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libuv/src/unix/tty.c  view on Meta::CPAN

  while (saved_flags == -1 && errno == EINTR);

  if (saved_flags == -1)
    return UV__ERR(errno);
  mode = saved_flags & O_ACCMODE;

  /* Reopen the file descriptor when it refers to a tty. This lets us put the
   * tty in non-blocking mode without affecting other processes that share it
   * with us.
   *
   * Example: `node | cat` - if we put our fd 0 in non-blocking mode, it also
   * affects fd 1 of `cat` because both file descriptors refer to the same
   * struct file in the kernel. When we reopen our fd 0, it points to a
   * different struct file, hence changing its properties doesn't affect
   * other processes.
   */
  if (type == UV_TTY) {
    /* Reopening a pty in master mode won't work either because the reopened
     * pty will be in slave mode (*BSD) or reopening will allocate a new
     * master/slave pair (Linux). Therefore check if the fd points to a
     * slave device.
     */
    if (uv__tty_is_slave(fd) && ttyname_r(fd, path, sizeof(path)) == 0)
      r = uv__open_cloexec(path, mode);
    else
      r = -1;

    if (r < 0) {
      /* fallback to using blocking writes */
      if (mode != O_RDONLY)
        flags |= UV_HANDLE_BLOCKING_WRITES;
      goto skip;
    }

    newfd = r;

    r = uv__dup2_cloexec(newfd, fd);
    if (r < 0 && r != UV_EINVAL) {
      /* EINVAL means newfd == fd which could conceivably happen if another
       * thread called close(fd) between our calls to isatty() and open().
       * That's a rather unlikely event but let's handle it anyway.
       */
      uv__close(newfd);
      return r;
    }

    fd = newfd;
  }

skip:
  uv__stream_init(loop, (uv_stream_t*) tty, UV_TTY);

  /* If anything fails beyond this point we need to remove the handle from
   * the handle queue, since it was added by uv__handle_init in uv_stream_init.
   */

  if (!(flags & UV_HANDLE_BLOCKING_WRITES))
    uv__nonblock(fd, 1);

#if defined(__APPLE__)
  r = uv__stream_try_select((uv_stream_t*) tty, &fd);
  if (r) {
    int rc = r;
    if (newfd != -1)
      uv__close(newfd);
    QUEUE_REMOVE(&tty->handle_queue);
    do
      r = fcntl(fd, F_SETFL, saved_flags);
    while (r == -1 && errno == EINTR);
    return rc;
  }
#endif

  if (mode != O_WRONLY)
    flags |= UV_HANDLE_READABLE;
  if (mode != O_RDONLY)
    flags |= UV_HANDLE_WRITABLE;

  uv__stream_open((uv_stream_t*) tty, fd, flags);
  tty->mode = UV_TTY_MODE_NORMAL;

  return 0;
}

static void uv__tty_make_raw(struct termios* tio) {
  assert(tio != NULL);

#if defined __sun || defined __MVS__
  /*
   * This implementation of cfmakeraw for Solaris and derivatives is taken from
   * http://www.perkin.org.uk/posts/solaris-portability-cfmakeraw.html.
   */
  tio->c_iflag &= ~(IMAXBEL | IGNBRK | BRKINT | PARMRK | ISTRIP | INLCR |
                    IGNCR | ICRNL | IXON);
  tio->c_oflag &= ~OPOST;
  tio->c_lflag &= ~(ECHO | ECHONL | ICANON | ISIG | IEXTEN);
  tio->c_cflag &= ~(CSIZE | PARENB);
  tio->c_cflag |= CS8;
#else
  cfmakeraw(tio);
#endif /* #ifdef __sun */
}

int uv_tty_set_mode(uv_tty_t* tty, uv_tty_mode_t mode) {
  struct termios tmp;
  int fd;

  if (tty->mode == (int) mode)
    return 0;

  fd = uv__stream_fd(tty);
  if (tty->mode == UV_TTY_MODE_NORMAL && mode != UV_TTY_MODE_NORMAL) {
    if (tcgetattr(fd, &tty->orig_termios))
      return UV__ERR(errno);

    /* This is used for uv_tty_reset_mode() */
    uv_spinlock_lock(&termios_spinlock);
    if (orig_termios_fd == -1) {
      orig_termios = tty->orig_termios;
      orig_termios_fd = fd;
    }