1 files changed, 82 insertions, 0 deletions
diff --git a/src/common/TracepointProvider.h b/src/common/TracepointProvider.h
new file mode 100644
index 000000000..fe447677c
--- /dev/null
+++ b/src/common/TracepointProvider.h
@@ -0,0 +1,82 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+
+#ifndef CEPH_TRACEPOINT_PROVIDER_H
+#define CEPH_TRACEPOINT_PROVIDER_H
+
+#include "common/ceph_context.h"
+#include "common/config_obs.h"
+#include "common/ceph_mutex.h"
+#include "include/dlfcn_compat.h"
+
+class TracepointProvider : public md_config_obs_t {
+public:
+  struct Traits {
+    const char *library;
+    const char *config_key;
+
+    Traits(const char *library, const char *config_key)
+      : library(library), config_key(config_key) {
+    }
+  };
+
+  class Singleton {
+  public:
+    Singleton(CephContext *cct, const char *library, const char *config_key)
+      : tracepoint_provider(new TracepointProvider(cct, library, config_key)) {
+    }
+    ~Singleton() {
+      delete tracepoint_provider;
+    }
+
+    inline bool is_enabled() const {
+      return tracepoint_provider->m_handle != nullptr;
+    }
+  private:
+    TracepointProvider *tracepoint_provider;
+  };
+
+  template <const Traits &traits>
+  class TypedSingleton : public Singleton {
+  public:
+    explicit TypedSingleton(CephContext *cct)
+      : Singleton(cct, traits.library, traits.config_key) {
+    }
+  };
+
+  TracepointProvider(CephContext *cct, const char *library,
+                     const char *config_key);
+  ~TracepointProvider() override;
+
+  TracepointProvider(const TracepointProvider&) = delete;
+  TracepointProvider operator =(const TracepointProvider&) = delete;
+  TracepointProvider(TracepointProvider&&) = delete;
+  TracepointProvider operator =(TracepointProvider&&) = delete;
+
+  template <const Traits &traits>
+  static void initialize(CephContext *cct) {
+#ifdef WITH_LTTNG
+     cct->lookup_or_create_singleton_object<TypedSingleton<traits>>(
+       traits.library, false, cct);
+#endif
+  }
+
+protected:
+  const char** get_tracked_conf_keys() const override {
+    return m_config_keys;
+  }
+  void handle_conf_change(const ConfigProxy& conf,
+			  const std::set <std::string> &changed) override;
+
+private:
+  CephContext *m_cct;
+  std::string m_library;
+  mutable const char* m_config_keys[2];
+
+  ceph::mutex m_lock = ceph::make_mutex("TracepointProvider::m_lock");
+  void* m_handle = nullptr;
+
+  void verify_config(const ConfigProxy& conf);
+};
+
+#endif // CEPH_TRACEPOINT_PROVIDER_H