[lttng-dev] [RFC PATCH lttng-tools v2 14/20] Add serialized versions of lttng_event structs

[Yannick Lamarre]

Serialized versions of lttng_event, lttng_event_function_attr and
lttng_event_probe_attr 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 across processes on
platforms supporting multiple pointer sizes (32bits vs 64bits) and this
creates mismatches in structure sizes.
Padding is also removed since it defeats the purpose of a packed struct
and is not used to extend the protocols.

Signed-off-by: Yannick Lamarre <ylamarre at efficios.com>
---
Reworded commit message to better justify removal of pointer and padding
fields.

 include/lttng/event-internal.h | 38 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/include/lttng/event-internal.h b/include/lttng/event-internal.h
index 09b4d232..a43007de 100644
--- a/include/lttng/event-internal.h
+++ b/include/lttng/event-internal.h
@@ -27,6 +27,44 @@
 
 struct lttng_userspace_probe_location;
 
+struct lttng_event_probe_attr_serialized {
+	uint64_t addr;
+
+	uint64_t offset;
+	char symbol_name[LTTNG_SYMBOL_NAME_LEN];
+} LTTNG_PACKED;
+
+struct lttng_event_function_attr_serialized {
+	char symbol_name[LTTNG_SYMBOL_NAME_LEN];
+} LTTNG_PACKED;
+
+struct lttng_event_serialized {
+	uint32_t type; /* enum lttng_event_type */
+
+	char name[LTTNG_SYMBOL_NAME_LEN];
+
+	uint32_t loglevel_type; /* enum lttng_loglevel_type */
+
+	int loglevel;
+
+	int32_t enabled;	/* Does not apply: -1 */
+
+	pid_t pid;
+
+	unsigned char filter;	/* filter enabled ? */
+
+	unsigned char exclusion; /* exclusions added ? */
+
+	/* Event flag, from 2.6 and above. */
+	uint32_t flags; /* enum lttng_event_flag */
+
+	/* Per event type configuration */
+	union {
+		struct lttng_event_probe_attr_serialized probe;
+		struct lttng_event_function_attr_serialized ftrace;
+	} attr;
+} LTTNG_PACKED;
+
 struct lttng_event_perf_counter_ctx_serialized {
 	uint32_t type;
 	uint64_t config;
-- 
2.11.0