aboutsummaryrefslogtreecommitdiff
path: root/libpod/container_attach.go
blob: 40d359ddd7d22445630caf3847253adc70297afc (plain)
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
190
package libpod

import (
	"fmt"
	"io"
	"net"
	"os"
	gosignal "os/signal"
	"path/filepath"

	"github.com/docker/docker/pkg/signal"
	"github.com/docker/docker/pkg/term"
	"github.com/pkg/errors"
	"github.com/projectatomic/libpod/pkg/kubeutils"
	"github.com/projectatomic/libpod/utils"
	"github.com/sirupsen/logrus"
	"golang.org/x/crypto/ssh/terminal"
	"golang.org/x/sys/unix"
	"k8s.io/client-go/tools/remotecommand"
)

/* Sync with stdpipe_t in conmon.c */
const (
	AttachPipeStdin  = 1
	AttachPipeStdout = 2
	AttachPipeStderr = 3
)

// resizeTty handles TTY resizing for Attach()
func resizeTty(resize chan remotecommand.TerminalSize) {
	sigchan := make(chan os.Signal, 1)
	gosignal.Notify(sigchan, signal.SIGWINCH)
	sendUpdate := func() {
		winsize, err := term.GetWinsize(os.Stdin.Fd())
		if err != nil {
			logrus.Warnf("Could not get terminal size %v", err)
			return
		}
		resize <- remotecommand.TerminalSize{
			Width:  winsize.Width,
			Height: winsize.Height,
		}
	}
	go func() {
		defer close(resize)
		// Update the terminal size immediately without waiting
		// for a SIGWINCH to get the correct initial size.
		sendUpdate()
		for range sigchan {
			sendUpdate()
		}
	}()
}

func (c *Container) attach(noStdin bool, keys string) error {
	// Check the validity of the provided keys first
	var err error
	detachKeys := []byte{}
	if len(keys) > 0 {
		detachKeys, err = term.ToBytes(keys)
		if err != nil {
			return errors.Wrapf(err, "invalid detach keys")
		}
	}

	// TODO: allow resize channel to be passed in for CRI-O use
	resize := make(chan remotecommand.TerminalSize)
	if terminal.IsTerminal(int(os.Stdin.Fd())) {
		resizeTty(resize)
	} else {
		defer close(resize)
	}

	logrus.Debugf("Attaching to container %s", c.ID())

	return c.attachContainerSocket(resize, noStdin, detachKeys)
}

// attachContainerSocket connects to the container's attach socket and deals with the IO
// TODO add a channel to allow interruptiong
func (c *Container) attachContainerSocket(resize <-chan remotecommand.TerminalSize, noStdIn bool, detachKeys []byte) error {
	inputStream := os.Stdin
	outputStream := os.Stdout
	errorStream := os.Stderr
	defer inputStream.Close()
	if terminal.IsTerminal(int(inputStream.Fd())) {
		oldTermState, err := term.SaveState(inputStream.Fd())
		if err != nil {
			return errors.Wrapf(err, "unable to save terminal state")
		}

		defer term.RestoreTerminal(inputStream.Fd(), oldTermState)
	}

	// Put both input and output into raw when we have a terminal
	if !noStdIn && c.config.Spec.Process.Terminal {
		term.SetRawTerminal(inputStream.Fd())
	}

	kubeutils.HandleResizing(resize, func(size remotecommand.TerminalSize) {
		controlPath := filepath.Join(c.bundlePath(), "ctl")
		controlFile, err := os.OpenFile(controlPath, unix.O_WRONLY, 0)
		if err != nil {
			logrus.Debugf("Could not open ctl file: %v", err)
			return
		}
		defer controlFile.Close()

		logrus.Debugf("Received a resize event: %+v", size)
		if _, err = fmt.Fprintf(controlFile, "%d %d %d\n", 1, size.Height, size.Width); err != nil {
			logrus.Warnf("Failed to write to control file to resize terminal: %v", err)
		}
	})
	logrus.Debug("connecting to socket ", c.attachSocketPath())

	conn, err := net.DialUnix("unixpacket", nil, &net.UnixAddr{Name: c.attachSocketPath(), Net: "unixpacket"})
	if err != nil {
		return errors.Wrapf(err, "failed to connect to container's attach socket: %v")
	}
	defer conn.Close()

	receiveStdoutError := make(chan error)
	if outputStream != nil || errorStream != nil {
		go func() {
			receiveStdoutError <- redirectResponseToOutputStreams(outputStream, errorStream, conn)
		}()
	}

	stdinDone := make(chan error)
	go func() {
		var err error
		if inputStream != nil && !noStdIn {
			_, err = utils.CopyDetachable(conn, inputStream, detachKeys)
			conn.CloseWrite()
		}
		stdinDone <- err
	}()

	select {
	case err := <-receiveStdoutError:
		return err
	case err := <-stdinDone:
		if _, ok := err.(utils.DetachError); ok {
			return nil
		}
		if outputStream != nil || errorStream != nil {
			return <-receiveStdoutError
		}
	}
	return nil
}

func redirectResponseToOutputStreams(outputStream, errorStream io.Writer, conn io.Reader) error {
	var err error
	buf := make([]byte, 8192+1) /* Sync with conmon STDIO_BUF_SIZE */
	for {
		nr, er := conn.Read(buf)
		if nr > 0 {
			var dst io.Writer
			switch buf[0] {
			case AttachPipeStdout:
				dst = outputStream
			case AttachPipeStderr:
				dst = errorStream
			default:
				logrus.Infof("Received unexpected attach type %+d", buf[0])
			}

			if dst != nil {
				nw, ew := dst.Write(buf[1:nr])
				if ew != nil {
					err = ew
					break
				}
				if nr != nw+1 {
					err = io.ErrShortWrite
					break
				}
			}
		}
		if er == io.EOF {
			break
		}
		if er != nil {
			err = er
			break
		}
	}
	return err
}