[v2,0/3] libtracefs: Add APIs for user_events to libtracefs

Message

Beau Belgrave Feb. 22, 2022, 11:23 p.m. UTC

New APIs added:
struct tracefs_user_event_group *tracefs_user_event_group_open(void);

void tracefs_user_event_group_close(struct tracefs_user_event_group *group);

int tracefs_user_event_delete(const char *name);

struct tracefs_user_event *
tracefs_user_event_register(struct tracefs_user_event_group *group,
                            const char *name, enum tracefs_uevent_flags flags,
                            struct tracefs_uevent_item *items);

bool tracefs_user_event_enabled(struct tracefs_user_event *event);

int tracefs_user_event_record(struct tracefs_user_event *event,
			      struct tracefs_uevent_item *items);

Documentation updates in this series describes the various APIs and the reason
for a group.

Items are described with a struct to better ensure contracts for things like
custom structs or static length strings. Items are allowed to be mixed/different
than what they were when registered. This allows callers the ability to describe
events verbosely, but write out via packed structs in their own code if needed.

V2:
Renamed tracefs_user_event_group_create() to tracefs_user_event_group_open()
Renamed tracefs_user_event_test() to tracefs_user_event_enabled()
Renamed tracefs_user_event_write() to tracefs_user_event_record()
Updated documentation to new function names
Moved to trace_seq vs snprintf for register commands
Split struct tracefs_user_event into external and internal sides for inlining
Changed tracefs_user_event_enabled to inline function
Fixed nits and whitespaces
Keep track of user view size to allow backward / forward compat if needed
Couldn't get variadic helper macro to work well, not including it here for now

Beau Belgrave (3):
  libtracefs: Add user_events to libtracefs sources
  libtracefs: Add documentation and sample code for user_events
  libtracefs: Add unit tests for user_events

 Documentation/libtracefs-userevents.txt | 260 ++++++++++++
 Makefile                                |   8 +
 include/tracefs-local.h                 |  24 ++
 include/tracefs.h                       |  67 +++
 samples/Makefile                        |   4 +
 src/Makefile                            |   4 +
 src/tracefs-userevents.c                | 516 ++++++++++++++++++++++++
 utest/tracefs-utest.c                   | 233 +++++++++++
 8 files changed, 1116 insertions(+)
 create mode 100644 Documentation/libtracefs-userevents.txt
 create mode 100644 src/tracefs-userevents.c


base-commit: e579ba38ff6bc07cd2278faf9d3ac08c15d4e9e8