xref: /linux/tools/perf/util/trace-event.c (revision cf2f33a4e54096f90652cca3511fd6a456ea5abe)
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 <api/fs/tracing_path.h>
12 #include "trace-event.h"
13 #include "machine.h"
14 #include "util.h"
15 
16 /*
17  * global trace_event object used by trace_event__tp_format
18  *
19  * TODO There's no cleanup call for this. Add some sort of
20  * __exit function support and call trace_event__cleanup
21  * there.
22  */
23 static struct trace_event tevent;
24 static bool tevent_initialized;
25 
26 int trace_event__init(struct trace_event *t)
27 {
28 	struct pevent *pevent = pevent_alloc();
29 
30 	if (pevent) {
31 		t->plugin_list = traceevent_load_plugins(pevent);
32 		t->pevent  = pevent;
33 	}
34 
35 	return pevent ? 0 : -1;
36 }
37 
38 static int trace_event__init2(void)
39 {
40 	int be = traceevent_host_bigendian();
41 	struct pevent *pevent;
42 
43 	if (trace_event__init(&tevent))
44 		return -1;
45 
46 	pevent = tevent.pevent;
47 	pevent_set_flag(pevent, PEVENT_NSEC_OUTPUT);
48 	pevent_set_file_bigendian(pevent, be);
49 	pevent_set_host_bigendian(pevent, be);
50 	tevent_initialized = true;
51 	return 0;
52 }
53 
54 int trace_event__register_resolver(struct machine *machine,
55 				   pevent_func_resolver_t *func)
56 {
57 	if (!tevent_initialized && trace_event__init2())
58 		return -1;
59 
60 	return pevent_set_function_resolver(tevent.pevent, func, machine);
61 }
62 
63 void trace_event__cleanup(struct trace_event *t)
64 {
65 	traceevent_unload_plugins(t->plugin_list, t->pevent);
66 	pevent_free(t->pevent);
67 }
68 
69 static struct event_format*
70 tp_format(const char *sys, const char *name)
71 {
72 	struct pevent *pevent = tevent.pevent;
73 	struct event_format *event = NULL;
74 	char path[PATH_MAX];
75 	size_t size;
76 	char *data;
77 
78 	scnprintf(path, PATH_MAX, "%s/%s/%s/format",
79 		  tracing_events_path, sys, name);
80 
81 	if (filename__read_str(path, &data, &size))
82 		return NULL;
83 
84 	pevent_parse_format(pevent, &event, data, size, sys);
85 
86 	free(data);
87 	return event;
88 }
89 
90 struct event_format*
91 trace_event__tp_format(const char *sys, const char *name)
92 {
93 	if (!tevent_initialized && trace_event__init2())
94 		return NULL;
95 
96 	return tp_format(sys, name);
97 }
98