code review 86190043: go.crypto/ssh: import gosshnew.

ssh/terminal/util_windows.go

Index: ssh/terminal/util_windows.go
===================================================================
new file mode 100644
--- /dev/null
+++ b/ssh/terminal/util_windows.go
@@ -0,0 +1,171 @@
+// 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 windows
+
+// 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"
+)
+
+const (
+	enableLineInput       = 2
+	enableEchoInput       = 4
+	enableProcessedInput  = 1
+	enableWindowInput     = 8
+	enableMouseInput      = 16
+	enableInsertMode      = 32
+	enableQuickEditMode   = 64
+	enableExtendedFlags   = 128
+	enableAutoPosition    = 256
+	enableProcessedOutput = 1
+	enableWrapAtEolOutput = 2
+)
+
+var kernel32 = syscall.NewLazyDLL("kernel32.dll")
+
+var (
+	procGetConsoleMode             = kernel32.NewProc("GetConsoleMode")
+	procSetConsoleMode             = kernel32.NewProc("SetConsoleMode")
+	procGetConsoleScreenBufferInfo = kernel32.NewProc("GetConsoleScreenBufferInfo")
+)
+
+type (
+	short int16
+	word  uint16
+
+	coord struct {
+		x short
+		y short
+	}
+	smallRect struct {
+		left   short
+		top    short
+		right  short
+		bottom short
+	}
+	consoleScreenBufferInfo struct {
+		size              coord
+		cursorPosition    coord
+		attributes        word
+		window            smallRect
+		maximumWindowSize coord
+	}
+)
+
+type State struct {
+	mode uint32
+}
+
+// IsTerminal returns true if the given file descriptor is a terminal.
+func IsTerminal(fd int) bool {
+	var st uint32
+	r, _, e := syscall.Syscall(procGetConsoleMode.Addr(), 2, uintptr(fd), uintptr(unsafe.Pointer(&st)), 0)
+	return r != 0 && 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, error) {
+	var st uint32
+	_, _, e := syscall.Syscall(procGetConsoleMode.Addr(), 2, uintptr(fd), uintptr(unsafe.Pointer(&st)), 0)
+	if e != 0 {
+		return nil, error(e)
+	}
+	st &^= (enableEchoInput | enableProcessedInput | enableLineInput | enableProcessedOutput)
+	_, _, e = syscall.Syscall(procSetConsoleMode.Addr(), 2, uintptr(fd), uintptr(st), 0)
+	if e != 0 {
+		return nil, error(e)
+	}
+	return &State{st}, nil
+}
+
+// GetState returns the current state of a terminal which may be useful to
+// restore the terminal after a signal.
+func GetState(fd int) (*State, error) {
+	var st uint32
+	_, _, e := syscall.Syscall(procGetConsoleMode.Addr(), 2, uintptr(fd), uintptr(unsafe.Pointer(&st)), 0)
+	if e != 0 {
+		return nil, error(e)
+	}
+	return &State{st}, nil
+}
+
+// Restore restores the terminal connected to the given file descriptor to a
+// previous state.
+func Restore(fd int, state *State) error {
+	_, _, err := syscall.Syscall(procSetConsoleMode.Addr(), 2, uintptr(fd), uintptr(state.mode), 0)
+	return err
+}
+
+// GetSize returns the dimensions of the given terminal.
+func GetSize(fd int) (width, height int, err error) {
+	var info consoleScreenBufferInfo
+	_, _, e := syscall.Syscall(procGetConsoleScreenBufferInfo.Addr(), 2, uintptr(fd), uintptr(unsafe.Pointer(&info)), 0)
+	if e != 0 {
+		return 0, 0, error(e)
+	}
+	return int(info.size.x), int(info.size.y), 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 st uint32
+	_, _, e := syscall.Syscall(procGetConsoleMode.Addr(), 2, uintptr(fd), uintptr(unsafe.Pointer(&st)), 0)
+	if e != 0 {
+		return nil, error(e)
+	}
+	old := st
+
+	st &^= (enableEchoInput)
+	st |= (enableProcessedInput | enableLineInput | enableProcessedOutput)
+	_, _, e = syscall.Syscall(procSetConsoleMode.Addr(), 2, uintptr(fd), uintptr(st), 0)
+	if e != 0 {
+		return nil, error(e)
+	}
+
+	defer func() {
+		syscall.Syscall(procSetConsoleMode.Addr(), 2, uintptr(fd), uintptr(old), 0)
+	}()
+
+	var buf [16]byte
+	var ret []byte
+	for {
+		n, err := syscall.Read(syscall.Handle(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
+}