// HandleChannel handles one SSH channel
func (c *Client) HandleChannel(newChannel ssh.NewChannel) error {
if newChannel.ChannelType() != "session" {
logrus.Debugf("Unknown channel type: %s", newChannel.ChannelType())
newChannel.Reject(ssh.UnknownChannelType, "unknown channel type")
return nil
}
channel, requests, err := newChannel.Accept()
if err != nil {
logrus.Errorf("newChannel.Accept failed: %v", err)
return err
}
c.ChannelIdx++
logrus.Debugf("HandleChannel.channel (client=%d channel=%d): %v", c.Idx, c.ChannelIdx, channel)
logrus.Debug("Creating pty...")
f, tty, err := pty.Open()
if err != nil {
logrus.Errorf("pty.Open failed: %v", err)
return nil
}
c.Tty = tty
c.Pty = f
c.HandleChannelRequests(channel, requests)
return nil
}
// HandleChannelRequests handles channel requests
func (c *Client) HandleChannelRequests(channel ssh.Channel, requests <-chan *ssh.Request) {
go func(in <-chan *ssh.Request) {
defer c.Tty.Close()
for req := range in {
ok := false
switch req.Type {
case "shell":
logrus.Debugf("HandleChannelRequests.req shell")
if len(req.Payload) != 0 {
break
}
ok = true
var cmd *exec.Cmd
var err error
if c.Config.IsLocal {
cmd = exec.Command("/bin/bash")
} else {
// checking if a container already exists for this user
existingContainer := ""
if !c.Server.NoJoin {
cmd := exec.Command("docker", "ps", "--filter=label=ssh2docker", fmt.Sprintf("--filter=label=image=%s", c.Config.ImageName), fmt.Sprintf("--filter=label=user=%s", c.Config.RemoteUser), "--quiet", "--no-trunc")
cmd.Env = c.Config.Env.List()
buf, err := cmd.CombinedOutput()
if err != nil {
logrus.Warnf("docker ps ... failed: %v", err)
continue
}
existingContainer = strings.TrimSpace(string(buf))
}
// Opening Docker process
if existingContainer != "" {
// Attaching to an existing container
shell := c.Server.DefaultShell
if c.Config.EntryPoint != "" {
shell = c.Config.EntryPoint
}
args := []string{"exec", "-it", existingContainer, shell}
logrus.Debugf("Executing 'docker %s'", strings.Join(args, " "))
cmd = exec.Command("docker", args...)
cmd.Env = c.Config.Env.List()
} else {
// Creating and attaching to a new container
args := []string{"run"}
args = append(args, c.Server.DockerRunArgs...)
args = append(args, "--label=ssh2docker", fmt.Sprintf("--label=user=%s", c.Config.RemoteUser), fmt.Sprintf("--label=image=%s", c.Config.ImageName))
if c.Config.User != "" {
args = append(args, "-u", c.Config.User)
}
if c.Config.EntryPoint != "" {
args = append(args, "--entrypoint", c.Config.EntryPoint)
}
args = append(args, c.Config.ImageName)
if c.Config.Command != nil {
args = append(args, c.Config.Command...)
} else {
args = append(args, c.Server.DefaultShell)
}
logrus.Debugf("Executing 'docker %s'", strings.Join(args, " "))
cmd = exec.Command("docker", args...)
cmd.Env = c.Config.Env.List()
}
}
if c.Server.Banner != "" {
banner := c.Server.Banner
banner = strings.Replace(banner, "\r", "", -1)
banner = strings.Replace(banner, "\n", "\n\r", -1)
fmt.Fprintf(channel, "%s\n\r", banner)
}
cmd.Stdout = c.Tty
cmd.Stdin = c.Tty
cmd.Stderr = c.Tty
cmd.SysProcAttr = &syscall.SysProcAttr{
Setctty: true,
Setsid: true,
}
err = cmd.Start()
if err != nil {
logrus.Warnf("cmd.Start failed: %v", err)
continue
}
var once sync.Once
close := func() {
channel.Close()
logrus.Debug("session closed")
}
go func() {
io.Copy(channel, c.Pty)
once.Do(close)
}()
go func() {
io.Copy(c.Pty, channel)
once.Do(close)
}()
go func() {
if err := cmd.Wait(); err != nil {
logrus.Warnf("cmd.Wait failed: %v", err)
}
once.Do(close)
}()
case "exec":
command := string(req.Payload)
logrus.Debugf("HandleChannelRequests.req exec: %q", command)
ok = false
fmt.Fprintln(channel, "⚠️ ssh2docker: exec is not yet implemented. https://github.com/moul/ssh2docker/issues/51.")
time.Sleep(3 * time.Second)
case "pty-req":
ok = true
termLen := req.Payload[3]
c.Config.Env["TERM"] = string(req.Payload[4 : termLen+4])
w, h := parseDims(req.Payload[termLen+4:])
SetWinsize(c.Pty.Fd(), w, h)
logrus.Debugf("HandleChannelRequests.req pty-req: TERM=%q w=%q h=%q", c.Config.Env["TERM"], int(w), int(h))
case "window-change":
w, h := parseDims(req.Payload)
SetWinsize(c.Pty.Fd(), w, h)
continue
case "env":
keyLen := req.Payload[3]
key := string(req.Payload[4 : keyLen+4])
valueLen := req.Payload[keyLen+7]
value := string(req.Payload[keyLen+8 : keyLen+8+valueLen])
logrus.Debugf("HandleChannelRequets.req 'env': %s=%q", key, value)
c.Config.Env[key] = value
default:
logrus.Debugf("Unhandled request type: %q: %v", req.Type, req)
}
if req.WantReply {
if !ok {
logrus.Debugf("Declining %s request...", req.Type)
}
req.Reply(ok, nil)
}
}
}(requests)
}