0001_Revise_socket_emulation_for_win32_backend.patch

diff --git a/src/backend/libpq/pqcomm.c b/src/backend/libpq/pqcomm.c
index 605d891..c92851e 100644
--- a/src/backend/libpq/pqcomm.c
+++ b/src/backend/libpq/pqcomm.c
@@ -795,10 +795,6 @@ pq_set_nonblocking(bool nonblocking)
 	if (MyProcPort->noblock == nonblocking)
 		return;
 
-#ifdef WIN32
-	pgwin32_noblock = nonblocking ? 1 : 0;
-#else
-
 	/*
 	 * Use COMMERROR on failure, because ERROR would try to send the error to
 	 * the client, which might require changing the mode again, leading to
@@ -816,7 +812,7 @@ pq_set_nonblocking(bool nonblocking)
 			ereport(COMMERROR,
 					(errmsg("could not set socket to blocking mode: %m")));
 	}
-#endif
+
 	MyProcPort->noblock = nonblocking;
 }
 
diff --git a/src/backend/port/win32/socket.c b/src/backend/port/win32/socket.c
index c981169..f0ff3e7 100644
--- a/src/backend/port/win32/socket.c
+++ b/src/backend/port/win32/socket.c
@@ -21,11 +21,8 @@
  * 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;
+static fd_set		nonblockset;
 
 #undef socket
 #undef accept
@@ -33,6 +30,7 @@ int			pgwin32_noblock = 0;
 #undef select
 #undef recv
 #undef send
+#undef closesocket
 
 /*
  * Blocking socket functions implemented so they listen on both
@@ -40,6 +38,34 @@ int			pgwin32_noblock = 0;
  */
 
 /*
+ * Set blocking mode for each socket
+ */
+void
+pgwin32_set_socket_nonblock(SOCKET s, int nonblock)
+{
+	if (nonblock)
+		FD_SET(s, &nonblockset);
+	else
+		FD_CLR(s, &nonblockset);
+
+	/*
+	 * fd_set cannot have more than FD_SETSIZE entries. It's not likey to come
+	 * close to this limit but if it goes above the limit, non blocking state
+	 * of some existing sockets will be discarded.
+	 */
+	if (nonblockset.fd_count >= FD_SETSIZE)
+		elog(FATAL, "Too many sockets requested to be nonblocking mode.");
+}
+
+void
+pgwin32_nonblockset_init()
+{
+	FD_ZERO(&nonblockset);
+}
+
+#define socket_is_nonblocking(s) FD_ISSET((s), &nonblockset)
+
+/*
  * Convert the last socket error code into errno
  */
 static void
@@ -256,6 +282,10 @@ pgwin32_socket(int af, int type, int protocol)
 		TranslateSocketError();
 		return INVALID_SOCKET;
 	}
+
+	/* newly cerated socket should be in blocking mode  */
+	pgwin32_set_socket_nonblock(s, false);
+
 	errno = 0;
 
 	return s;
@@ -334,7 +364,7 @@ pgwin32_recv(SOCKET s, char *buf, int len, int f)
 		return -1;
 	}
 
-	if (pgwin32_noblock)
+	if (socket_is_nonblocking(s))
 	{
 		/*
 		 * No data received, and we are in "emulated non-blocking mode", so
@@ -420,7 +450,7 @@ pgwin32_send(SOCKET s, const void *buf, int len, int flags)
 			return -1;
 		}
 
-		if (pgwin32_noblock)
+		if (socket_is_nonblocking(s))
 		{
 			/*
 			 * No data sent, and we are in "emulated non-blocking mode", so
@@ -645,6 +675,15 @@ pgwin32_select(int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, c
 
 
 /*
+ * Unused entry in nonblockset needs to be removed when closing socket.
+ */
+int pgwin32_closesocket(SOCKET s)
+{
+	pgwin32_set_socket_nonblock(s, false);
+	return closesocket(s);
+}
+
+/*
  * Return win32 error string, since strerror can't
  * handle winsock codes
  */
diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index c7f41a5..72e0576 100644
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -3255,22 +3255,10 @@ PgstatCollectorMain(int argc, char *argv[])
 			/*
 			 * Try to receive and process a message.  This will not block,
 			 * since the socket is set to non-blocking mode.
-			 *
-			 * XXX On Windows, we have to force pgwin32_recv to cooperate,
-			 * despite the previous use of pg_set_noblock() on the socket.
-			 * This is extremely broken and should be fixed someday.
 			 */
-#ifdef WIN32
-			pgwin32_noblock = 1;
-#endif
-
 			len = recv(pgStatSock, (char *) &msg,
 					   sizeof(PgStat_Msg), 0);
 
-#ifdef WIN32
-			pgwin32_noblock = 0;
-#endif
-
 			if (len < 0)
 			{
 				if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR)
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index b190cf5..5d32de6 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -896,6 +896,10 @@ PostmasterMain(int argc, char *argv[])
 	 */
 	InitializeMaxBackends();
 
+#ifdef WIN32	
+	pgwin32_nonblockset_init();
+#endif
+
 	/*
 	 * Establish input sockets.
 	 */
diff --git a/src/include/port/win32.h b/src/include/port/win32.h
index 550c3ec..b0df45e 100644
--- a/src/include/port/win32.h
+++ b/src/include/port/win32.h
@@ -368,6 +368,7 @@ void		pg_queue_signal(int signum);
 #define select(n, r, w, e, timeout) pgwin32_select(n, r, w, e, timeout)
 #define recv(s, buf, len, flags) pgwin32_recv(s, buf, len, flags)
 #define send(s, buf, len, flags) pgwin32_send(s, buf, len, flags)
+#define closesocket(s) pgwin32_closesocket(s)
 
 SOCKET		pgwin32_socket(int af, int type, int protocol);
 SOCKET		pgwin32_accept(SOCKET s, struct sockaddr * addr, int *addrlen);
@@ -375,11 +376,12 @@ int			pgwin32_connect(SOCKET s, const struct sockaddr * name, int namelen);
 int			pgwin32_select(int nfds, fd_set *readfs, fd_set *writefds, fd_set *exceptfds, const struct timeval * timeout);
 int			pgwin32_recv(SOCKET s, char *buf, int len, int flags);
 int			pgwin32_send(SOCKET s, const void *buf, int len, int flags);
+int			pgwin32_closesocket(SOCKET s);
 
 const char *pgwin32_socket_strerror(int err);
 int			pgwin32_waitforsinglesocket(SOCKET s, int what, int timeout);
-
-extern int	pgwin32_noblock;
+void		pgwin32_set_socket_nonblock(SOCKET s, int nonblock);
+void		pgwin32_nonblockset_init();
 
 /* in backend/port/win32/security.c */
 extern int	pgwin32_is_admin(void);
diff --git a/src/port/noblock.c b/src/port/noblock.c
index 1da0339..d6cc6a2 100644
--- a/src/port/noblock.c
+++ b/src/port/noblock.c
@@ -25,9 +25,18 @@ pg_set_noblock(pgsocket sock)
 #else
 	unsigned long ioctlsocket_ret = 1;
 
+#ifndef FRONTEND
+	/*
+	 * sockets on non-frontend processes on win32 is wrapped and blocking mode
+	 * is controlled there. See socket.c for the details.
+	 */
+	pgwin32_set_socket_nonblock(sock, true);
+	return 1;
+#else
 	/* Returns non-0 on failure, while fcntl() returns -1 on failure */
 	return (ioctlsocket(sock, FIONBIO, &ioctlsocket_ret) == 0);
-#endif
+#endif /* FRONTEND */
+#endif /* !WIN32   */
 }
 
 
@@ -41,10 +50,16 @@ pg_set_block(pgsocket sock)
 	if (flags < 0 || fcntl(sock, F_SETFL, (long) (flags & ~O_NONBLOCK)))
 		return false;
 	return true;
-#else
+#else /* !WIN32   */
 	unsigned long ioctlsocket_ret = 0;
 
+#ifndef FRONTEND
+	/*  See pg_set_noblock */
+	pgwin32_set_socket_nonblock(sock, false);
+	return 1;
+#else
 	/* Returns non-0 on failure, while fcntl() returns -1 on failure */
 	return (ioctlsocket(sock, FIONBIO, &ioctlsocket_ret) == 0);
-#endif
+#endif /* FRONTEND */
+#endif /* !WIN32   */
 }