LXR linux/tools/perf/util/trace-event.c

   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#include "util.h"
  18
  19/*
  20 * global trace_event object used by trace_event__tp_format
  21 *
  22 * TODO There's no cleanup call for this. Add some sort of
  23 * __exit function support and call trace_event__cleanup
  24 * there.
  25 */
  26static struct trace_event tevent;
  27static bool tevent_initialized;
  28
  29int trace_event__init(struct trace_event *t)
  30{
  31        struct tep_handle *pevent = tep_alloc();
  32
  33        if (pevent) {
  34                t->plugin_list = tep_load_plugins(pevent);
  35                t->pevent  = pevent;
  36        }
  37
  38        return pevent ? 0 : -1;
  39}
  40
  41static int trace_event__init2(void)
  42{
  43        int be = tep_is_bigendian();
  44        struct tep_handle *pevent;
  45
  46        if (trace_event__init(&tevent))
  47                return -1;
  48
  49        pevent = tevent.pevent;
  50        tep_set_flag(pevent, TEP_NSEC_OUTPUT);
  51        tep_set_file_bigendian(pevent, be);
  52        tep_set_local_bigendian(pevent, be);
  53        tevent_initialized = true;
  54        return 0;
  55}
  56
  57int trace_event__register_resolver(struct machine *machine,
  58                                   tep_func_resolver_t *func)
  59{
  60        if (!tevent_initialized && trace_event__init2())
  61                return -1;
  62
  63        return tep_set_function_resolver(tevent.pevent, func, machine);
  64}
  65
  66void trace_event__cleanup(struct trace_event *t)
  67{
  68        tep_unload_plugins(t->plugin_list, t->pevent);
  69        tep_free(t->pevent);
  70}
  71
  72/*
  73 * Returns pointer with encoded error via <linux/err.h> interface.
  74 */
  75static struct tep_event*
  76tp_format(const char *sys, const char *name)
  77{
  78        char *tp_dir = get_events_file(sys);
  79        struct tep_handle *pevent = tevent.pevent;
  80        struct tep_event *event = NULL;
  81        char path[PATH_MAX];
  82        size_t size;
  83        char *data;
  84        int err;
  85
  86        if (!tp_dir)
  87                return ERR_PTR(-errno);
  88
  89        scnprintf(path, PATH_MAX, "%s/%s/format", tp_dir, name);
  90        put_events_file(tp_dir);
  91
  92        err = filename__read_str(path, &data, &size);
  93        if (err)
  94                return ERR_PTR(err);
  95
  96        tep_parse_format(pevent, &event, data, size, sys);
  97
  98        free(data);
  99        return event;
 100}
 101
 102/*
 103 * Returns pointer with encoded error via <linux/err.h> interface.
 104 */
 105struct tep_event*
 106trace_event__tp_format(const char *sys, const char *name)
 107{
 108        if (!tevent_initialized && trace_event__init2())
 109                return ERR_PTR(-ENOMEM);
 110
 111        return tp_format(sys, name);
 112}
 113
 114struct tep_event *trace_event__tp_format_id(int id)
 115{
 116        if (!tevent_initialized && trace_event__init2())
 117                return ERR_PTR(-ENOMEM);
 118
 119        return tep_find_event(tevent.pevent, id);
 120}
 121