Re: select() on non-sockets in eval.c

Nobu,

I fixed up your patch a bit, so now it works:

static int
is_socket(int fd)
{
    int type;
    size_t len;

    len = sizeof(type);
    if (getsockopt(fd, SOL_SOCKET, SO_TYPE, (void *)&type, &len) == 0)
        return 1;
    if (errno == ENOTSOCK) errno = 0;

    return 0;
}

#undef select

int
rb_vms_select(int maxfd, fd_set *rfd, fd_set *wfd, fd_set *efd, struct
timeval *tv) {
    int i, maxsock, ret, socks, nsocks;
    fd_set rs, ws, es, *rp = 0, *wp = 0, *ep = 0;
    struct timeval z;

    FD_ZERO(&rs);
    FD_ZERO(&ws);
    FD_ZERO(&es);

    /* count socket and non-socket fds, and move socket bits to local
     * fd_sets */
    maxsock = socks = nsocks = 0;
    if (rfd || wfd || efd) {
	for (i = 0; i < maxfd; ++i) {
	    int r = (rfd != 0) && FD_ISSET(i, rfd);
	    int w = (wfd != 0) && FD_ISSET(i, wfd);
	    int e = (efd != 0) && FD_ISSET(i, efd);
	    if (!r && !w && !e) continue;
	    if (is_socket(i)) {
		if (r) {
		    FD_SET(i, (rp = &rs));
		    FD_CLR(i, rfd);
		}
		if (w) {
		    FD_SET(i, (wp = &ws));
		    FD_CLR(i, wfd);
		}
		if (e) {
		    FD_SET(i, (ep = &es));
		    FD_CLR(i, efd);
		}
		maxsock = i + 1;
		socks++;
	    }
	    else {
		nsocks += r + w + e;
	    }
	}
    }

    if (!nsocks) {
	/* sockets only */
        ret = select(maxsock, rp, wp, ep, tv);
        if (rfd) *rfd = rs;
        if (wfd) *wfd = ws;
        if (efd) *efd = es;
	return ret;
    }

    if (!socks) {
	/* assuming non-socket fds are always ready */
	return nsocks;
    }

    /* check if sockets are ready */
    z.tv_sec = 0;
    z.tv_usec = 0;
    ret = select(maxsock, rp, wp, ep, &z);
    if (ret <= 0) {
	return nsocks;
    }

    /* copy set bits back */
    for (i = 0; i < maxsock; ++i) {
	if (rp && FD_ISSET(i, rp)) FD_SET(i, rfd);
	if (wp && FD_ISSET(i, wp)) FD_SET(i, wfd);
	if (ep && FD_ISSET(i, ep)) FD_SET(i, efd);
    }
    ret += nsocks;

    return ret;
}