xref: /openbmc/linux/tools/perf/util/trace-event.c (revision 0da85d1e)
1 
2 #include <stdio.h>
3 #include <unistd.h>
4 #include <stdlib.h>
5 #include <errno.h>
6 #include <sys/types.h>
7 #include <sys/stat.h>
8 #include <fcntl.h>
9 #include <linux/kernel.h>
10 #include <traceevent/event-parse.h>
11 #include "trace-event.h"
12 #include "util.h"
13 
14 /*
15  * global trace_event object used by trace_event__tp_format
16  *
17  * TODO There's no cleanup call for this. Add some sort of
18  * __exit function support and call trace_event__cleanup
19  * there.
20  */
21 static struct trace_event tevent;
22 
23 int trace_event__init(struct trace_event *t)
24 {
25 	struct pevent *pevent = pevent_alloc();
26 
27 	if (pevent) {
28 		t->plugin_list = traceevent_load_plugins(pevent);
29 		t->pevent  = pevent;
30 	}
31 
32 	return pevent ? 0 : -1;
33 }
34 
35 void trace_event__cleanup(struct trace_event *t)
36 {
37 	traceevent_unload_plugins(t->plugin_list, t->pevent);
38 	pevent_free(t->pevent);
39 }
40 
41 static struct event_format*
42 tp_format(const char *sys, const char *name)
43 {
44 	struct pevent *pevent = tevent.pevent;
45 	struct event_format *event = NULL;
46 	char path[PATH_MAX];
47 	size_t size;
48 	char *data;
49 
50 	scnprintf(path, PATH_MAX, "%s/%s/%s/format",
51 		  tracing_events_path, sys, name);
52 
53 	if (filename__read_str(path, &data, &size))
54 		return NULL;
55 
56 	pevent_parse_format(pevent, &event, data, size, sys);
57 
58 	free(data);
59 	return event;
60 }
61 
62 struct event_format*
63 trace_event__tp_format(const char *sys, const char *name)
64 {
65 	static bool initialized;
66 
67 	if (!initialized) {
68 		int be = traceevent_host_bigendian();
69 		struct pevent *pevent;
70 
71 		if (trace_event__init(&tevent))
72 			return NULL;
73 
74 		pevent = tevent.pevent;
75 		pevent_set_flag(pevent, PEVENT_NSEC_OUTPUT);
76 		pevent_set_file_bigendian(pevent, be);
77 		pevent_set_host_bigendian(pevent, be);
78 		initialized = true;
79 	}
80 
81 	return tp_format(sys, name);
82 }
83