From b4cc35fbb709bd6fcae8998f041fd731c9acbf42 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Mon, 31 Jul 2017 11:33:46 -0400
Subject: [PATCH] Tighten coding for non-composite case in plperl's
return_next.
Coverity complained about this code's practice of using scalar variables
as single-element arrays. While that's really just nitpicking, it probably
is more readable to declare them as arrays, so let's do that. A more
important point is that the code was just blithely assuming that the
result tupledesc has exactly one column; if it doesn't, we'd likely get
a crash of some sort in tuplestore_putvalues. Since the tupledesc is
manufactured outside of plperl, that seems like an uncomfortably long
chain of assumptions. We can nail it down at little cost with a sanity
check earlier in the function.
---
src/pl/plperl/plperl.c | 28 +++++++++++++++++-----------
1 file changed, 17 insertions(+), 11 deletions(-)
diff --git a/src/pl/plperl/plperl.c b/src/pl/plperl/plperl.c
index b10b4434aa7..afebec910d6 100644
--- a/src/pl/plperl/plperl.c
+++ b/src/pl/plperl/plperl.c
@@ -3247,12 +3247,18 @@ plperl_return_next_internal(SV *sv)
/*
* This is the first call to return_next in the current PL/Perl
- * function call, so memoize some lookups
+ * function call, so identify the output tuple descriptor and create a
+ * tuplestore to hold the result rows.
*/
if (prodesc->fn_retistuple)
(void) get_call_result_type(fcinfo, NULL, &tupdesc);
else
+ {
tupdesc = rsi->expectedDesc;
+ /* Protect assumption below that we return exactly one column */
+ if (tupdesc == NULL || tupdesc->natts != 1)
+ elog(ERROR, "expected single-column result descriptor for non-composite SETOF result");
+ }
/*
* Make sure the tuple_store and ret_tdesc are sufficiently
@@ -3300,20 +3306,20 @@ plperl_return_next_internal(SV *sv)
}
else
{
- Datum ret;
- bool isNull;
+ Datum ret[1];
+ bool isNull[1];
- ret = plperl_sv_to_datum(sv,
- prodesc->result_oid,
- -1,
- fcinfo,
- &prodesc->result_in_func,
- prodesc->result_typioparam,
- &isNull);
+ ret[0] = plperl_sv_to_datum(sv,
+ prodesc->result_oid,
+ -1,
+ fcinfo,
+ &prodesc->result_in_func,
+ prodesc->result_typioparam,
+ &isNull[0]);
tuplestore_putvalues(current_call_data->tuple_store,
current_call_data->ret_tdesc,
- &ret, &isNull);
+ ret, isNull);
}
MemoryContextSwitchTo(old_cxt);
--
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