Fix deadlock in ApiClient::SendMessage

fixes #6368

lib/base/tlsstream.cpp

@@ -20,6 +20,7 @@
 #include "base/tlsstream.hpp"
 #include "base/utility.hpp"
 #include "base/exception.hpp"
+#include "base/objectlock.hpp"
 #include "base/logger_fwd.hpp"
 #include <boost/bind.hpp>
 #include <iostream>
@@ -183,6 +184,32 @@ size_t TlsStream::Read(void *buffer, size_t count)
 }
 
 void TlsStream::Write(const void *buffer, size_t count)
+{
+	{
+		ObjectLock olock(&m_SendQ);
+		m_SendQ.Write(buffer, count);
+	}
+
+	Utility::QueueAsyncCallback(boost::bind(&TlsStream::FinishAsyncWrite, this));
+}
+
+void TlsStream::FinishAsyncWrite(void)
+{
+	boost::mutex::scoped_lock lock(m_WriteMutex);
+	
+	for (;;) {
+		ObjectLock olock(&m_SendQ);
+		char buffer[1024];
+		size_t count = m_SendQ.Read(buffer, sizeof(buffer));
+		
+		if (count == 0)
+			break; /* No more data in the sendq */
+		
+		WriteSync(buffer, count);
+	}
+}
+
+void TlsStream::WriteSync(const void *buffer, size_t count)
 {
 	size_t left = count;
 

lib/base/tlsstream.hpp

@@ -23,6 +23,7 @@
 #include "base/i2-base.hpp"
 #include "base/socket.hpp"
 #include "base/stream.hpp"
+#include "base/fifo.hpp"
 #include "base/tlsutility.hpp"
 
 namespace icinga
@@ -49,6 +50,7 @@ public:
 
 	virtual size_t Read(void *buffer, size_t count);
 	virtual void Write(const void *buffer, size_t count);
+        void WriteSync(const void *buffer, size_t count);
 
 	virtual bool IsEof(void) const;
 
@@ -56,6 +58,9 @@ private:
 	boost::mutex m_SSLLock;
 	shared_ptr<SSL> m_SSL;
 	BIO *m_BIO;
+        
+        boost::mutex m_WriteMutex;
+        FIFO m_SendQ;
 
 	Socket::Ptr m_Socket;
 	ConnectionRole m_Role;
@@ -64,6 +69,8 @@ private:
 	static bool m_SSLIndexInitialized;
 
 	static void NullCertificateDeleter(X509 *certificate);
+        
+        void FinishAsyncWrite(void);
 };
 
 }