[lttng-dev] [RFC PATCH lttng-tools 10/18] Add serialized versions of lttng_event_context structs

Yannick Lamarre ylamarre at efficios.com
Thu Apr 18 12:18:42 EDT 2019


Serialized versions of lttng_event_context and lttng_event_perf_counter_ctx are
packed structures to be used in communication protocols for consistent
sizes across platforms. The serialized versions are stripped of pointers
and padding.

Pointers are removed since their size can vary on platforms supporting
variable sized registers (x86-64).
Padding is also removed since it defeats the purpose of a packed struct.

Signed-off-by: Yannick Lamarre <ylamarre at efficios.com>
---
 include/lttng/event-internal.h | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/include/lttng/event-internal.h b/include/lttng/event-internal.h
index f8130e3b..25a88448 100644
--- a/include/lttng/event-internal.h
+++ b/include/lttng/event-internal.h
@@ -27,6 +27,17 @@
 
 struct lttng_userspace_probe_location;
 
+struct lttng_event_perf_counter_ctx_serialized {
+	uint32_t type;
+	uint64_t config;
+	char name[LTTNG_SYMBOL_NAME_LEN];
+} LTTNG_PACKED;
+
+struct lttng_event_context_serialized {
+	uint32_t ctx; /* enum lttng_event_context_type */
+	struct lttng_event_perf_counter_ctx_serialized perf_counter;
+} LTTNG_PACKED;
+
 struct lttng_event_extended {
 	/*
 	 * exclusions and filter_expression are only set when the lttng_event
-- 
2.11.0



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