trace: Hook lib/trace as a subsystem

Signed-off-by: David Goulet <dgoulet@torproject.org>

src/app/main/subsystem_list.c

@@ -26,6 +26,7 @@
 #include "lib/thread/thread_sys.h"
 #include "lib/time/time_sys.h"
 #include "lib/tls/tortls_sys.h"
+#include "lib/trace/trace_sys.h"
 #include "lib/wallclock/wallclock_sys.h"
 #include "lib/evloop/evloop_sys.h"
 
@@ -47,6 +48,8 @@ const subsys_fns_t *tor_subsystems[] = {
   &sys_logging,
   &sys_threads,
 
+  &sys_tracing,
+
   &sys_time,
 
   &sys_crypto,

src/lib/trace/.may_include

@@ -1,3 +1,4 @@
 orconfig.h
 lib/log/*.h
 lib/trace/*.h
+lib/subsys/*.h

src/lib/trace/include.am

@@ -4,11 +4,13 @@ noinst_LIBRARIES += \
 
 # ADD_C_FILE: INSERT SOURCES HERE.
 LIBTOR_TRACE_A_SOURCES = \
-	src/lib/trace/trace.c
+	src/lib/trace/trace.c	\
+	src/lib/trace/trace_sys.c
 
 # ADD_C_FILE: INSERT HEADERS HERE.
 TRACEHEADERS = \
-	src/lib/trace/trace.h \
+	src/lib/trace/trace.h		\
+	src/lib/trace/trace_sys.h	\
 	src/lib/trace/events.h
 
 if USE_TRACING_INSTRUMENTATION_LOG_DEBUG

src/lib/trace/trace.c

@@ -1,4 +1,4 @@
-/* Copyright (c) 2017-2020, The Tor Project, Inc. */
+/* Copyright (c) 2020, The Tor Project, Inc. */
 /* See LICENSE for licensing information */
 
 /**
@@ -15,3 +15,9 @@ void
 tor_trace_init(void)
 {
 }
+
+/** Free all the tracing library. */
+void
+tor_trace_free_all(void)
+{
+}

src/lib/trace/trace.h

@@ -1,4 +1,4 @@
-/* Copyright (c) 2017-2020, The Tor Project, Inc. */
+/* Copyright (c) 2020, The Tor Project, Inc. */
 /* See LICENSE for licensing information */
 
 /**
@@ -6,9 +6,10 @@
  * \brief Header for trace.c
  **/
 
-#ifndef TOR_TRACE_TRACE_H
-#define TOR_TRACE_TRACE_H
+#ifndef TOR_LIB_TRACE_TRACE_H
+#define TOR_LIB_TRACE_TRACE_H
 
 void tor_trace_init(void);
+void tor_trace_free_all(void);
 
-#endif /* !defined(TOR_TRACE_TRACE_H) */
+#endif /* !defined(TOR_LIB_TRACE_TRACE_H) */

src/lib/trace/trace_sys.c

@@ -0,0 +1,33 @@
+/* Copyright (c) 2018-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file log_sys.c
+ * \brief Setup and tear down the tracing module.
+ **/
+
+#include "lib/subsys/subsys.h"
+
+#include "lib/trace/trace.h"
+#include "lib/trace/trace_sys.h"
+
+static int
+subsys_tracing_initialize(void)
+{
+  tor_trace_init();
+  return 0;
+}
+
+static void
+subsys_tracing_shutdown(void)
+{
+  tor_trace_free_all();
+}
+
+const subsys_fns_t sys_tracing = {
+  .name = "tracing",
+  .supported = true,
+  .level = -85,
+  .initialize = subsys_tracing_initialize,
+  .shutdown = subsys_tracing_shutdown,
+};

src/lib/trace/trace_sys.h

@@ -0,0 +1,14 @@
+/* Copyright (c) 2018-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file log_sys.h
+ * \brief Declare subsystem object for the logging module.
+ **/
+
+#ifndef TOR_TRACE_SYS_H
+#define TOR_TRACE_SYS_H
+
+extern const struct subsys_fns_t sys_tracing;
+
+#endif /* !defined(TOR_TRACE_SYS_H) */