From 4f896dac17f7015b34347e278fc3db4047b86e43 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Thu, 22 Mar 2007 19:55:04 +0000
Subject: [PATCH] Arrange for PreventTransactionChain to reject commands
submitted as part of a multi-statement simple-Query message. This bug goes
all the way back, but unfortunately is not nearly so easy to fix in existing
releases; it is only the recent ProcessUtility API change that makes it
fixable in HEAD. Per report from William Garrison.
---
src/backend/access/transam/xact.c | 12 +++++++-----
src/backend/tcop/postgres.c | 16 +++++++++++++---
2 files changed, 20 insertions(+), 8 deletions(-)
diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c
index 51a41ca4453..f8058a8f5e9 100644
--- a/src/backend/access/transam/xact.c
+++ b/src/backend/access/transam/xact.c
@@ -10,7 +10,7 @@
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/access/transam/xact.c,v 1.237 2007/03/13 14:32:25 petere Exp $
+ * $PostgreSQL: pgsql/src/backend/access/transam/xact.c,v 1.238 2007/03/22 19:55:04 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -2503,9 +2503,10 @@ AbortCurrentTransaction(void)
* completes). Subtransactions are verboten too.
*
* isTopLevel: passed down from ProcessUtility to determine whether we are
- * inside a function. (We will always fail if this is false, but it's
- * convenient to centralize the check here instead of making callers do it.)
- * stmtType: statement type name, for error messages.
+ * inside a function or multi-query querystring. (We will always fail if
+ * this is false, but it's convenient to centralize the check here instead of
+ * making callers do it.)
+ * stmtType: statement type name, for error messages.
*/
void
PreventTransactionChain(bool isTopLevel, const char *stmtType)
@@ -2537,7 +2538,8 @@ PreventTransactionChain(bool isTopLevel, const char *stmtType)
ereport(ERROR,
(errcode(ERRCODE_ACTIVE_SQL_TRANSACTION),
/* translator: %s represents an SQL statement name */
- errmsg("%s cannot be executed from a function", stmtType)));
+ errmsg("%s cannot be executed from a function or multi-command string",
+ stmtType)));
/* If we got past IsTransactionBlock test, should be in default state */
if (CurrentTransactionState->blockState != TBLOCK_DEFAULT &&
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index f997d524101..9f55ba2e387 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/tcop/postgres.c,v 1.528 2007/03/13 00:33:42 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/tcop/postgres.c,v 1.529 2007/03/22 19:55:04 tgl Exp $
*
* NOTES
* this is the "main" module of the postgres backend and
@@ -765,6 +765,7 @@ exec_simple_query(const char *query_string)
ListCell *parsetree_item;
bool save_log_statement_stats = log_statement_stats;
bool was_logged = false;
+ bool isTopLevel;
char msec_str[32];
/*
@@ -824,6 +825,15 @@ exec_simple_query(const char *query_string)
*/
MemoryContextSwitchTo(oldcontext);
+ /*
+ * We'll tell PortalRun it's a top-level command iff there's exactly
+ * one raw parsetree. If more than one, it's effectively a transaction
+ * block and we want PreventTransactionChain to reject unsafe commands.
+ * (Note: we're assuming that query rewrite cannot add commands that are
+ * significant to PreventTransactionChain.)
+ */
+ isTopLevel = (list_length(parsetree_list) == 1);
+
/*
* Run through the raw parsetree(s) and process each one.
*/
@@ -944,7 +954,7 @@ exec_simple_query(const char *query_string)
*/
(void) PortalRun(portal,
FETCH_ALL,
- true, /* top level */
+ isTopLevel,
receiver,
receiver,
completionTag);
@@ -1810,7 +1820,7 @@ exec_execute_message(const char *portal_name, long max_rows)
completed = PortalRun(portal,
max_rows,
- true, /* top level */
+ true, /* always top level */
receiver,
receiver,
completionTag);
--
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