Thread: pgsql: Address set of issues with errno handling

pgsql: Address set of issues with errno handling

From
Michael Paquier
Date:
Address set of issues with errno handling

System calls mixed up in error code paths are causing two issues which
several code paths have not correctly handled:
1) For write() calls, sometimes the system may return less bytes than
what has been written without errno being set.  Some paths were careful
enough to consider that case, and assumed that errno should be set to
ENOSPC, other calls missed that.
2) errno generated by a system call is overwritten by other system calls
which may succeed once an error code path is taken, causing what is
reported to the user to be incorrect.

This patch uses the brute-force approach of correcting all those code
paths.  Some refactoring could happen in the future, but this is let as
future work, which is not targeted for back-branches anyway.

Author: Michael Paquier
Reviewed-by: Ashutosh Sharma
Discussion: https://postgr.es/m/20180622061535.GD5215@paquier.xyz

Branch
------
REL9_5_STABLE

Details
-------
https://git.postgresql.org/pg/commitdiff/910e2aca129cf0cda759c57920141c044aa1a8ba

Modified Files
--------------
src/backend/access/heap/rewriteheap.c           |  5 +++++
src/backend/access/transam/twophase.c           | 23 +++++++++++++++++++++++
src/backend/access/transam/xlog.c               |  7 +++++++
src/backend/replication/basebackup.c            |  3 +++
src/backend/replication/logical/origin.c        | 15 +++++++++++++++
src/backend/replication/logical/reorderbuffer.c |  4 +++-
src/backend/replication/logical/snapbuild.c     | 20 ++++++++++++++++++++
src/backend/replication/slot.c                  |  7 ++++++-
src/bin/pg_basebackup/receivelog.c              | 13 ++++++++++++-
9 files changed, 94 insertions(+), 3 deletions(-)