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 957f0fc7d9f9e75c70acee98c54ada427409f9da..78b23221b7ae3930a94622a66378373a6eec4f57 100644 (file)
--- a/src/backend/utils/adt/ruleutils.c
+++ b/src/backend/utils/adt/ruleutils.c
@@ -37,6 +37,7 @@
 #include "commands/tablespace.h"
 #include "executor/spi.h"
 #include "funcapi.h"
+#include "miscadmin.h"
 #include "nodes/makefuncs.h"
 #include "nodes/nodeFuncs.h"
 #include "optimizer/tlist.h"
@@ -4133,6 +4134,10 @@ 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
@@ -4689,6 +4694,10 @@ 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;
@@ -6526,6 +6535,10 @@ 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