API refactoring: introduce probe context

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

diff --git a/include/lttng/ust-events.h b/include/lttng/ust-events.h
index 5e94bafeb567789e827a1abfc6e35abe01dd38c7..cae9e71a55ef1cecbc2ebbc9b3e06222e6ddbb98 100644 (file)
--- a/include/lttng/ust-events.h
+++ b/include/lttng/ust-events.h
@@ -300,6 +300,26 @@ struct lttng_ust_probe_desc {
 
 /* Data structures used by the tracer. */
 
+/*
+ * IMPORTANT: this structure is part of the ABI between the probe 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.
+ *
+ * The probe_ctx is not const because it may be extended to add future
+ * fields which could be modified by callbacks.
+ */
+struct lttng_ust_probe_ctx {
+       uint32_t struct_size;                   /* Size of this structure. */
+
+       void *ip;                               /* caller ip address */
+
+       /* End of base ABI. Fields below should be used after checking struct_size. */
+};
+
 /*
  * lttng_event structure is referred to by the tracing fast path. It
  * must be kept small.
@@ -351,6 +371,7 @@ struct lttng_ust_event_common {
        int eval_filter;                                /* Need to evaluate filters */
        int (*run_filter)(const struct lttng_ust_event_common *event,
                const char *stack_data,
+               struct lttng_ust_probe_ctx *probe_ctx,
                void *filter_ctx);
 
        /* End of base ABI. Fields below should be used after checking struct_size. */
@@ -395,7 +416,6 @@ struct lttng_ust_event_recorder {
 struct lttng_ust_notification_ctx {
        uint32_t struct_size;           /* Size of this structure. */
        int eval_capture;               /* Capture evaluation available. */
-
        /* End of base ABI. Fields below should be used after checking struct_size. */
 };
 
@@ -424,6 +444,7 @@ struct lttng_ust_event_notifier {
        int eval_capture;                               /* Need to evaluate capture */
        void (*notification_send)(const struct lttng_ust_event_notifier *event_notifier,
                const char *stack_data,
+               struct lttng_ust_probe_ctx *probe_ctx,
                struct lttng_ust_notification_ctx *notif_ctx);
 
        /* End of base ABI. Fields below should be used after checking struct_size. */