Auditing caudium.c : f_parse_query_string()

[Bertrand LUPART <bertrand.lupart AT linkeo.com>]

Hello,

Let's start a community-driven effort for chasing possible memory  
leaks in caudium.c

Since i don't know how to use the hilfe module in Caudium, let's try  
to simulate that with top of the art of our technologies: Pike 7.6.66  
and Caudium 1.5.1-20010130:

----8<----8<----8<----8<----
$ pike -M /sw/lib/caudium1.5/etc/modules/ -I /sw/lib/caudium1.5/etc/ 
include/ -I /sw/lib/caudium1.5/base_server/ -M /sw/lib/caudium1.5/lib/ 
7.6.66/
Pike v7.6 release 66 running Hilfe v3.5 (Incremental Pike Frontend)
> indices(_Caudium);
(1) Result: ({ /* 24 elements */
                "parse_query_string",
                "http_encode_string",
                "http_encode_cookie",
                "_make_tag_attributes",
                "html_encode_mapping",
                "xml_encode_mapping",
                "program_object_memory_usage",
                "ParseHTTP",
                "is_modified",
                "parse_date",
                "strftime",
                "getdate",
                "parse_entities",
                "http_decode_url",
                "http_encode_url",
                "http_date",
                "cern_http_date",
                "http_decode",
                "http_encode",
                "extension",
                "get_port",
                "parse_prestates",
                "parse_headers",
                "get_address"
            })
---->8---->8---->8---->8----

Let's try the first one: parse_query_string()

For testing that, I cooked a Test.pmod which builds random query  
strings.

Ready?

----8<----8<----8<----8<----
$ pike -M /sw/lib/caudium1.5/etc/modules/ -I /sw/lib/caudium1.5/etc/ 
include/ -I /sw/lib/caudium1.5/base_server/ -M /sw/lib/caudium1.5/lib/ 
7.6.66/ -M /Users/bertrand/Code/Caudium/testing/
Pike v7.6 release 66 running Hilfe v3.5 (Incremental Pike Frontend)
> dump memory
             Num   Bytes
array        354   43236 (42.2 kb)
callable     224    8152 (8.0 kb)
callback       4    4128 (4.0 kb)
frame          7   16300 (15.9 kb)
mapping       97   91634 (89.5 kb)
multiset      36   19980 (19.5 kb)
object        95   22768 (22.2 kb)
program      146  171360 (167.3 kb)
string      4586  178997 (174.8 kb)
---->8---->8---->8---->8----

Let's build 10000 random queries of 100 variables (with a random  
amount of unset variables), indices and values size set to 10  
characters:

----8<----8<----8<----8<----
> array queries = Test.random_queries(10000, 100);
> dump memory
             Num   Bytes
array       1565  289160 (282.4 kb)
callable     234   16304 (15.9 kb)
callback       4    4128 (4.0 kb)
frame          7   16300 (15.9 kb)
mapping      564  296275 (289.3 kb)
multiset      54   28572 (27.9 kb)
object       284   60272 (58.9 kb)
program      423  517416 (505.3 kb)
string     20201  35340830 (33.7 Mb)
---->8---->8---->8---->8----

That's our base memory footprint. Now, just parse all that:

----8<----8<----8<----8<----
> foreach(queries, string query){
>> mapping variables = ([ ]);
>> multiset unset = (< >);
>> _Caudium.parse_query_string(query, variables, unset);
>> }
Ok.
> dump memory
             Num   Bytes
array       1569  289368 (282.6 kb)
callable     256   16304 (15.9 kb)
callback       4    4128 (4.0 kb)
frame          7   16300 (15.9 kb)
mapping      564  295339 (288.4 kb)
multiset      40   18176 (17.8 kb)
object       285   60272 (58.9 kb)
program      425  518932 (506.8 kb)
string    2019810  107488870 (102.5 Mb)
---->8---->8---->8---->8----

Call the garbage collector, just in case:

----8<----8<----8<----8<----
> gc();
(1) Result: 0
> dump memory
             Num   Bytes
array       1569  289344 (282.6 kb)
callable     256   16304 (15.9 kb)
callback       4    4128 (4.0 kb)
frame          7   16300 (15.9 kb)
mapping      564  295339 (288.4 kb)
multiset      40   18176 (17.8 kb)
object       285   60272 (58.9 kb)
program      425  518932 (506.8 kb)
string    2019810  107488703 (102.5 Mb)
---->8---->8---->8---->8----

Am i wrong somewhere or are we leaking strings here?

--
Bertrand LUPART
                             Linkeo.com | http://www.linkeo.com
                      +33 1 72 71 71 84 | 17, rue de la Banque -  
F75002 Paris