Fix: add provider ABI compatibility check

[lttng-ust.git] / include / lttng / ust-events.h

diff --git a/include/lttng/ust-events.h b/include/lttng/ust-events.h
index 749478a6a335b3b9b14ab0ceb3dd87787f469b30..0b8664c3cbae0635c441f777e11d4d359e21ba5d 100644 (file)
--- a/include/lttng/ust-events.h
+++ b/include/lttng/ust-events.h
@@ -37,6 +37,15 @@
 
 #define LTTNG_UST_UUID_LEN             16
 
+/*
+ * Tracepoint provider version. Compatibility based on the major number.
+ * Older tracepoint providers can always register to newer lttng-ust
+ * library, but the opposite is rejected: a newer tracepoint provider is
+ * rejected by an older lttng-ust library.
+ */
+#define LTTNG_UST_PROVIDER_MAJOR       1
+#define LTTNG_UST_PROVIDER_MINOR       0
+
 struct lttng_channel;
 struct lttng_session;
 struct lttng_ust_lib_ring_buffer_ctx;
@@ -251,7 +260,7 @@ struct lttng_event_desc {
        } u;
 };
 
-#define LTTNG_UST_PROBE_DESC_PADDING   20
+#define LTTNG_UST_PROBE_DESC_PADDING   12
 struct lttng_probe_desc {
        const char *provider;
        const struct lttng_event_desc **event_desc;
@@ -259,6 +268,8 @@ struct lttng_probe_desc {
        struct cds_list_head head;              /* chain registered probes */
        struct cds_list_head lazy_init_head;
        int lazy;                               /* lazy registration */
+       uint32_t major;
+       uint32_t minor;
        char padding[LTTNG_UST_PROBE_DESC_PADDING];
 };