The default of lazy symbol resolution means that when the postmaster
first reaches the select() call in ServerLoop, it'll need to resolve
the link to that libc entry point. NetBSD's dynamic loader takes
an internal lock while doing that, and if a signal interrupts the
operation then there is a risk of self-deadlock should the signal
handler do anything that requires that lock, as several of the
postmaster signal handlers do. The window for this is pretty narrow,
and timing considerations make it unlikely that a signal would arrive
right then anyway. But it's semi-repeatable on slow single-CPU
machines, and in principle the race could happen with any hardware.
The least messy solution to this is to force binding of dynamic
symbols at postmaster start, using the "-z now" linker option.
While we're at it, also use "-z relro" so as to provide a small
security gain.
It's not entirely clear whether any other platforms share this
issue, but for now we'll assume it's NetBSD-specific. (We might
later try to use "-z now" on more platforms for performance
reasons, but that would not likely be something to back-patch.)
Report and patch by me; the idea to fix it this way is from
Andres Freund.
Discussion: https://postgr.es/m/3384826.1661802235@sss.pgh.pa.us
Move the platform-dependent logic that sets CFLAGS_SL from
src/makefiles/Makefile.foo to src/template/foo, so that the value
is determined at configure time and thus is available while running
configure's tests.
On a couple of platforms this might save a few microseconds of build
time by eliminating a test that make otherwise has to do over and over.
Otherwise it's pretty much a wash for build purposes; in particular,
this makes no difference to anyone who might be overriding CFLAGS_SL
via a make option.
This patch in itself does nothing with the value and thus should not
change any behavior, though you'll probably have to re-run configure
to get a correctly updated Makefile.global. We'll use the new
configure variable in a follow-on patch.
Per gripe from Kyotaro Horiguchi. Back-patch to all supported branches,
because the follow-on patch is a portability bug fix.
Discussion: https://postgr.es/m/20191010.144533.263180400.horikyota.ntt@gmail.com
Allow additional thread flags to be added via port templates.
Change thread flag names to PTHREAD_CFLAGS and PTHREAD_LIBS to match new
configure script.
variable.
Remove thread locking for non-thread-safe functions, instead throw a
compile error.
Platforms will have to re-run tools/thread to record their thread
safety.
* use non-*_r function names if they are all thread-safe
* (NEED_REENTRANT_FUNCS=no)
* use *_r functions if they exist (configure test)
* do our own locking and copying of non-threadsafe functions
New to this patch is the last option.
Makefile.port, since they are of no use to configure and much of the
library magic happens in Makefile.port anyway.
Use __alpha, not __alpha__, since the former is universally available.
Remove -DNOFIXADE from the compile command line and put it in the port
include file.
CPP) to create platform independent files. Unfortunately, that means that
every config.status (or configure) run invariably causes a relink of the
postmaster and also that we can't put these files in the distribution
(usefully). So we make it a little smarter: when the output files already
exist and it notices that it would recreate them in identical form, it
doesn't touch them. In order to avoid re-running the make rule all the time
we update a timestamp file instead.
Update release_prep accordingly. Also make Gen_fmgrtab.sh use the awk that
is detected at configure time, not necessarily named `awk' and have it check
for exit statuses a little better.
In other news... Remove USE_LOCALE from the templates, it was set to `no'
everywhere anyway. Also remove YACC and YFLAGS from the templates, configure
is smart enough to find bison or yacc itself. Use AC_PROG_YACC for that
instead of the hand-crafted code. Do not set YFLAGS to `-d'. The make rules
that need this flag should explicitly invoke it. YFLAGS should be a user
variable. Update the makefiles to that effect.
Tom Lane
Bruce Momjian
Magnus Hagander
Peter Eisentraut
Marc G. Fournier