postgres.git / summary / log / commit / refs

commit    dd9d78f595a124591eadb97d71813fc71fd767a5
Author:   Tom Lane <tgl@sss.pgh.pa.us>
Date:     Mon Jan 26 17:18:25 2015 +0000

    Fix volatile-safety issue in pltcl_SPI_execute_plan().
    
    The "callargs" variable is modified within PG_TRY and then referenced
    within PG_CATCH, which is exactly the coding pattern we've now found
    to be unsafe.  Marking "callargs" volatile would be problematic because
    it is passed by reference to some Tcl functions, so fix the problem
    by not modifying it within PG_TRY.  We can just postpone the free()
    till we exit the PG_TRY construct, as is already done elsewhere in this
    same file.
    
    Also, fix failure to free(callargs) when exiting on too-many-arguments
    error.  This is only a minor memory leak, but a leak nonetheless.
    
    In passing, remove some unnecessary "volatile" markings in the same
    function.  Those doubtless are there because gcc 2.95.3 whinged about
    them, but we now know that its algorithm for complaining is many bricks
    shy of a load.
    
    This is certainly a live bug with compilers that optimize similarly
    to current gcc, so back-patch to all active branches.


 src/pl/tcl/pltcl.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/src/pl/tcl/pltcl.c b/src/pl/tcl/pltcl.c
index a53cca4f275..bb6994ce92d 100644
--- a/src/pl/tcl/pltcl.c
+++ b/src/pl/tcl/pltcl.c
@@ -2235,9 +2235,9 @@ pltcl_SPI_execute_plan(ClientData cdata, Tcl_Interp *interp,
 	int			j;
 	Tcl_HashEntry *hashent;
 	pltcl_query_desc *qdesc;
-	const char *volatile nulls = NULL;
-	CONST84 char *volatile arrayname = NULL;
-	CONST84 char *volatile loop_body = NULL;
+	const char *nulls = NULL;
+	CONST84 char *arrayname = NULL;
+	CONST84 char *loop_body = NULL;
 	int			count = 0;
 	int			callnargs;
 	CONST84 char **callargs = NULL;
@@ -2367,6 +2367,8 @@ pltcl_SPI_execute_plan(ClientData cdata, Tcl_Interp *interp,
 	if (i != argc)
 	{
 		Tcl_SetResult(interp, usage, TCL_STATIC);
+		if (callargs)
+			ckfree((char *) callargs);
 		return TCL_ERROR;
 	}
 
@@ -2405,10 +2407,6 @@ pltcl_SPI_execute_plan(ClientData cdata, Tcl_Interp *interp,
 			}
 		}
 
-		if (callargs)
-			ckfree((char *) callargs);
-		callargs = NULL;
-
 		/************************************************************
 		 * Execute the plan
 		 ************************************************************/
@@ -2435,6 +2433,9 @@ pltcl_SPI_execute_plan(ClientData cdata, Tcl_Interp *interp,
 	}
 	PG_END_TRY();
 
+	if (callargs)
+		ckfree((char *) callargs);
+
 	return my_rc;
 }
 


[parent: df923be03d11]