Re: warn if GUC set to an invalid shared library

Justin Pryzby <pryzby@telsasoft.com>

From: Justin Pryzby <pryzby@telsasoft.com>

To: Robert Haas <robertmhaas@gmail.com>

Cc: pgsql-hackers@lists.postgresql.org, Tom Lane <tgl@sss.pgh.pa.us>, "David G. Johnston" <david.g.johnston@gmail.com>, Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>, Cary Huang <cary.huang@highgo.ca>, Maciek Sakrejda <m.sakrejda@gmail.com>

Date: 2024-07-22T16:28:23Z

Lists: pgsql-hackers

Attachments

0001-change-function-SET-to-use-a-separate-GUC-source.patch (text/x-diff)

On Fri, May 24, 2024 at 01:15:13PM -0400, Robert Haas wrote:
> + /* Note that filename was already canonicalized */
> 
> I see that this comment is copied from load_libraries(), but I don't
> immediately see where the canonicalization actually happens. Do you
> know, or can you find out? Because that's crucial here, else stat()
> might not target the real filename. I wonder if it will anyway. Like,
> couldn't the library be versioned, and might not dlopen() try a few
> possibilities?

This comment made me realize that we've been fixated on the warning.
But the patch was broken, and would've always warned.  I think almost
all of the previous patch versions had this issue - oops.

I added a call to expand_dynamic_library_name(), which seems to answer
your question.

And added a preparatory patch to distinguish ALTER USER/DATABASE SET
from SET in a function, to avoid warning in that case.

-- 
Justin