xref: /freebsd/crypto/openssl/crypto/ui/ui_openssl.c (revision 6f9291ce)

/* crypto/ui/ui_openssl.c -*- mode:C; c-file-style: "eay" -*- */
/*
 * Written by Richard Levitte (richard@levitte.org) and others for the
 * OpenSSL project 2001.
 */
/* ====================================================================
 * Copyright (c) 2001 The OpenSSL Project.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
 *
 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    openssl-core@openssl.org.
 *
 * 5. Products derived from this software may not be called "OpenSSL"
 *    nor may "OpenSSL" appear in their names without prior written
 *    permission of the OpenSSL Project.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
 *
 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 * ====================================================================
 *
 * This product includes cryptographic software written by Eric Young
 * (eay@cryptsoft.com).  This product includes software written by Tim
 * Hudson (tjh@cryptsoft.com).
 *
 */

/*-
 * The lowest level part of this file was previously in crypto/des/read_pwd.c,
 * Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 *
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 *
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 *
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.]
 */

#include <openssl/e_os2.h>

/*
 * need for #define _POSIX_C_SOURCE arises whenever you pass -ansi to gcc
 * [maybe others?], because it masks interfaces not discussed in standard,
 * sigaction and fileno included. -pedantic would be more appropriate for the
 * intended purposes, but we can't prevent users from adding -ansi.
 */
#if defined(OPENSSL_SYSNAME_VXWORKS)
# include <sys/types.h>
#endif

#if !defined(_POSIX_C_SOURCE) && defined(OPENSSL_SYS_VMS)
# ifndef _POSIX_C_SOURCE
#  define _POSIX_C_SOURCE 2
# endif
#endif
#include <signal.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>

#if !defined(OPENSSL_SYS_MSDOS) && !defined(OPENSSL_SYS_VMS)
# ifdef OPENSSL_UNISTD
#  include OPENSSL_UNISTD
# else
#  include <unistd.h>
# endif
/*
 * If unistd.h defines _POSIX_VERSION, we conclude that we are on a POSIX
 * system and have sigaction and termios.
 */
# if defined(_POSIX_VERSION)

#  define SIGACTION
#  if !defined(TERMIOS) && !defined(TERMIO) && !defined(SGTTY)
#   define TERMIOS
#  endif

# endif
#endif

#ifdef WIN16TTY
# undef OPENSSL_SYS_WIN16
# undef WIN16
# undef _WINDOWS
# include <graph.h>
#endif

/* 06-Apr-92 Luke Brennan    Support for VMS */
#include "ui_locl.h"
#include "cryptlib.h"

#ifdef OPENSSL_SYS_VMS          /* prototypes for sys$whatever */
# include <starlet.h>
# ifdef __DECC
#  pragma message disable DOLLARID
# endif
#endif

#ifdef WIN_CONSOLE_BUG
# include <windows.h>
# ifndef OPENSSL_SYS_WINCE
#  include <wincon.h>
# endif
#endif

/*
 * There are 5 types of terminal interface supported, TERMIO, TERMIOS, VMS,
 * MSDOS and SGTTY.
 *
 * If someone defines one of the macros TERMIO, TERMIOS or SGTTY, it will
 * remain respected.  Otherwise, we default to TERMIOS except for a few
 * systems that require something different.
 *
 * Note: we do not use SGTTY unless it's defined by the configuration.  We
 * may eventually opt to remove it's use entirely.
 */

#if !defined(TERMIOS) && !defined(TERMIO) && !defined(SGTTY)

# if defined(_LIBC)
#  undef  TERMIOS
#  define TERMIO
#  undef  SGTTY
/*
 * We know that VMS, MSDOS, VXWORKS, NETWARE use entirely other mechanisms.
 * MAC_OS_GUSI_SOURCE should probably go away, but that needs to be confirmed.
 */
# elif !defined(OPENSSL_SYS_VMS) \
	&& !defined(OPENSSL_SYS_MSDOS) \
	&& !defined(OPENSSL_SYS_MACINTOSH_CLASSIC) \
	&& !defined(MAC_OS_GUSI_SOURCE) \
	&& !defined(OPENSSL_SYS_VXWORKS) \
	&& !defined(OPENSSL_SYS_NETWARE)
#  define TERMIOS
#  undef  TERMIO
#  undef  SGTTY
# endif

#endif

#ifdef TERMIOS
# include <termios.h>
# define TTY_STRUCT             struct termios
# define TTY_FLAGS              c_lflag
# define TTY_get(tty,data)      tcgetattr(tty,data)
# define TTY_set(tty,data)      tcsetattr(tty,TCSANOW,data)
#endif

#ifdef TERMIO
# include <termio.h>
# define TTY_STRUCT             struct termio
# define TTY_FLAGS              c_lflag
# define TTY_get(tty,data)      ioctl(tty,TCGETA,data)
# define TTY_set(tty,data)      ioctl(tty,TCSETA,data)
#endif

#ifdef SGTTY
# include <sgtty.h>
# define TTY_STRUCT             struct sgttyb
# define TTY_FLAGS              sg_flags
# define TTY_get(tty,data)      ioctl(tty,TIOCGETP,data)
# define TTY_set(tty,data)      ioctl(tty,TIOCSETP,data)
#endif

#if !defined(_LIBC) && !defined(OPENSSL_SYS_MSDOS) && !defined(OPENSSL_SYS_VMS) && !defined(OPENSSL_SYS_MACINTOSH_CLASSIC) && !defined(OPENSSL_SYS_SUNOS)
# include <sys/ioctl.h>
#endif

#ifdef OPENSSL_SYS_MSDOS
# include <conio.h>
#endif

#ifdef OPENSSL_SYS_VMS
# include <ssdef.h>
# include <iodef.h>
# include <ttdef.h>
# include <descrip.h>
struct IOSB {
    short iosb$w_value;
    short iosb$w_count;
    long iosb$l_info;
};
#endif

#ifdef OPENSSL_SYS_SUNOS
typedef int sig_atomic_t;
#endif

#if defined(OPENSSL_SYS_MACINTOSH_CLASSIC) || defined(MAC_OS_GUSI_SOURCE) || defined(OPENSSL_SYS_NETWARE)
/*
 * This one needs work. As a matter of fact the code is unoperational
 * and this is only a trick to get it compiled.
 *                                      <appro@fy.chalmers.se>
 */
# define TTY_STRUCT int
#endif

#ifndef NX509_SIG
# define NX509_SIG 32
#endif

/* Define globals.  They are protected by a lock */
#ifdef SIGACTION
static struct sigaction savsig[NX509_SIG];
#else
static void (*savsig[NX509_SIG]) (int);
#endif

#ifdef OPENSSL_SYS_VMS
static struct IOSB iosb;
static $DESCRIPTOR(terminal, "TT");
static long tty_orig[3], tty_new[3]; /* XXX Is there any guarantee that this
                                      * will always suffice for the actual
                                      * structures? */
static long status;
static unsigned short channel = 0;
#else
# if !defined(OPENSSL_SYS_MSDOS) || defined(__DJGPP__)
static TTY_STRUCT tty_orig, tty_new;
# endif
#endif
static FILE *tty_in, *tty_out;
static int is_a_tty;

/* Declare static functions */
#if !defined(OPENSSL_SYS_WIN16) && !defined(OPENSSL_SYS_WINCE)
static int read_till_nl(FILE *);
static void recsig(int);
static void pushsig(void);
static void popsig(void);
#endif
#if defined(OPENSSL_SYS_MSDOS) && !defined(OPENSSL_SYS_WIN16)
static int noecho_fgets(char *buf, int size, FILE *tty);
#endif
static int read_string_inner(UI *ui, UI_STRING *uis, int echo, int strip_nl);

static int read_string(UI *ui, UI_STRING *uis);
static int write_string(UI *ui, UI_STRING *uis);

static int open_console(UI *ui);
static int echo_console(UI *ui);
static int noecho_console(UI *ui);
static int close_console(UI *ui);

static UI_METHOD ui_openssl = {
    "OpenSSL default user interface",
    open_console,
    write_string,
    NULL,                       /* No flusher is needed for command lines */
    read_string,
    close_console,
    NULL
};

/* The method with all the built-in thingies */
UI_METHOD *UI_OpenSSL(void)
{
    return &ui_openssl;
}

/*
 * The following function makes sure that info and error strings are printed
 * before any prompt.
 */
static int write_string(UI *ui, UI_STRING *uis)
{
    switch (UI_get_string_type(uis)) {
    case UIT_ERROR:
    case UIT_INFO:
        fputs(UI_get0_output_string(uis), tty_out);
        fflush(tty_out);
        break;
    default:
        break;
    }
    return 1;
}

static int read_string(UI *ui, UI_STRING *uis)
{
    int ok = 0;

    switch (UI_get_string_type(uis)) {
    case UIT_BOOLEAN:
        fputs(UI_get0_output_string(uis), tty_out);
        fputs(UI_get0_action_string(uis), tty_out);
        fflush(tty_out);
        return read_string_inner(ui, uis,
                                 UI_get_input_flags(uis) & UI_INPUT_FLAG_ECHO,
                                 0);
    case UIT_PROMPT:
        fputs(UI_get0_output_string(uis), tty_out);
        fflush(tty_out);
        return read_string_inner(ui, uis,
                                 UI_get_input_flags(uis) & UI_INPUT_FLAG_ECHO,
                                 1);
    case UIT_VERIFY:
        fprintf(tty_out, "Verifying - %s", UI_get0_output_string(uis));
        fflush(tty_out);
        if ((ok = read_string_inner(ui, uis,
                                    UI_get_input_flags(uis) &
                                    UI_INPUT_FLAG_ECHO, 1)) <= 0)
            return ok;
        if (strcmp(UI_get0_result_string(uis), UI_get0_test_string(uis)) != 0) {
            fprintf(tty_out, "Verify failure\n");
            fflush(tty_out);
            return 0;
        }
        break;
    default:
        break;
    }
    return 1;
}

#if !defined(OPENSSL_SYS_WIN16) && !defined(OPENSSL_SYS_WINCE)
/* Internal functions to read a string without echoing */
static int read_till_nl(FILE *in)
{
# define SIZE 4
    char buf[SIZE + 1];

    do {
        if (!fgets(buf, SIZE, in))
            return 0;
    } while (strchr(buf, '\n') == NULL);
    return 1;
}

static volatile sig_atomic_t intr_signal;
#endif

static int read_string_inner(UI *ui, UI_STRING *uis, int echo, int strip_nl)
{
    static int ps;
    int ok;
    char result[BUFSIZ];
    int maxsize = BUFSIZ - 1;
#if !defined(OPENSSL_SYS_WIN16) && !defined(OPENSSL_SYS_WINCE)
    char *p;

    intr_signal = 0;
    ok = 0;
    ps = 0;

    pushsig();
    ps = 1;

    if (!echo && !noecho_console(ui))
        goto error;
    ps = 2;

    result[0] = '\0';
# ifdef OPENSSL_SYS_MSDOS
    if (!echo) {
        noecho_fgets(result, maxsize, tty_in);
        p = result;             /* FIXME: noecho_fgets doesn't return errors */
    } else
        p = fgets(result, maxsize, tty_in);
# else
    p = fgets(result, maxsize, tty_in);
# endif
    if (!p)
        goto error;
    if (feof(tty_in))
        goto error;
    if (ferror(tty_in))
        goto error;
    if ((p = (char *)strchr(result, '\n')) != NULL) {
        if (strip_nl)
            *p = '\0';
    } else if (!read_till_nl(tty_in))
        goto error;
    if (UI_set_result(ui, uis, result) >= 0)
        ok = 1;

 error:
    if (intr_signal == SIGINT)
        ok = -1;
    if (!echo)
        fprintf(tty_out, "\n");
    if (ps >= 2 && !echo && !echo_console(ui))
        ok = 0;

    if (ps >= 1)
        popsig();
#else
    ok = 1;
#endif

    OPENSSL_cleanse(result, BUFSIZ);
    return ok;
}

/* Internal functions to open, handle and close a channel to the console.  */
static int open_console(UI *ui)
{
    CRYPTO_w_lock(CRYPTO_LOCK_UI);
    is_a_tty = 1;

#if defined(OPENSSL_SYS_MACINTOSH_CLASSIC) || defined(OPENSSL_SYS_VXWORKS) || defined(OPENSSL_SYS_NETWARE) || defined(OPENSSL_SYS_BEOS)
    tty_in = stdin;
    tty_out = stderr;
#else
# ifdef OPENSSL_SYS_MSDOS
#  define DEV_TTY "con"
# else
#  define DEV_TTY "/dev/tty"
# endif
    if ((tty_in = fopen(DEV_TTY, "r")) == NULL)
        tty_in = stdin;
    if ((tty_out = fopen(DEV_TTY, "w")) == NULL)
        tty_out = stderr;
#endif

#if defined(TTY_get) && !defined(OPENSSL_SYS_VMS)
    if (TTY_get(fileno(tty_in), &tty_orig) == -1) {
# ifdef ENOTTY
        if (errno == ENOTTY)
            is_a_tty = 0;
        else
# endif
# ifdef EINVAL
            /*
             * Ariel Glenn ariel@columbia.edu reports that solaris can return
             * EINVAL instead.  This should be ok
             */
        if (errno == EINVAL)
            is_a_tty = 0;
        else
# endif
            return 0;
    }
#endif
#ifdef OPENSSL_SYS_VMS
    status = sys$assign(&terminal, &channel, 0, 0);
    if (status != SS$_NORMAL)
        return 0;
    status =
        sys$qiow(0, channel, IO$_SENSEMODE, &iosb, 0, 0, tty_orig, 12, 0, 0,
                 0, 0);
    if ((status != SS$_NORMAL) || (iosb.iosb$w_value != SS$_NORMAL))
        return 0;
#endif
    return 1;
}

static int noecho_console(UI *ui)
{
#ifdef TTY_FLAGS
    memcpy(&(tty_new), &(tty_orig), sizeof(tty_orig));
    tty_new.TTY_FLAGS &= ~ECHO;
#endif

#if defined(TTY_set) && !defined(OPENSSL_SYS_VMS)
    if (is_a_tty && (TTY_set(fileno(tty_in), &tty_new) == -1))
        return 0;
#endif
#ifdef OPENSSL_SYS_VMS
    tty_new[0] = tty_orig[0];
    tty_new[1] = tty_orig[1] | TT$M_NOECHO;
    tty_new[2] = tty_orig[2];
    status =
        sys$qiow(0, channel, IO$_SETMODE, &iosb, 0, 0, tty_new, 12, 0, 0, 0,
                 0);
    if ((status != SS$_NORMAL) || (iosb.iosb$w_value != SS$_NORMAL))
        return 0;
#endif
    return 1;
}

static int echo_console(UI *ui)
{
#if defined(TTY_set) && !defined(OPENSSL_SYS_VMS)
    memcpy(&(tty_new), &(tty_orig), sizeof(tty_orig));
    tty_new.TTY_FLAGS |= ECHO;
#endif

#if defined(TTY_set) && !defined(OPENSSL_SYS_VMS)
    if (is_a_tty && (TTY_set(fileno(tty_in), &tty_new) == -1))
        return 0;
#endif
#ifdef OPENSSL_SYS_VMS
    tty_new[0] = tty_orig[0];
    tty_new[1] = tty_orig[1] & ~TT$M_NOECHO;
    tty_new[2] = tty_orig[2];
    status =
        sys$qiow(0, channel, IO$_SETMODE, &iosb, 0, 0, tty_new, 12, 0, 0, 0,
                 0);
    if ((status != SS$_NORMAL) || (iosb.iosb$w_value != SS$_NORMAL))
        return 0;
#endif
    return 1;
}

static int close_console(UI *ui)
{
    if (tty_in != stdin)
        fclose(tty_in);
    if (tty_out != stderr)
        fclose(tty_out);
#ifdef OPENSSL_SYS_VMS
    status = sys$dassgn(channel);
#endif
    CRYPTO_w_unlock(CRYPTO_LOCK_UI);

    return 1;
}

#if !defined(OPENSSL_SYS_WIN16) && !defined(OPENSSL_SYS_WINCE)
/* Internal functions to handle signals and act on them */
static void pushsig(void)
{
# ifndef OPENSSL_SYS_WIN32
    int i;
# endif
# ifdef SIGACTION
    struct sigaction sa;

    memset(&sa, 0, sizeof sa);
    sa.sa_handler = recsig;
# endif

# ifdef OPENSSL_SYS_WIN32
    savsig[SIGABRT] = signal(SIGABRT, recsig);
    savsig[SIGFPE] = signal(SIGFPE, recsig);
    savsig[SIGILL] = signal(SIGILL, recsig);
    savsig[SIGINT] = signal(SIGINT, recsig);
    savsig[SIGSEGV] = signal(SIGSEGV, recsig);
    savsig[SIGTERM] = signal(SIGTERM, recsig);
# else
    for (i = 1; i < NX509_SIG; i++) {
#  ifdef SIGUSR1
        if (i == SIGUSR1)
            continue;
#  endif
#  ifdef SIGUSR2
        if (i == SIGUSR2)
            continue;
#  endif
#  ifdef SIGKILL
        if (i == SIGKILL)       /* We can't make any action on that. */
            continue;
#  endif
#  ifdef SIGACTION
        sigaction(i, &sa, &savsig[i]);
#  else
        savsig[i] = signal(i, recsig);
#  endif
    }
# endif

# ifdef SIGWINCH
    signal(SIGWINCH, SIG_DFL);
# endif
}

static void popsig(void)
{
# ifdef OPENSSL_SYS_WIN32
    signal(SIGABRT, savsig[SIGABRT]);
    signal(SIGFPE, savsig[SIGFPE]);
    signal(SIGILL, savsig[SIGILL]);
    signal(SIGINT, savsig[SIGINT]);
    signal(SIGSEGV, savsig[SIGSEGV]);
    signal(SIGTERM, savsig[SIGTERM]);
# else
    int i;
    for (i = 1; i < NX509_SIG; i++) {
#  ifdef SIGUSR1
        if (i == SIGUSR1)
            continue;
#  endif
#  ifdef SIGUSR2
        if (i == SIGUSR2)
            continue;
#  endif
#  ifdef SIGACTION
        sigaction(i, &savsig[i], NULL);
#  else
        signal(i, savsig[i]);
#  endif
    }
# endif
}

static void recsig(int i)
{
    intr_signal = i;
}
#endif

/* Internal functions specific for Windows */
#if defined(OPENSSL_SYS_MSDOS) && !defined(OPENSSL_SYS_WIN16) && !defined(OPENSSL_SYS_WINCE)
static int noecho_fgets(char *buf, int size, FILE *tty)
{
    int i;
    char *p;

    p = buf;
    for (;;) {
        if (size == 0) {
            *p = '\0';
            break;
        }
        size--;
# ifdef WIN16TTY
        i = _inchar();
# elif defined(_WIN32)
        i = _getch();
# else
        i = getch();
# endif
        if (i == '\r')
            i = '\n';
        *(p++) = i;
        if (i == '\n') {
            *p = '\0';
            break;
        }
    }
# ifdef WIN_CONSOLE_BUG
    /*
     * Win95 has several evil console bugs: one of these is that the last
     * character read using getch() is passed to the next read: this is
     * usually a CR so this can be trouble. No STDIO fix seems to work but
     * flushing the console appears to do the trick.
     */
    {
        HANDLE inh;
        inh = GetStdHandle(STD_INPUT_HANDLE);
        FlushConsoleInputBuffer(inh);
    }
# endif
    return (strlen(buf));
}
#endif