tools/perf/util/trace-event.c

   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 <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
  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
  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
  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
  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*
  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*
 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
 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 }