ssh/terminal: implement ReadPassword and IsTerminal

Fixes golang/go#13085.

Change-Id: I2fcdd60e5e8db032d6fa3ce76198bdc7a63f3cf6
Reviewed-on: https://go-review.googlesource.com/16722
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>

util_solaris.go

@@ -0,0 +1,73 @@
+// Copyright 2015 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 solaris
+
+package terminal // import "golang.org/x/crypto/ssh/terminal"
+
+import (
+	"golang.org/x/sys/unix"
+	"io"
+	"syscall"
+)
+
+// 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 {
+	// see: http://src.illumos.org/source/xref/illumos-gate/usr/src/lib/libbc/libc/gen/common/isatty.c
+	var termio unix.Termio
+	err := unix.IoctlSetTermio(fd, unix.TCGETA, &termio)
+	return err == 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) {
+	// see also: http://src.illumos.org/source/xref/illumos-gate/usr/src/lib/libast/common/uwin/getpass.c
+	val, err := unix.IoctlGetTermios(fd, unix.TCGETS)
+	if err != nil {
+		return nil, err
+	}
+	oldState := *val
+
+	newState := oldState
+	newState.Lflag &^= syscall.ECHO
+	newState.Lflag |= syscall.ICANON | syscall.ISIG
+	newState.Iflag |= syscall.ICRNL
+	err = unix.IoctlSetTermios(fd, unix.TCSETS, &newState)
+	if err != nil {
+		return nil, err
+	}
+
+	defer unix.IoctlSetTermios(fd, unix.TCSETS, &oldState)
+
+	var buf [16]byte
+	var ret []byte
+	for {
+		n, err := syscall.Read(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
+}