pgpool2.git / summary / log / commit / refs

commit    47564e79f7440a034e2ca83fc04cfb59219ca051
Author:   Muhammad Usama <m.usama@gmail.com>
Date:     Thu May 28 12:17:35 2015 +0000

    Fixing a problem in elog.c when forwarding a message to frontend clients.
    
    Error while forwarding the message to the frontend client can potentially cause
    the infinite recursion and terminate the child with ERRORDATA_STACK_SIZE exceeded error.
    Fix is to check the recursion depth of send_message_to_frontend() function
    and pulling the plug if it is more than two levels deep.


 src/utils/error/elog.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/src/utils/error/elog.c b/src/utils/error/elog.c
index 879863d5d..d9fc252a3 100644
--- a/src/utils/error/elog.c
+++ b/src/utils/error/elog.c
@@ -162,6 +162,8 @@ static int	errordata_stack_depth = -1; /* index of topmost active frame */
 
 static int	recursion_depth = 0;	/* to detect actual recursion */
 
+static int	frontend_error_recursion_depth = 0;	/* to detect recursion in delivering error to frontend clients */
+
 
 /* Macro for checking errordata_stack_depth is reasonable */
 #define CHECK_STACK_DEPTH() \
@@ -302,6 +304,7 @@ errstart(int elevel, const char *filename, int lineno,
 		if (in_error_recursion_trouble())
 		{
 			error_context_stack = NULL;
+			output_to_client = false;
 		}
 	}
 	if (++errordata_stack_depth >= ERRORDATA_STACK_SIZE)
@@ -1225,6 +1228,7 @@ FlushErrorState(void)
 	 */
 	errordata_stack_depth = -1;
 	recursion_depth = 0;
+	frontend_error_recursion_depth = 0;
 	/* Delete all data in ErrorContext */
 	MemoryContextResetAndDeleteChildren(ErrorContext);
 }
@@ -1730,6 +1734,11 @@ send_message_to_frontend(ErrorData *edata)
 
 	if (pool_frontend_exists() < 0 )
 		return;
+	/*
+	 * Leave if we are failing on sending the message to frontend.
+	 */
+	if (++frontend_error_recursion_depth > 2)
+		return;
 
 	if(processType == PT_CHILD)
 	{
@@ -1737,7 +1746,10 @@ send_message_to_frontend(ErrorData *edata)
 		 * Do not forward the debug messages to client before session is initialized
 		 */
 		if (edata->elevel < ERROR && pool_get_session_context(true) == NULL)
+		{
+			frontend_error_recursion_depth--;
 			return;
+		}
 		protoVersion = get_frontend_protocol_version();
 		set_pg_frontend_blocking(false);
 	}
@@ -1835,6 +1847,8 @@ send_message_to_frontend(ErrorData *edata)
 
 	if (processType == PT_CHILD)
 		set_pg_frontend_blocking(true);
+
+	frontend_error_recursion_depth--;
 }
 
 /*


[parent: 23236af1976c]