X-Git-Url: http://git.lttng.org/?a=blobdiff_plain;f=include%2Flttng%2Ftracepoint-types.h;h=5354c3698abc478dd41c6167f5cff07098f7de63;hb=2adb7ad28124fdbc0ad61bcada1c7dbceb03e9ab;hp=9b104b07be6698e927dc4362b200eb99b16d86d7;hpb=2253b139ffb6a4eca7291b60083cc5206a6e128d;p=lttng-ust.git

diff --git a/include/lttng/tracepoint-types.h b/include/lttng/tracepoint-types.h
index 9b104b07..5354c369 100644
--- a/include/lttng/tracepoint-types.h
+++ b/include/lttng/tracepoint-types.h
@@ -1,32 +1,50 @@
+/*
+ * SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2011-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ */
+
 #ifndef _LTTNG_TRACEPOINT_TYPES_H
 #define _LTTNG_TRACEPOINT_TYPES_H
 
+#include <stdint.h>
+
 /*
- * Copyright (c) 2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- *
- * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
- * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
+ * Tracepoint probe definition
  *
- * Permission is hereby granted to use or copy this program
- * for any purpose,  provided the above notices are retained on all copies.
- * Permission to modify the code and to distribute modified code is granted,
- * provided the above notices are retained, and a notice that the code was
- * modified is included with the above copyright notice.
+ * IMPORTANT: this structure is part of the ABI between instrumented
+ * applications and UST. This structure is fixed-size because it is part
+ * of a public array of structures. Rather than extending this
+ * structure, struct lttng_ust_tracepoint should be extended instead.
  */
 
-struct tracepoint_probe {
-	void *func;
+struct lttng_ust_tracepoint_probe {
+	void (*func)(void);
 	void *data;
 };
 
-#define TRACEPOINT_PADDING	16
-struct tracepoint {
+/*
+ * Tracepoint definition
+ *
+ * IMPORTANT: this structure is part of the ABI between instrumented
+ * applications and UST. Fields need to be only added at the end, never
+ * reordered, never removed.
+ *
+ * The field @struct_size should be used to determine the size of the
+ * structure. It should be queried before using additional fields added
+ * at the end of the structure.
+ */
+
+struct lttng_ust_tracepoint {
+	uint32_t struct_size;
+
 	const char *name;
 	int state;
-	struct tracepoint_probe *probes;
+	struct lttng_ust_tracepoint_probe *probes;
 	int *tracepoint_provider_ref;
 	const char *signature;
-	char padding[TRACEPOINT_PADDING];
+
+	/* End of base ABI. Fields below should be used after checking struct_size. */
 };
 
 #endif /* _LTTNG_TRACEPOINT_TYPES_H */