tools/perf/util/trace-event.c

   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 <linux/err.h>
  11 #include <traceevent/event-parse.h>
  12 #include <api/fs/tracing_path.h>
  13 #include "trace-event.h"
  14 #include "machine.h"
  15 #include "util.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 pevent *pevent = pevent_alloc();
  30
  31         if (pevent) {
  32                 t->plugin_list = traceevent_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 = traceevent_host_bigendian();
  42         struct pevent *pevent;
  43
  44         if (trace_event__init(&tevent))
  45                 return -1;
  46
  47         pevent = tevent.pevent;
  48         pevent_set_flag(pevent, PEVENT_NSEC_OUTPUT);
  49         pevent_set_file_bigendian(pevent, be);
  50         pevent_set_host_bigendian(pevent, be);
  51         tevent_initialized = true;
  52         return 0;
  53 }
  54
  55 int trace_event__register_resolver(struct machine *machine,
  56                                    pevent_func_resolver_t *func)
  57 {
  58         if (!tevent_initialized && trace_event__init2())
  59                 return -1;
  60
  61         return pevent_set_function_resolver(tevent.pevent, func, machine);
  62 }
  63
  64 void trace_event__cleanup(struct trace_event *t)
  65 {
  66         traceevent_unload_plugins(t->plugin_list, t->pevent);
  67         pevent_free(t->pevent);
  68 }
  69
  70 /*
  71  * Returns pointer with encoded error via <linux/err.h> interface.
  72  */
  73 static struct event_format*
  74 tp_format(const char *sys, const char *name)
  75 {
  76         struct pevent *pevent = tevent.pevent;
  77         struct event_format *event = NULL;
  78         char path[PATH_MAX];
  79         size_t size;
  80         char *data;
  81         int err;
  82
  83         scnprintf(path, PATH_MAX, "%s/%s/%s/format",
  84                   tracing_events_path, sys, name);
  85
  86         err = filename__read_str(path, &data, &size);
  87         if (err)
  88                 return ERR_PTR(err);
  89
  90         pevent_parse_format(pevent, &event, data, size, sys);
  91
  92         free(data);
  93         return event;
  94 }
  95
  96 /*
  97  * Returns pointer with encoded error via <linux/err.h> interface.
  98  */
  99 struct event_format*
 100 trace_event__tp_format(const char *sys, const char *name)
 101 {
 102         if (!tevent_initialized && trace_event__init2())
 103                 return ERR_PTR(-ENOMEM);
 104
 105         return tp_format(sys, name);
 106 }