474 lines
10 KiB
Go
474 lines
10 KiB
Go
package gottyclient
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import (
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"crypto/tls"
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"encoding/base64"
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"encoding/json"
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"fmt"
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"io"
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"io/ioutil"
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"net/http"
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"net/url"
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"os"
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"regexp"
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"strings"
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"sync"
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"time"
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"github.com/creack/goselect"
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"github.com/gorilla/websocket"
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"github.com/sirupsen/logrus"
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"golang.org/x/crypto/ssh/terminal"
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)
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// GetAuthTokenURL transforms a GoTTY http URL to its AuthToken file URL
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func GetAuthTokenURL(httpURL string) (*url.URL, *http.Header, error) {
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header := http.Header{}
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target, err := url.Parse(httpURL)
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if err != nil {
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return nil, nil, err
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}
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target.Path = strings.TrimLeft(target.Path+"auth_token.js", "/")
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if target.User != nil {
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header.Add("Authorization", "Basic "+base64.StdEncoding.EncodeToString([]byte(target.User.String())))
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target.User = nil
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}
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return target, &header, nil
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}
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// GetURLQuery returns url.query
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func GetURLQuery(rawurl string) (url.Values, error) {
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target, err := url.Parse(rawurl)
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if err != nil {
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return nil, err
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}
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return target.Query(), nil
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}
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// GetWebsocketURL transforms a GoTTY http URL to its WebSocket URL
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func GetWebsocketURL(httpURL string) (*url.URL, *http.Header, error) {
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header := http.Header{}
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target, err := url.Parse(httpURL)
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if err != nil {
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return nil, nil, err
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}
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if target.Scheme == "https" {
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target.Scheme = "wss"
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} else {
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target.Scheme = "ws"
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}
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target.Path = strings.TrimLeft(target.Path+"ws", "/")
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if target.User != nil {
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header.Add("Authorization", "Basic "+base64.StdEncoding.EncodeToString([]byte(target.User.String())))
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target.User = nil
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}
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return target, &header, nil
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}
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type Client struct {
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Dialer *websocket.Dialer
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Conn *websocket.Conn
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URL string
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WriteMutex *sync.Mutex
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Output io.Writer
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poison chan bool
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SkipTLSVerify bool
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UseProxyFromEnv bool
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Connected bool
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EscapeKeys []byte
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}
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type querySingleType struct {
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AuthToken string `json:"AuthToken"`
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Arguments string `json:"Arguments"`
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}
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func (c *Client) write(data []byte) error {
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c.WriteMutex.Lock()
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defer c.WriteMutex.Unlock()
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return c.Conn.WriteMessage(websocket.TextMessage, data)
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}
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// GetAuthToken retrieves an Auth Token from dynamic auth_token.js file
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func (c *Client) GetAuthToken() (string, error) {
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target, header, err := GetAuthTokenURL(c.URL)
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if err != nil {
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return "", err
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}
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logrus.Debugf("Fetching auth token auth-token: %q", target.String())
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req, err := http.NewRequest("GET", target.String(), nil)
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req.Header = *header
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tr := &http.Transport{}
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if c.SkipTLSVerify {
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conf := &tls.Config{InsecureSkipVerify: true}
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tr.TLSClientConfig = conf
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}
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if c.UseProxyFromEnv {
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tr.Proxy = http.ProxyFromEnvironment
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}
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client := &http.Client{Transport: tr}
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resp, err := client.Do(req)
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if err != nil {
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return "", err
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}
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switch resp.StatusCode {
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case 200:
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// Everything is OK
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default:
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return "", fmt.Errorf("unknown status code: %d (%s)", resp.StatusCode, http.StatusText(resp.StatusCode))
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}
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defer resp.Body.Close()
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body, err := ioutil.ReadAll(resp.Body)
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if err != nil {
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return "", err
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}
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re := regexp.MustCompile("var gotty_auth_token = '(.*)'")
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output := re.FindStringSubmatch(string(body))
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if len(output) == 0 {
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return "", fmt.Errorf("Cannot fetch GoTTY auth-token, please upgrade your GoTTY server.")
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}
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return output[1], nil
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}
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// Connect tries to dial a websocket server
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func (c *Client) Connect() error {
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// Retrieve AuthToken
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authToken, err := c.GetAuthToken()
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if err != nil {
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return err
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}
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logrus.Debugf("Auth-token: %q", authToken)
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// Open WebSocket connection
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target, header, err := GetWebsocketURL(c.URL)
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if err != nil {
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return err
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}
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logrus.Debugf("Connecting to websocket: %q", target.String())
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if c.SkipTLSVerify {
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c.Dialer.TLSClientConfig = &tls.Config{InsecureSkipVerify: true}
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}
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if c.UseProxyFromEnv {
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c.Dialer.Proxy = http.ProxyFromEnvironment
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}
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conn, _, err := c.Dialer.Dial(target.String(), *header)
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if err != nil {
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return err
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}
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c.Conn = conn
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c.Connected = true
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// Pass arguments and auth-token
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query, err := GetURLQuery(c.URL)
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if err != nil {
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return err
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}
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querySingle := querySingleType{
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Arguments: "?" + query.Encode(),
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AuthToken: authToken,
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}
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json, err := json.Marshal(querySingle)
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if err != nil {
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logrus.Errorf("Failed to parse init message %v", err)
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return err
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}
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// Send Json
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logrus.Debugf("Sending arguments and auth-token")
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err = c.write(json)
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if err != nil {
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return err
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}
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go c.pingLoop()
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return nil
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}
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func (c *Client) pingLoop() {
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for {
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logrus.Debugf("Sending ping")
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c.write([]byte("1"))
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time.Sleep(30 * time.Second)
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}
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}
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// Close will nicely close the dialer
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func (c *Client) Close() {
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c.Conn.Close()
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}
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// ExitLoop will kill all goroutines launched by c.Loop()
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// ExitLoop() -> wait Loop() -> Close()
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func (c *Client) ExitLoop() {
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fname := "ExitLoop"
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openPoison(fname, c.poison)
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}
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// Loop will look indefinitely for new messages
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func (c *Client) Loop() error {
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if !c.Connected {
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err := c.Connect()
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if err != nil {
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return err
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}
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}
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wg := &sync.WaitGroup{}
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wg.Add(1)
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go c.termsizeLoop(wg)
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wg.Add(1)
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go c.readLoop(wg)
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wg.Add(1)
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go c.writeLoop(wg)
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/* Wait for all of the above goroutines to finish */
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wg.Wait()
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logrus.Debug("Client.Loop() exiting")
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return nil
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}
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type winsize struct {
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Rows uint16 `json:"rows"`
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Columns uint16 `json:"columns"`
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// unused
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x uint16
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y uint16
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}
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type posionReason int
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const (
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committedSuicide = iota
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killed
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)
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func openPoison(fname string, poison chan bool) posionReason {
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logrus.Debug(fname + " suicide")
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/*
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* The close() may raise panic if multiple goroutines commit suicide at the
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* same time. Prevent that panic from bubbling up.
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*/
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defer func() {
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if r := recover(); r != nil {
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logrus.Debug("Prevented panic() of simultaneous suicides", r)
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}
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}()
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/* Signal others to die */
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close(poison)
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return committedSuicide
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}
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func die(fname string, poison chan bool) posionReason {
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logrus.Debug(fname + " died")
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wasOpen := <-poison
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if wasOpen {
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logrus.Error("ERROR: The channel was open when it wasn't suppoed to be")
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}
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return killed
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}
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func (c *Client) termsizeLoop(wg *sync.WaitGroup) posionReason {
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defer wg.Done()
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fname := "termsizeLoop"
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ch := make(chan os.Signal, 1)
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notifySignalSIGWINCH(ch)
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defer resetSignalSIGWINCH()
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for {
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if b, err := syscallTIOCGWINSZ(); err != nil {
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logrus.Warn(err)
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} else {
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if err = c.write(append([]byte("2"), b...)); err != nil {
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logrus.Warnf("ws.WriteMessage failed: %v", err)
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}
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}
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select {
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case <-c.poison:
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/* Somebody poisoned the well; die */
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return die(fname, c.poison)
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case <-ch:
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}
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}
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}
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type exposeFd interface {
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Fd() uintptr
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}
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func (c *Client) writeLoop(wg *sync.WaitGroup) posionReason {
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defer wg.Done()
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fname := "writeLoop"
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buff := make([]byte, 128)
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oldState, err := terminal.MakeRaw(0)
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if err == nil {
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defer terminal.Restore(0, oldState)
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}
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rdfs := &goselect.FDSet{}
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reader := io.ReadCloser(os.Stdin)
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pr := NewEscapeProxy(reader, c.EscapeKeys)
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defer reader.Close()
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for {
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select {
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case <-c.poison:
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/* Somebody poisoned the well; die */
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return die(fname, c.poison)
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default:
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}
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rdfs.Zero()
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rdfs.Set(reader.(exposeFd).Fd())
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err := goselect.Select(1, rdfs, nil, nil, 50*time.Millisecond)
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if err != nil {
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return openPoison(fname, c.poison)
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}
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if rdfs.IsSet(reader.(exposeFd).Fd()) {
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size, err := pr.Read(buff)
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if err != nil {
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if err == io.EOF {
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// Send EOF to GoTTY
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// Send 'Input' marker, as defined in GoTTY::client_context.go,
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// followed by EOT (a translation of Ctrl-D for terminals)
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err = c.write(append([]byte("0"), byte(4)))
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if err != nil {
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return openPoison(fname, c.poison)
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}
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continue
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} else {
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return openPoison(fname, c.poison)
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}
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}
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if size <= 0 {
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continue
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}
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data := buff[:size]
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err = c.write(append([]byte("0"), data...))
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if err != nil {
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return openPoison(fname, c.poison)
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}
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}
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}
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}
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func (c *Client) readLoop(wg *sync.WaitGroup) posionReason {
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defer wg.Done()
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fname := "readLoop"
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type MessageNonBlocking struct {
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Data []byte
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Err error
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}
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msgChan := make(chan MessageNonBlocking)
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for {
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go func() {
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_, data, err := c.Conn.ReadMessage()
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msgChan <- MessageNonBlocking{Data: data, Err: err}
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}()
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select {
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case <-c.poison:
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/* Somebody poisoned the well; die */
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return die(fname, c.poison)
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case msg := <-msgChan:
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if msg.Err != nil {
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if _, ok := msg.Err.(*websocket.CloseError); !ok {
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logrus.Warnf("c.Conn.ReadMessage: %v", msg.Err)
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}
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return openPoison(fname, c.poison)
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}
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if len(msg.Data) == 0 {
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logrus.Warnf("An error has occured")
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return openPoison(fname, c.poison)
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}
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switch msg.Data[0] {
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case '0': // data
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buf, err := base64.StdEncoding.DecodeString(string(msg.Data[1:]))
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if err != nil {
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logrus.Warnf("Invalid base64 content: %q", msg.Data[1:])
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break
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}
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c.Output.Write(buf)
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case '1': // pong
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case '2': // new title
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newTitle := string(msg.Data[1:])
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fmt.Fprintf(c.Output, "\033]0;%s\007", newTitle)
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case '3': // json prefs
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logrus.Debugf("Unhandled protocol message: json pref: %s", string(msg.Data[1:]))
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case '4': // autoreconnect
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logrus.Debugf("Unhandled protocol message: autoreconnect: %s", string(msg.Data))
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default:
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logrus.Warnf("Unhandled protocol message: %s", string(msg.Data))
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}
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}
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}
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}
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// SetOutput changes the output stream
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func (c *Client) SetOutput(w io.Writer) {
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c.Output = w
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}
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// ParseURL parses an URL which may be incomplete and tries to standardize it
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func ParseURL(input string) (string, error) {
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parsed, err := url.Parse(input)
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if err != nil {
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return "", err
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}
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switch parsed.Scheme {
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case "http", "https":
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// everything is ok
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default:
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return ParseURL(fmt.Sprintf("http://%s", input))
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}
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return parsed.String(), nil
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}
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// NewClient returns a GoTTY client object
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func NewClient(inputURL string) (*Client, error) {
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url, err := ParseURL(inputURL)
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if err != nil {
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return nil, err
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}
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return &Client{
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Dialer: &websocket.Dialer{},
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URL: url,
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WriteMutex: &sync.Mutex{},
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Output: os.Stdout,
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poison: make(chan bool),
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}, nil
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}
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