1 // Copyright 2011 The Go Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style
3 // license that can be found in the LICENSE file.
5 // +build darwin dragonfly freebsd linux,!appengine netbsd openbsd
7 // Package terminal provides support functions for dealing with terminals, as
8 // commonly found on UNIX systems.
10 // Putting a terminal into raw mode is the most common requirement:
12 // oldState, err := terminal.MakeRaw(0)
16 // defer terminal.Restore(0, oldState)
17 package terminal // import "golang.org/x/crypto/ssh/terminal"
24 // State contains the state of a terminal.
26 termios syscall.Termios
29 // IsTerminal returns true if the given file descriptor is a terminal.
30 func IsTerminal(fd int) bool {
31 var termios syscall.Termios
32 _, _, err := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), ioctlReadTermios, uintptr(unsafe.Pointer(&termios)), 0, 0, 0)
36 // MakeRaw put the terminal connected to the given file descriptor into raw
37 // mode and returns the previous state of the terminal so that it can be
39 func MakeRaw(fd int) (*State, error) {
41 if _, _, err := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), ioctlReadTermios, uintptr(unsafe.Pointer(&oldState.termios)), 0, 0, 0); err != 0 {
45 newState := oldState.termios
46 // This attempts to replicate the behaviour documented for cfmakeraw in
47 // the termios(3) manpage.
48 newState.Iflag &^= syscall.IGNBRK | syscall.BRKINT | syscall.PARMRK | syscall.ISTRIP | syscall.INLCR | syscall.IGNCR | syscall.ICRNL | syscall.IXON
49 newState.Oflag &^= syscall.OPOST
50 newState.Lflag &^= syscall.ECHO | syscall.ECHONL | syscall.ICANON | syscall.ISIG | syscall.IEXTEN
51 newState.Cflag &^= syscall.CSIZE | syscall.PARENB
52 newState.Cflag |= syscall.CS8
53 if _, _, err := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), ioctlWriteTermios, uintptr(unsafe.Pointer(&newState)), 0, 0, 0); err != 0 {
60 // GetState returns the current state of a terminal which may be useful to
61 // restore the terminal after a signal.
62 func GetState(fd int) (*State, error) {
64 if _, _, err := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), ioctlReadTermios, uintptr(unsafe.Pointer(&oldState.termios)), 0, 0, 0); err != 0 {
71 // Restore restores the terminal connected to the given file descriptor to a
73 func Restore(fd int, state *State) error {
74 if _, _, err := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), ioctlWriteTermios, uintptr(unsafe.Pointer(&state.termios)), 0, 0, 0); err != 0 {
80 // GetSize returns the dimensions of the given terminal.
81 func GetSize(fd int) (width, height int, err error) {
82 var dimensions [4]uint16
84 if _, _, err := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), uintptr(syscall.TIOCGWINSZ), uintptr(unsafe.Pointer(&dimensions)), 0, 0, 0); err != 0 {
87 return int(dimensions[1]), int(dimensions[0]), nil
90 // passwordReader is an io.Reader that reads from a specific file descriptor.
91 type passwordReader int
93 func (r passwordReader) Read(buf []byte) (int, error) {
94 return syscall.Read(int(r), buf)
97 // ReadPassword reads a line of input from a terminal without local echo. This
98 // is commonly used for inputting passwords and other sensitive data. The slice
99 // returned does not include the \n.
100 func ReadPassword(fd int) ([]byte, error) {
101 var oldState syscall.Termios
102 if _, _, err := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), ioctlReadTermios, uintptr(unsafe.Pointer(&oldState)), 0, 0, 0); err != 0 {
107 newState.Lflag &^= syscall.ECHO
108 newState.Lflag |= syscall.ICANON | syscall.ISIG
109 newState.Iflag |= syscall.ICRNL
110 if _, _, err := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), ioctlWriteTermios, uintptr(unsafe.Pointer(&newState)), 0, 0, 0); err != 0 {
115 syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), ioctlWriteTermios, uintptr(unsafe.Pointer(&oldState)), 0, 0, 0)
118 return readPasswordLine(passwordReader(fd))