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Subject: Re: [PHP-DEV] Curl POST emalloc leak?
From: rasmus@lerdorf.com (Rasmus Lerdorf)

Cristian Rodríguez wrote:
> Rasmus Lerdorf escribió:
>> Can someone spot why this code
>>
>> (tested in both 5.2.5 and 5.3)
>>
>> <?php
>> function curl($post) {
>>   $ch = curl_init();
>>   curl_setopt($ch, CURLOPT_URL, "www.fdhfkdsslak.bogus");
>>   curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
>>   if($post) {
>>     curl_setopt($ch, CURLOPT_POST, 1);
>>     for($args='',$i=0;$i<75;$i++) $args .= "a=$i&";
>>     curl_setopt($ch, CURLOPT_POSTFIELDS, $args);
>>     unset($args);
>>   }
>>   curl_exec($ch);
>>   curl_close($ch);
>> }
>> echo "start ".memory_get_usage()."\n";
>> for($i=0;$i<10;$i++) {
>>   curl(0);
>>   echo "GET ".memory_get_usage()."\n";
>> }
>> for($i=0;$i<10;$i++) {
>>   curl(1);
>>   echo "POST ".memory_get_usage()."\n";
>> }
>> ?>
>>
>> outputs:
> 
> for me
> 
> start 120400
> GET 122624
> GET 122624
> GET 122624
> GET 122624
> GET 122624
> GET 122624
> GET 122624
> GET 122624
> GET 122624
> GET 122624
> POST 124968
> POST 125928
> POST 126608
> POST 127272
> POST 127920
> POST 128552
> POST 129168
> POST 129768
> POST 130352
> POST 130920
> 
> when I request for  $real_usage the results are constant..

Yes, I'm not saying there is a malloc leak.  I haven't seen that, but 
the emalloc leak means that eventually a script that repeatedly sends 
post requests is going to hit the memory limit no matter how much 
cleanup it does.

Note that you don't actually need to send the request.  It looks like 
repeatedly doing:

$ch = curl_init();
curl_setopt($ch, CURLOPT_POSTFIELDS, $args);
curl_close($ch);

Is enough to do it.  Still looking at the code.  Seems like 
zend_llist_clean(&ch->to_free.str); isn't doing the right thing somehow.

-Rasmus