4 files changed, 49 insertions, 4 deletions
diff --git a/src/lib/trace/events.h b/src/lib/trace/events.h
index b1b31fdc9b..fcd31e24e1 100644
--- a/src/lib/trace/events.h
+++ b/src/lib/trace/events.h
@@ -3,7 +3,7 @@
 
 /**
  * \file events.h
- * \brief Header file for Tor event tracing.
+ * \brief Header file for Tor tracing instrumentation definition.
  **/
 
 #ifndef TOR_LIB_TRACE_EVENTS_H
@@ -13,15 +13,20 @@
 
 #ifdef HAVE_TRACING
 
-#define tor_trace(subsystem, event_name, ...)           \
-  do {                                                  \
-    TOR_TRACE_LOG_DEBUG(tor_ ## subsystem, event_name); \
+#define tor_trace(subsystem, event_name, ...)                       \
+  do {                                                              \
+    TOR_TRACE_LOG_DEBUG(tor_ ## subsystem, event_name);             \
+    TOR_TRACE_USDT(tor_ ## subsystem, event_name, ## __VA_ARGS__);  \
   } while (0)
 
 /* This corresponds to the --enable-tracing-instrumentation-log-debug
  * configure option which maps all tracepoints to a log_debug() statement. */
 #include "lib/trace/debug.h"
 
+/* This corresponds to the --enable-tracing-instrumentation-usdt configure
+ * option which will generate USDT probes for each tracepoints. */
+#include "lib/trace/usdt/usdt.h"
+
 #else /* !defined(HAVE_TRACING) */
 
 /* Reaching this point, tracing is disabled thus we NOP every tracepoints
diff --git a/src/lib/trace/include.am b/src/lib/trace/include.am
index 312fd4e87d..01ea0c8a1d 100644
--- a/src/lib/trace/include.am
+++ b/src/lib/trace/include.am
@@ -18,6 +18,10 @@ TRACEHEADERS += \
 	src/lib/trace/debug.h
 endif
 
+if USE_TRACING_INSTRUMENTATION_USDT
+include src/lib/trace/usdt/include.am
+endif
+
 src_lib_libtor_trace_a_SOURCES = $(LIBTOR_TRACE_A_SOURCES)
 
 noinst_HEADERS+= $(TRACEHEADERS)
diff --git a/src/lib/trace/usdt/include.am b/src/lib/trace/usdt/include.am
new file mode 100644
index 0000000000..4e7e04c326
--- /dev/null
+++ b/src/lib/trace/usdt/include.am
@@ -0,0 +1,3 @@
+# ADD_C_FILE: INSERT HEADERS HERE.
+TRACEHEADERS += \
+	src/lib/trace/usdt/usdt.h
diff --git a/src/lib/trace/usdt/usdt.h b/src/lib/trace/usdt/usdt.h
new file mode 100644
index 0000000000..0b5fd6c444
--- /dev/null
+++ b/src/lib/trace/usdt/usdt.h
@@ -0,0 +1,33 @@
+/* Copyright (c) 2020, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file trace.h
+ * \brief Header for usdt.h
+ **/
+
+#ifndef TOR_TRACE_USDT_USDT_H
+#define TOR_TRACE_USDT_USDT_H
+
+#ifdef USE_TRACING_INSTRUMENTATION_USDT
+
+#ifdef HAVE_SYS_SDT_H
+#define SDT_USE_VARIADIC
+#include <sys/sdt.h>
+#define TOR_STAP_PROBEV STAP_PROBEV
+#else /* defined(HAVE_SYS_SDT_H) */
+#define TOR_STAP_PROBEV(...)
+#endif
+
+/* Map events to an USDT probe. */
+#define TOR_TRACE_USDT(subsystem, event_name, ...) \
+  TOR_STAP_PROBEV(subsystem, event_name, ## __VA_ARGS__);
+
+#else /* !defined(USE_TRACING_INSTRUMENTATION_USDT) */
+
+/* NOP event. */
+#define TOR_TRACE_USDT(subsystem, event_name, ...)
+
+#endif /* !defined(USE_TRACING_INSTRUMENTATION_USDT) */
+
+#endif /* !defined(TOR_TRACE_USDT_USDT_H) */