input.cc

/* 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.hh>
#endif

#include <fcntl.h>
#include <sys/types.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.hh"
#endif /* HAVE_STDLIB_H */

#include <signal.h>

#include "posixselect.hh"

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

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

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

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

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

#include "rlprivate.hh"
#include "rlshell.hh"
#include "xmalloc.hh"

/* 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));

/* Windows isatty returns true for every character device, including the
   null device, so we need to perform additional checks. */
#if defined(_WIN32) && !defined(__CYGWIN__)
#include <conio.h>
#include <io.h>
#define WIN32_LEAN_AND_MEAN 1
#include <windows.h>

int win32_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) win32_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;
   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 */