Message-ID: <5ce9de1e-0b89-4c62-ab3e-9e4513ba69b7@dunslane.net>
Date: Sat, 30 May 2026 09:21:21 -0400
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Subject: Re: Avoid leaking system path from pg_available_extensions
To: Matheus Alcantara <matheusssilv97@gmail.com>,
 Chao Li <li.evan.chao@gmail.com>
Cc: Jim Jones <jim.jones@uni-muenster.de>,
 PostgreSQL-development <pgsql-hackers@postgresql.org>
References: <357C774A-ECE9-4455-B641-315205D4D9A1@gmail.com>
 <96203151-6929-4d88-85a0-d552ee258a24@gmail.com>
 <cf40d36e-e45a-41c2-aea1-7834bcb62da9@uni-muenster.de>
 <87c8f8ac-614b-4679-afc7-f591b76c8ff7@gmail.com>
 <83AF10FE-7655-43DF-A302-3CAC796B572F@gmail.com>
 <bd4b316a-d0cd-4ccf-b9fe-18621c953645@gmail.com>
From: Andrew Dunstan <andrew@dunslane.net>
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On 2026-05-26 Tu 9:29 AM, Matheus Alcantara wrote:
> On 26/05/26 04:14, Chao Li wrote:
>>
>>
>>> On May 22, 2026, at 23:40, Matheus Alcantara 
>>> <matheusssilv97@gmail.com> wrote:
>>>
>>> On 22/05/26 04:25, Jim Jones wrote:
>>>> On 21/05/2026 17:12, Matheus Alcantara wrote:
>>>>> I've reproduced the issue and the fix looks correct to me.
>>>> same here, +1
>>>
>>> Thank you for also testing.
>>>
>>>> I was wondering if creating a constant for it would be, stylistically
>>>> speaking, a cleaner solution. For instance:
>>>> #define EXTENSION_SYSTEM_MACRO  "$system"
>>>> I realize that it's used only inside 
>>>> get_extension_control_directories()
>>>> but since it is even mentioned in the docs, I guess it wouldn't be 
>>>> a bad
>>>> idea.
>>>
>>> I'm not against it but I don't think that it's necessary since as 
>>> you mention, only get_extension_control_directories() use.
>>>
>>
>> In theory, I’m not against the idea either. In practice, there are 
>> many hard-coded strings in the source tree, and I’m not sure where 
>> the right place would be to define this macro.
>>
>> Since this string is only used in 
>> get_extension_control_directories(), and now it is used three times, 
>> I defined it at the beginning of the function and undefined it at the 
>> end. Let’s see if there are any objections to that.
>>
>> Please see the attached v2.
>>
>
> We have such pattern in other parts of the codebase (e.g 
> pg_resetwal.c), so it works for me.
>
> Thanks for the patch.
>
>

Pushed.


cheers


andrew

--
Andrew Dunstan
EDB: https://www.enterprisedb.com