Fix pg_dump's errno checking for zlib I/O
Some error reports were reporting strerror(errno), which for some error
conditions coming from zlib are wrong, resulting in confusing reports
such as
pg_restore: [compress_io] could not read from input file: Success
which makes no sense. To correctly extract the error message we need to
use gzerror(), so let's do that.
This isn't as comprehensive or as neat as I would like, but at least it
should improve things in many common cases. The zlib abstraction in
compress_io does not seem to be applied consistently enough; we could
perhaps improve that, but it seems master-only material, not a bug fix
for back-patching.
This problem goes back all the way, but I decided to apply back to 9.4
only, because older branches don't contain commit 14ea89366 which this
change depends on.
Authors: Vladimir Kunschikov, Álvaro Herrera
Discussion: https://postgr.es/m/1498120508308.9826@infotecs.ru
Branch
------
REL9_6_STABLE
Details
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https://git.postgresql.org/pg/commitdiff/060393f2a13651bf53c7626a3587baaf82942023
Modified Files
--------------
src/bin/pg_dump/compress_io.c | 24 +++++++++++++++++++++++-
src/bin/pg_dump/compress_io.h | 1 +
src/bin/pg_dump/pg_backup_directory.c | 10 +++++++---
src/bin/pg_dump/pg_backup_tar.c | 8 +++++++-
4 files changed, 38 insertions(+), 5 deletions(-)