sslobodr | d046be8 | 2019-01-16 10:02:22 -0500 | [diff] [blame] | 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. |
| 4 | |
| 5 | // +build aix darwin dragonfly freebsd linux,!appengine netbsd openbsd |
| 6 | |
| 7 | // Package terminal provides support functions for dealing with terminals, as |
| 8 | // commonly found on UNIX systems. |
| 9 | // |
| 10 | // Putting a terminal into raw mode is the most common requirement: |
| 11 | // |
| 12 | // oldState, err := terminal.MakeRaw(0) |
| 13 | // if err != nil { |
| 14 | // panic(err) |
| 15 | // } |
| 16 | // defer terminal.Restore(0, oldState) |
| 17 | package terminal // import "golang.org/x/crypto/ssh/terminal" |
| 18 | |
| 19 | import ( |
| 20 | "golang.org/x/sys/unix" |
| 21 | ) |
| 22 | |
| 23 | // State contains the state of a terminal. |
| 24 | type State struct { |
| 25 | termios unix.Termios |
| 26 | } |
| 27 | |
| 28 | // IsTerminal returns whether the given file descriptor is a terminal. |
| 29 | func IsTerminal(fd int) bool { |
| 30 | _, err := unix.IoctlGetTermios(fd, ioctlReadTermios) |
| 31 | return err == nil |
| 32 | } |
| 33 | |
| 34 | // MakeRaw put the terminal connected to the given file descriptor into raw |
| 35 | // mode and returns the previous state of the terminal so that it can be |
| 36 | // restored. |
| 37 | func MakeRaw(fd int) (*State, error) { |
| 38 | termios, err := unix.IoctlGetTermios(fd, ioctlReadTermios) |
| 39 | if err != nil { |
| 40 | return nil, err |
| 41 | } |
| 42 | |
| 43 | oldState := State{termios: *termios} |
| 44 | |
| 45 | // This attempts to replicate the behaviour documented for cfmakeraw in |
| 46 | // the termios(3) manpage. |
| 47 | termios.Iflag &^= unix.IGNBRK | unix.BRKINT | unix.PARMRK | unix.ISTRIP | unix.INLCR | unix.IGNCR | unix.ICRNL | unix.IXON |
| 48 | termios.Oflag &^= unix.OPOST |
| 49 | termios.Lflag &^= unix.ECHO | unix.ECHONL | unix.ICANON | unix.ISIG | unix.IEXTEN |
| 50 | termios.Cflag &^= unix.CSIZE | unix.PARENB |
| 51 | termios.Cflag |= unix.CS8 |
| 52 | termios.Cc[unix.VMIN] = 1 |
| 53 | termios.Cc[unix.VTIME] = 0 |
| 54 | if err := unix.IoctlSetTermios(fd, ioctlWriteTermios, termios); err != nil { |
| 55 | return nil, err |
| 56 | } |
| 57 | |
| 58 | return &oldState, nil |
| 59 | } |
| 60 | |
| 61 | // GetState returns the current state of a terminal which may be useful to |
| 62 | // restore the terminal after a signal. |
| 63 | func GetState(fd int) (*State, error) { |
| 64 | termios, err := unix.IoctlGetTermios(fd, ioctlReadTermios) |
| 65 | if err != nil { |
| 66 | return nil, err |
| 67 | } |
| 68 | |
| 69 | return &State{termios: *termios}, nil |
| 70 | } |
| 71 | |
| 72 | // Restore restores the terminal connected to the given file descriptor to a |
| 73 | // previous state. |
| 74 | func Restore(fd int, state *State) error { |
| 75 | return unix.IoctlSetTermios(fd, ioctlWriteTermios, &state.termios) |
| 76 | } |
| 77 | |
| 78 | // GetSize returns the dimensions of the given terminal. |
| 79 | func GetSize(fd int) (width, height int, err error) { |
| 80 | ws, err := unix.IoctlGetWinsize(fd, unix.TIOCGWINSZ) |
| 81 | if err != nil { |
| 82 | return -1, -1, err |
| 83 | } |
| 84 | return int(ws.Col), int(ws.Row), nil |
| 85 | } |
| 86 | |
| 87 | // passwordReader is an io.Reader that reads from a specific file descriptor. |
| 88 | type passwordReader int |
| 89 | |
| 90 | func (r passwordReader) Read(buf []byte) (int, error) { |
| 91 | return unix.Read(int(r), buf) |
| 92 | } |
| 93 | |
| 94 | // ReadPassword reads a line of input from a terminal without local echo. This |
| 95 | // is commonly used for inputting passwords and other sensitive data. The slice |
| 96 | // returned does not include the \n. |
| 97 | func ReadPassword(fd int) ([]byte, error) { |
| 98 | termios, err := unix.IoctlGetTermios(fd, ioctlReadTermios) |
| 99 | if err != nil { |
| 100 | return nil, err |
| 101 | } |
| 102 | |
| 103 | newState := *termios |
| 104 | newState.Lflag &^= unix.ECHO |
| 105 | newState.Lflag |= unix.ICANON | unix.ISIG |
| 106 | newState.Iflag |= unix.ICRNL |
| 107 | if err := unix.IoctlSetTermios(fd, ioctlWriteTermios, &newState); err != nil { |
| 108 | return nil, err |
| 109 | } |
| 110 | |
| 111 | defer unix.IoctlSetTermios(fd, ioctlWriteTermios, termios) |
| 112 | |
| 113 | return readPasswordLine(passwordReader(fd)) |
| 114 | } |