Previously pgwin32_is_service() would falsely return true when postgres is
started from somewhere within a service, but not as a service. That is
e.g. always the case with windows docker containers, which some CI services
use to run windows tests in.
When postgres falsely thinks its running as a service, no messages are
writting to stdout / stderr. That can be very confusing and causes a few tests
to fail.
To fix additionally check if stderr is invalid in pgwin32_is_service(). For
that to work in backend processes, pg_ctl is changed to pass down handles so
that postgres can do the same check (otherwise "default" handles are created).
While this problem exists in all branches, there have been no reports by
users, the prospective CI usage currently is only for master, and I am not a
windows expert. So doing the change in only master for now seems the sanest
approach.
Author: Andres Freund <andres@anarazel.de>
Reviewed-By: Magnus Hagander <magnus@hagander.net>
Discussion: https://postgr.es/m/20210305185752.3up5eq2eanb7ofmb@alap3.anarazel.de
src/port/README
libpgport
=========
libpgport must have special behavior. It supplies functions to both
libraries and applications. However, there are two complexities:
1) Libraries need to use object files that are compiled with exactly
the same flags as the library. libpgport might not use the same flags,
so it is necessary to recompile the object files for individual
libraries. This is done by removing -lpgport from the link line:
# Need to recompile any libpgport object files
LIBS := $(filter-out -lpgport, $(LIBS))
and adding infrastructure to recompile the object files:
OBJS= execute.o typename.o descriptor.o data.o error.o prepare.o memory.o \
connect.o misc.o path.o exec.o \
$(filter strlcat.o, $(LIBOBJS))
The problem is that there is no testing of which object files need to be
added, but missing functions usually show up when linking user
applications.
2) For applications, we use -lpgport before -lpq, so the static files
from libpgport are linked first. This avoids having applications
dependent on symbols that are _used_ by libpq, but not intended to be
exported by libpq. libpq's libpgport usage changes over time, so such a
dependency is a problem. Windows, Linux, AIX, and macOS use an export
list to control the symbols exported by libpq.
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