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|
/*-------------------------------------------------------------------------
*
* socket.c
* Microsoft Windows Win32 Socket Functions
*
* Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/port/win32/socket.c,v 1.25 2010/02/17 05:51:40 mha Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
/*
* Indicate if pgwin32_recv() should operate in non-blocking mode.
*
* Since the socket emulation layer always sets the actual socket to
* non-blocking mode in order to be able to deliver signals, we must
* specify this in a separate flag if we actually need non-blocking
* operation.
*
* This flag changes the behaviour *globally* for all socket operations,
* so it should only be set for very short periods of time.
*/
int pgwin32_noblock = 0;
#undef socket
#undef accept
#undef connect
#undef select
#undef recv
#undef send
/*
* Blocking socket functions implemented so they listen on both
* the socket and the signal event, required for signal handling.
*/
/*
* Convert the last socket error code into errno
*/
static void
TranslateSocketError(void)
{
switch (WSAGetLastError())
{
case WSANOTINITIALISED:
case WSAENETDOWN:
case WSAEINPROGRESS:
case WSAEINVAL:
case WSAESOCKTNOSUPPORT:
case WSAEFAULT:
case WSAEINVALIDPROVIDER:
case WSAEINVALIDPROCTABLE:
case WSAEMSGSIZE:
errno = EINVAL;
break;
case WSAEAFNOSUPPORT:
errno = EAFNOSUPPORT;
break;
case WSAEMFILE:
errno = EMFILE;
break;
case WSAENOBUFS:
errno = ENOBUFS;
break;
case WSAEPROTONOSUPPORT:
case WSAEPROTOTYPE:
errno = EPROTONOSUPPORT;
break;
case WSAECONNREFUSED:
errno = ECONNREFUSED;
break;
case WSAEINTR:
errno = EINTR;
break;
case WSAENOTSOCK:
errno = EBADFD;
break;
case WSAEOPNOTSUPP:
errno = EOPNOTSUPP;
break;
case WSAEWOULDBLOCK:
errno = EWOULDBLOCK;
break;
case WSAEACCES:
errno = EACCES;
break;
case WSAENOTCONN:
case WSAENETRESET:
case WSAECONNRESET:
case WSAESHUTDOWN:
case WSAECONNABORTED:
case WSAEDISCON:
errno = ECONNREFUSED; /* ENOTCONN? */
break;
default:
ereport(NOTICE,
(errmsg_internal("Unknown win32 socket error code: %i", WSAGetLastError())));
errno = EINVAL;
}
}
static int
pgwin32_poll_signals(void)
{
if (UNBLOCKED_SIGNAL_QUEUE())
{
pgwin32_dispatch_queued_signals();
errno = EINTR;
return 1;
}
return 0;
}
static int
isDataGram(SOCKET s)
{
int type;
int typelen = sizeof(type);
if (getsockopt(s, SOL_SOCKET, SO_TYPE, (char *) &type, &typelen))
return 1;
return (type == SOCK_DGRAM) ? 1 : 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;
}
/*
* Create a socket, setting it to overlapped and non-blocking
*/
SOCKET
pgwin32_socket(int af, int type, int protocol)
{
SOCKET s;
unsigned long on = 1;
s = WSASocket(af, type, protocol, NULL, 0, WSA_FLAG_OVERLAPPED);
if (s == INVALID_SOCKET)
{
TranslateSocketError();
return INVALID_SOCKET;
}
if (ioctlsocket(s, FIONBIO, &on))
{
TranslateSocketError();
return INVALID_SOCKET;
}
errno = 0;
return s;
}
SOCKET
pgwin32_accept(SOCKET s, struct sockaddr * addr, int *addrlen)
{
SOCKET rs;
/*
* Poll for signals, but don't return with EINTR, since we don't handle
* that in pqcomm.c
*/
pgwin32_poll_signals();
rs = WSAAccept(s, addr, addrlen, NULL, 0);
if (rs == INVALID_SOCKET)
{
TranslateSocketError();
return INVALID_SOCKET;
}
return rs;
}
/* No signal delivery during connect. */
int
pgwin32_connect(SOCKET s, const struct sockaddr * addr, int addrlen)
{
int r;
r = WSAConnect(s, addr, addrlen, NULL, NULL, NULL, NULL);
if (r == 0)
return 0;
if (WSAGetLastError() != WSAEWOULDBLOCK)
{
TranslateSocketError();
return -1;
}
while (pgwin32_waitforsinglesocket(s, FD_CONNECT, INFINITE) == 0)
{
/* Loop endlessly as long as we are just delivering signals */
}
return 0;
}
int
pgwin32_recv(SOCKET s, char *buf, int len, int f)
{
WSABUF wbuf;
int r;
DWORD b;
DWORD flags = f;
int n;
if (pgwin32_poll_signals())
return -1;
wbuf.len = len;
wbuf.buf = buf;
r = WSARecv(s, &wbuf, 1, &b, &flags, NULL, NULL);
if (r != SOCKET_ERROR && b > 0)
/* Read succeeded right away */
return b;
if (r == SOCKET_ERROR &&
WSAGetLastError() != WSAEWOULDBLOCK)
{
TranslateSocketError();
return -1;
}
if (pgwin32_noblock)
{
/*
* No data received, and we are in "emulated non-blocking mode", so return
* indicating that we'd block if we were to continue.
*/
errno = EWOULDBLOCK;
return -1;
}
/* No error, zero bytes (win2000+) or error+WSAEWOULDBLOCK (<=nt4) */
for (n = 0; n < 5; n++)
{
if (pgwin32_waitforsinglesocket(s, FD_READ | FD_CLOSE | FD_ACCEPT,
INFINITE) == 0)
return -1; /* errno already set */
r = WSARecv(s, &wbuf, 1, &b, &flags, NULL, NULL);
if (r == SOCKET_ERROR)
{
if (WSAGetLastError() == WSAEWOULDBLOCK)
{
/*
* There seem to be cases on win2k (at least) where WSARecv
* can return WSAEWOULDBLOCK even when
* pgwin32_waitforsinglesocket claims the socket is readable.
* In this case, just sleep for a moment and try again. We try
* up to 5 times - if it fails more than that it's not likely
* to ever come back.
*/
pg_usleep(10000);
continue;
}
TranslateSocketError();
return -1;
}
return b;
}
ereport(NOTICE,
(errmsg_internal("Failed to read from ready socket (after retries)")));
errno = EWOULDBLOCK;
return -1;
}
int
pgwin32_send(SOCKET s, char *buf, int len, int flags)
{
WSABUF wbuf;
int r;
DWORD b;
if (pgwin32_poll_signals())
return -1;
wbuf.len = len;
wbuf.buf = buf;
/*
* Readiness of socket to send data to UDP socket may be not true: socket
* can become busy again! So loop until send or error occurs.
*/
for (;;)
{
r = WSASend(s, &wbuf, 1, &b, flags, NULL, NULL);
if (r != SOCKET_ERROR && b > 0)
/* Write succeeded right away */
return b;
if (r == SOCKET_ERROR &&
WSAGetLastError() != WSAEWOULDBLOCK)
{
TranslateSocketError();
return -1;
}
/* No error, zero bytes (win2000+) or error+WSAEWOULDBLOCK (<=nt4) */
if (pgwin32_waitforsinglesocket(s, FD_WRITE | FD_CLOSE, INFINITE) == 0)
return -1;
}
return -1;
}
/*
* Wait for activity on one or more sockets.
* While waiting, allow signals to run
*
* NOTE! Currently does not implement exceptfds check,
* since it is not used in postgresql!
*/
int
pgwin32_select(int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, const struct timeval * timeout)
{
WSAEVENT events[FD_SETSIZE * 2]; /* worst case is readfds totally
* different from writefds, so
* 2*FD_SETSIZE sockets */
SOCKET sockets[FD_SETSIZE * 2];
int numevents = 0;
int i;
int r;
DWORD timeoutval = WSA_INFINITE;
FD_SET outreadfds;
FD_SET outwritefds;
int nummatches = 0;
Assert(exceptfds == NULL);
if (pgwin32_poll_signals())
return -1;
FD_ZERO(&outreadfds);
FD_ZERO(&outwritefds);
/*
* Write FDs are different in the way that it is only flagged by
* WSASelectEvent() if we have tried to write to them first. So try an
* empty write
*/
if (writefds)
{
for (i = 0; i < writefds->fd_count; i++)
{
char c;
WSABUF buf;
DWORD sent;
buf.buf = &c;
buf.len = 0;
r = WSASend(writefds->fd_array[i], &buf, 1, &sent, 0, NULL, NULL);
if (r == 0) /* Completed - means things are fine! */
FD_SET (writefds->fd_array[i], &outwritefds);
else
{ /* Not completed */
if (WSAGetLastError() != WSAEWOULDBLOCK)
/*
* Not completed, and not just "would block", so an error
* occured
*/
FD_SET (writefds->fd_array[i], &outwritefds);
}
}
if (outwritefds.fd_count > 0)
{
memcpy(writefds, &outwritefds, sizeof(fd_set));
if (readfds)
FD_ZERO(readfds);
return outwritefds.fd_count;
}
}
/* Now set up for an actual select */
if (timeout != NULL)
{
/* timeoutval is in milliseconds */
timeoutval = timeout->tv_sec * 1000 + timeout->tv_usec / 1000;
}
if (readfds != NULL)
{
for (i = 0; i < readfds->fd_count; i++)
{
events[numevents] = WSACreateEvent();
sockets[numevents] = readfds->fd_array[i];
numevents++;
}
}
if (writefds != NULL)
{
for (i = 0; i < writefds->fd_count; i++)
{
if (!readfds ||
!FD_ISSET(writefds->fd_array[i], readfds))
{
/* If the socket is not in the read list */
events[numevents] = WSACreateEvent();
sockets[numevents] = writefds->fd_array[i];
numevents++;
}
}
}
for (i = 0; i < numevents; i++)
{
int flags = 0;
if (readfds && FD_ISSET(sockets[i], readfds))
flags |= FD_READ | FD_ACCEPT | FD_CLOSE;
if (writefds && FD_ISSET(sockets[i], writefds))
flags |= FD_WRITE | FD_CLOSE;
if (WSAEventSelect(sockets[i], events[i], flags) == SOCKET_ERROR)
{
TranslateSocketError();
for (i = 0; i < numevents; i++)
WSACloseEvent(events[i]);
return -1;
}
}
events[numevents] = pgwin32_signal_event;
r = WaitForMultipleObjectsEx(numevents + 1, events, FALSE, timeoutval, TRUE);
if (r != WAIT_TIMEOUT && r != WAIT_IO_COMPLETION && r != (WAIT_OBJECT_0 + numevents))
{
/*
* We scan all events, even those not signalled, in case more than one
* event has been tagged but Wait.. can only return one.
*/
WSANETWORKEVENTS resEvents;
for (i = 0; i < numevents; i++)
{
ZeroMemory(&resEvents, sizeof(resEvents));
if (WSAEnumNetworkEvents(sockets[i], events[i], &resEvents) == SOCKET_ERROR)
ereport(FATAL,
(errmsg_internal("failed to enumerate network events: %i", (int) GetLastError())));
/* Read activity? */
if (readfds && FD_ISSET(sockets[i], readfds))
{
if ((resEvents.lNetworkEvents & FD_READ) ||
(resEvents.lNetworkEvents & FD_ACCEPT) ||
(resEvents.lNetworkEvents & FD_CLOSE))
{
FD_SET (sockets[i], &outreadfds);
nummatches++;
}
}
/* Write activity? */
if (writefds && FD_ISSET(sockets[i], writefds))
{
if ((resEvents.lNetworkEvents & FD_WRITE) ||
(resEvents.lNetworkEvents & FD_CLOSE))
{
FD_SET (sockets[i], &outwritefds);
nummatches++;
}
}
}
}
/* Clean up all handles */
for (i = 0; i < numevents; i++)
{
WSAEventSelect(sockets[i], events[i], 0);
WSACloseEvent(events[i]);
}
if (r == WSA_WAIT_TIMEOUT)
{
if (readfds)
FD_ZERO(readfds);
if (writefds)
FD_ZERO(writefds);
return 0;
}
if (r == WAIT_OBJECT_0 + numevents)
{
pgwin32_dispatch_queued_signals();
errno = EINTR;
if (readfds)
FD_ZERO(readfds);
if (writefds)
FD_ZERO(writefds);
return -1;
}
/* Overwrite socket sets with our resulting values */
if (readfds)
memcpy(readfds, &outreadfds, sizeof(fd_set));
if (writefds)
memcpy(writefds, &outwritefds, sizeof(fd_set));
return nummatches;
}
/*
* Return win32 error string, since strerror can't
* handle winsock codes
*/
static char wserrbuf[256];
const char *
pgwin32_socket_strerror(int err)
{
static HANDLE handleDLL = INVALID_HANDLE_VALUE;
if (handleDLL == INVALID_HANDLE_VALUE)
{
handleDLL = LoadLibraryEx("netmsg.dll", NULL, DONT_RESOLVE_DLL_REFERENCES | LOAD_LIBRARY_AS_DATAFILE);
if (handleDLL == NULL)
ereport(FATAL,
(errmsg_internal("Failed to load netmsg.dll: %i", (int) GetLastError())));
}
ZeroMemory(&wserrbuf, sizeof(wserrbuf));
if (FormatMessage(FORMAT_MESSAGE_IGNORE_INSERTS | FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_FROM_HMODULE,
handleDLL,
err,
MAKELANGID(LANG_ENGLISH, SUBLANG_DEFAULT),
wserrbuf,
sizeof(wserrbuf) - 1,
NULL) == 0)
{
/* Failed to get id */
sprintf(wserrbuf, "Unknown winsock error %i", err);
}
return wserrbuf;
}
|