From 8c912ed353240ecfa49ee3a9f1f7c65141e9d0d6 Mon Sep 17 00:00:00 2001
From: Tristan Partin <tristan@neon.tech>
Date: Thu, 6 Jul 2023 15:25:14 -0500
Subject: [PATCH v2 1/2] Use signal-safe functions in signal handler

According to signal-safety(7), exit(3) and puts(3) are not safe to call
in a signal handler.
---
 src/bin/pg_test_fsync/pg_test_fsync.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/src/bin/pg_test_fsync/pg_test_fsync.c b/src/bin/pg_test_fsync/pg_test_fsync.c
index 435df8d808..42d0845b06 100644
--- a/src/bin/pg_test_fsync/pg_test_fsync.c
+++ b/src/bin/pg_test_fsync/pg_test_fsync.c
@@ -595,9 +595,12 @@ signal_cleanup(SIGNAL_ARGS)
 	/* Delete the file if it exists. Ignore errors */
 	if (needs_unlink)
 		unlink(filename);
-	/* Finish incomplete line on stdout */
-	puts("");
-	exit(1);
+	/*
+	 * Finish incomplete line on stdout. fileno(3) is not signal-safe, and
+	 * STDOUT_FILENO is not portable.
+	 */
+	write(1, "\n", 1);
+	_exit(1);
 }
 
 #ifdef HAVE_FSYNC_WRITETHROUGH
-- 
Tristan Partin
Neon (https://neon.tech)