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
  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 */
  25static struct trace_event tevent;
  26static bool tevent_initialized;
  27
  28int 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
  40static 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
  56int 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
  65void 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 */
  74static struct tep_event*
  75tp_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 */
 104struct tep_event*
 105trace_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
 113struct 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