Attached is a patch to remove the check, and a minimal reproducer (curlexe.zip) for others to run on macOS.
Here are some logs: Postgres working as expected:
$ LC_ALL="C" /opt/homebrew/opt/postgresql@16/bin/postgres -D /opt/homebrew/var/postgresql@16 2024-01-22 23:18:51.203 GMT [50388] LOG: starting PostgreSQL 16.1 (Homebrew) on aarch64-apple-darwin23.2.0, compiled by Apple clang version 15.0.0 (clang-1500.1.0.2.5), 64-bit 2024-01-22 23:18:51.204 GMT [50388] LOG: listening on IPv6 address "::1", port 5432 2024-01-22 23:18:51.204 GMT [50388] LOG: listening on IPv4 address "127.0.0.1", port 5432 2024-01-22 23:18:51.205 GMT [50388] LOG: listening on Unix socket "/tmp/.s.PGSQL.5432" 2024-01-22 23:18:51.207 GMT [50391] LOG: database system was shut down at 2023-12-21 23:12:10 GMT 2024-01-22 23:18:51.211 GMT [50388] LOG: database system is ready to accept connections ^C2024-01-22 23:18:53.797 GMT [50388] LOG: received fast shutdown request 2024-01-22 23:18:53.798 GMT [50388] LOG: aborting any active transactions 2024-01-22 23:18:53.800 GMT [50388] LOG: background worker "logical replication launcher" (PID 50394) exited with exit code 1 2024-01-22 23:18:53.801 GMT [50389] LOG: shutting down 2024-01-22 23:18:53.801 GMT [50389] LOG: checkpoint starting: shutdown immediate 2024-01-22 23:18:53.805 GMT [50389] LOG: checkpoint complete: wrote 3 buffers (0.0%); 0 WAL file(s) added, 0 removed, 0 recycled; write=0.002 s, sync=0.001 s, total=0.005 s; sync files=2, longest=0.001 s, average=0.001 s; distance=0 kB, estimate=0 kB; lsn=0/4BE77E0, redo lsn=0/4BE77E0 2024-01-22 23:18:53.809 GMT [50388] LOG: database system is shut down
Postgres not working with attached extension preloaded:
$ echo shared_preload_libraries=curlexe >> /opt/homebrew/var/postgresql@16/postgresql.conf $ LC_ALL="C" /opt/homebrew/opt/postgresql@16/bin/postgres -D /opt/homebrew/var/postgresql@16 2024-01-22 23:19:01.108 GMT [50395] LOG: starting PostgreSQL 16.1 (Homebrew) on aarch64-apple-darwin23.2.0, compiled by Apple clang version 15.0.0 (clang-1500.1.0.2.5), 64-bit 2024-01-22 23:19:01.110 GMT [50395] LOG: listening on IPv6 address "::1", port 5432 2024-01-22 23:19:01.110 GMT [50395] LOG: listening on IPv4 address "127.0.0.1", port 5432 2024-01-22 23:19:01.111 GMT [50395] LOG: listening on Unix socket "/tmp/.s.PGSQL.5432" 2024-01-22 23:19:01.113 GMT [50395] FATAL: postmaster became multithreaded during startup 2024-01-22 23:19:01.113 GMT [50395] HINT: Set the LC_ALL environment variable to a valid locale. 2024-01-22 23:19:01.114 GMT [50395] LOG: database system is shut down
Same as previous, but without IPv6 support in libcurl:
$ DYLD_LIBRARY_PATH=/opt/homebrew/opt/curl-without-ipv6/lib LC_ALL="C" /opt/homebrew/opt/postgresql@16/bin/postgres -D /opt/homebrew/var/postgresql@16 2024-01-22 23:23:17.151 GMT [50546] LOG: starting PostgreSQL 16.1 (Homebrew) on aarch64-apple-darwin23.2.0, compiled by Apple clang version 15.0.0 (clang-1500.1.0.2.5), 64-bit 2024-01-22 23:23:17.152 GMT [50546] LOG: listening on IPv6 address "::1", port 5432 2024-01-22 23:23:17.152 GMT [50546] LOG: listening on IPv4 address "127.0.0.1", port 5432 2024-01-22 23:23:17.152 GMT [50546] LOG: listening on Unix socket "/tmp/.s.PGSQL.5432" 2024-01-22 23:23:17.155 GMT [50549] LOG: database system was shut down at 2024-01-22 23:23:10 GMT 2024-01-22 23:23:17.158 GMT [50546] LOG: database system is ready to accept connections ^C2024-01-22 23:23:26.997 GMT [50546] LOG: received fast shutdown request 2024-01-22 23:23:26.998 GMT [50546] LOG: aborting any active transactions 2024-01-22 23:23:27.000 GMT [50546] LOG: background worker "logical replication launcher" (PID 50552) exited with exit code 1 2024-01-22 23:23:27.000 GMT [50547] LOG: shutting down 2024-01-22 23:23:27.001 GMT [50547] LOG: checkpoint starting: shutdown immediate 2024-01-22 23:23:27.002 GMT [50547] LOG: checkpoint complete: wrote 3 buffers (0.0%); 0 WAL file(s) added, 0 removed, 0 recycled; write=0.001 s, sync=0.001 s, total=0.003 s; sync files=2, longest=0.001 s, average=0.001 s; distance=0 kB, estimate=0 kB; lsn=0/4BE78D0, redo lsn=0/4BE78D0 2024-01-22 23:23:27.005 GMT [50546] LOG: database system is shut down
[0]: https://github.com/curl/curl/commit/8b7cbe9decc205b08ec8258eb184c89a33e3084b [1]: https://developer.apple.com/documentation/systemconfiguration/1517088-scdynamicstorecopyproxies -- Tristan Partin Neon (https://neon.tech)
<<attachment: curlexe.zip>>
From 0a514e7a8ea2af21d98cbcc2e4da799745786155 Mon Sep 17 00:00:00 2001
From: Tristan Partin <tris...@neon.tech>
Date: Tue, 23 Jan 2024 13:14:33 -0600
Subject: [PATCH v1] Remove pthread_is_threaded_np() checks in postmaster
These checks are not effective for what they are trying to prevent.
Libraries that are preloaded can easily cause this check to fail.
---
configure | 2 +-
configure.ac | 1 -
meson.build | 1 -
src/backend/postmaster/postmaster.c | 27 ---------------------------
src/include/pg_config.h.in | 3 ---
5 files changed, 1 insertion(+), 33 deletions(-)
diff --git a/configure b/configure
index 70a1968003..e790015c2f 100755
--- a/configure
+++ b/configure
@@ -15573,7 +15573,7 @@ fi
LIBS_including_readline="$LIBS"
LIBS=`echo "$LIBS" | sed -e 's/-ledit//g' -e 's/-lreadline//g'`
-for ac_func in backtrace_symbols copyfile getifaddrs getpeerucred inet_pton kqueue mbstowcs_l memset_s posix_fallocate ppoll pthread_is_threaded_np setproctitle setproctitle_fast strchrnul strsignal syncfs sync_file_range uselocale wcstombs_l
+for ac_func in backtrace_symbols copyfile getifaddrs getpeerucred inet_pton kqueue mbstowcs_l memset_s posix_fallocate ppoll setproctitle setproctitle_fast strchrnul strsignal syncfs sync_file_range uselocale wcstombs_l
do :
as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh`
ac_fn_c_check_func "$LINENO" "$ac_func" "$as_ac_var"
diff --git a/configure.ac b/configure.ac
index 52fd7af446..69356df254 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1784,7 +1784,6 @@ AC_CHECK_FUNCS(m4_normalize([
memset_s
posix_fallocate
ppoll
- pthread_is_threaded_np
setproctitle
setproctitle_fast
strchrnul
diff --git a/meson.build b/meson.build
index 55184db248..56573c1585 100644
--- a/meson.build
+++ b/meson.build
@@ -2441,7 +2441,6 @@ func_checks = [
['ppoll'],
['pstat'],
['pthread_barrier_wait', {'dependencies': [thread_dep]}],
- ['pthread_is_threaded_np', {'dependencies': [thread_dep]}],
['sem_init', {'dependencies': [rt_dep, thread_dep], 'skip': sema_kind != 'unnamed_posix', 'define': false}],
['setproctitle', {'dependencies': [util_dep]}],
['setproctitle_fast'],
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index feb471dd1d..40968aadc5 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -1426,24 +1426,6 @@ PostmasterMain(int argc, char *argv[])
*/
}
-#ifdef HAVE_PTHREAD_IS_THREADED_NP
-
- /*
- * On macOS, libintl replaces setlocale() with a version that calls
- * CFLocaleCopyCurrent() when its second argument is "" and every relevant
- * environment variable is unset or empty. CFLocaleCopyCurrent() makes
- * the process multithreaded. The postmaster calls sigprocmask() and
- * calls fork() without an immediate exec(), both of which have undefined
- * behavior in a multithreaded program. A multithreaded postmaster is the
- * normal case on Windows, which offers neither fork() nor sigprocmask().
- */
- if (pthread_is_threaded_np() != 0)
- ereport(FATAL,
- (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
- errmsg("postmaster became multithreaded during startup"),
- errhint("Set the LC_ALL environment variable to a valid locale.")));
-#endif
-
/*
* Remember postmaster startup time
*/
@@ -1849,15 +1831,6 @@ ServerLoop(void)
if (StartWorkerNeeded || HaveCrashedWorker)
maybe_start_bgworkers();
-#ifdef HAVE_PTHREAD_IS_THREADED_NP
-
- /*
- * With assertions enabled, check regularly for appearance of
- * additional threads. All builds check at start and exit.
- */
- Assert(pthread_is_threaded_np() == 0);
-#endif
-
/*
* Lastly, check to see if it's time to do some things that we don't
* want to do every single time through the loop, because they're a
diff --git a/src/include/pg_config.h.in b/src/include/pg_config.h.in
index 288bb9cb42..922882b26f 100644
--- a/src/include/pg_config.h.in
+++ b/src/include/pg_config.h.in
@@ -336,9 +336,6 @@
/* Define to 1 if you have the `pthread_barrier_wait' function. */
#undef HAVE_PTHREAD_BARRIER_WAIT
-/* Define to 1 if you have the `pthread_is_threaded_np' function. */
-#undef HAVE_PTHREAD_IS_THREADED_NP
-
/* Have PTHREAD_PRIO_INHERIT. */
#undef HAVE_PTHREAD_PRIO_INHERIT
--
Tristan Partin
Neon (https://neon.tech)
