Horton

Incorrect errno used with %m for backend code

Michael Paquier <michael@paquier.xyz>

View thread View on postgr.es
From: Michael Paquier <michael@paquier.xyz>
To: Postgres hackers <pgsql-hackers@postgresql.org>
Date: 2018-06-22T06:15:35Z
Lists: pgsql-hackers

Attachments

Hi all,

I have been reviewing the use of errno in the backend code when %m is
used in the logs, and found more places than when I looked at improving
the error messages for read() calls which bloat the errno value because
of intermediate system calls.  As the problem is separate and should be
back-patched, I have preferred beginning a new thread.

A couple of places use CloseTransientFile without bothering much that
this can overwrite errno.  I was tempted in keeping errno saved and kept
if set to a non-zero value, but refrained from doing so as some callers
may rely on the existing behavior, and the attached shows better the
intention. 

Attached is a patch with everything I have spotted.  Any opinions or
thoughts in getting this back-patched?

Thanks,
--
Michael

Commits

  1. Address set of issues with errno handling