From ea0d24809d24445f27b156b357b4b60be699b363 Mon Sep 17 00:00:00 2001
From: Vincent Richard <vincent@vincent-richard.net>
Date: Thu, 6 Sep 2018 20:09:54 +0200
Subject: [PATCH] Useless mutex does not make nl_langinfo() thread-safe.

---
 src/vmime/platforms/posix/posixHandler.cpp | 53 ++++------------------
 1 file changed, 9 insertions(+), 44 deletions(-)

diff --git a/src/vmime/platforms/posix/posixHandler.cpp b/src/vmime/platforms/posix/posixHandler.cpp
index 20c0f342..f8861315 100644
--- a/src/vmime/platforms/posix/posixHandler.cpp
+++ b/src/vmime/platforms/posix/posixHandler.cpp
@@ -55,9 +55,6 @@
 #include <cassert>
 #include <cstdlib>
 
-#if VMIME_HAVE_PTHREAD
-#	include <pthread.h>
-#endif // VMIME_HAVE_PTHREAD
 
 /*
 #ifdef _POSIX_PRIORITY_SCHEDULING
@@ -66,45 +63,6 @@
 */
 
 
-#if VMIME_HAVE_PTHREAD
-
-namespace {
-
-	// This construction ensures mutex will be initialized in compile-time
-	// and will be available any time in the runtime.
-	pthread_mutex_t g_mutex = PTHREAD_MUTEX_INITIALIZER;
-
-	// Helper lock, to be exception safe all the time.
-	class PLockHelper {
-
-	public:
-
-		PLockHelper() {
-
-			if (pthread_mutex_lock(&g_mutex) != 0) {
-				assert(!"unable to lock mutex - thread safety's void");
-			}
-		}
-
-		~PLockHelper() {
-
-			if (pthread_mutex_unlock(&g_mutex) != 0) {
-				assert(!"unable to unlock mutex - application's dead...");
-			}
-		}
-
-	private:
-
-		// Object cannot be copied
-		PLockHelper(const PLockHelper&);
-		const PLockHelper& operator=(const PLockHelper&);
-	};
-
-} // unnamed namespace
-
-#endif // VMIME_HAVE_PTHREAD
-
-
 namespace vmime {
 namespace platforms {
 namespace posix {
@@ -173,9 +131,16 @@ const vmime::datetime posixHandler::getCurrentLocalTime() const {
 
 const vmime::charset posixHandler::getLocalCharset() const {
 
-	const PLockHelper lock;
+	// Note: nl_langinfo() might be affected by calls to setlocale()
+	// in a multithread environment. There is not MT-safe alternative
+	// to nl_langinfo().
+	auto codeset = ::nl_langinfo(CODESET);
 
-	return vmime::charset(::nl_langinfo(CODESET));
+	if (codeset) {
+		return vmime::charset(codeset);
+	}
+
+	return vmime::charset();
 }