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schmorp.h  view on Meta::CPAN

#  define eventfd(initval,flags) -1
# endif
#endif

typedef struct {
  int fd[2]; /* read, write fd, might be equal */
  int len; /* write length (1 pipe/socket, 8 eventfd) */
} s_epipe;

static int
s_epipe_new (s_epipe *epp)
{
  s_epipe ep;

  ep.fd [0] = ep.fd [1] = eventfd (0, 0);

  if (ep.fd [0] >= 0)
    {
      s_fd_prepare (ep.fd [0]);
      ep.len = 8;
    }
  else
    {
      if (s_pipe (ep.fd))
        return -1;

      if (s_fd_prepare (ep.fd [0])
          || s_fd_prepare (ep.fd [1]))
        {
           dTHX;

           close (ep.fd [0]);
           close (ep.fd [1]);
           return -1;
        }

      ep.len = 1;
    }

  *epp = ep;
  return 0;
}

static void
s_epipe_destroy (s_epipe *epp)
{
  dTHX;

  close (epp->fd [0]);

  if (epp->fd [1] != epp->fd [0])
    close (epp->fd [1]);

  epp->len = 0;
}

static void
s_epipe_signal (s_epipe *epp)
{
#ifdef _WIN32
  /* perl overrides send with a function that crashes in other threads.
   * unfortunately, it overrides it with an argument-less macro, so
   * there is no way to force usage of the real send function.
   * incompetent windows programmers - is this redundant?
   */
  DWORD dummy;
  WriteFile (S_TO_HANDLE (epp->fd [1]), (LPCVOID)&dummy, 1, &dummy, 0);
#else
  static uint64_t counter = 1;
  /* some modules accept fd's from outside, support eventfd here */
  if (write (epp->fd [1], &counter, epp->len) < 0
      && errno == EINVAL
      && epp->len != 8)
    write (epp->fd [1], &counter, (epp->len = 8));
#endif
}

static void
s_epipe_drain (s_epipe *epp)
{
  dTHX;
  char buf [9];

#ifdef _WIN32
  recv (epp->fd [0], buf, sizeof (buf), 0);
#else
  read (epp->fd [0], buf, sizeof (buf));
#endif
}

/* like new, but dups over old */
static int
s_epipe_renew (s_epipe *epp)
{
  dTHX;
  s_epipe epn;

  if (epp->fd [1] != epp->fd [0])
    close (epp->fd [1]);

  if (s_epipe_new (&epn))
    return -1;

  if (epp->len)
    {
      if (dup2 (epn.fd [0], epp->fd [0]) < 0)
        croak ("unable to dup over old event pipe"); /* should not croak */

      close (epn.fd [0]);

      if (epn.fd [0] == epn.fd [1])
        epn.fd [1] = epp->fd [0];

      epn.fd [0] = epp->fd [0];
    }

  *epp = epn;

  return 0;
}