func rawConnectionFromSerial() (net.Conn, error) {
log.Info("opening ttyS0 for backchannel")
f, err := os.OpenFile(pathPrefix+"/ttyS0", os.O_RDWR|os.O_SYNC|syscall.O_NOCTTY, backchannelMode)
if err != nil {
detail := fmt.Errorf("failed to open serial port for backchannel: %s", err)
log.Error(detail)
return nil, detail
}
// set the provided FDs to raw if it's a termial
// 0 is the uninitialized value for Fd
if f.Fd() != 0 && terminal.IsTerminal(int(f.Fd())) {
log.Debug("setting terminal to raw mode")
s, err := terminal.MakeRaw(int(f.Fd()))
if err != nil {
return nil, err
}
log.Infof("s = %#v", s)
}
var conn net.Conn
log.Infof("creating raw connection from ttyS0 (fd=%d)", f.Fd())
conn, err = serial.NewFileConn(f)
return conn, err
}
func (t *attachServerSSH) Start() error {
defer trace.End(trace.Begin(""))
var err error
rand.Reader, err = os.Open(pathPrefix + "/urandom")
if err != nil {
detail := fmt.Sprintf("failed to open new urandom device: %s", err)
log.Error(detail)
return errors.New(detail)
}
log.Info("opening ttyS0 for backchannel")
f, err := os.OpenFile(pathPrefix+"/ttyS0", os.O_RDWR|os.O_SYNC|syscall.O_NOCTTY, backchannelMode)
if err != nil {
detail := fmt.Sprintf("failed to open serial port for backchannel: %s", err)
log.Error(detail)
return errors.New(detail)
}
// set the provided FDs to raw if it's a termial
// 0 is the uninitialized value for Fd
if f.Fd() != 0 && terminal.IsTerminal(int(f.Fd())) {
log.Debug("setting terminal to raw mode")
s, err := terminal.MakeRaw(int(f.Fd()))
if err != nil {
return err
}
log.Infof("s = %#v", s)
}
log.Infof("creating raw connection from ttyS0 (fd=%d)\n", f.Fd())
var conn net.Conn
conn, err = serial.NewFileConn(f)
if err != nil {
detail := fmt.Sprintf("failed to create raw connection from ttyS0 file handle: %s", err)
log.Error(detail)
return errors.New(detail)
}
t.conn = &conn
return nil
}