X-Original-To: pgsql-hackers-postgresql.org@localhost.postgresql.org
Received: from localhost (unknown [200.46.204.144])
	by svr1.postgresql.org (Postfix) with ESMTP id 1AC7B5299A
	for <pgsql-hackers-postgresql.org@localhost.postgresql.org>;
	Tue, 12 Jul 2005 15:59:42 -0300 (ADT)
Received: from svr1.postgresql.org ([200.46.204.71])
	by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
	with ESMTP id 47512-08
	for <pgsql-hackers-postgresql.org@localhost.postgresql.org>;
	Tue, 12 Jul 2005 18:59:40 +0000 (GMT)
Received: from trolak.mydnsbox2.com (ns1.mydnsbox2.com [207.44.142.118])
	by svr1.postgresql.org (Postfix) with ESMTP id 2322252986
	for <pgsql-hackers@postgresql.org>;
	Tue, 12 Jul 2005 15:59:39 -0300 (ADT)
Received: from [192.168.1.103] (cpe-024-211-165-134.nc.res.rr.com
	[24.211.165.134]) (authenticated (0 bits))
	by trolak.mydnsbox2.com (8.11.6/8.11.6) with ESMTP id j6CIDqm08355;
	Tue, 12 Jul 2005 13:13:52 -0500
Message-ID: <42D41319.70107@dunslane.net>
Date: Tue, 12 Jul 2005 14:59:37 -0400
From: Andrew Dunstan <andrew@dunslane.net>
User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US;
	rv:1.7.8) Gecko/20050513 Fedora/1.7.8-1.3.1
X-Accept-Language: en-us, en
MIME-Version: 1.0
To: Michael Fuhr <mike@fuhr.org>
Cc: pgsql-hackers@postgresql.org
Subject: Re: PL/Perl list value return causes segfault
References: <20050712130452.GA84564@winnie.fuhr.org>
In-Reply-To: <20050712130452.GA84564@winnie.fuhr.org>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
X-Virus-Scanned: by amavisd-new at hub.org
X-Spam-Status: No, hits=0.044 tagged_above=0 required=5 tests=AWL
X-Spam-Level: 
X-Archive-Number: 200507/438
X-Sequence-Number: 70490



Michael Fuhr wrote:

>In the latest HEAD, a PL/Perl function that returns a list value
>instead of a reference causes a segmentation fault:
>
>CREATE FUNCTION foo() RETURNS integer[] AS $$
>return (1, 2, 3, 4);
>$$ LANGUAGE plperl;
>
>SELECT foo();
>server closed the connection unexpectedly
>
>Here's the stack trace:
>
>#0  0xfed45bcc in plperl_call_handler (fcinfo=0xffbfe230) at plperl.c:1031
>#1  0x0010e7d4 in ExecMakeFunctionResult (fcache=0x44af00, econtext=0x44ae58, 
>    isNull=0x44b470 "\177~\177\177\177\177\177\177", isDone=0x44b4d8) at execQual.c:1031
>#2  0x001122b0 in ExecProject (projInfo=0x44af00, isDone=0x44ae58) at execQual.c:3607
>  
>


Patch below fixes the SEGV, and you will see instead:

andrew=# select foo();
ERROR:  array value must start with "{" or dimension information

which might not immediately point you to the source of the error :-( , 
but is certainly better than a SEGV.

Note that all plperl functions are called in scalar context, and it is 
always wrong to return a list (as opposed to a listref). In fact, the 
value received might surprise you even if it worked (it would be the 
value of the last member of the list).

cheers

andrew


Index: plperl.c
===================================================================
RCS file: /projects/cvsroot/pgsql/src/pl/plperl/plperl.c,v
retrieving revision 1.85
diff -c -r1.85 plperl.c
*** plperl.c    12 Jul 2005 01:16:21 -0000      1.85
--- plperl.c    12 Jul 2005 18:52:54 -0000
***************
*** 1021,1027 ****
          char *val;
  
 
!         if (prodesc->fn_retisarray && SvTYPE(SvRV(perlret)) == SVt_PVAV)
          {
              array_ret = plperl_convert_to_pg_array(perlret);
              SvREFCNT_dec(perlret);
--- 1021,1028 ----
          char *val;
  
 
!         if (prodesc->fn_retisarray && SvROK(perlret) &&
!                       SvTYPE(SvRV(perlret)) == SVt_PVAV)
          {
              array_ret = plperl_convert_to_pg_array(perlret);
              SvREFCNT_dec(perlret);