| // Copyright 2011 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| // +build linux |
| |
| // Package terminal provides support functions for dealing with terminals, as |
| // commonly found on UNIX systems. |
| // |
| // Putting a terminal into raw mode is the most common requirement: |
| // |
| // oldState, err := terminal.MakeRaw(0) |
| // if err != nil { |
| // panic(err) |
| // } |
| // defer terminal.Restore(0, oldState) |
| package terminal |
| |
| import ( |
| "io" |
| "syscall" |
| "unsafe" |
| ) |
| |
| // State contains the state of a terminal. |
| type State struct { |
| termios syscall.Termios |
| } |
| |
| // IsTerminal returns true if the given file descriptor is a terminal. |
| func IsTerminal(fd int) bool { |
| var termios syscall.Termios |
| err := syscall.Tcgetattr(fd, &termios) |
| return err == 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 err := syscall.Tcgetattr(fd, &oldState.termios); err != nil { |
| return nil, err |
| } |
| |
| 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 err := syscall.Tcsetattr(fd, syscall.TCSANOW, &newState); err != nil { |
| return nil, err |
| } |
| |
| return &oldState, nil |
| } |
| |
| // Restore restores the terminal connected to the given file descriptor to a |
| // previous state. |
| func Restore(fd int, state *State) error { |
| err := syscall.Tcsetattr(fd, syscall.TCSANOW, &state.termios) |
| return err |
| } |
| |
| //extern ioctl |
| func ioctl(int, int, unsafe.Pointer) int |
| |
| // GetSize returns the dimensions of the given terminal. |
| func GetSize(fd int) (width, height int, err error) { |
| var dimensions [4]uint16 |
| |
| if ioctl(fd, syscall.TIOCGWINSZ, unsafe.Pointer(&dimensions)) < 0 { |
| return -1, -1, syscall.GetErrno() |
| } |
| return int(dimensions[1]), int(dimensions[0]), nil |
| } |
| |
| // 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 err := syscall.Tcgetattr(fd, &oldState); err != nil { |
| return nil, err |
| } |
| |
| newState := oldState |
| newState.Lflag &^= syscall.ECHO |
| if err := syscall.Tcsetattr(fd, syscall.TCSANOW, &newState); err != nil { |
| return nil, err |
| } |
| |
| defer func() { |
| syscall.Tcsetattr(fd, syscall.TCSANOW, &oldState) |
| }() |
| |
| var buf [16]byte |
| var ret []byte |
| for { |
| n, err := syscall.Read(fd, buf[:]) |
| if err != nil { |
| return nil, err |
| } |
| 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 |
| } |