// 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. // 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.String()) // } // defer terminal.Restore(0, oldState) package terminal import ( "os" "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 _, _, e := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), uintptr(syscall.TCGETS), uintptr(unsafe.Pointer(&termios)), 0, 0, 0) return e == 0 } // 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, os.Error) { var oldState State if _, _, e := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), uintptr(syscall.TCGETS), uintptr(unsafe.Pointer(&oldState.termios)), 0, 0, 0); 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.Syscall6(syscall.SYS_IOCTL, uintptr(fd), uintptr(syscall.TCSETS), uintptr(unsafe.Pointer(&newState)), 0, 0, 0); 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) os.Error { _, _, e := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), uintptr(syscall.TCSETS), uintptr(unsafe.Pointer(&state.termios)), 0, 0, 0) return os.Errno(e) } // 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, os.Error) { var oldState syscall.Termios if _, _, e := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), uintptr(syscall.TCGETS), uintptr(unsafe.Pointer(&oldState)), 0, 0, 0); e != 0 { return nil, os.Errno(e) } newState := oldState newState.Lflag &^= syscall.ECHO if _, _, e := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), uintptr(syscall.TCSETS), uintptr(unsafe.Pointer(&newState)), 0, 0, 0); e != 0 { return nil, os.Errno(e) } defer func() { syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), uintptr(syscall.TCSETS), uintptr(unsafe.Pointer(&oldState)), 0, 0, 0) }() 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, os.EOF } break } if buf[n-1] == '\n' { n-- } ret = append(ret, buf[:n]...) if n < len(buf) { break } } return ret, nil }