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
9namespace logging {
10
11using base::win::EtwEventLevel;
12using base::win::EtwMofEvent;
13
14DEFINE_GUID(kLogEventId,
15    0x7fe69228, 0x633e, 0x4f06, 0x80, 0xc1, 0x52, 0x7f, 0xea, 0x23, 0xe3, 0xa7);
16
17LogEventProvider::LogEventProvider() : old_log_level_(LOG_NONE) {
18}
19
20LogEventProvider* LogEventProvider::GetInstance() {
21  return Singleton<LogEventProvider,
22                   StaticMemorySingletonTraits<LogEventProvider> >::get();
23}
24
25bool 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
98void 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
108void LogEventProvider::Uninitialize() {
109  LogEventProvider::GetInstance()->Unregister();
110}
111
112void 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
133void LogEventProvider::OnEventsDisabled() {
134  // Restore the old log level.
135  SetMinLogLevel(old_log_level_);
136}
137
138}  // namespace logging
139