From 545a05a3d282d507b22fbffe07eefd9353058859 Mon Sep 17 00:00:00 2001
From: Yoshiyuki Asaba <y-asaba at pgfoundry.org>
Date: Wed, 25 Jul 2007 06:42:40 +0000
Subject: [PATCH] Fix hang up and SEGV if Parse message contains a warning
 statement.

  SELECT '\'';
  WARNING:  nonstandard use of \' in a string literal

If pgpool receives a warning message that is NoticeMessage('N') under
the extended query protocol, it reads a next message.
---
 pool_process_query.c | 87 +++++++++++++++++++++++++++++---------------
 1 file changed, 57 insertions(+), 30 deletions(-)

diff --git a/pool_process_query.c b/pool_process_query.c
index 5ec0f6e..af4ce1f 100644
--- a/pool_process_query.c
+++ b/pool_process_query.c
@@ -841,30 +841,33 @@ static POOL_STATUS Execute(POOL_CONNECTION *frontend,
 
 	stmt = lookup_prepared_statement_by_portal(&prepared_list, string);
 
-	/* load balance trick */
-	if (stmt && load_balance_enabled(backend, stmt->prepared_string))
-		start_load_balance(backend);
-	else if (MASTER_SLAVE)
+	if (stmt)
 	{
-		master_slave_was_enabled = 1;
-		MASTER_SLAVE = 0;
-		master_slave_dml = 1;
-	}
-	else if (REPLICATION && !pool_config.replicate_select && is_select_query(stmt->prepared_string) && !is_sequence_query(stmt->prepared_string))
-	{
-		int i;
-
-		/* save backend connection slots */
-		for (i=0;i<backend->num;i++)
+		/* load balance trick */
+		if (stmt && load_balance_enabled(backend, stmt->prepared_string))
+			start_load_balance(backend);
+		else if (MASTER_SLAVE)
 		{
-			slots[i] = backend->slots[i];
+			master_slave_was_enabled = 1;
+			MASTER_SLAVE = 0;
+			master_slave_dml = 1;
 		}
+		else if (REPLICATION && !pool_config.replicate_select && is_select_query(stmt->prepared_string) && !is_sequence_query(stmt->prepared_string))
+		{
+			int i;
 
-		/* send query to master only. */
-		replication_was_enabled = 1;
-		REPLICATION = 0;
-		in_load_balance = 1;
-		select_in_transaction = 1;
+			/* save backend connection slots */
+			for (i=0;i<backend->num;i++)
+			{
+				slots[i] = backend->slots[i];
+			}
+
+			/* send query to master only. */
+			replication_was_enabled = 1;
+			REPLICATION = 0;
+			in_load_balance = 1;
+			select_in_transaction = 1;
+		}
 	}
 
 	for (i = 0;i < backend->num;i++)
@@ -2549,8 +2552,8 @@ POOL_STATUS SimpleForwardToFrontend(char kind, POOL_CONNECTION *frontend, POOL_C
 
 	/*
 	 * Check if packet kind == 'C'(Command complete), '1'(Parse
-	 * complete), '3'(Close complete). If so, then register or unregister
-	 * pending prepared statement.
+	 * complete), '3'(Close complete). If so, then register or
+	 * unregister pending prepared statement.
 	 */
 	if ((kind == 'C' || kind == '1' || kind == '3') &&
 		pending_function &&	pending_prepared_stmt)
@@ -2560,8 +2563,15 @@ POOL_STATUS SimpleForwardToFrontend(char kind, POOL_CONNECTION *frontend, POOL_C
 	else if (kind == 'C' && select_in_transaction)
 		select_in_transaction = 0;
 
-	pending_function = NULL;
-	pending_prepared_stmt = NULL;
+	/* 
+	 * Remove a pending function if a received message is not
+	 * NoticeResponse.
+	 */
+	if (kind != 'N')
+	{
+		pending_function = NULL;
+		pending_prepared_stmt = NULL;
+	}
 
 	status = pool_read(MASTER(backend), &len, sizeof(len));
 	if (status < 0)
@@ -2901,6 +2911,12 @@ POOL_STATUS SimpleForwardToBackend(char kind, POOL_CONNECTION *frontend, POOL_CO
 				break;
 		}
 
+
+		/*
+		 * Describe message with a portal name receive two messages.
+		 * 1. ParameterDescription
+		 * 2. RowDescriptions or NoData
+		 */
 		if (kind == 'D' && *p == 'S')
 		{
 			kind1 = pool_read_kind(backend);
@@ -2913,14 +2929,25 @@ POOL_STATUS SimpleForwardToBackend(char kind, POOL_CONNECTION *frontend, POOL_CO
 			pool_flush(frontend);
 		}
 
-		kind1 = pool_read_kind(backend);
-		if (kind1 < 0)
+		for (;;)
 		{
-			pool_error("SimpleForwardToBackend: pool_read_kind error");
-			return POOL_ERROR;
+			kind1 = pool_read_kind(backend);
+			if (kind1 < 0)
+			{
+				pool_error("SimpleForwardToBackend: pool_read_kind error");
+				return POOL_ERROR;
+			}
+			SimpleForwardToFrontend(kind1, frontend, backend);
+			if (pool_flush(frontend) < 0)
+				return POOL_ERROR;
+
+			/*
+			 * If warning or log messages are received, we must read
+			 * one message from backend.
+			 */
+			if (kind1 != 'N') /* Notice Message */
+				break;
 		}
-		SimpleForwardToFrontend(kind1, frontend, backend);
-		return pool_flush(frontend);
 	}
 	else
 	{
-- 
2.39.5