xref: /openbmc/linux/tools/perf/util/trace-event.c (revision 378ef0f5)
1 // SPDX-License-Identifier: GPL-2.0
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 <linux/err.h>
11 #include <traceevent/event-parse.h>
12 #include <api/fs/tracing_path.h>
13 #include <api/fs/fs.h>
14 #include "trace-event.h"
15 #include "machine.h"
16 
17 /*
18  * global trace_event object used by trace_event__tp_format
19  *
20  * TODO There's no cleanup call for this. Add some sort of
21  * __exit function support and call trace_event__cleanup
22  * there.
23  */
24 static struct trace_event tevent;
25 static bool tevent_initialized;
26 
trace_event__init(struct trace_event * t)27 int trace_event__init(struct trace_event *t)
28 {
29 	struct tep_handle *pevent = tep_alloc();
30 
31 	if (pevent) {
32 		t->plugin_list = tep_load_plugins(pevent);
33 		t->pevent  = pevent;
34 	}
35 
36 	return pevent ? 0 : -1;
37 }
38 
trace_event__init2(void)39 static int trace_event__init2(void)
40 {
41 	int be = tep_is_bigendian();
42 	struct tep_handle *pevent;
43 
44 	if (trace_event__init(&tevent))
45 		return -1;
46 
47 	pevent = tevent.pevent;
48 	tep_set_flag(pevent, TEP_NSEC_OUTPUT);
49 	tep_set_file_bigendian(pevent, be);
50 	tep_set_local_bigendian(pevent, be);
51 	tevent_initialized = true;
52 	return 0;
53 }
54 
trace_event__register_resolver(struct machine * machine,tep_func_resolver_t * func)55 int trace_event__register_resolver(struct machine *machine,
56 				   tep_func_resolver_t *func)
57 {
58 	if (!tevent_initialized && trace_event__init2())
59 		return -1;
60 
61 	return tep_set_function_resolver(tevent.pevent, func, machine);
62 }
63 
trace_event__cleanup(struct trace_event * t)64 void trace_event__cleanup(struct trace_event *t)
65 {
66 	tep_unload_plugins(t->plugin_list, t->pevent);
67 	tep_free(t->pevent);
68 }
69 
70 /*
71  * Returns pointer with encoded error via <linux/err.h> interface.
72  */
73 static struct tep_event*
tp_format(const char * sys,const char * name)74 tp_format(const char *sys, const char *name)
75 {
76 	char *tp_dir = get_events_file(sys);
77 	struct tep_handle *pevent = tevent.pevent;
78 	struct tep_event *event = NULL;
79 	char path[PATH_MAX];
80 	size_t size;
81 	char *data;
82 	int err;
83 
84 	if (!tp_dir)
85 		return ERR_PTR(-errno);
86 
87 	scnprintf(path, PATH_MAX, "%s/%s/format", tp_dir, name);
88 	put_events_file(tp_dir);
89 
90 	err = filename__read_str(path, &data, &size);
91 	if (err)
92 		return ERR_PTR(err);
93 
94 	tep_parse_format(pevent, &event, data, size, sys);
95 
96 	free(data);
97 	return event;
98 }
99 
100 /*
101  * Returns pointer with encoded error via <linux/err.h> interface.
102  */
103 struct tep_event*
trace_event__tp_format(const char * sys,const char * name)104 trace_event__tp_format(const char *sys, const char *name)
105 {
106 	if (!tevent_initialized && trace_event__init2())
107 		return ERR_PTR(-ENOMEM);
108 
109 	return tp_format(sys, name);
110 }
111 
trace_event__tp_format_id(int id)112 struct tep_event *trace_event__tp_format_id(int id)
113 {
114 	if (!tevent_initialized && trace_event__init2())
115 		return ERR_PTR(-ENOMEM);
116 
117 	return tep_find_event(tevent.pevent, id);
118 }
119