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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       case LOG_ERROR_REPORT:
     41         level = TRACE_LEVEL_ERROR;
     42         break;
     43       case LOG_FATAL:
     44         level = TRACE_LEVEL_FATAL;
     45         break;
     46     }
     47   } else {  // severity < 0 is VLOG verbosity levels.
     48     level = TRACE_LEVEL_INFORMATION - severity;
     49   }
     50 
     51   // Bail if we're not logging, not at that level,
     52   // or if we're post-atexit handling.
     53   LogEventProvider* provider = LogEventProvider::GetInstance();
     54   if (provider == NULL || level > provider->enable_level())
     55     return false;
     56 
     57   // And now log the event.
     58   if (provider->enable_flags() & ENABLE_LOG_MESSAGE_ONLY) {
     59     EtwMofEvent<1> event(kLogEventId, LOG_MESSAGE, level);
     60     event.SetField(0, message.length() + 1 - message_start,
     61         message.c_str() + message_start);
     62 
     63     provider->Log(event.get());
     64   } else {
     65     const size_t kMaxBacktraceDepth = 32;
     66     void* backtrace[kMaxBacktraceDepth];
     67     DWORD depth = 0;
     68 
     69     // Capture a stack trace if one is requested.
     70     // requested per our enable flags.
     71     if (provider->enable_flags() & ENABLE_STACK_TRACE_CAPTURE)
     72       depth = CaptureStackBackTrace(2, kMaxBacktraceDepth, backtrace, NULL);
     73 
     74     EtwMofEvent<5> event(kLogEventId, LOG_MESSAGE_FULL, level);
     75     if (file == NULL)
     76       file = "";
     77 
     78     // Add the stack trace.
     79     event.SetField(0, sizeof(depth), &depth);
     80     event.SetField(1, sizeof(backtrace[0]) * depth, &backtrace);
     81     // The line.
     82     event.SetField(2, sizeof(line), &line);
     83     // The file.
     84     event.SetField(3, strlen(file) + 1, file);
     85     // And finally the message.
     86     event.SetField(4, message.length() + 1 - message_start,
     87         message.c_str() + message_start);
     88 
     89     provider->Log(event.get());
     90   }
     91 
     92   // Don't increase verbosity in other log destinations.
     93   if (severity < provider->old_log_level_)
     94     return true;
     95 
     96   return false;
     97 }
     98 
     99 void LogEventProvider::Initialize(const GUID& provider_name) {
    100   LogEventProvider* provider = LogEventProvider::GetInstance();
    101 
    102   provider->set_provider_name(provider_name);
    103   provider->Register();
    104 
    105   // Register our message handler with logging.
    106   SetLogMessageHandler(LogMessage);
    107 }
    108 
    109 void LogEventProvider::Uninitialize() {
    110   LogEventProvider::GetInstance()->Unregister();
    111 }
    112 
    113 void LogEventProvider::OnEventsEnabled() {
    114   // Grab the old log level so we can restore it later.
    115   old_log_level_ = GetMinLogLevel();
    116 
    117   // Convert the new trace level to a logging severity
    118   // and enable logging at that level.
    119   EtwEventLevel level = enable_level();
    120   if (level == TRACE_LEVEL_NONE || level == TRACE_LEVEL_FATAL) {
    121     SetMinLogLevel(LOG_FATAL);
    122   } else if (level == TRACE_LEVEL_ERROR) {
    123     SetMinLogLevel(LOG_ERROR);
    124   } else if (level == TRACE_LEVEL_WARNING) {
    125     SetMinLogLevel(LOG_WARNING);
    126   } else if (level == TRACE_LEVEL_INFORMATION) {
    127     SetMinLogLevel(LOG_INFO);
    128   } else if (level >= TRACE_LEVEL_VERBOSE) {
    129     // Above INFO, we enable verbose levels with negative severities.
    130     SetMinLogLevel(TRACE_LEVEL_INFORMATION - level);
    131   }
    132 }
    133 
    134 void LogEventProvider::OnEventsDisabled() {
    135   // Restore the old log level.
    136   SetMinLogLevel(old_log_level_);
    137 }
    138 
    139 }  // namespace logging
    140