xref: /openbmc/linux/tools/perf/util/trace-event.c (revision 08283d30)
1 // SPDX-License-Identifier: GPL-2.0
2 
3 #include <stdio.h>
4 #include <unistd.h>
5 #include <stdlib.h>
6 #include <errno.h>
7 #include <sys/types.h>
8 #include <sys/stat.h>
9 #include <fcntl.h>
10 #include <linux/kernel.h>
11 #include <linux/err.h>
12 #include <traceevent/event-parse.h>
13 #include <api/fs/tracing_path.h>
14 #include <api/fs/fs.h>
15 #include "trace-event.h"
16 #include "machine.h"
17 
18 /*
19  * global trace_event object used by trace_event__tp_format
20  *
21  * TODO There's no cleanup call for this. Add some sort of
22  * __exit function support and call trace_event__cleanup
23  * there.
24  */
25 static struct trace_event tevent;
26 static bool tevent_initialized;
27 
28 int trace_event__init(struct trace_event *t)
29 {
30 	struct tep_handle *pevent = tep_alloc();
31 
32 	if (pevent) {
33 		t->plugin_list = tep_load_plugins(pevent);
34 		t->pevent  = pevent;
35 	}
36 
37 	return pevent ? 0 : -1;
38 }
39 
40 static int trace_event__init2(void)
41 {
42 	int be = tep_is_bigendian();
43 	struct tep_handle *pevent;
44 
45 	if (trace_event__init(&tevent))
46 		return -1;
47 
48 	pevent = tevent.pevent;
49 	tep_set_flag(pevent, TEP_NSEC_OUTPUT);
50 	tep_set_file_bigendian(pevent, be);
51 	tep_set_local_bigendian(pevent, be);
52 	tevent_initialized = true;
53 	return 0;
54 }
55 
56 int trace_event__register_resolver(struct machine *machine,
57 				   tep_func_resolver_t *func)
58 {
59 	if (!tevent_initialized && trace_event__init2())
60 		return -1;
61 
62 	return tep_set_function_resolver(tevent.pevent, func, machine);
63 }
64 
65 void trace_event__cleanup(struct trace_event *t)
66 {
67 	tep_unload_plugins(t->plugin_list, t->pevent);
68 	tep_free(t->pevent);
69 }
70 
71 /*
72  * Returns pointer with encoded error via <linux/err.h> interface.
73  */
74 static struct tep_event*
75 tp_format(const char *sys, const char *name)
76 {
77 	char *tp_dir = get_events_file(sys);
78 	struct tep_handle *pevent = tevent.pevent;
79 	struct tep_event *event = NULL;
80 	char path[PATH_MAX];
81 	size_t size;
82 	char *data;
83 	int err;
84 
85 	if (!tp_dir)
86 		return ERR_PTR(-errno);
87 
88 	scnprintf(path, PATH_MAX, "%s/%s/format", tp_dir, name);
89 	put_events_file(tp_dir);
90 
91 	err = filename__read_str(path, &data, &size);
92 	if (err)
93 		return ERR_PTR(err);
94 
95 	tep_parse_format(pevent, &event, data, size, sys);
96 
97 	free(data);
98 	return event;
99 }
100 
101 /*
102  * Returns pointer with encoded error via <linux/err.h> interface.
103  */
104 struct tep_event*
105 trace_event__tp_format(const char *sys, const char *name)
106 {
107 	if (!tevent_initialized && trace_event__init2())
108 		return ERR_PTR(-ENOMEM);
109 
110 	return tp_format(sys, name);
111 }
112 
113 struct tep_event *trace_event__tp_format_id(int id)
114 {
115 	if (!tevent_initialized && trace_event__init2())
116 		return ERR_PTR(-ENOMEM);
117 
118 	return tep_find_event(tevent.pevent, id);
119 }
120