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      1 // Copyright (c) 2011 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/logging_win.h"
      6 #include "base/memory/singleton.h"
      7 #include <initguid.h>  // NOLINT
      8 
      9 namespace logging {
     10 
     11 using base::win::EtwEventLevel;
     12 using base::win::EtwMofEvent;
     13 
     14 DEFINE_GUID(kLogEventId,
     15     0x7fe69228, 0x633e, 0x4f06, 0x80, 0xc1, 0x52, 0x7f, 0xea, 0x23, 0xe3, 0xa7);
     16 
     17 LogEventProvider::LogEventProvider() : old_log_level_(LOG_NONE) {
     18 }
     19 
     20 LogEventProvider* LogEventProvider::GetInstance() {
     21   return Singleton<LogEventProvider,
     22                    StaticMemorySingletonTraits<LogEventProvider> >::get();
     23 }
     24 
     25 bool LogEventProvider::LogMessage(logging::LogSeverity severity,
     26     const char* file, int line, size_t message_start,
     27     const std::string& message) {
     28   EtwEventLevel level = TRACE_LEVEL_NONE;
     29 
     30   // Convert the log severity to the most appropriate ETW trace level.
     31   if (severity >= 0) {
     32     switch (severity) {
     33       case LOG_INFO:
     34         level = TRACE_LEVEL_INFORMATION;
     35         break;
     36       case LOG_WARNING:
     37         level = TRACE_LEVEL_WARNING;
     38         break;
     39       case LOG_ERROR:
     40         level = TRACE_LEVEL_ERROR;
     41         break;
     42       case LOG_FATAL:
     43         level = TRACE_LEVEL_FATAL;
     44         break;
     45     }
     46   } else {  // severity < 0 is VLOG verbosity levels.
     47     level = TRACE_LEVEL_INFORMATION - severity;
     48   }
     49 
     50   // Bail if we're not logging, not at that level,
     51   // or if we're post-atexit handling.
     52   LogEventProvider* provider = LogEventProvider::GetInstance();
     53   if (provider == NULL || level > provider->enable_level())
     54     return false;
     55 
     56   // And now log the event.
     57   if (provider->enable_flags() & ENABLE_LOG_MESSAGE_ONLY) {
     58     EtwMofEvent<1> event(kLogEventId, LOG_MESSAGE, level);
     59     event.SetField(0, message.length() + 1 - message_start,
     60         message.c_str() + message_start);
     61 
     62     provider->Log(event.get());
     63   } else {
     64     const size_t kMaxBacktraceDepth = 32;
     65     void* backtrace[kMaxBacktraceDepth];
     66     DWORD depth = 0;
     67 
     68     // Capture a stack trace if one is requested.
     69     // requested per our enable flags.
     70     if (provider->enable_flags() & ENABLE_STACK_TRACE_CAPTURE)
     71       depth = CaptureStackBackTrace(2, kMaxBacktraceDepth, backtrace, NULL);
     72 
     73     EtwMofEvent<5> event(kLogEventId, LOG_MESSAGE_FULL, level);
     74     if (file == NULL)
     75       file = "";
     76 
     77     // Add the stack trace.
     78     event.SetField(0, sizeof(depth), &depth);
     79     event.SetField(1, sizeof(backtrace[0]) * depth, &backtrace);
     80     // The line.
     81     event.SetField(2, sizeof(line), &line);
     82     // The file.
     83     event.SetField(3, strlen(file) + 1, file);
     84     // And finally the message.
     85     event.SetField(4, message.length() + 1 - message_start,
     86         message.c_str() + message_start);
     87 
     88     provider->Log(event.get());
     89   }
     90 
     91   // Don't increase verbosity in other log destinations.
     92   if (severity < provider->old_log_level_)
     93     return true;
     94 
     95   return false;
     96 }
     97 
     98 void LogEventProvider::Initialize(const GUID& provider_name) {
     99   LogEventProvider* provider = LogEventProvider::GetInstance();
    100 
    101   provider->set_provider_name(provider_name);
    102   provider->Register();
    103 
    104   // Register our message handler with logging.
    105   SetLogMessageHandler(LogMessage);
    106 }
    107 
    108 void LogEventProvider::Uninitialize() {
    109   LogEventProvider::GetInstance()->Unregister();
    110 }
    111 
    112 void LogEventProvider::OnEventsEnabled() {
    113   // Grab the old log level so we can restore it later.
    114   old_log_level_ = GetMinLogLevel();
    115 
    116   // Convert the new trace level to a logging severity
    117   // and enable logging at that level.
    118   EtwEventLevel level = enable_level();
    119   if (level == TRACE_LEVEL_NONE || level == TRACE_LEVEL_FATAL) {
    120     SetMinLogLevel(LOG_FATAL);
    121   } else if (level == TRACE_LEVEL_ERROR) {
    122     SetMinLogLevel(LOG_ERROR);
    123   } else if (level == TRACE_LEVEL_WARNING) {
    124     SetMinLogLevel(LOG_WARNING);
    125   } else if (level == TRACE_LEVEL_INFORMATION) {
    126     SetMinLogLevel(LOG_INFO);
    127   } else if (level >= TRACE_LEVEL_VERBOSE) {
    128     // Above INFO, we enable verbose levels with negative severities.
    129     SetMinLogLevel(TRACE_LEVEL_INFORMATION - level);
    130   }
    131 }
    132 
    133 void LogEventProvider::OnEventsDisabled() {
    134   // Restore the old log level.
    135   SetMinLogLevel(old_log_level_);
    136 }
    137 
    138 }  // namespace logging
    139