use own reentrant mutex implementation

src/lib/utils/thread.cpp

@@ -105,4 +105,25 @@ bool WaitThread::Wait(int seconds) {
   return isRunning();
 }
 
+
+Mutex::Mutex() {
+  pthread_mutexattr_t attr;
+  pthread_mutexattr_init(&attr);
+  pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE);
+  pthread_mutex_init(&m_mutex, &attr);
+  pthread_mutexattr_destroy(&attr);
+}
+
+Mutex::~Mutex() {
+  pthread_mutex_destroy(&m_mutex);
+}
+
+void Mutex::lock() {
+  pthread_mutex_lock(&m_mutex);
+}
+
+void Mutex::unlock() {
+  pthread_mutex_unlock(&m_mutex);
+}
+
 }  // namespace ebusd

src/lib/utils/thread.h

@@ -142,6 +142,37 @@ class WaitThread : public Thread {
   pthread_cond_t m_cond;
 };
 
+
+/**
+ * A simple mutex.
+ */
+class Mutex {
+ public:
+  /**
+   * Constructor.
+   */
+  Mutex();
+
+  /**
+   * Destructor.
+   */
+  virtual ~Mutex();
+
+  /**
+   * Lock this mutex.
+   */
+  void lock();
+
+  /**
+   * Unlock this mutex.
+   */
+  void unlock();
+
+ private:
+  /** the mutex for waiting. */
+  pthread_mutex_t m_mutex;
+};
+
 }  // namespace ebusd
 
 #endif  // LIB_UTILS_THREAD_H_