1// Copyright (c) 2012 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4//
5#include "base/win/event_trace_provider.h"
6#include <windows.h>
7#include <cguid.h>
8
9namespace base {
10namespace win {
11
12TRACE_GUID_REGISTRATION EtwTraceProvider::obligatory_guid_registration_ = {
13  &GUID_NULL,
14  NULL
15};
16
17EtwTraceProvider::EtwTraceProvider(const GUID& provider_name)
18    : provider_name_(provider_name), registration_handle_(NULL),
19      session_handle_(NULL), enable_flags_(0), enable_level_(0) {
20}
21
22EtwTraceProvider::EtwTraceProvider()
23    : provider_name_(GUID_NULL), registration_handle_(NULL),
24      session_handle_(NULL), enable_flags_(0), enable_level_(0) {
25}
26
27EtwTraceProvider::~EtwTraceProvider() {
28  Unregister();
29}
30
31ULONG EtwTraceProvider::EnableEvents(void* buffer) {
32  session_handle_ = ::GetTraceLoggerHandle(buffer);
33  if (NULL == session_handle_) {
34    return ::GetLastError();
35  }
36
37  enable_flags_ = ::GetTraceEnableFlags(session_handle_);
38  enable_level_ = ::GetTraceEnableLevel(session_handle_);
39
40  // Give subclasses a chance to digest the state change.
41  OnEventsEnabled();
42
43  return ERROR_SUCCESS;
44}
45
46ULONG EtwTraceProvider::DisableEvents() {
47  // Give subclasses a chance to digest the state change.
48  OnEventsDisabled();
49
50  enable_level_ = 0;
51  enable_flags_ = 0;
52  session_handle_ = NULL;
53
54  PostEventsDisabled();
55
56  return ERROR_SUCCESS;
57}
58
59ULONG EtwTraceProvider::Callback(WMIDPREQUESTCODE request, void* buffer) {
60  switch (request) {
61    case WMI_ENABLE_EVENTS:
62      return EnableEvents(buffer);
63    case WMI_DISABLE_EVENTS:
64      return DisableEvents();
65    default:
66      return ERROR_INVALID_PARAMETER;
67  }
68  // Not reached.
69}
70
71ULONG WINAPI EtwTraceProvider::ControlCallback(WMIDPREQUESTCODE request,
72    void* context, ULONG *reserved, void* buffer) {
73  EtwTraceProvider *provider = reinterpret_cast<EtwTraceProvider*>(context);
74
75  return provider->Callback(request, buffer);
76}
77
78ULONG EtwTraceProvider::Register() {
79  if (provider_name_ == GUID_NULL)
80    return ERROR_INVALID_NAME;
81
82  return ::RegisterTraceGuids(ControlCallback, this, &provider_name_,
83      1, &obligatory_guid_registration_, NULL, NULL, &registration_handle_);
84}
85
86ULONG EtwTraceProvider::Unregister() {
87  // If a session is active, notify subclasses that it's going away.
88  if (session_handle_ != NULL)
89    DisableEvents();
90
91  ULONG ret = ::UnregisterTraceGuids(registration_handle_);
92
93  registration_handle_ = NULL;
94
95  return ret;
96}
97
98ULONG EtwTraceProvider::Log(const EtwEventClass& event_class,
99    EtwEventType type, EtwEventLevel level, const char *message) {
100  if (NULL == session_handle_ || enable_level_ < level)
101    return ERROR_SUCCESS;  // No one listening.
102
103  EtwMofEvent<1> event(event_class, type, level);
104
105  event.fields[0].DataPtr = reinterpret_cast<ULONG64>(message);
106  event.fields[0].Length = message ?
107      static_cast<ULONG>(sizeof(message[0]) * (1 + strlen(message))) : 0;
108
109  return ::TraceEvent(session_handle_, &event.header);
110}
111
112ULONG EtwTraceProvider::Log(const EtwEventClass& event_class,
113    EtwEventType type, EtwEventLevel level, const wchar_t *message) {
114  if (NULL == session_handle_ || enable_level_ < level)
115    return ERROR_SUCCESS;  // No one listening.
116
117  EtwMofEvent<1> event(event_class, type, level);
118
119  event.fields[0].DataPtr = reinterpret_cast<ULONG64>(message);
120  event.fields[0].Length = message ?
121      static_cast<ULONG>(sizeof(message[0]) * (1 + wcslen(message))) : 0;
122
123  return ::TraceEvent(session_handle_, &event.header);
124}
125
126ULONG EtwTraceProvider::Log(EVENT_TRACE_HEADER* event) {
127  if (enable_level_ < event->Class.Level)
128    return ERROR_SUCCESS;
129
130  return ::TraceEvent(session_handle_, event);
131}
132
133}  // namespace win
134}  // namespace base
135