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.

diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c
index 51a41ca44536cf095c0d72ae4a1adff49e55580c..f8058a8f5e9369d5fff83e6d7b1446c9d2d001a7 100644 (file)
--- 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 f997d5241015930cd1ebe2e797aaad7cce8b7cc1..9f55ba2e387a2a3f5553d9d76c02a4f25759e161 100644 (file)
--- 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);