Re: [naviserver-devel] commit/naviserver: gustafn: - Fix to prevent multiple DriverAccepts on the same socket. The original coded relied on the fact that later accepts

[Stephen D. <sd...@gm...>]

On Mon, Apr 12, 2010 at 2:33 PM, Gustaf Neumann <ne...@wu...> wrote:
>
> Without the patch naviserver hangs (blocks) on that machine already
> at the first or second request.


This should never happen as the listen socket is set to non-blocking mode, here:

  http://bitbucket.org/naviserver/naviserver/src/tip/nssock/nssock.c#cl-131

nssock.c:Accept() calls nsd/sock.c:Ns_SockAccept() which calls
accept(2), who's man page says:

    If no pending connections are present on the queue, and the socket
is not marked
    as non-blocking, accept() blocks the caller until a connection is
present.  If the socket
    is marked non-blocking and no pending connections are present on
the queue, accept()
    fails with the error EAGAIN or EWOULDBLOCK.

In which case, Ns_SockAccept looks wrong:

SOCKET
Ns_SockAccept(SOCKET lsock, struct sockaddr *saPtr, int *lenPtr)
{
    SOCKET sock;

    sock = accept(lsock, saPtr, (socklen_t *) lenPtr);

    if (sock != INVALID_SOCKET) {
        sock = SockSetup(sock);
    }

    return sock;
}


Shouldn't this be something more like:

    if (sock > -1) {
        sock = SockSetup(sock);
    }

as INVALID_SOCKET is -1 but there is more than one possible error state?

(I haven't tried this...)