From 55c4ef408b7e2305d1449c49d82d64ad095c949a Mon Sep 17 00:00:00 2001
From: Alex Chi Z <iskyzh@gmail.com>
Date: Wed, 20 Mar 2024 15:22:25 -0400
Subject: [PATCH] safekeeper: correctly handle signals (#7167)

errno is not preserved in the signal handler. This pull request fixes
it. Maybe related: https://github.com/neondatabase/neon/issues/6969, but
does not fix the flaky test problem.

Signed-off-by: Alex Chi Z <chi@neon.tech>
---
 pgxn/neon/walproposer_pg.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/pgxn/neon/walproposer_pg.c b/pgxn/neon/walproposer_pg.c
index c46fd9b3ec..002bf4e2ce 100644
--- a/pgxn/neon/walproposer_pg.c
+++ b/pgxn/neon/walproposer_pg.c
@@ -549,9 +549,10 @@ walprop_pg_init_standalone_sync_safekeepers(void)
 static void
 walprop_sigusr2(SIGNAL_ARGS)
 {
+	int			save_errno = errno;
 	got_SIGUSR2 = true;
-
 	SetLatch(MyLatch);
+	errno = save_errno;
 }
 
 static void