readline/input.c

/* input.c -- character input functions for readline. */

/* Copyright (C) 1994-2017 Free Software Foundation, Inc.

   This file is part of the GNU Readline Library (Readline), a library
   for reading lines of text with interactive input and history editing.      

   Readline is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   Readline is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with Readline.  If not, see <http://www.gnu.org/licenses/>.
*/

#define READLINE_LIBRARY

#if defined (__TANDEM)
#  include <floss.h>
#endif

#if defined (HAVE_CONFIG_H)
#  include <config.h>
#endif

#include <sys/types.h>
#include <fcntl.h>
#if defined (HAVE_SYS_FILE_H)
#  include <sys/file.h>
#endif /* HAVE_SYS_FILE_H */

#if defined (HAVE_UNISTD_H)
#  include <unistd.h>
#endif /* HAVE_UNISTD_H */

#if defined (HAVE_STDLIB_H)
#  include <stdlib.h>
#else
#  include "ansi_stdlib.h"
#endif /* HAVE_STDLIB_H */

#include <signal.h>

#include "posixselect.h"

#if defined (FIONREAD_IN_SYS_IOCTL)
#  include <sys/ioctl.h>
#endif

#include <stdio.h>
#include <errno.h>

#if !defined (errno)
extern int errno;
#endif /* !errno */

/* System-specific feature definitions and include files. */
#include "rldefs.h"
#include "rlmbutil.h"

/* Some standard library routines. */
#include "readline.h"

#include "rlprivate.h"
#include "rlshell.h"
#include "xmalloc.h"

/* What kind of non-blocking I/O do we have? */
#if !defined (O_NDELAY) && defined (O_NONBLOCK)
#  define O_NDELAY O_NONBLOCK	/* Posix style */
#endif

#if defined (HAVE_PSELECT)
extern sigset_t _rl_orig_sigset;
#endif

/* Non-null means it is a pointer to a function to run while waiting for
   character input. */
rl_hook_func_t *rl_event_hook = (rl_hook_func_t *)NULL;

/* A function to call if a read(2) is interrupted by a signal. */
rl_hook_func_t *rl_signal_event_hook = (rl_hook_func_t *)NULL;

/* A function to replace _rl_input_available for applications using the
   callback interface. */
rl_hook_func_t *rl_input_available_hook = (rl_hook_func_t *)NULL;

rl_getc_func_t *rl_getc_function = rl_getc;

static int _keyboard_input_timeout = 100000;		/* 0.1 seconds; it's in usec */

static int ibuffer_space PARAMS((void));
static int rl_get_char PARAMS((int *));
static int rl_gather_tyi PARAMS((void));

#if defined (_WIN32) && !defined (__CYGWIN__)

/* 'isatty' in the Windows runtime returns non-zero for every
   character device, including the null device.  Repair that.  */
#include <io.h>
#include <conio.h>
#define WIN32_LEAN_AND_MEAN 1
#include <windows.h>

int w32_isatty (int fd)
{
  if (_isatty(fd))
    {
      HANDLE h;
      DWORD ignored;

      if ((h = (HANDLE) _get_osfhandle (fd)) == INVALID_HANDLE_VALUE)
	{
	  errno = EBADF;
	  return 0;
	}
      if (GetConsoleMode (h, &ignored) != 0)
	return 1;
    }
  errno = ENOTTY;
  return 0;
}

#define isatty(x)  w32_isatty(x)
#endif

/* **************************************************************** */
/*								    */
/*			Character Input Buffering       	    */
/*								    */
/* **************************************************************** */

static int pop_index, push_index;
static unsigned char ibuffer[512];
static int ibuffer_len = sizeof (ibuffer) - 1;

#define any_typein (push_index != pop_index)

int
_rl_any_typein (void)
{
  return any_typein;
}

int
_rl_pushed_input_available (void)
{
  return (push_index != pop_index);
}

/* Return the amount of space available in the buffer for stuffing
   characters. */
static int
ibuffer_space (void)
{
  if (pop_index > push_index)
    return (pop_index - push_index - 1);
  else
    return (ibuffer_len - (push_index - pop_index));
}

/* Get a key from the buffer of characters to be read.
   Return the key in KEY.
   Result is non-zero if there was a key, or 0 if there wasn't. */
static int
rl_get_char (int *key)
{
  if (push_index == pop_index)
    return (0);

  *key = ibuffer[pop_index++];
#if 0
  if (pop_index >= ibuffer_len)
#else
  if (pop_index > ibuffer_len)
#endif
    pop_index = 0;

  return (1);
}

/* Stuff KEY into the *front* of the input buffer.
   Returns non-zero if successful, zero if there is
   no space left in the buffer. */
int
_rl_unget_char (int key)
{
  if (ibuffer_space ())
    {
      pop_index--;
      if (pop_index < 0)
	pop_index = ibuffer_len;
      ibuffer[pop_index] = key;
      return (1);
    }
  return (0);
}

/* If a character is available to be read, then read it and stuff it into
   IBUFFER.  Otherwise, just return.  Returns number of characters read
   (0 if none available) and -1 on error (EIO). */
static int
rl_gather_tyi (void)
{
  int tty;
  register int tem, result;
  int chars_avail, k;
  char input;
#if defined(HAVE_SELECT)
  fd_set readfds, exceptfds;
  struct timeval timeout;
#endif

  chars_avail = 0;
  input = 0;
  tty = fileno (rl_instream);

#if defined (HAVE_SELECT)
  FD_ZERO (&readfds);
  FD_ZERO (&exceptfds);
  FD_SET (tty, &readfds);
  FD_SET (tty, &exceptfds);
  USEC_TO_TIMEVAL (_keyboard_input_timeout, timeout);
  result = select (tty + 1, &readfds, (fd_set *)NULL, &exceptfds, &timeout);
  if (result <= 0)
    return 0;	/* Nothing to read. */
#endif

  result = -1;
  errno = 0;
#if defined (FIONREAD)
  result = ioctl (tty, FIONREAD, &chars_avail);
  if (result == -1 && errno == EIO)
    return -1;
  if (result == -1)
    chars_avail = 0;
#endif

#if defined (O_NDELAY)
  if (result == -1)
    {
      tem = fcntl (tty, F_GETFL, 0);

      fcntl (tty, F_SETFL, (tem | O_NDELAY));
      chars_avail = read (tty, &input, 1);

      fcntl (tty, F_SETFL, tem);
      if (chars_avail == -1 && errno == EAGAIN)
	return 0;
      if (chars_avail == -1 && errno == EIO)
	return -1;
      if (chars_avail == 0)	/* EOF */
	{
	  rl_stuff_char (EOF);
	  return (0);
	}
    }
#endif /* O_NDELAY */

#if defined (__MINGW32__)
  /* Use getch/_kbhit to check for available console input, in the same way
     that we read it normally. */
   chars_avail = isatty (tty) ? _kbhit () : 0;
   result = 0;
#endif

  /* If there's nothing available, don't waste time trying to read
     something. */
  if (chars_avail <= 0)
    return 0;

  tem = ibuffer_space ();

  if (chars_avail > tem)
    chars_avail = tem;

  /* One cannot read all of the available input.  I can only read a single
     character at a time, or else programs which require input can be
     thwarted.  If the buffer is larger than one character, I lose.
     Damn! */
  if (tem < ibuffer_len)
    chars_avail = 0;

  if (result != -1)
    {
      while (chars_avail--)
	{
	  RL_CHECK_SIGNALS ();
	  k = (*rl_getc_function) (rl_instream);
	  if (rl_stuff_char (k) == 0)
	    break;			/* some problem; no more room */
	  if (k == NEWLINE || k == RETURN)
	    break;
	}
    }
  else
    {
      if (chars_avail)
	rl_stuff_char (input);
    }

  return 1;
}

int
rl_set_keyboard_input_timeout (int u)
{
  int o;

  o = _keyboard_input_timeout;
  if (u >= 0)
    _keyboard_input_timeout = u;
  return (o);
}

/* Is there input available to be read on the readline input file
   descriptor?  Only works if the system has select(2) or FIONREAD.
   Uses the value of _keyboard_input_timeout as the timeout; if another
   readline function wants to specify a timeout and not leave it up to
   the user, it should use _rl_input_queued(timeout_value_in_microseconds)
   instead. */
int
_rl_input_available (void)
{
#if defined(HAVE_SELECT)
  fd_set readfds, exceptfds;
  struct timeval timeout;
#endif
#if !defined (HAVE_SELECT) && defined(FIONREAD)
  int chars_avail;
#endif
  int tty;

  if (rl_input_available_hook)
    return (*rl_input_available_hook) ();

  tty = fileno (rl_instream);

#if defined (HAVE_SELECT)
  FD_ZERO (&readfds);
  FD_ZERO (&exceptfds);
  FD_SET (tty, &readfds);
  FD_SET (tty, &exceptfds);
  timeout.tv_sec = 0;
  timeout.tv_usec = _keyboard_input_timeout;
  return (select (tty + 1, &readfds, (fd_set *)NULL, &exceptfds, &timeout) > 0);
#else

#if defined (FIONREAD)
  if (ioctl (tty, FIONREAD, &chars_avail) == 0)
    return (chars_avail);
#endif

#endif

#if defined (__MINGW32__)
  if (isatty (tty))
    return (_kbhit ());
#endif

  return 0;
}

int
_rl_input_queued (int t)
{
  int old_timeout, r;

  old_timeout = rl_set_keyboard_input_timeout (t);
  r = _rl_input_available ();
  rl_set_keyboard_input_timeout (old_timeout);
  return r;
}

void
_rl_insert_typein (int c)
{    	
  int key, t, i;
  char *string;

  i = key = 0;
  string = (char *)xmalloc (ibuffer_len + 1);
  string[i++] = (char) c;

  while ((t = rl_get_char (&key)) &&
	 _rl_keymap[key].type == ISFUNC &&
	 _rl_keymap[key].function == rl_insert)
    string[i++] = key;

  if (t)
    _rl_unget_char (key);

  string[i] = '\0';
  rl_insert_text (string);
  xfree (string);
}

/* Add KEY to the buffer of characters to be read.  Returns 1 if the
   character was stuffed correctly; 0 otherwise. */
int
rl_stuff_char (int key)
{
  if (ibuffer_space () == 0)
    return 0;

  if (key == EOF)
    {
      key = NEWLINE;
      rl_pending_input = EOF;
      RL_SETSTATE (RL_STATE_INPUTPENDING);
    }
  ibuffer[push_index++] = key;
#if 0
  if (push_index >= ibuffer_len)
#else
  if (push_index > ibuffer_len)
#endif
    push_index = 0;

  return 1;
}

/* Make C be the next command to be executed. */
int
rl_execute_next (int c)
{
  rl_pending_input = c;
  RL_SETSTATE (RL_STATE_INPUTPENDING);
  return 0;
}

/* Clear any pending input pushed with rl_execute_next() */
int
rl_clear_pending_input (void)
{
  rl_pending_input = 0;
  RL_UNSETSTATE (RL_STATE_INPUTPENDING);
  return 0;
}

/* **************************************************************** */
/*								    */
/*			     Character Input			    */
/*								    */
/* **************************************************************** */

/* Read a key, including pending input. */
int
rl_read_key (void)
{
  int c, r;

  if (rl_pending_input)
    {
      c = rl_pending_input;	/* XXX - cast to unsigned char if > 0? */
      rl_clear_pending_input ();
    }
  else
    {
      /* If input is coming from a macro, then use that. */
      if (c = _rl_next_macro_key ())
	return ((unsigned char)c);

      /* If the user has an event function, then call it periodically. */
      if (rl_event_hook)
	{
	  while (rl_event_hook)
	    {
	      if (rl_get_char (&c) != 0)
		break;
		
	      if ((r = rl_gather_tyi ()) < 0)	/* XXX - EIO */
		{
		  rl_done = 1;
		  return (errno == EIO ? (RL_ISSTATE (RL_STATE_READCMD) ? READERR : EOF) : '\n');
		}
	      else if (r > 0)			/* read something */
		continue;

	      RL_CHECK_SIGNALS ();
	      if (rl_done)		/* XXX - experimental */
		return ('\n');
	      (*rl_event_hook) ();
	    }
	}
      else
	{
	  if (rl_get_char (&c) == 0)
	    c = (*rl_getc_function) (rl_instream);
/* fprintf(stderr, "rl_read_key: calling RL_CHECK_SIGNALS: _rl_caught_signal = %d", _rl_caught_signal); */
	  RL_CHECK_SIGNALS ();
	}
    }

  return (c);
}

int
rl_getc (FILE *stream)
{
  int result;
  unsigned char c;
#if defined (HAVE_PSELECT)
  sigset_t empty_set;
  fd_set readfds;
#endif

  while (1)
    {
      RL_CHECK_SIGNALS ();

      /* We know at this point that _rl_caught_signal == 0 */

#if defined (__MINGW32__)
      if (isatty (fileno (stream)))
	return (_getch ());	/* "There is no error return." */
#endif
      result = 0;
#if defined (HAVE_PSELECT)
      FD_ZERO (&readfds);
      FD_SET (fileno (stream), &readfds);
#  if defined (HANDLE_SIGNALS)
      result = pselect (fileno (stream) + 1, &readfds, NULL, NULL, NULL, &_rl_orig_sigset);
#  else
      sigemptyset (&empty_set);
      sigprocmask (SIG_BLOCK, (sigset_t *)NULL, &empty_set);
      result = pselect (fileno (stream) + 1, &readfds, NULL, NULL, NULL, &empty_set);
#  endif /* HANDLE_SIGNALS */
#endif
      if (result >= 0)
	result = read (fileno (stream), &c, sizeof (unsigned char));

      if (result == sizeof (unsigned char))
	return (c);

      /* If zero characters are returned, then the file that we are
	 reading from is empty!  Return EOF in that case. */
      if (result == 0)
	return (EOF);

#if defined (__BEOS__)
      if (errno == EINTR)
	continue;
#endif

#if defined (EWOULDBLOCK)
#  define X_EWOULDBLOCK EWOULDBLOCK
#else
#  define X_EWOULDBLOCK -99
#endif

#if defined (EAGAIN)
#  define X_EAGAIN EAGAIN
#else
#  define X_EAGAIN -99
#endif

      if (errno == X_EWOULDBLOCK || errno == X_EAGAIN)
	{
	  if (sh_unset_nodelay_mode (fileno (stream)) < 0)
	    return (EOF);
	  continue;
	}

#undef X_EWOULDBLOCK
#undef X_EAGAIN

/* fprintf(stderr, "rl_getc: result = %d errno = %d\n", result, errno); */

handle_error:
      /* If the error that we received was EINTR, then try again,
	 this is simply an interrupted system call to read ().  We allow
	 the read to be interrupted if we caught SIGHUP, SIGTERM, or any
	 of the other signals readline treats specially. If the
	 application sets an event hook, call it for other signals.
	 Otherwise (not EINTR), some error occurred, also signifying EOF. */
      if (errno != EINTR)
	return (RL_ISSTATE (RL_STATE_READCMD) ? READERR : EOF);
      /* fatal signals of interest */
#if defined (SIGHUP)
      else if (_rl_caught_signal == SIGHUP || _rl_caught_signal == SIGTERM)
#else
      else if (_rl_caught_signal == SIGTERM)
#endif
	return (RL_ISSTATE (RL_STATE_READCMD) ? READERR : EOF);
      /* keyboard-generated signals of interest */
#if defined (SIGQUIT)
      else if (_rl_caught_signal == SIGINT || _rl_caught_signal == SIGQUIT)
#else
      else if (_rl_caught_signal == SIGINT)
#endif
        RL_CHECK_SIGNALS ();
      /* non-keyboard-generated signals of interest */
#if defined (SIGWINCH)
      else if (_rl_caught_signal == SIGWINCH)
	RL_CHECK_SIGNALS ();
#endif /* SIGWINCH */
#if defined (SIGALRM)
      else if (_rl_caught_signal == SIGALRM
#  if defined (SIGVTALRM)
		|| _rl_caught_signal == SIGVTALRM
#  endif
	      )
        RL_CHECK_SIGNALS ();
#endif  /* SIGALRM */

      if (rl_signal_event_hook)
	(*rl_signal_event_hook) ();
    }
}

#if defined (HANDLE_MULTIBYTE)
/* read multibyte char */
int
_rl_read_mbchar (char *mbchar, int size)
{
  int mb_len, c;
  size_t mbchar_bytes_length;
  wchar_t wc;
  mbstate_t ps, ps_back;

  memset(&ps, 0, sizeof (mbstate_t));
  memset(&ps_back, 0, sizeof (mbstate_t));

  mb_len = 0;  
  while (mb_len < size)
    {
      RL_SETSTATE(RL_STATE_MOREINPUT);
      c = rl_read_key ();
      RL_UNSETSTATE(RL_STATE_MOREINPUT);

      if (c < 0)
	break;

      mbchar[mb_len++] = c;

      mbchar_bytes_length = mbrtowc (&wc, mbchar, mb_len, &ps);
      if (mbchar_bytes_length == (size_t)(-1))
	break;		/* invalid byte sequence for the current locale */
      else if (mbchar_bytes_length == (size_t)(-2))
	{
	  /* shorted bytes */
	  ps = ps_back;
	  continue;
	} 
      else if (mbchar_bytes_length == 0)
	{
	  mbchar[0] = '\0';	/* null wide character */
	  mb_len = 1;
	  break;
	}
      else if (mbchar_bytes_length > (size_t)(0))
	break;
    }

  return mb_len;
}

/* Read a multibyte-character string whose first character is FIRST into
   the buffer MB of length MLEN.  Returns the last character read, which
   may be FIRST.  Used by the search functions, among others.  Very similar
   to _rl_read_mbchar. */
int
_rl_read_mbstring (int first, char *mb, int mlen)
{
  int i, c, n;
  mbstate_t ps;

  c = first;
  memset (mb, 0, mlen);
  for (i = 0; c >= 0 && i < mlen; i++)
    {
      mb[i] = (char)c;
      memset (&ps, 0, sizeof (mbstate_t));
      n = _rl_get_char_len (mb, &ps);
      if (n == -2)
	{
	  /* Read more for multibyte character */
	  RL_SETSTATE (RL_STATE_MOREINPUT);
	  c = rl_read_key ();
	  RL_UNSETSTATE (RL_STATE_MOREINPUT);
	}
      else
	break;
    }
  return c;
}
#endif /* HANDLE_MULTIBYTE */