int
pgwin32_waitforsinglesocket(SOCKET s, int what, int timeout)
{
static HANDLE waitevent = INVALID_HANDLE_VALUE;
static SOCKET current_socket = INVALID_SOCKET;
static int isUDP = 0;
HANDLE events[2];
int r;
/* Create an event object just once and use it on all future calls */
if (waitevent == INVALID_HANDLE_VALUE)
{
waitevent = CreateEvent(NULL, TRUE, FALSE, NULL);
if (waitevent == INVALID_HANDLE_VALUE)
ereport(ERROR,
(errmsg_internal("could not create socket waiting event: error code %lu", GetLastError())));
}
else if (!ResetEvent(waitevent))
ereport(ERROR,
(errmsg_internal("could not reset socket waiting event: error code %lu", GetLastError())));
/*
* Track whether socket is UDP or not. (NB: most likely, this is both
* useless and wrong; there is no reason to think that the behavior of
* WSAEventSelect is different for TCP and UDP.)
*/
if (current_socket != s)
isUDP = isDataGram(s);
current_socket = s;
/*
* Attach event to socket. NOTE: we must detach it again before
* returning, since other bits of code may try to attach other events to
* the socket.
*/
if (WSAEventSelect(s, waitevent, what) != 0)
{
TranslateSocketError();
return 0;
}
events[0] = pgwin32_signal_event;
events[1] = waitevent;
/*
* Just a workaround of unknown locking problem with writing in UDP socket
* under high load: Client's pgsql backend sleeps infinitely in
* WaitForMultipleObjectsEx, pgstat process sleeps in pgwin32_select().
* So, we will wait with small timeout(0.1 sec) and if socket is still
* blocked, try WSASend (see comments in pgwin32_select) and wait again.
*/
if ((what & FD_WRITE) && isUDP)
{
for (;;)
{
r = WaitForMultipleObjectsEx(2, events, FALSE, 100, TRUE);
if (r == WAIT_TIMEOUT)
{
char c;
WSABUF buf;
DWORD sent;
buf.buf = &c;
buf.len = 0;
r = WSASend(s, &buf, 1, &sent, 0, NULL, NULL);
if (r == 0) /* Completed - means things are fine! */
{
WSAEventSelect(s, NULL, 0);
return 1;
}
else if (WSAGetLastError() != WSAEWOULDBLOCK)
{
TranslateSocketError();
WSAEventSelect(s, NULL, 0);
return 0;
}
}
else
break;
}
}
else
r = WaitForMultipleObjectsEx(2, events, FALSE, timeout, TRUE);
WSAEventSelect(s, NULL, 0);
if (r == WAIT_OBJECT_0 || r == WAIT_IO_COMPLETION)
{
pgwin32_dispatch_queued_signals();
errno = EINTR;
return 0;
}
if (r == WAIT_OBJECT_0 + 1)
return 1;
if (r == WAIT_TIMEOUT)
{
errno = EWOULDBLOCK;
return 0;
}
ereport(ERROR,
(errmsg_internal("unrecognized return value from WaitForMultipleObjects: %d (error code %lu)", r, GetLastError())));
return 0;
}
int
pgwin32_waitforsinglesocket(SOCKET s, int what, int timeout)
{
static HANDLE waitevent = INVALID_HANDLE_VALUE;
static SOCKET current_socket = -1;
static int isUDP = 0;
HANDLE events[2];
int r;
if (waitevent == INVALID_HANDLE_VALUE)
{
waitevent = CreateEvent(NULL, TRUE, FALSE, NULL);
if (waitevent == INVALID_HANDLE_VALUE)
ereport(ERROR,
(errmsg_internal("Failed to create socket waiting event: %i", (int) GetLastError())));
}
else if (!ResetEvent(waitevent))
ereport(ERROR,
(errmsg_internal("Failed to reset socket waiting event: %i", (int) GetLastError())));
/*
* make sure we don't multiplex this kernel event object with a different
* socket from a previous call
*/
if (current_socket != s)
{
if (current_socket != -1)
WSAEventSelect(current_socket, waitevent, 0);
isUDP = isDataGram(s);
}
current_socket = s;
if (WSAEventSelect(s, waitevent, what) == SOCKET_ERROR)
{
TranslateSocketError();
return 0;
}
events[0] = pgwin32_signal_event;
events[1] = waitevent;
/*
* Just a workaround of unknown locking problem with writing in UDP socket
* under high load: Client's pgsql backend sleeps infinitely in
* WaitForMultipleObjectsEx, pgstat process sleeps in pgwin32_select().
* So, we will wait with small timeout(0.1 sec) and if sockect is still
* blocked, try WSASend (see comments in pgwin32_select) and wait again.
*/
if ((what & FD_WRITE) && isUDP)
{
for (;;)
{
r = WaitForMultipleObjectsEx(2, events, FALSE, 100, TRUE);
if (r == WAIT_TIMEOUT)
{
char c;
WSABUF buf;
DWORD sent;
buf.buf = &c;
buf.len = 0;
r = WSASend(s, &buf, 1, &sent, 0, NULL, NULL);
if (r == 0) /* Completed - means things are fine! */
return 1;
else if (WSAGetLastError() != WSAEWOULDBLOCK)
{
TranslateSocketError();
return 0;
}
}
else
break;
}
}
else
r = WaitForMultipleObjectsEx(2, events, FALSE, timeout, TRUE);
if (r == WAIT_OBJECT_0 || r == WAIT_IO_COMPLETION)
{
pgwin32_dispatch_queued_signals();
errno = EINTR;
return 0;
}
if (r == WAIT_OBJECT_0 + 1)
return 1;
if (r == WAIT_TIMEOUT)
return 0;
ereport(ERROR,
(errmsg_internal("Bad return from WaitForMultipleObjects: %i (%i)", r, (int) GetLastError())));
return 0;
}
