thread-value: Defer cleanup handling to thread termination on Windows

Instead of cleaning up all thread-values during destruction, cleanup handler
is invoked when a thread detaches. Thread detaching is cough using the Windows
DllMain() entry point, and allows us to basically revert 204098a7.

Using this mechanism, we make sure that the cleanup handler is invoked by the
the correct thread. Further, this mechanism works for externally-spawned
threads which run outside of our thread_cb() routine, and works more efficiently
with short-running threads.

3 files changed, 51 insertions, 40 deletions

diff --git a/src/libstrongswan/threading/windows/thread.c b/src/libstrongswan/threading/windows/thread.c
index 2b273413c..8792237e6 100644
--- a/src/libstrongswan/threading/windows/thread.c
+++ b/src/libstrongswan/threading/windows/thread.c
@@ -246,36 +246,6 @@ void* thread_tls_remove(void *key)
 }
 
 /**
- * See header.
- */
-void thread_tls_remove_all(void *key)
-{
-	private_thread_t *thread;
-	enumerator_t *enumerator;
-	void *value;
-	bool old;
-
-	old = set_leak_detective(FALSE);
-	threads_lock->lock(threads_lock);
-
-	enumerator = threads->create_enumerator(threads);
-	while (enumerator->enumerate(enumerator, NULL, &thread))
-	{
-		value = thread->tls->remove(thread->tls, key);
-		if (value)
-		{
-			set_leak_detective(old);
-			thread_tls_cleanup(value);
-			set_leak_detective(FALSE);
-		}
-	}
-	enumerator->destroy(enumerator);
-
-	threads_lock->unlock(threads_lock);
-	set_leak_detective(old);
-}
-
-/**
  * Thread cleanup data
  */
 typedef struct {
@@ -634,6 +604,50 @@ void thread_exit(void *val)
 	ExitThread(0);
 }
 
+/**
+ * Clean up thread data while it detaches
+ */
+static void cleanup_tls()
+{
+	private_thread_t *this;
+	bool old;
+
+	old = set_leak_detective(FALSE);
+	threads_lock->lock(threads_lock);
+
+	this = threads->remove(threads, (void*)(uintptr_t)GetCurrentThreadId());
+
+	threads_lock->unlock(threads_lock);
+	set_leak_detective(old);
+
+	if (this)
+	{
+		/* If the thread exited, but has not been joined, it is in terminated
+		 * state. We must not mangle it, as we target externally spawned
+		 * threads only. */
+		if (!this->terminated && !this->detached)
+		{
+			destroy(this);
+		}
+	}
+}
+
+/**
+ * DllMain called for dll events
+ */
+BOOL WINAPI DllMain(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpvReserved)
+{
+	switch (fdwReason)
+	{
+		case DLL_THREAD_DETACH:
+			cleanup_tls();
+			break;
+		default:
+			break;
+	}
+	return TRUE;
+}
+
 /*
  * Described in header.
  */
diff --git a/src/libstrongswan/threading/windows/thread.h b/src/libstrongswan/threading/windows/thread.h
index 3c470522b..965d9690e 100644
--- a/src/libstrongswan/threading/windows/thread.h
+++ b/src/libstrongswan/threading/windows/thread.h
@@ -61,15 +61,6 @@ void* thread_tls_get(void *key);
 void* thread_tls_remove(void *key);
 
 /**
- * Remove a thread specific value from all threads.
- *
- * For each found TLS value thread_tls_cleanup() is invoked.
- *
- * @param key		unique key specifying the TLS variable
- */
-void thread_tls_remove_all(void *key);
-
-/**
  * Cleanup function for thread specific value.
  *
  * This is called whenever a thread exits to clean up thread specific data.
diff --git a/src/libstrongswan/threading/windows/thread_value.c b/src/libstrongswan/threading/windows/thread_value.c
index 1dd8a7816..d7bd7e64c 100644
--- a/src/libstrongswan/threading/windows/thread_value.c
+++ b/src/libstrongswan/threading/windows/thread_value.c
@@ -104,7 +104,13 @@ METHOD(thread_value_t, tls_get, void*,
 METHOD(thread_value_t, tls_destroy, void,
 	private_thread_value_t *this)
 {
-	thread_tls_remove_all(this);
+	entry_t *entry;
+
+	entry = thread_tls_remove(this);
+	if (entry)
+	{
+		thread_tls_cleanup(entry);
+	}
 	free(this);
 }