// ReadPassword reads a line of input from a terminal without local echo. This
// is commonly used for inputting passwords and other sensitive data. The slice
// returned does not include the \n.
func ReadPassword(fd int) ([]byte, error) {
var oldState syscall.Termios
if e := syscall.Tcgetattr(fd, &oldState); e != 0 {
return nil, os.Errno(e)
}
newState := oldState
newState.Lflag &^= syscall.ECHO
if e := syscall.Tcsetattr(fd, syscall.TCSANOW, &newState); e != 0 {
return nil, os.Errno(e)
}
defer func() {
syscall.Tcsetattr(fd, syscall.TCSANOW, &oldState)
}()
var buf [16]byte
var ret []byte
for {
n, errno := syscall.Read(fd, buf[:])
if errno != 0 {
return nil, os.Errno(errno)
}
if n == 0 {
if len(ret) == 0 {
return nil, io.EOF
}
break
}
if buf[n-1] == '\n' {
n--
}
ret = append(ret, buf[:n]...)
if n < len(buf) {
break
}
}
return ret, nil
}
// MakeRaw put the terminal connected to the given file descriptor into raw
// mode and returns the previous state of the terminal so that it can be
// restored.
func MakeRaw(fd int) (*State, error) {
var oldState State
if e := syscall.Tcgetattr(fd, &oldState.termios); e != 0 {
return nil, os.Errno(e)
}
newState := oldState.termios
newState.Iflag &^= syscall.ISTRIP | syscall.INLCR | syscall.ICRNL | syscall.IGNCR | syscall.IXON | syscall.IXOFF
newState.Lflag &^= syscall.ECHO | syscall.ICANON | syscall.ISIG
if e := syscall.Tcsetattr(fd, syscall.TCSANOW, &newState); e != 0 {
return nil, os.Errno(e)
}
return &oldState, nil
}
// Restore restores the terminal connected to the given file descriptor to a
// previous state.
func Restore(fd int, state *State) error {
e := syscall.Tcsetattr(fd, syscall.TCSANOW, &state.termios)
return os.Errno(e)
}