Check for interrupts and stack overflow during rule/view dumps.

Since ruleutils.c recurses, it could be driven to stack overflow by
deeply nested constructs.  Very large queries might also take long
enough to deparse that a check for interrupts seems like a good idea.
Stick appropriate tests into a couple of key places.

Noted by Greg Stark.  Back-patch to all supported branches.

diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c
index b96fa3bbf7680ba15a93f9147c84386be88363d2..0aa63ae750581d64972cd3f629caf689dab6abbe 100644 (file)
--- a/src/backend/utils/adt/ruleutils.c
+++ b/src/backend/utils/adt/ruleutils.c
@@ -36,6 +36,7 @@
 #include "commands/tablespace.h"
 #include "executor/spi.h"
 #include "funcapi.h"
+#include "miscadmin.h"
 #include "nodes/makefuncs.h"
 #include "nodes/nodeFuncs.h"
 #include "optimizer/clauses.h"
@@ -4000,6 +4001,10 @@ get_query_def(Query *query, StringInfo buf, List *parentnamespace,
    deparse_context context;
    deparse_namespace dpns;
 
+   /* Guard against excessively long or deeply-nested queries */
+   CHECK_FOR_INTERRUPTS();
+   check_stack_depth();
+
    /*
     * Before we begin to examine the query, acquire locks on referenced
     * relations, and fix up deleted columns in JOIN RTEs.  This ensures
@@ -4556,6 +4561,10 @@ get_setop_query(Node *setOp, Query *query, deparse_context *context,
    StringInfo  buf = context->buf;
    bool        need_paren;
 
+   /* Guard against excessively long or deeply-nested queries */
+   CHECK_FOR_INTERRUPTS();
+   check_stack_depth();
+
    if (IsA(setOp, RangeTblRef))
    {
        RangeTblRef *rtr = (RangeTblRef *) setOp;
@@ -6393,6 +6402,10 @@ get_rule_expr(Node *node, deparse_context *context,
    if (node == NULL)
        return;
 
+   /* Guard against excessively long or deeply-nested queries */
+   CHECK_FOR_INTERRUPTS();
+   check_stack_depth();
+
    /*
     * Each level of get_rule_expr must emit an indivisible term
     * (parenthesized if necessary) to ensure result is reparsed into the same