Feedback-ID: ie0a040ee:Fastmail
Message-ID: <515199be-2f4d-4e47-9b6e-d3f3ed11e510@eisentraut.org>
Date: Tue, 26 Mar 2024 08:19:09 +0100
MIME-Version: 1.0
User-Agent: Mozilla Thunderbird
Subject: Re: Regression tests fail with musl libc because libpq.so can't be
 loaded
To: Tom Lane <tgl@sss.pgh.pa.us>, Thomas Munro <thomas.munro@gmail.com>
Cc: Bruce Momjian <bruce@momjian.us>, walther@technowledgy.de,
 Christophe Pettus <xof@thebuild.com>, Andrew Dunstan <andrew@dunslane.net>,
 PostgreSQL Bugs <pgsql-bugs@lists.postgresql.org>,
 Robert Haas <robertmhaas@gmail.com>
References: 
 <CA+hUKGK2cSx3dveMqBD+E9N=zJ0WawBcbk_jnPqmdWBM0DT_3Q@mail.gmail.com>
 <477fa513-6bf0-456d-8d24-1e22a19df671@technowledgy.de>
 <ZfrmN4WHuJgD95fw@momjian.us>
 <CA+hUKGJzC4rr2Yr=QZyx9W83Wv=TVJHndKF1anjNLNXVUM7TqQ@mail.gmail.com>
 <f98cd8de-1c66-491a-8409-e62c09932080@technowledgy.de>
 <36690fcf-f0c8-4d60-af49-6a7efa0e2b14@technowledgy.de>
 <CA+hUKGJAkTZUa9JGr-zsadaqsN=K0P71t-1L2t2=MQFDMc4GuQ@mail.gmail.com>
 <ZfzLsiXbguTDatiZ@momjian.us>
 <a2463df1-be45-4a76-b90f-7676d778e7b1@technowledgy.de>
 <Zf2JU0_GDdbeBm5j@momjian.us> <Zf3fnKpHIGpe5mOi@momjian.us>
 <443430b4-0c10-49f3-8c8a-e5e76602f309@eisentraut.org>
 <CA+hUKGKU_0hmqem_EmAwePjVtMrjZNyNN0niUdBhuABajRwyhw@mail.gmail.com>
 <2712381.1711408552@sss.pgh.pa.us> <2715727.1711410188@sss.pgh.pa.us>
Content-Language: en-US
From: Peter Eisentraut <peter@eisentraut.org>
In-Reply-To: <2715727.1711410188@sss.pgh.pa.us>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Archived-At: 
 <https://www.postgresql.org/message-id/515199be-2f4d-4e47-9b6e-d3f3ed11e510%40eisentraut.org>
Precedence: bulk

On 26.03.24 00:43, Tom Lane wrote:
> I wrote:
>> Thomas Munro <thomas.munro@gmail.com> writes:
>>> I had originally proposed to avoid anything beginning "LD_" but Tom
>>> suggested being more specific.  I doubt LD_PRELOAD can really hurt you
>>> though (the linker probably only needs the value at the start by
>>> definition, not at later dlopen() time (?)).
> 
>> Oh, good point.  So we could simplify the patch by only looking for
>> LD_LIBRARY_PATH.
> 
> I looked at the musl source code you identified and confirmed that
> only the LD_LIBRARY_PATH string is remembered in a static variable;
> LD_PRELOAD is only accessed locally in that initialization function.
> So we only need to do the attached.  (I failed to resist the
> temptation to rewrite the comments.)

Yeah, I was more looking for a comment for posterity for *why* we need 
to preserve this variable in particular.  The updated comment looks 
reasonable.