TODOs for index opclass strategy number validation

This patch addresses TODOs in the BRIN, GIN, GIST and SP-GIST index
code. Opclass validation is modified to add strategy number bounds
checking specific to each index type.

1) For BRIN and SP-GIST, the maximum strategy number from the list
   of strategies common to these index types is used as the limit.
2) For SP-GIST, the number of GIS object types and the strategy
   numbers per type are used to calculate the maximum strategy
   number.
3) For GIN, custom strategy numbers may be defined, so the highest
   possible limit of 63 is retained.

Author: Priyanka Sangam

src/backend/access/brin/brin_validate.c

@@ -142,7 +142,7 @@ brinvalidate(Oid opclassoid)
 		Form_pg_amop oprform = (Form_pg_amop) GETSTRUCT(oprtup);
 
 		/* Check that only allowed strategy numbers exist */
-		if (oprform->amopstrategy < 1 || oprform->amopstrategy > 63)
+		if (oprform->amopstrategy < 1 || oprform->amopstrategy > RTMaxStrategyNumber)
 		{
 			ereport(INFO,
 					(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),

src/backend/access/gin/ginvalidate.c

@@ -165,8 +165,8 @@ ginvalidate(Oid opclassoid)
 		HeapTuple	oprtup = &oprlist->members[i]->tuple;
 		Form_pg_amop oprform = (Form_pg_amop) GETSTRUCT(oprtup);
 
-		/* TODO: Check that only allowed strategy numbers exist */
-		if (oprform->amopstrategy < 1 || oprform->amopstrategy > 63)
+		/* Check that only allowed strategy numbers exist */
+		if (oprform->amopstrategy < 1 || oprform->amopstrategy > MaxStrategyNumber)
 		{
 			ereport(INFO,
 					(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),

src/backend/access/gist/gistproc.c

@@ -1330,12 +1330,6 @@ gist_point_consistent_internal(StrategyNumber strategy,
 	return result;
 }
 
-#define GeoStrategyNumberOffset		20
-#define PointStrategyNumberGroup	0
-#define BoxStrategyNumberGroup		1
-#define PolygonStrategyNumberGroup	2
-#define CircleStrategyNumberGroup	3
-
 Datum
 gist_point_consistent(PG_FUNCTION_ARGS)
 {

src/backend/access/gist/gistvalidate.c

@@ -174,8 +174,9 @@ gistvalidate(Oid opclassoid)
 		Form_pg_amop oprform = (Form_pg_amop) GETSTRUCT(oprtup);
 		Oid			op_rettype;
 
-		/* TODO: Check that only allowed strategy numbers exist */
-		if (oprform->amopstrategy < 1)
+		/* Check that only allowed strategy numbers exist */
+		if (oprform->amopstrategy < 1 ||
+			oprform->amopstrategy >= (GeoStrategyNumberOffset * (GeoMaxStrategyNumberGroup + 1)))
 		{
 			ereport(INFO,
 					(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),

src/backend/access/spgist/spgvalidate.c

@@ -205,8 +205,8 @@ spgvalidate(Oid opclassoid)
 		Form_pg_amop oprform = (Form_pg_amop) GETSTRUCT(oprtup);
 		Oid			op_rettype;
 
-		/* TODO: Check that only allowed strategy numbers exist */
-		if (oprform->amopstrategy < 1 || oprform->amopstrategy > 63)
+		/* Check that only allowed strategy numbers exist */
+		if (oprform->amopstrategy < 1 || oprform->amopstrategy > RTMaxStrategyNumber)
 		{
 			ereport(INFO,
 					(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),

src/include/access/stratnum.h

@@ -42,6 +42,18 @@ typedef uint16 StrategyNumber;
 
 #define HTMaxStrategyNumber				1
 
+/*
+ * Strategy number groups used by GIST, one for each GIS object type. Each number
+ * group can contain up to 'GeoStrategyNumberOffset' strategies.
+ */
+#define GeoStrategyNumberOffset		20
+#define PointStrategyNumberGroup	0
+#define BoxStrategyNumberGroup		1
+#define PolygonStrategyNumberGroup	2
+#define CircleStrategyNumberGroup	3
+
+#define GeoMaxStrategyNumberGroup	3
+
 /*
  * Strategy numbers common to (some) GiST, SP-GiST and BRIN opclasses.
  *
@@ -80,6 +92,6 @@ typedef uint16 StrategyNumber;
 #define RTOldAboveStrategyNumber		30	/* for old spelling of |>> */
 
 #define RTMaxStrategyNumber				30
-
+#define MaxStrategyNumber				63
 
 #endif							/* STRATNUM_H */