/* Copyright (C) 1999 DJ Delorie, see COPYING.DJ for details */
/* Copyright (C) 1996 DJ Delorie, see COPYING.DJ for details */
/*
 * tminit.c - initializer and main part of termios emulation.
 *   designed for DJGPP by Daisuke Aoyama <jack@st.rim.or.jp>
 *   special thanks to Ryo Shimizu
 */

#include <libc/stubs.h>
#include <fcntl.h>
#include <go32.h>
#include <io.h>
#include <limits.h>
#include <signal.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <termios.h>
#include <unistd.h>
#include <sys/exceptn.h>
#include <libc/bss.h>
#include <libc/file.h>
#include <libc/dosio.h>
#include <libc/ttyprvt.h>
#include <libc/farptrgs.h>

#define _DEV_STDIN  0x0001
#define _DEV_STDOUT 0x0002
#define _DEV_NUL    0x0004
#define _DEV_CLOCK  0x0008
#define _DEV_RAW    0x0020
#define _DEV_CDEV   0x0080
#define _DEV_IOCTRL 0x4000

#define CPMEOF 0x1a /* Ctrl+Z */

/* tty buffers */
unsigned char __libc_tty_queue_buffer[_TTY_QUEUE_SIZE];
struct tty __libc_tty_internal = TTYDEFAULT;
struct tty *__libc_tty_p = &__libc_tty_internal;
struct tty_editline __libc_tty_editline = { 0, { 0 }, { 0 }, };

/* global only in the termios functions */
int __libc_termios_hook_common_count = -1;

/* static functions */
static void __libc_termios_fflushall (void);
static ssize_t __libc_termios_read (int handle, void *buffer, size_t count, ssize_t *rv);
static ssize_t __libc_termios_read_cooked_tty (int handle, void *buffer, size_t count);
static ssize_t __libc_termios_read_raw_tty (int handle, void *buffer, size_t count);
static ssize_t __libc_termios_write (int handle, const void *buffer, size_t count, ssize_t *rv);
static ssize_t __libc_termios_write_cooked_tty (int handle, const void *buffer, size_t count);
static ssize_t __libc_termios_write_raw_tty (int handle, const void *buffer, size_t count);
static void __libc_termios_echo_ctrl (unsigned char ch);
static void __libc_termios_maybe_echo_ctrl (unsigned char ch);
static void __libc_termios_maybe_echo (unsigned char ch);
static void __libc_termios_maybe_erase1 (void);
static void __libc_termios_erase_editline (void);
static void __libc_termios_kill_editline (void);
static void __libc_termios_insert_editline (unsigned char ch);
static int __libc_termios_exist_queue (void);
static void __libc_termios_clear_queue (void);
static int __libc_termios_get_queue (void);
static int __libc_termios_put_queue (unsigned char ch);
static void __libc_termios_fill_queue (void);

/* direct I/O functions */
static inline int __direct_keysense (void);
static inline unsigned char __direct_keyinput (void);
static inline int __direct_ctrlsense (void);
static inline void __direct_output (unsigned char ch);
static inline void __direct_outputs (const unsigned char *s);

/******************************************************************************/
/* initialize function ********************************************************/

static void
__libc_termios_fflushall (void)
{
#if 0 /* don't work on djgpp */
  fflush (NULL);
#else
  _fwalk ((void (*) (FILE*)) fflush);
#endif
}

void
__libc_termios_init (void)
{
  if (__libc_termios_hook_common_count != __bss_count)
    {
      __libc_termios_hook_common_count = __bss_count;

      /* flush all buffered streams */
      __libc_termios_fflushall ();

      /* set special hooks */
      __libc_read_termios_hook = __libc_termios_read;
      __libc_write_termios_hook = __libc_termios_write;

      /* import parameters */
      /* __libc_tty_p = ...; */
    }
}

/******************************************************************************/
/* direct I/O function (inlined) **********************************************/

#define _REG_STATUS_ZF 0x40

static inline int
__direct_keysense (void)
{
  __dpmi_regs r;

  r.h.ah = 0x01;
  __dpmi_int (0x16, &r);
  if (r.x.flags & _REG_STATUS_ZF)
    return 0;

  return 1;
}

static inline unsigned char
__direct_keyinput (void)
{
  __dpmi_regs r;

  r.h.ah = 0x00;
  __dpmi_int (0x16, &r);

  return r.h.al;
}

#define _KEY_INS  0x80
#define _KEY_CAPS 0x40
#define _KEY_NUM  0x20
#define _KEY_SCRL 0x10
#define _KEY_ALT  0x08
#define _KEY_CTRL 0x04
#define _KEY_LSFT 0x02
#define _KEY_RSFT 0x01

static inline int
__direct_ctrlsense (void)
{
  __dpmi_regs r;

  r.h.ah = 0x02;
  __dpmi_int (0x16, &r);
  if (r.h.al & _KEY_CTRL)
    return 1;

  return 0;
}

static inline void
__direct_output (unsigned char ch)
{
  __dpmi_regs r;

  if (ch == 0xff)
    return;

  r.h.al = ch;
  __dpmi_int (0x29, &r);
}

static inline void
__direct_outputs (const unsigned char *s)
{
  while (*s)
    __direct_output (*s++);
}

/******************************************************************************/
/* special read function ******************************************************/

static ssize_t
__libc_termios_read (int handle, void *buffer, size_t count, ssize_t *rv)
{
  short devmod;
  ssize_t bytes;

  /* check handle whether valid or not */
  devmod = _get_dev_info (handle);
  if (devmod == -1)
    {
      *rv = -1;
      return 1;
    }

  /* special case */
  if (count == 0)
    {
      *rv = 0;
      return 1;
    }

  /* console only... */
  if ((devmod & _DEV_CDEV) && (devmod & (_DEV_STDIN|_DEV_STDOUT)))
    {
      /* character device */
      if ((devmod & _DEV_RAW) && (__file_handle_modes[handle] & O_BINARY))
	*rv = __libc_termios_read_raw_tty (handle, buffer, count);
      else
	*rv = __libc_termios_read_cooked_tty (handle, buffer, count);
      return 1;
    }

  if (__file_handle_modes[handle] & O_BINARY)
    {
      bytes = _read (handle, buffer, count);
      if (bytes < 0)
	{
	  *rv = -1;
	  return 1;
	}
    }
  else
    {
      unsigned char *rp, *wp;
      ssize_t n;

      bytes = _read (handle, buffer, count);
      if (bytes < 0)
	{
	  *rv = -1;
	  return 1;
	}

      rp = wp = buffer;
      n = bytes;
      while (--n >= 0)
	{
	  unsigned char ch;

	  ch = *rp++;
	  if (ch == CPMEOF)
	    {
	      ++n;
	      (void) lseek (handle, -n, SEEK_CUR);
	      break;
	    }
	  else if (ch == '\r')
	    {
	      if (n > 0)
		{
		  /* peek next character */
		  if (*rp == '\n')
		    {
		      /* if found '\n', delete '\r' */
		      ch = *rp++;
		      --n;
		    }
		}
	      else
		{
		  unsigned char tmpch;

		  /* read a character to peek */
		  if (_read (handle, &tmpch, 1) == 1)
		    {
		      if (tmpch == '\n')
			ch = tmpch;
		      else
			(void) lseek (handle, -1, SEEK_CUR);
		    }
		}
	    }
	  *wp++ = ch;
	}
      bytes = wp - (unsigned char *) buffer;
    }

  /* result of read() */
  *rv =  bytes;
  return 1;
}

static ssize_t
__libc_termios_read_cooked_tty (int handle, void *buffer, size_t count)
{
  unsigned char *wp;
  ssize_t n;

  wp = buffer;
  n = count;

#if 0
  /* clear cooked queue */
  if (__libc_termios_exist_queue ())
    __libc_termios_clear_queue ();
#endif

  if (__libc_tty_p->t_lflag & ICANON)
    {
      /* get inputs (wait for NL or EOT) */
      if (! __libc_termios_exist_queue ())
	__libc_termios_fill_queue ();

      while (--n >= 0)
	{
	  if (! __libc_termios_exist_queue ())
	    break;

	  *wp++ = __libc_termios_get_queue ();
	}
    }
  else
    {
      /* block until getting inputs */
      while (! __libc_termios_exist_queue ())
	{
	  __dpmi_yield ();
	  __libc_termios_fill_queue ();
	}

      while (--n >= 0)
	{
	  *wp++ = __libc_termios_get_queue ();

	  if (! __libc_termios_exist_queue ())
	    {
	      __libc_termios_fill_queue ();
	      if (! __libc_termios_exist_queue ())
		break;
	    }
	}
    }

  return (ssize_t) (wp - (unsigned char *) buffer);
}

static ssize_t
__libc_termios_read_raw_tty (int handle, void *buffer, size_t count)
{
  unsigned char *wp;
  unsigned char ch;
  ssize_t n;

  n = count;
  wp = buffer;

  /* clear cooked queue */
  if (__libc_termios_exist_queue ())
    __libc_termios_clear_queue ();

  /* block until getting inputs */
  while (! __direct_keysense ())
    __dpmi_yield ();

  while (--n >= 0)
    {
      /* exhaust inputs ? */
      if (! __direct_keysense ())
	break;

      /* realy get */
      ch = __direct_keyinput ();

      /* replace CTRL+SPACE with 0x00 */
      if (ch == ' ' && __direct_ctrlsense ())
	ch = '\0';

      /* copy a character into buffer and echo */
      *wp++ = ch;
      __libc_termios_maybe_echo (ch);
    }

  return (ssize_t) (wp - (unsigned char *) buffer);
}

/******************************************************************************/
/* special write function *****************************************************/

static unsigned char __libc_termios_write_sbuf_internal[64];
static unsigned char *__libc_termios_write_sbuf = NULL;
static size_t __libc_termios_write_sbuflen = 0;
static int __libc_termios_write_count = -1;

static ssize_t
__libc_termios_write (int handle, const void *buffer, size_t count, ssize_t *rv)
{
  short devmod;
  ssize_t bytes;

  /* check handle whether valid or not */
  devmod = _get_dev_info (handle);
  if (devmod == -1)
    {
      *rv = -1;
      return 1;
    }

  /* special case */
  if (count == 0)
    {
      *rv = 0;
      return 1;
    }

  /* console only... */
  if ((devmod & _DEV_CDEV) && (devmod & (_DEV_STDIN|_DEV_STDOUT)))
    {
      /* character device */
      if ((devmod & _DEV_RAW) && (__file_handle_modes[handle] & O_BINARY))
	*rv = __libc_termios_write_raw_tty (handle, buffer, count);
      else
	*rv = __libc_termios_write_cooked_tty (handle, buffer, count);
      return 1;
    }

  if (__file_handle_modes[handle] & O_BINARY)
    {
      bytes = _write (handle, buffer, count);
      if (bytes < 0)
	{
	  *rv = -1;
	  return 1;
	}
    }
  else
    {
      const unsigned char *rp;
      unsigned char *tp, *ep;
      ssize_t n;

      /* initialize local buffer */
      if (__libc_termios_write_count != __bss_count)
	{
	  __libc_termios_write_count = __bss_count;
	  __libc_termios_write_sbuflen = _go32_info_block.size_of_transfer_buffer;
	  __libc_termios_write_sbuf = malloc (__libc_termios_write_sbuflen);
	  if (__libc_termios_write_sbuf == NULL)
	    {
	      __libc_termios_write_sbuf = &__libc_termios_write_sbuf_internal[0];
	      __libc_termios_write_sbuflen = sizeof (__libc_termios_write_sbuf_internal);
	    }
	}

      rp = buffer;
      tp = __libc_termios_write_sbuf;
      ep = tp + __libc_termios_write_sbuflen;
      n = count;
      bytes = 0;
      while (n >= 0)
	{
	  unsigned char *wp;
	  unsigned char ch;
	  ssize_t ncr, wbytes;

	  /* fill local buffer */
	  wp = tp;
	  ncr = 0;
	  while ((wp < ep) && (--n >= 0))
	    {
	      /* get character */
	      ch = *rp++;

	      /* LF conversion */
	      if (ch == '\n')
		{
		  if (wp == (ep - 1))
		    {
		      n++;
		      rp--;
		      break;
		    }
		  *wp++ = '\r';
		  ncr++;
		}

	      /* put character */
	      *wp++ = ch;
	    }

	  /* write on handle */
	  wbytes = _write (handle, tp, (size_t) (wp - tp));
	  if (wbytes < 0)
	    {
	      *rv = -1;
	      return 1;
	    }
	  if (wbytes < (ssize_t) (wp - tp))
	    {
	      /* detected disk full, but the result is not reality */
	      *rv = bytes + (wbytes > ncr ? wbytes - ncr : 0);
	      return 1;
	    }

	  /* don't count CR */
	  bytes += wbytes - ncr;
	}
    }

  /* result of write() */
  *rv =  bytes;
  return 1;
}

static ssize_t
__libc_termios_write_cooked_tty (int handle, const void *buffer, size_t count)
{
  ssize_t bytes;

  /* output process if need */
  if (__libc_tty_p->t_oflag & OPOST)
    {
      const unsigned char *rp;
      unsigned char ch;
      ssize_t n;

      rp = buffer;
      n = count;
      while (--n >= 0)
	{
	  /* get character */
	  ch = *rp++;

	  /* NOTE: multibyte character don't contain control character */
	  /* map NL to CRNL */
	  if (ch == '\n' && (__libc_tty_p->t_oflag & ONLCR))
	    __direct_output ('\r');
	  /* map CR to NL */
	  else if (ch == '\r' && (__libc_tty_p->t_oflag & OCRNL))
	    ch = '\n';
	  /* produce spaces until the next TAB stop */
	  else if (ch == '\t')
	    {
	      int col, max_col;

	      _farsetsel (_dos_ds);
	      /* current column (cursor position) on the active page */
	      col = _farnspeekw (0x450 + _farnspeekb (0x462)) & 0xff;
	      /* the number of displayed character columns */
	      max_col = _farnspeekw (0x44a);

	      for (__direct_output (' '), col += 1; col % 8; col++)
		{
		  if (col >= max_col - 1)
		    col = -1;
		  __direct_output (' ');
		}
	      continue;
	    }

	  __direct_output (ch);
	}

      /* don't count CR */
      bytes = count;
    }
  else
    {
      /* output with no effect */
      bytes = __libc_termios_write_raw_tty (handle, buffer, count);
    }

  return bytes;
}

static ssize_t
__libc_termios_write_raw_tty (int handle, const void *buffer, size_t count)
{
  const unsigned char *rp;
  ssize_t n;

  rp = buffer;
  n = count;
  while (--n >= 0)
    __direct_output (*rp++);

  return count;
}

/******************************************************************************/
/* echo routines **************************************************************/

static void
__libc_termios_echo_ctrl (unsigned char ch)
{
  ch ^= 0x40;
  __direct_output ('^');
  __direct_output (ch);
}

static void
__libc_termios_maybe_echo_ctrl (unsigned char ch)
{
  if (__libc_tty_p->t_lflag & ECHOCTL)
    __libc_termios_echo_ctrl (ch);
}

static void
__libc_termios_maybe_echo (unsigned char ch)
{
  if (! (__libc_tty_p->t_lflag & ECHO))
    {
      /* don't echo but newline is required ? */
      if (ch == '\n' && (__libc_tty_p->t_lflag & ECHONL))
	{
	  if (__libc_tty_p->t_oflag & ONLCR)
	    __direct_output ('\r');
	  __direct_output ('\n');
	}
      return;
    }

  /* check literal flag */
  if ((__libc_tty_p->t_status & _TS_LNCH) && (ch < 0x20))
    {
      __libc_termios_echo_ctrl (ch);
      return;
    }

  /* output process if need */
  if (__libc_tty_p->t_oflag & OPOST)
    {
      /* map NL to CRNL */
      if (ch == '\n' && (__libc_tty_p->t_oflag & ONLCR))
	{
	  __direct_output ('\r');
	  __direct_output ('\n');
	  return;
	}
      /* map CR to NL */
      else if (ch == '\r' && (__libc_tty_p->t_oflag & OCRNL))
	{
	  __direct_output ('\n');
	  return;
	}
      /* discard EOT */
      else if (_CC_EQU (VEOF, ch) && (__libc_tty_p->t_oflag & ONOEOT))
	{
	  return;
	}
    }

  /* control character except newline */
  if ((ch < 0x20 || ch == 0x7f) && (__libc_tty_p->t_lflag & ECHOCTL) && ch != '\n')
    {
      __libc_termios_echo_ctrl (ch);
      return;
    }

  /* no effect */
  __direct_output (ch);
}

/******************************************************************************/
/* edit routines **************************************************************/

static void
__libc_termios_maybe_erase1 (void)
{
  if (__libc_tty_p->t_lflag & ECHO)
    {
      /* eat prev. character by BS SPC BS */
      __direct_output ('\010');
      if (__libc_tty_p->t_lflag & ECHOE)
	{
	  __direct_output (' ');
	  __direct_output ('\010');
	}
    }
}

/* erase one prev. character of editline */
static void
__libc_termios_erase_editline (void)
{
  int col;
  char pf;

  col = __libc_tty_editline.col;
  if (col == 0) /* no more */
    return;

  /* get position flag */
  pf = __libc_tty_editline.flag[col - 1];
  if (pf == _TTY_EDITLINE_INVALID || pf < 0)
    {
      /* erase all invalid character */
      while (col > 0 && __libc_tty_editline.flag[col - 1] < 0)
	{
	  __libc_termios_maybe_erase1 ();
	  --col;
	}
    }
  else if (pf == _TTY_EDITLINE_CTRL)
    {
      if (__libc_tty_p->t_lflag & ECHOCTL)
	{
	  /* erase one of "^X" */
	  __libc_termios_maybe_erase1 ();
	  --col;
	}
      __libc_termios_maybe_erase1 ();
      --col;
    }
  else
    {
      /* erase single or multibyte charcter */
      while (--pf >= 0)
	{
	  __libc_termios_maybe_erase1 ();
	  --col;
	}
    }

  /* set next insert position */
  __libc_tty_editline.col = col;
}

/* erase all editline */
static void
__libc_termios_kill_editline (void)
{
  if (__libc_tty_p->t_lflag & ECHOKE)
    {
      while (__libc_tty_editline.col != 0)
	__libc_termios_erase_editline ();
    }
  else
    __libc_tty_editline.col = 0;

  if (__libc_tty_p->t_lflag & ECHOK)
    __libc_termios_maybe_echo ('\n');
}

static void
__libc_termios_insert_editline (unsigned char ch)
{
  int mbsize;
  int col;

  col = __libc_tty_editline.col;
  if (col >= _TTY_EDITLINE_SIZE)
    {
      /* detected over flow */
      if (__libc_tty_p->t_iflag & IMAXBEL)
	__direct_output ('\007');
      return;
    }

  __libc_tty_editline.buf[col] = ch;
  if (col == 0 || ((col > 0)
		   && __libc_tty_editline.flag[col - 1] != _TTY_EDITLINE_INVALID))
    {
      /* check multibyte length */
      mbsize = mblen (__libc_tty_editline.buf + col, 1);
      if (mbsize == 1)
	{
	  /* single character */
	  if ((ch < 0x20) || ch == 0x7f)
	    __libc_tty_editline.flag[col] = _TTY_EDITLINE_CTRL;
	  else
	    __libc_tty_editline.flag[col] = _TTY_EDITLINE_SINGLE;
	  __libc_termios_maybe_echo (ch);
	}
      else
	{
	  /* first of multibyte or invalid character */
	  __libc_tty_editline.flag[col] = _TTY_EDITLINE_INVALID;
	  __libc_tty_p->t_status |= _TS_LNCH;
	}
    }
  else
    {
      int pcol;

      /* look for non fixed flag */
      pcol = col;
      while (__libc_tty_editline.flag[pcol - 1] == _TTY_EDITLINE_INVALID)
	if (--pcol <= 0)
	  break;

      /* check whether it's multibyte sequence */
      mbsize = mblen (__libc_tty_editline.buf + pcol, (col - pcol + 1));
      if (mbsize > 1)
	{
	  /* multibyte sequence is good */
	  while (pcol < col)
	    {
	      /* set negative size for dividing sequence */
	      __libc_tty_editline.flag[pcol] = -mbsize;
	      __libc_termios_maybe_echo (__libc_tty_editline.buf[pcol]);
	      pcol++;
	    }
	  /* last flag is always positive size */
	  __libc_tty_editline.flag[col] = mbsize;
	  __libc_termios_maybe_echo (ch);
	}
      else
	{
	  if ((col - pcol + 1) > MB_CUR_MAX)
	    {
	      /* it's terrible... */
	      while (pcol <= col)
		{
		  /* replace all with valid character */
		  __libc_tty_editline.flag[pcol] = _TTY_EDITLINE_SINGLE;
		  __libc_tty_editline.buf[pcol] = 'X';
		  __libc_termios_maybe_echo ('X');
		  pcol++;
		}
	    }

	  /* continuous multibyte character */
	  __libc_tty_editline.flag[col] = _TTY_EDITLINE_INVALID;
	  __libc_tty_p->t_status |= _TS_LNCH;
	}
    }

  /* set next insert position */
  col++;
  __libc_tty_editline.col = col;
}

/******************************************************************************/
/* queued input routines ******************************************************/

static int
__libc_termios_exist_queue (void)
{
  return __libc_tty_p->t_count;
}

static void
__libc_termios_clear_queue (void)
{
  __libc_tty_p->t_count = 0;
  __libc_tty_p->t_rpos = __libc_tty_p->t_top;
  __libc_tty_p->t_wpos = __libc_tty_p->t_top;
}

static int
__libc_termios_get_queue (void)
{
  int ch;

  if (__libc_tty_p->t_count == 0)
    return -1;

  ch = *__libc_tty_p->t_rpos++;
  __libc_tty_p->t_count--;

  if (__libc_tty_p->t_rpos >= __libc_tty_p->t_bottom)
    __libc_tty_p->t_rpos = __libc_tty_p->t_top;

  return ch;
}

static int
__libc_termios_put_queue (unsigned char ch)
{
  if (__libc_tty_p->t_count >= __libc_tty_p->t_size)
    return -1;

  *__libc_tty_p->t_wpos++ = ch;
  __libc_tty_p->t_count++;

  if (__libc_tty_p->t_wpos >= __libc_tty_p->t_bottom)
    __libc_tty_p->t_wpos = __libc_tty_p->t_top;

  return 0;
}

static void
__libc_termios_fill_queue (void)
{
  unsigned char ch;

  while (1)
    {
      /* exhaust inputs ? */
      if (! __direct_keysense ())
	{
	  if (__libc_tty_p->t_lflag & ICANON)
	    {
	      /* wait for NL or EOT */
	      __dpmi_yield ();
	      continue;
	    }
	  return;
	}

      /* realy get */
      ch = __direct_keyinput ();

      /* replace CTRL+SPACE with 0x00 */
      if (ch == ' ' && __direct_ctrlsense ())
	ch = '\0';

      /* input process if need */
      if (! (__libc_tty_p->t_status & _TS_LNCH) || ch != (unsigned char) _POSIX_VDISABLE)
	{
	  /* software signals */
	  if (__libc_tty_p->t_lflag & ISIG)
	    {
	      if (! (__libc_tty_p->t_iflag & IGNBRK) && _CC_EQU (VINTR, ch))
		{
		  /* Only raise the signal if SIGINT generation by the
		     INTR key is disabled; otherwise the signal was
		     already raised and what we see here is the key
		     which generated it that wasn't removed from the
		     keyboard buffer.  */
		  if (__libc_tty_p->t_iflag & BRKINT)
		    {
		      if (__djgpp_set_ctrl_c (-1) == 0)
			{
			  __libc_termios_maybe_echo_ctrl (ch);
			  kill (getpid (), SIGINT);
			}
		      continue;
		    }
		  else
		    {
		      ch = '\0';
		      goto proc_skip;
		    }
		}
	      /* See the commentary about SIGINT above.  */
	      else if (_CC_EQU (VQUIT, ch))
		{
		  if (__djgpp_set_ctrl_c (-1) == 0)
		    {
		      __libc_termios_maybe_echo_ctrl (ch);
		      kill (getpid(), SIGQUIT);
		    }
		  continue;
		}
	      else if (_CC_EQU (VSUSP, ch))
		{
		  __libc_termios_maybe_echo_ctrl (ch);
#ifdef SIGTSTP
		  kill (getpid(), SIGTSTP);
#else /* djgpp don't have ... */
		  {
		    char oldcwd[PATH_MAX];
		    int fds[5] = { -1, -1, -1, -1, -1 };
		    int i;

		    for (i = 0; i < 5; i++)
		      if ((fds[i] = fcntl (i, F_DUPFD, 20)) < 0)
		        __direct_outputs ("Suspend: cannot save fds\r\n");

		    __direct_outputs ("\r\nSuspended\r\n");
		    /* keep cwd on exec */
		    getcwd (oldcwd, sizeof (oldcwd));
		    system ("");
		    chdir (oldcwd);

		    for (i = 0; i < 5; i++)
		      if (fds[i] >= 0)
			{
			  dup2 (fds[i], i);
			  close (fds[i]);
			}
		  }
#endif /* !SIGTSTP */
		  continue;
		}
	    }

	  /* flow control... */
	  if (_CC_EQU (VSTART, ch) && (__libc_tty_p->t_iflag & IXOFF))
	    {
	      continue;
	    }
	  else if (_CC_EQU (VSTOP, ch) && (__libc_tty_p->t_iflag & IXOFF))
	    {
	      continue;
	    }

	  /* CR/LF process */
	  if (ch == '\r')
	    {
	      if (__libc_tty_p->t_iflag & IGNCR)
		continue;
	      if (__libc_tty_p->t_iflag & ICRNL)
		ch = '\n';
	    }
	  else if ((ch == '\n') && (__libc_tty_p->t_iflag & INLCR))
	    ch = '\r';

	  /* strip 8th-bit */
	  if (__libc_tty_p->t_iflag & ISTRIP)
	    ch &= 0x7f;
	}

proc_skip:
      if (__libc_tty_p->t_lflag & ICANON)
	{
	  if (__libc_tty_p->t_status & _TS_LNCH)
	    {
	      __libc_tty_p->t_status &= ~_TS_LNCH;
	      __libc_termios_insert_editline (ch);
	    }
	  else
	    {
	      if (_CC_EQU (VERASE, ch))
		__libc_termios_erase_editline ();
	      else if (_CC_EQU (VKILL, ch))
		__libc_termios_kill_editline ();
	      else if (ch == '\n' || _CC_EQU (VEOF, ch) || _CC_EQU (VEOL, ch))
		{
		  int col = __libc_tty_editline.col;
		  unsigned char *p = __libc_tty_editline.buf;

		  /* clear column for next access */
		  __libc_tty_editline.col = 0;

		  /* copy editline into tty queue */
		  while (--col >= 0)
		    __libc_termios_put_queue (*p++);

		  /* echo terminate character and put it */
		  __libc_termios_maybe_echo (ch);
		  if (_CC_NEQU (VEOF, ch))
		    __libc_termios_put_queue (ch);

		  return;
		}
	      else
		__libc_termios_insert_editline (ch);
	    } /* !_TS_LNCH */
	}
      else /* !ICANON */
	{
	  __libc_termios_maybe_echo (ch);
	  __libc_tty_p->t_status &= ~_TS_LNCH;
	  __libc_termios_put_queue (ch);
	}
    } /* end of while (1) */
}

/******************************************************************************/