Horton

Re: Thread-unsafe coding in ecpg

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Michael Meskes <meskes@postgresql.org>
Cc: pgsql-hackers@lists.postgresql.org
Date: 2019-01-20T20:04:36Z
Lists: pgsql-hackers

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I wrote:
> On the third hand, the lack of previous reports suggests that maybe
> this whole thing is seldom a problem in practice.  Maybe we should
> just use uselocale() where available and otherwise hope it's OK
> to keep on doing what we were doing.

If we go with that approach, I think we need to adapt the patch
as attached.  I autoconfiscated it and fixed a portability problem
(it didn't compile on macOS, which has these decls in <xlocale.h>).

I've verified that this fixes the problem I was seeing on OpenBSD 6.4.
I've not bothered to test on a platform lacking uselocale() --- I
think it's clear by inspection that the patch doesn't change anything
in that case.

Not sure if we need to document this or not.  On platforms with
uselocale(), it should fix the problem without any need for user
attention.  On platforms without, there's no change, and given
the lack of previous complaints I'm not sure it's really an issue.

			regards, tom lane

Commits

  1. Remove _configthreadlocale() calls in ecpg test suite.

  2. Remove infinite-loop hazards in ecpg test suite.

  3. Blind attempt to fix _configthreadlocale() failures on MinGW.

  4. Avoid thread-safety problem in ecpglib.

  5. Second try at fixing ecpglib thread-safety problem.