Add more infinite recursion detection while locking a view.

tatsuo-ishii · tatsuo-ishii · commit 03030512d1e4 · 2018-04-17T16:59:17.000+09:00
Also add regression test cases for detecting infinite recursion in
locking view tests.  Some document enhancements. Patch by Yugo Nagata.
diff --git a/doc/src/sgml/ref/lock.sgml b/doc/src/sgml/ref/lock.sgml
@@ -46,8 +46,8 @@ LOCK [ TABLE ] [ ONLY ] <replaceable class="parameter">name</replaceable> [ * ]
   </para>
 
   <para>
-   When a view is specified to be locked, all relations appearing in the view
-   definition query are also locked recursively with the same lock mode. 
+   When a view is locked, all relations appearing in the view definition
+   query are also locked recursively with the same lock mode.
   </para>
 
   <para>
@@ -173,6 +173,13 @@ LOCK [ TABLE ] [ ONLY ] <replaceable class="parameter">name</replaceable> [ * ]
     or <literal>TRUNCATE</literal> privileges.
    </para>
 
+   <para>
+    The user performing the lock on the view must have the corresponding privilege
+    on the view.  In addition the view's owner must have the relevant privileges on
+    the underlying base relations, but the user performing the lock does
+    not need any permissions on the underlying base relations.
+   </para>
+
    <para>
     <command>LOCK TABLE</command> is useless outside a transaction block: the lock
     would remain held only to the completion of the statement.  Therefore
diff --git a/src/backend/commands/lockcmds.c b/src/backend/commands/lockcmds.c
@@ -31,7 +31,7 @@ static void LockTableRecurse(Oid reloid, LOCKMODE lockmode, bool nowait, Oid use
 static AclResult LockTableAclCheck(Oid relid, LOCKMODE lockmode, Oid userid);
 static void RangeVarCallbackForLockTable(const RangeVar *rv, Oid relid,
 							 Oid oldrelid, void *arg);
-static void LockViewRecurse(Oid reloid, Oid root_reloid, LOCKMODE lockmode, bool nowait);
+static void LockViewRecurse(Oid reloid, LOCKMODE lockmode, bool nowait, List *ancestor_views);
 
 /*
  * LOCK TABLE
@@ -67,7 +67,7 @@ LockTableCommand(LockStmt *lockstmt)
 										  (void *) &lockstmt->mode);
 
 		if (get_rel_relkind(reloid) == RELKIND_VIEW)
-			LockViewRecurse(reloid, reloid, lockstmt->mode, lockstmt->nowait);
+			LockViewRecurse(reloid, lockstmt->mode, lockstmt->nowait, NIL);
 		else if (recurse)
 			LockTableRecurse(reloid, lockstmt->mode, lockstmt->nowait, GetUserId());
 	}
@@ -92,7 +92,6 @@ RangeVarCallbackForLockTable(const RangeVar *rv, Oid relid, Oid oldrelid,
 		return;					/* woops, concurrently dropped; no permissions
 								 * check */
 
-
 	/* Currently, we only allow plain tables or views to be locked */
 	if (relkind != RELKIND_RELATION && relkind != RELKIND_PARTITIONED_TABLE &&
 		relkind != RELKIND_VIEW)
@@ -178,11 +177,11 @@ LockTableRecurse(Oid reloid, LOCKMODE lockmode, bool nowait, Oid userid)
 
 typedef struct
 {
-	Oid root_reloid;
-	LOCKMODE lockmode;
-	bool nowait;
-	Oid viewowner;
-	Oid viewoid;
+	LOCKMODE	lockmode;		/* lock mode to use */
+	bool		nowait;			/* no wait mode */
+	Oid			viewowner;		/* view owner for checking the privilege */
+	Oid			viewoid;		/* OID of the view to be locked */
+	List	   *ancestor_views;	/* OIDs of ancestor views */
 } LockViewRecurse_context;
 
 static bool
@@ -193,19 +192,22 @@ LockViewRecurse_walker(Node *node, LockViewRecurse_context *context)
 
 	if (IsA(node, Query))
 	{
-		Query		*query = (Query *) node;
-		ListCell	*rtable;
+		Query	   *query = (Query *) node;
+		ListCell   *rtable;
 
 		foreach(rtable, query->rtable)
 		{
-			RangeTblEntry	*rte = lfirst(rtable);
-			AclResult		 aclresult;
+			RangeTblEntry *rte = lfirst(rtable);
+			AclResult	aclresult;
 
-			Oid relid = rte->relid;
-			char relkind = rte->relkind;
-			char *relname = get_rel_name(relid);
+			Oid			relid = rte->relid;
+			char		relkind = rte->relkind;
+			char	   *relname = get_rel_name(relid);
 
-			/* The OLD and NEW placeholder entries in the view's rtable are skipped. */
+			/*
+			 * The OLD and NEW placeholder entries in the view's rtable are
+			 * skipped.
+			 */
 			if (relid == context->viewoid &&
 				(!strcmp(rte->eref->aliasname, "old") || !strcmp(rte->eref->aliasname, "new")))
 				continue;
@@ -216,11 +218,11 @@ LockViewRecurse_walker(Node *node, LockViewRecurse_context *context)
 				continue;
 
 			/* Check infinite recursion in the view definition. */
-			if (relid == context->root_reloid)
+			if (list_member_oid(context->ancestor_views, relid))
 				ereport(ERROR,
 						(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
-						errmsg("infinite recursion detected in rules for relation \"%s\"",
-								get_rel_name(context->root_reloid))));
+						 errmsg("infinite recursion detected in rules for relation \"%s\"",
+								get_rel_name(relid))));
 
 			/* Check permissions with the view owner's privilege. */
 			aclresult = LockTableAclCheck(relid, context->lockmode, context->viewowner);
@@ -233,11 +235,11 @@ LockViewRecurse_walker(Node *node, LockViewRecurse_context *context)
 			else if (!ConditionalLockRelationOid(relid, context->lockmode))
 				ereport(ERROR,
 						(errcode(ERRCODE_LOCK_NOT_AVAILABLE),
-						errmsg("could not obtain lock on relation \"%s\"",
+						 errmsg("could not obtain lock on relation \"%s\"",
 								relname)));
 
 			if (relkind == RELKIND_VIEW)
-				LockViewRecurse(relid, context->root_reloid, context->lockmode, context->nowait);
+				LockViewRecurse(relid, context->lockmode, context->nowait, context->ancestor_views);
 			else if (rte->inh)
 				LockTableRecurse(relid, context->lockmode, context->nowait, context->viewowner);
 		}
@@ -254,24 +256,26 @@ LockViewRecurse_walker(Node *node, LockViewRecurse_context *context)
 }
 
 static void
-LockViewRecurse(Oid reloid, Oid root_reloid, LOCKMODE lockmode, bool nowait)
+LockViewRecurse(Oid reloid, LOCKMODE lockmode, bool nowait, List *ancestor_views)
 {
 	LockViewRecurse_context context;
 
-	Relation		 view;
-	Query			*viewquery;
+	Relation	view;
+	Query	   *viewquery;
 
 	view = heap_open(reloid, NoLock);
 	viewquery = get_view_query(view);
 
-	context.root_reloid = root_reloid;
 	context.lockmode = lockmode;
 	context.nowait = nowait;
 	context.viewowner = view->rd_rel->relowner;
 	context.viewoid = reloid;
+	context.ancestor_views = lcons_oid(reloid, ancestor_views);
 
 	LockViewRecurse_walker((Node *) viewquery, &context);
 
+	ancestor_views = list_delete_oid(ancestor_views, reloid);
+
 	heap_close(view, NoLock);
 }
 
diff --git a/src/test/regress/expected/lock.out b/src/test/regress/expected/lock.out
@@ -120,6 +120,17 @@ select relname from pg_locks l, pg_class c
  lock_view6
 (2 rows)
 
+ROLLBACK;
+-- detecting infinite recursions in view definitions
+CREATE OR REPLACE VIEW lock_view2 AS SELECT * from lock_view3;
+BEGIN TRANSACTION;
+LOCK TABLE lock_view2 IN EXCLUSIVE MODE;
+ERROR:  infinite recursion detected in rules for relation "lock_view2"
+ROLLBACK;
+CREATE VIEW lock_view7 AS SELECT * from lock_view2;
+BEGIN TRANSACTION;
+LOCK TABLE lock_view7 IN EXCLUSIVE MODE;
+ERROR:  infinite recursion detected in rules for relation "lock_view2"
 ROLLBACK;
 -- Verify that we can lock a table with inheritance children.
 CREATE TABLE lock_tbl2 (b BIGINT) INHERITS (lock_tbl1);
@@ -142,11 +153,12 @@ RESET ROLE;
 --
 -- Clean up
 --
+DROP VIEW lock_view7;
 DROP VIEW lock_view6;
 DROP VIEW lock_view5;
 DROP VIEW lock_view4;
-DROP VIEW lock_view3;
-DROP VIEW lock_view2;
+DROP VIEW lock_view3 CASCADE;
+NOTICE:  drop cascades to view lock_view2
 DROP VIEW lock_view1;
 DROP TABLE lock_tbl3;
 DROP TABLE lock_tbl2;
diff --git a/src/test/regress/sql/lock.sql b/src/test/regress/sql/lock.sql
@@ -84,6 +84,15 @@ select relname from pg_locks l, pg_class c
  where l.relation = c.oid and relname like '%lock_%' and mode = 'ExclusiveLock'
  order by relname;
 ROLLBACK;
+-- detecting infinite recursions in view definitions
+CREATE OR REPLACE VIEW lock_view2 AS SELECT * from lock_view3;
+BEGIN TRANSACTION;
+LOCK TABLE lock_view2 IN EXCLUSIVE MODE;
+ROLLBACK;
+CREATE VIEW lock_view7 AS SELECT * from lock_view2;
+BEGIN TRANSACTION;
+LOCK TABLE lock_view7 IN EXCLUSIVE MODE;
+ROLLBACK;
 
 -- Verify that we can lock a table with inheritance children.
 CREATE TABLE lock_tbl2 (b BIGINT) INHERITS (lock_tbl1);
@@ -107,11 +116,11 @@ RESET ROLE;
 --
 -- Clean up
 --
+DROP VIEW lock_view7;
 DROP VIEW lock_view6;
 DROP VIEW lock_view5;
 DROP VIEW lock_view4;
-DROP VIEW lock_view3;
-DROP VIEW lock_view2;
+DROP VIEW lock_view3 CASCADE;
 DROP VIEW lock_view1;
 DROP TABLE lock_tbl3;
 DROP TABLE lock_tbl2;
