119 lines
4.2 KiB
Go
119 lines
4.2 KiB
Go
// Copyright 2011 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// +build darwin dragonfly freebsd linux,!appengine netbsd openbsd
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// Package terminal provides support functions for dealing with terminals, as
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// commonly found on UNIX systems.
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//
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// Putting a terminal into raw mode is the most common requirement:
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//
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// oldState, err := terminal.MakeRaw(0)
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// if err != nil {
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// panic(err)
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// }
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// defer terminal.Restore(0, oldState)
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package terminal // import "golang.org/x/crypto/ssh/terminal"
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import (
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"syscall"
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"unsafe"
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)
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// State contains the state of a terminal.
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type State struct {
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termios syscall.Termios
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}
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// IsTerminal returns true if the given file descriptor is a terminal.
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func IsTerminal(fd int) bool {
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var termios syscall.Termios
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_, _, err := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), ioctlReadTermios, uintptr(unsafe.Pointer(&termios)), 0, 0, 0)
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return err == 0
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}
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// MakeRaw put the terminal connected to the given file descriptor into raw
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// mode and returns the previous state of the terminal so that it can be
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// restored.
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func MakeRaw(fd int) (*State, error) {
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var oldState State
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if _, _, err := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), ioctlReadTermios, uintptr(unsafe.Pointer(&oldState.termios)), 0, 0, 0); err != 0 {
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return nil, err
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}
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newState := oldState.termios
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// This attempts to replicate the behaviour documented for cfmakeraw in
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// the termios(3) manpage.
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newState.Iflag &^= syscall.IGNBRK | syscall.BRKINT | syscall.PARMRK | syscall.ISTRIP | syscall.INLCR | syscall.IGNCR | syscall.ICRNL | syscall.IXON
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newState.Oflag &^= syscall.OPOST
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newState.Lflag &^= syscall.ECHO | syscall.ECHONL | syscall.ICANON | syscall.ISIG | syscall.IEXTEN
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newState.Cflag &^= syscall.CSIZE | syscall.PARENB
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newState.Cflag |= syscall.CS8
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if _, _, err := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), ioctlWriteTermios, uintptr(unsafe.Pointer(&newState)), 0, 0, 0); err != 0 {
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return nil, err
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}
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return &oldState, nil
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}
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// GetState returns the current state of a terminal which may be useful to
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// restore the terminal after a signal.
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func GetState(fd int) (*State, error) {
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var oldState State
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if _, _, err := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), ioctlReadTermios, uintptr(unsafe.Pointer(&oldState.termios)), 0, 0, 0); err != 0 {
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return nil, err
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}
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return &oldState, nil
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}
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// Restore restores the terminal connected to the given file descriptor to a
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// previous state.
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func Restore(fd int, state *State) error {
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if _, _, err := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), ioctlWriteTermios, uintptr(unsafe.Pointer(&state.termios)), 0, 0, 0); err != 0 {
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return err
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}
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return nil
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}
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// GetSize returns the dimensions of the given terminal.
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func GetSize(fd int) (width, height int, err error) {
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var dimensions [4]uint16
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if _, _, err := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), uintptr(syscall.TIOCGWINSZ), uintptr(unsafe.Pointer(&dimensions)), 0, 0, 0); err != 0 {
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return -1, -1, err
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}
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return int(dimensions[1]), int(dimensions[0]), nil
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}
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// passwordReader is an io.Reader that reads from a specific file descriptor.
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type passwordReader int
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func (r passwordReader) Read(buf []byte) (int, error) {
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return syscall.Read(int(r), buf)
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}
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// ReadPassword reads a line of input from a terminal without local echo. This
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// is commonly used for inputting passwords and other sensitive data. The slice
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// returned does not include the \n.
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func ReadPassword(fd int) ([]byte, error) {
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var oldState syscall.Termios
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if _, _, err := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), ioctlReadTermios, uintptr(unsafe.Pointer(&oldState)), 0, 0, 0); err != 0 {
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return nil, err
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}
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newState := oldState
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newState.Lflag &^= syscall.ECHO
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newState.Lflag |= syscall.ICANON | syscall.ISIG
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newState.Iflag |= syscall.ICRNL
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if _, _, err := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), ioctlWriteTermios, uintptr(unsafe.Pointer(&newState)), 0, 0, 0); err != 0 {
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return nil, err
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}
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defer func() {
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syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), ioctlWriteTermios, uintptr(unsafe.Pointer(&oldState)), 0, 0, 0)
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}()
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return readPasswordLine(passwordReader(fd))
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}
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