToStdin SocketDest = iota
// ToStderr indicates traffuc should go to stderr
ToStderr SocketDest = iota
// TerminalResize indicates a terminal resize event has occurred
// and data should be passed to resizer
TerminalResize SocketDest = iota
// Quit and detach
Quit SocketDest = iota
)
// IntToSocketDest returns a socketdest based on integer input
func IntToSocketDest(i int) SocketDest {
switch i {
case ToStdout.Int():
return ToStdout
case ToStderr.Int():
return ToStderr
case ToStdin.Int():
return ToStdin
case TerminalResize.Int():
return TerminalResize
case Quit.Int():
return Quit
default:
return ToStderr
}
}
// Int returns the integer representation of the socket dest
func (sd SocketDest) Int() int {
return int(sd)
}
// VirtWriteCloser are writers for attach which include the dest
// of the data
type VirtWriteCloser struct {
writer *bufio.Writer
dest SocketDest
}
// NewVirtWriteCloser is a constructor
func NewVirtWriteCloser(w *bufio.Writer, dest SocketDest) VirtWriteCloser {
return VirtWriteCloser{w, dest}
}
// Close is a required method for a writecloser
func (v VirtWriteCloser) Close() error {
return nil
}
// Write prepends a header to the input message. The header is
// 8bytes. Position one contains the destination. Positions
// 5,6,7,8 are a big-endian encoded uint32 for len of the message.
func (v VirtWriteCloser) Write(input []byte) (int, error) {
header := []byte{byte(v.dest), 0, 0, 0}
// Go makes us define the byte for big endian
mlen := make([]byte, 4)
binary.BigEndian.PutUint32(mlen, uint32(len(input)))
// append the message len to the header
msg := append(header, mlen...)
// append the message to the header
msg = append(msg, input...)
_, err := v.writer.Write(msg)
if err != nil {
return 0, err
}
err = v.writer.Flush()
return len(input), err
}
// Reader decodes the content that comes over the wire and directs it to the proper destination.
func Reader(r *bufio.Reader, output, errput, input io.Writer, resize chan remotecommand.TerminalSize, execEcChan chan int) error {
var messageSize int64
headerBytes := make([]byte, 8)
if r == nil {
return errors.Errorf("Reader must not be nil")
}
for {
n, err := io.ReadFull(r, headerBytes)
if err != nil {
return errors.Wrapf(err, "Virtual Read failed, %d", n)
}
if n < 8 {
return errors.New("short read and no full header read")
}
messageSize = int64(binary.BigEndian.Uint32(headerBytes[4:8]))
switch IntToSocketDest(int(headerBytes[0])) {
case ToStdout:
if output != nil {
_, err := io.CopyN(output, r, messageSize)
if err != nil {
return errors.Wrapf(err, "issue stdout")
}
}
case ToStderr:
if errput != nil {
_, err := io.CopyN(errput, r, messageSize)
if err != nil {
return err
return errors.Wrapf(err, "issue stderr")
}
}
case ToStdin:
if input != nil {
_, err := io.CopyN(input, r, messageSize)
if err != nil {
return errors.Wrapf(err, "issue stdin")
}
}
case TerminalResize:
if resize != nil {
out := make([]byte, messageSize)
if messageSize > 0 {
_, err = io.ReadFull(r, out)
if err != nil {
return errors.Wrapf(err, "issue resizing")
}
}
// Resize events come over in bytes, need to be reserialized
resizeEvent := remotecommand.TerminalSize{}
if err := json.Unmarshal(out, &resizeEvent); err != nil {
return errors.Wrapf(err, "issue resizing")
}
resize <- resizeEvent
}
case Quit:
out := make([]byte, messageSize)
if messageSize > 0 {
_, err = io.ReadFull(r, out)
if err != nil {
return errors.Wrapf(err, "issue quitting")
}
}
if execEcChan != nil {
ecInt := binary.BigEndian.Uint32(out)
execEcChan <- int(ecInt)
}
return nil
default:
// Something really went wrong
return errors.New("unknown multiplex destination")
}
}
}
// HangUp sends message to peer to close connection
func HangUp(writer *bufio.Writer, ec int) (err error) {
n := 0
msg := make([]byte, 4)
binary.BigEndian.PutUint32(msg, uint32(ec))
writeQuit := NewVirtWriteCloser(writer, Quit)
if n, err = writeQuit.Write(msg); err != nil {
return
}
if n != len(msg) {
return errors.Errorf("Failed to send complete %s message", string(msg))
}
return
}
|
