base/win/event_trace_provider.cc

   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
   9 namespace base {
  10 namespace win {
  11
  12 TRACE_GUID_REGISTRATION EtwTraceProvider::obligatory_guid_registration_ = {
  13   &GUID_NULL,
  14   NULL
  15 };
  16
  17 EtwTraceProvider::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
  22 EtwTraceProvider::EtwTraceProvider()
  23     : provider_name_(GUID_NULL), registration_handle_(NULL),
  24       session_handle_(NULL), enable_flags_(0), enable_level_(0) {
  25 }
  26
  27 EtwTraceProvider::~EtwTraceProvider() {
  28   Unregister();
  29 }
  30
  31 ULONG 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
  46 ULONG 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
  59 ULONG 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
  71 ULONG 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
  78 ULONG 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
  86 ULONG 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
  98 ULONG 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
 112 ULONG 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
 126 ULONG 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