From db4f63a1f9b0e669c7c7248e5bd1bf069cdee7e8 Mon Sep 17 00:00:00 2001
From: Graham Percival <gperciva@tarsnap.com>
Date: Sun, 14 Jan 2024 16:12:55 -0800
Subject: [PATCH] tests/optional_mutex: check counter within a lock

The variables "value" and "counter" are modified within mutex locks, so
it's good "lock hygiene" to do the same for the final check.

Reported by:	Coverity scan
---
 tests/optional_mutex/main.c | 36 ++++++++++++++++++++++++++++++++++--
 1 file changed, 34 insertions(+), 2 deletions(-)

diff --git a/tests/optional_mutex/main.c b/tests/optional_mutex/main.c
index fbe5248e..e5379bc5 100644
--- a/tests/optional_mutex/main.c
+++ b/tests/optional_mutex/main.c
@@ -95,6 +95,38 @@ test_pthread(void)
 }
 #endif
 
+/* Return 0 if everything matches; 1 if they do not match; -1 on error. */
+static int
+check_counter(int counter_expected)
+{
+	int rc, match;
+
+	/* Lock if we're using pthread. */
+	if ((rc = optional_mutex_lock(&mutex)) != 0) {
+		warn0("optional_mutex_lock: %s", strerror(rc));
+		goto err0;
+	}
+
+	/* Check the value and counter. */
+	if ((value == 0) && (counter == counter_expected))
+		match = 0;
+	else
+		match = 1;
+
+	/* Unlock if we're using pthread. */
+	if ((rc = optional_mutex_unlock(&mutex)) != 0) {
+		warn0("optional_mutex_unlock: %s", strerror(rc));
+		goto err0;
+	}
+
+	/* Success! */
+	return (match);
+
+err0:
+	/* Failure! */
+	return (-1);
+}
+
 int
 main(int argc, char * argv[])
 {
@@ -112,8 +144,8 @@ main(int argc, char * argv[])
 	inc_dec_counter(NULL);
 #endif
 
-	/* Check the counter. */
-	if ((value != 0) || (counter != counter_expected))
+	/* Check that the counter has the expected value. */
+	if (check_counter(counter_expected))
 		goto err0;
 
 	/* Success! */