base/logging.cc - chromium/src - Git at Google

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 #include "base/logging.h"

 #if defined(OS_WIN)
 #include <io.h>
 #include <windows.h>
 typedef HANDLE FileHandle;
 typedef HANDLE MutexHandle;
 // Windows warns on using write().  It prefers _write().
 #define write(fd, buf, count) _write(fd, buf, static_cast<unsigned int>(count))
 // Windows doesn't define STDERR_FILENO.  Define it here.
 #define STDERR_FILENO 2
 #elif defined(OS_MACOSX)
 #include <mach/mach.h>
 #include <mach/mach_time.h>
 #include <mach-o/dyld.h>
 #elif defined(OS_POSIX)
 #if defined(OS_NACL)
 #include <sys/time.h> // timespec doesn't seem to be in <time.h>
 #else
 #include <sys/syscall.h>
 #endif
 #include <time.h>
 #endif

 #if defined(OS_POSIX)
 #include <errno.h>
 #include <pthread.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 #define MAX_PATH PATH_MAX
 typedef FILE* FileHandle;
 typedef pthread_mutex_t* MutexHandle;
 #endif

 #include <algorithm>
 #include <cstring>
 #include <ctime>
 #include <iomanip>
 #include <ostream>
 #include <string>

 #include "base/base_switches.h"
 #include "base/command_line.h"
 #include "base/debug/alias.h"
 #include "base/debug/debugger.h"
 #include "base/debug/stack_trace.h"
 #include "base/posix/eintr_wrapper.h"
 #include "base/strings/string_piece.h"
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/synchronization/lock_impl.h"
 #include "base/threading/platform_thread.h"
 #include "base/vlog.h"
 #if defined(OS_POSIX)
 #include "base/safe_strerror_posix.h"
 #endif

 #if defined(OS_ANDROID)
 #include <android/log.h>
 #endif

 namespace logging {

 namespace {

 VlogInfo* g_vlog_info = NULL;
 VlogInfo* g_vlog_info_prev = NULL;

 const char* const log_severity_names[LOG_NUM_SEVERITIES] = {
   "INFO", "WARNING", "ERROR", "FATAL" };

 const char* log_severity_name(int severity)
 {
   if (severity >= 0 && severity < LOG_NUM_SEVERITIES)
     return log_severity_names[severity];
   return "UNKNOWN";
 }

 int min_log_level = 0;

 LoggingDestination logging_destination = LOG_DEFAULT;

 // For LOG_ERROR and above, always print to stderr.
 const int kAlwaysPrintErrorLevel = LOG_ERROR;

 // Which log file to use? This is initialized by InitLogging or
 // will be lazily initialized to the default value when it is
 // first needed.
 #if defined(OS_WIN)
 typedef std::wstring PathString;
 #else
 typedef std::string PathString;
 #endif
 PathString* log_file_name = NULL;

 // this file is lazily opened and the handle may be NULL
 FileHandle log_file = NULL;

 // what should be prepended to each message?
 bool log_process_id = false;
 bool log_thread_id = false;
 bool log_timestamp = true;
 bool log_tickcount = false;

 // Should we pop up fatal debug messages in a dialog?
 bool show_error_dialogs = false;

 // An assert handler override specified by the client to be called instead of
 // the debug message dialog and process termination.
 LogAssertHandlerFunction log_assert_handler = NULL;
 // A log message handler that gets notified of every log message we process.
 LogMessageHandlerFunction log_message_handler = NULL;

 // Helper functions to wrap platform differences.

 int32 CurrentProcessId() {
 #if defined(OS_WIN)
   return GetCurrentProcessId();
 #elif defined(OS_POSIX)
   return getpid();
 #endif
 }

 uint64 TickCount() {
 #if defined(OS_WIN)
   return GetTickCount();
 #elif defined(OS_MACOSX)
   return mach_absolute_time();
 #elif defined(OS_NACL)
   // NaCl sadly does not have _POSIX_TIMERS enabled in sys/features.h
   // So we have to use clock() for now.
   return clock();
 #elif defined(OS_POSIX)
   struct timespec ts;
   clock_gettime(CLOCK_MONOTONIC, &ts);

   uint64 absolute_micro =
     static_cast<int64>(ts.tv_sec) * 1000000 +
     static_cast<int64>(ts.tv_nsec) / 1000;

   return absolute_micro;
 #endif
 }

 void DeleteFilePath(const PathString& log_name) {
 #if defined(OS_WIN)
   DeleteFile(log_name.c_str());
 #elif defined (OS_NACL)
   // Do nothing; unlink() isn't supported on NaCl.
 #else
   unlink(log_name.c_str());
 #endif
 }

 PathString GetDefaultLogFile() {
 #if defined(OS_WIN)
   // On Windows we use the same path as the exe.
   wchar_t module_name[MAX_PATH];
   GetModuleFileName(NULL, module_name, MAX_PATH);

   PathString log_file = module_name;
   PathString::size_type last_backslash =
       log_file.rfind('\\', log_file.size());
   if (last_backslash != PathString::npos)
     log_file.erase(last_backslash + 1);
   log_file += L"debug.log";
   return log_file;
 #elif defined(OS_POSIX)
   // On other platforms we just use the current directory.
   return PathString("debug.log");
 #endif
 }

 // This class acts as a wrapper for locking the logging files.
 // LoggingLock::Init() should be called from the main thread before any logging
 // is done. Then whenever logging, be sure to have a local LoggingLock
 // instance on the stack. This will ensure that the lock is unlocked upon
 // exiting the frame.
 // LoggingLocks can not be nested.
 class LoggingLock {
  public:
   LoggingLock() {
     LockLogging();
   }

   ~LoggingLock() {
     UnlockLogging();
   }

   static void Init(LogLockingState lock_log, const PathChar* new_log_file) {
     if (initialized)
       return;
     lock_log_file = lock_log;
     if (lock_log_file == LOCK_LOG_FILE) {
 #if defined(OS_WIN)
       if (!log_mutex) {
         std::wstring safe_name;
         if (new_log_file)
           safe_name = new_log_file;
         else
           safe_name = GetDefaultLogFile();
         // \ is not a legal character in mutex names so we replace \ with /
         std::replace(safe_name.begin(), safe_name.end(), '\\', '/');
         std::wstring t(L"Global\\");
         t.append(safe_name);
         log_mutex = ::CreateMutex(NULL, FALSE, t.c_str());

         if (log_mutex == NULL) {
 #if DEBUG
           // Keep the error code for debugging
           int error = GetLastError();  // NOLINT
           base::debug::BreakDebugger();
 #endif
           // Return nicely without putting initialized to true.
           return;
         }
       }
 #endif
     } else {
       log_lock = new base::internal::LockImpl();
     }
     initialized = true;
   }

  private:
   static void LockLogging() {
     if (lock_log_file == LOCK_LOG_FILE) {
 #if defined(OS_WIN)
       ::WaitForSingleObject(log_mutex, INFINITE);
       // WaitForSingleObject could have returned WAIT_ABANDONED. We don't
       // abort the process here. UI tests might be crashy sometimes,
       // and aborting the test binary only makes the problem worse.
       // We also don't use LOG macros because that might lead to an infinite
       // loop. For more info see http://crbug.com/18028.
 #elif defined(OS_POSIX)
       pthread_mutex_lock(&log_mutex);
 #endif
     } else {
       // use the lock
       log_lock->Lock();
     }
   }

   static void UnlockLogging() {
     if (lock_log_file == LOCK_LOG_FILE) {
 #if defined(OS_WIN)
       ReleaseMutex(log_mutex);
 #elif defined(OS_POSIX)
       pthread_mutex_unlock(&log_mutex);
 #endif
     } else {
       log_lock->Unlock();
     }
   }

   // The lock is used if log file locking is false. It helps us avoid problems
   // with multiple threads writing to the log file at the same time.  Use
   // LockImpl directly instead of using Lock, because Lock makes logging calls.
   static base::internal::LockImpl* log_lock;

   // When we don't use a lock, we are using a global mutex. We need to do this
   // because LockFileEx is not thread safe.
 #if defined(OS_WIN)
   static MutexHandle log_mutex;
 #elif defined(OS_POSIX)
   static pthread_mutex_t log_mutex;
 #endif

   static bool initialized;
   static LogLockingState lock_log_file;
 };

 // static
 bool LoggingLock::initialized = false;
 // static
 base::internal::LockImpl* LoggingLock::log_lock = NULL;
 // static
 LogLockingState LoggingLock::lock_log_file = LOCK_LOG_FILE;

 #if defined(OS_WIN)
 // static
 MutexHandle LoggingLock::log_mutex = NULL;
 #elif defined(OS_POSIX)
 pthread_mutex_t LoggingLock::log_mutex = PTHREAD_MUTEX_INITIALIZER;
 #endif

 // Called by logging functions to ensure that debug_file is initialized
 // and can be used for writing. Returns false if the file could not be
 // initialized. debug_file will be NULL in this case.
 bool InitializeLogFileHandle() {
   if (log_file)
     return true;

   if (!log_file_name) {
     // Nobody has called InitLogging to specify a debug log file, so here we
     // initialize the log file name to a default.
     log_file_name = new PathString(GetDefaultLogFile());
   }

   if ((logging_destination & LOG_TO_FILE) != 0) {
 #if defined(OS_WIN)
     log_file = CreateFile(log_file_name->c_str(), GENERIC_WRITE,
                           FILE_SHARE_READ | FILE_SHARE_WRITE, NULL,
                           OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
     if (log_file == INVALID_HANDLE_VALUE || log_file == NULL) {
       // try the current directory
       log_file = CreateFile(L".\\debug.log", GENERIC_WRITE,
                             FILE_SHARE_READ | FILE_SHARE_WRITE, NULL,
                             OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
       if (log_file == INVALID_HANDLE_VALUE || log_file == NULL) {
         log_file = NULL;
         return false;
       }
     }
     SetFilePointer(log_file, 0, 0, FILE_END);
 #elif defined(OS_POSIX)
     log_file = fopen(log_file_name->c_str(), "a");
     if (log_file == NULL)
       return false;
 #endif
   }

   return true;
 }

 void CloseFile(FileHandle log) {
 #if defined(OS_WIN)
   CloseHandle(log);
 #else
   fclose(log);
 #endif
 }

 void CloseLogFileUnlocked() {
   if (!log_file)
     return;

   CloseFile(log_file);
   log_file = NULL;
 }

 }  // namespace

 LoggingSettings::LoggingSettings()
     : logging_dest(LOG_DEFAULT),
       log_file(NULL),
       lock_log(LOCK_LOG_FILE),
       delete_old(APPEND_TO_OLD_LOG_FILE) {}

 bool BaseInitLoggingImpl(const LoggingSettings& settings) {
 #if defined(OS_NACL)
   // Can log only to the system debug log.
   CHECK_EQ(settings.logging_dest & ~LOG_TO_SYSTEM_DEBUG_LOG, 0);
 #endif
   CommandLine* command_line = CommandLine::ForCurrentProcess();
   // Don't bother initializing g_vlog_info unless we use one of the
   // vlog switches.
   if (command_line->HasSwitch(switches::kV) ||
       command_line->HasSwitch(switches::kVModule)) {
     // NOTE: If g_vlog_info has already been initialized, it might be in use
     // by another thread. Don't delete the old VLogInfo, just create a second
     // one. We keep track of both to avoid memory leak warnings.
     CHECK(!g_vlog_info_prev);
     g_vlog_info_prev = g_vlog_info;

     g_vlog_info =
         new VlogInfo(command_line->GetSwitchValueASCII(switches::kV),
                      command_line->GetSwitchValueASCII(switches::kVModule),
                      &min_log_level);
   }

   logging_destination = settings.logging_dest;

   // ignore file options unless logging to file is set.
   if ((logging_destination & LOG_TO_FILE) == 0)
     return true;

   LoggingLock::Init(settings.lock_log, settings.log_file);
   LoggingLock logging_lock;

   // Calling InitLogging twice or after some log call has already opened the
   // default log file will re-initialize to the new options.
   CloseLogFileUnlocked();

   if (!log_file_name)
     log_file_name = new PathString();
   *log_file_name = settings.log_file;
   if (settings.delete_old == DELETE_OLD_LOG_FILE)
     DeleteFilePath(*log_file_name);

   return InitializeLogFileHandle();
 }

 void SetMinLogLevel(int level) {
   min_log_level = std::min(LOG_FATAL, level);
 }

 int GetMinLogLevel() {
   return min_log_level;
 }

 int GetVlogVerbosity() {
   return std::max(-1, LOG_INFO - GetMinLogLevel());
 }

 int GetVlogLevelHelper(const char* file, size_t N) {
   DCHECK_GT(N, 0U);
   // Note: g_vlog_info may change on a different thread during startup
   // (but will always be valid or NULL).
   VlogInfo* vlog_info = g_vlog_info;
   return vlog_info ?
       vlog_info->GetVlogLevel(base::StringPiece(file, N - 1)) :
       GetVlogVerbosity();
 }

 void SetLogItems(bool enable_process_id, bool enable_thread_id,
                  bool enable_timestamp, bool enable_tickcount) {
   log_process_id = enable_process_id;
   log_thread_id = enable_thread_id;
   log_timestamp = enable_timestamp;
   log_tickcount = enable_tickcount;
 }

 void SetShowErrorDialogs(bool enable_dialogs) {
   show_error_dialogs = enable_dialogs;
 }

 void SetLogAssertHandler(LogAssertHandlerFunction handler) {
   log_assert_handler = handler;
 }

 void SetLogMessageHandler(LogMessageHandlerFunction handler) {
   log_message_handler = handler;
 }

 LogMessageHandlerFunction GetLogMessageHandler() {
   return log_message_handler;
 }

 // Explicit instantiations for commonly used comparisons.
 template std::string* MakeCheckOpString<int, int>(
     const int&, const int&, const char* names);
 template std::string* MakeCheckOpString<unsigned long, unsigned long>(
     const unsigned long&, const unsigned long&, const char* names);
 template std::string* MakeCheckOpString<unsigned long, unsigned int>(
     const unsigned long&, const unsigned int&, const char* names);
 template std::string* MakeCheckOpString<unsigned int, unsigned long>(
     const unsigned int&, const unsigned long&, const char* names);
 template std::string* MakeCheckOpString<std::string, std::string>(
     const std::string&, const std::string&, const char* name);

 #if !defined(NDEBUG)
 // Displays a message box to the user with the error message in it.
 // Used for fatal messages, where we close the app simultaneously.
 // This is for developers only; we don't use this in circumstances
 // (like release builds) where users could see it, since users don't
 // understand these messages anyway.
 void DisplayDebugMessageInDialog(const std::string& str) {
   if (str.empty())
     return;

   if (!show_error_dialogs)
     return;

 #if defined(OS_WIN)
   // For Windows programs, it's possible that the message loop is
   // messed up on a fatal error, and creating a MessageBox will cause
   // that message loop to be run. Instead, we try to spawn another
   // process that displays its command line. We look for "Debug
   // Message.exe" in the same directory as the application. If it
   // exists, we use it, otherwise, we use a regular message box.
   wchar_t prog_name[MAX_PATH];
   GetModuleFileNameW(NULL, prog_name, MAX_PATH);
   wchar_t* backslash = wcsrchr(prog_name, '\\');
   if (backslash)
     backslash[1] = 0;
   wcscat_s(prog_name, MAX_PATH, L"debug_message.exe");

   std::wstring cmdline = base::UTF8ToWide(str);
   if (cmdline.empty())
     return;

   STARTUPINFO startup_info;
   memset(&startup_info, 0, sizeof(startup_info));
   startup_info.cb = sizeof(startup_info);

   PROCESS_INFORMATION process_info;
   if (CreateProcessW(prog_name, &cmdline[0], NULL, NULL, false, 0, NULL,
                      NULL, &startup_info, &process_info)) {
     WaitForSingleObject(process_info.hProcess, INFINITE);
     CloseHandle(process_info.hThread);
     CloseHandle(process_info.hProcess);
   } else {
     // debug process broken, let's just do a message box
     MessageBoxW(NULL, &cmdline[0], L"Fatal error",
                 MB_OK | MB_ICONHAND | MB_TOPMOST);
   }
 #else
   // We intentionally don't implement a dialog on other platforms.
   // You can just look at stderr.
 #endif
 }
 #endif  // !defined(NDEBUG)

 #if defined(OS_WIN)
 LogMessage::SaveLastError::SaveLastError() : last_error_(::GetLastError()) {
 }

 LogMessage::SaveLastError::~SaveLastError() {
   ::SetLastError(last_error_);
 }
 #endif  // defined(OS_WIN)

 LogMessage::LogMessage(const char* file, int line, LogSeverity severity)
     : severity_(severity), file_(file), line_(line) {
   Init(file, line);
 }

 LogMessage::LogMessage(const char* file, int line, std::string* result)
     : severity_(LOG_FATAL), file_(file), line_(line) {
   Init(file, line);
   stream_ << "Check failed: " << *result;
   delete result;
 }

 LogMessage::LogMessage(const char* file, int line, LogSeverity severity,
                        std::string* result)
     : severity_(severity), file_(file), line_(line) {
   Init(file, line);
   stream_ << "Check failed: " << *result;
   delete result;
 }

 LogMessage::~LogMessage() {
 #if !defined(NDEBUG) && !defined(OS_NACL) && !defined(__UCLIBC__)
   if (severity_ == LOG_FATAL) {
     // Include a stack trace on a fatal.
     base::debug::StackTrace trace;
     stream_ << std::endl;  // Newline to separate from log message.
     trace.OutputToStream(&stream_);
   }
 #endif
   stream_ << std::endl;
   std::string str_newline(stream_.str());

   // Give any log message handler first dibs on the message.
   if (log_message_handler &&
       log_message_handler(severity_, file_, line_,
                           message_start_, str_newline)) {
     // The handler took care of it, no further processing.
     return;
   }

   if ((logging_destination & LOG_TO_SYSTEM_DEBUG_LOG) != 0) {
 #if defined(OS_WIN)
     OutputDebugStringA(str_newline.c_str());
 #elif defined(OS_ANDROID)
     android_LogPriority priority =
         (severity_ < 0) ? ANDROID_LOG_VERBOSE : ANDROID_LOG_UNKNOWN;
     switch (severity_) {
       case LOG_INFO:
         priority = ANDROID_LOG_INFO;
         break;
       case LOG_WARNING:
         priority = ANDROID_LOG_WARN;
         break;
       case LOG_ERROR:
         priority = ANDROID_LOG_ERROR;
         break;
       case LOG_FATAL:
         priority = ANDROID_LOG_FATAL;
         break;
     }
     __android_log_write(priority, "chromium", str_newline.c_str());
 #endif
     ignore_result(fwrite(str_newline.data(), str_newline.size(), 1, stderr));
     fflush(stderr);
   } else if (severity_ >= kAlwaysPrintErrorLevel) {
     // When we're only outputting to a log file, above a certain log level, we
     // should still output to stderr so that we can better detect and diagnose
     // problems with unit tests, especially on the buildbots.
     ignore_result(fwrite(str_newline.data(), str_newline.size(), 1, stderr));
     fflush(stderr);
   }

   // write to log file
   if ((logging_destination & LOG_TO_FILE) != 0) {
     // We can have multiple threads and/or processes, so try to prevent them
     // from clobbering each other's writes.
     // If the client app did not call InitLogging, and the lock has not
     // been created do it now. We do this on demand, but if two threads try
     // to do this at the same time, there will be a race condition to create
     // the lock. This is why InitLogging should be called from the main
     // thread at the beginning of execution.
     LoggingLock::Init(LOCK_LOG_FILE, NULL);
     LoggingLock logging_lock;
     if (InitializeLogFileHandle()) {
 #if defined(OS_WIN)
       SetFilePointer(log_file, 0, 0, SEEK_END);
       DWORD num_written;
       WriteFile(log_file,
                 static_cast<const void*>(str_newline.c_str()),
                 static_cast<DWORD>(str_newline.length()),
                 &num_written,
                 NULL);
 #else
       ignore_result(fwrite(
           str_newline.data(), str_newline.size(), 1, log_file));
       fflush(log_file);
 #endif
     }
   }

   if (severity_ == LOG_FATAL) {
     // Ensure the first characters of the string are on the stack so they
     // are contained in minidumps for diagnostic purposes.
     char str_stack[1024];
     str_newline.copy(str_stack, arraysize(str_stack));
     base::debug::Alias(str_stack);

     if (log_assert_handler) {
       // Make a copy of the string for the handler out of paranoia.
       log_assert_handler(std::string(stream_.str()));
     } else {
       // Don't use the string with the newline, get a fresh version to send to
       // the debug message process. We also don't display assertions to the
       // user in release mode. The enduser can't do anything with this
       // information, and displaying message boxes when the application is
       // hosed can cause additional problems.
 #ifndef NDEBUG
       DisplayDebugMessageInDialog(stream_.str());
 #endif
       // Crash the process to generate a dump.
       base::debug::BreakDebugger();
     }
   }
 }

 // writes the common header info to the stream
 void LogMessage::Init(const char* file, int line) {
   base::StringPiece filename(file);
   size_t last_slash_pos = filename.find_last_of("\\/");
   if (last_slash_pos != base::StringPiece::npos)
     filename.remove_prefix(last_slash_pos + 1);

   // TODO(darin): It might be nice if the columns were fixed width.

   stream_ <<  '[';
   if (log_process_id)
     stream_ << CurrentProcessId() << ':';
   if (log_thread_id)
     stream_ << base::PlatformThread::CurrentId() << ':';
   if (log_timestamp) {
     time_t t = time(NULL);
     struct tm local_time = {0};
 #if _MSC_VER >= 1400
     localtime_s(&local_time, &t);
 #else
     localtime_r(&t, &local_time);
 #endif
     struct tm* tm_time = &local_time;
     stream_ << std::setfill('0')
             << std::setw(2) << 1 + tm_time->tm_mon
             << std::setw(2) << tm_time->tm_mday
             << '/'
             << std::setw(2) << tm_time->tm_hour
             << std::setw(2) << tm_time->tm_min
             << std::setw(2) << tm_time->tm_sec
             << ':';
   }
   if (log_tickcount)
     stream_ << TickCount() << ':';
   if (severity_ >= 0)
     stream_ << log_severity_name(severity_);
   else
     stream_ << "VERBOSE" << -severity_;

   stream_ << ":" << filename << "(" << line << ")] ";

   message_start_ = stream_.str().length();
 }

 #if defined(OS_WIN)
 // This has already been defined in the header, but defining it again as DWORD
 // ensures that the type used in the header is equivalent to DWORD. If not,
 // the redefinition is a compile error.
 typedef DWORD SystemErrorCode;
 #endif

 SystemErrorCode GetLastSystemErrorCode() {
 #if defined(OS_WIN)
   return ::GetLastError();
 #elif defined(OS_POSIX)
   return errno;
 #else
 #error Not implemented
 #endif
 }

 #if defined(OS_WIN)
 BASE_EXPORT std::string SystemErrorCodeToString(SystemErrorCode error_code) {
   const int error_message_buffer_size = 256;
   char msgbuf[error_message_buffer_size];
   DWORD flags = FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS;
   DWORD len = FormatMessageA(flags, NULL, error_code, 0, msgbuf,
                              arraysize(msgbuf), NULL);
   if (len) {
     // Messages returned by system end with line breaks.
     return base::CollapseWhitespaceASCII(msgbuf, true) +
         base::StringPrintf(" (0x%X)", error_code);
   }
   return base::StringPrintf("Error (0x%X) while retrieving error. (0x%X)",
                             GetLastError(), error_code);
 }
 #elif defined(OS_POSIX)
 BASE_EXPORT std::string SystemErrorCodeToString(SystemErrorCode error_code) {
   return safe_strerror(error_code);
 }
 #else
 #error Not implemented
 #endif


 #if defined(OS_WIN)
 Win32ErrorLogMessage::Win32ErrorLogMessage(const char* file,
                                            int line,
                                            LogSeverity severity,
                                            SystemErrorCode err)
     : err_(err),
       log_message_(file, line, severity) {
 }

 Win32ErrorLogMessage::~Win32ErrorLogMessage() {
   stream() << ": " << SystemErrorCodeToString(err_);
   // We're about to crash (CHECK). Put |err_| on the stack (by placing it in a
   // field) and use Alias in hopes that it makes it into crash dumps.
   DWORD last_error = err_;
   base::debug::Alias(&last_error);
 }
 #elif defined(OS_POSIX)
 ErrnoLogMessage::ErrnoLogMessage(const char* file,
                                  int line,
                                  LogSeverity severity,
                                  SystemErrorCode err)
     : err_(err),
       log_message_(file, line, severity) {
 }

 ErrnoLogMessage::~ErrnoLogMessage() {
   stream() << ": " << SystemErrorCodeToString(err_);
 }
 #endif  // OS_WIN

 void CloseLogFile() {
   LoggingLock logging_lock;
   CloseLogFileUnlocked();
 }

 void RawLog(int level, const char* message) {
   if (level >= min_log_level) {
     size_t bytes_written = 0;
     const size_t message_len = strlen(message);
     int rv;
     while (bytes_written < message_len) {
       rv = HANDLE_EINTR(
           write(STDERR_FILENO, message + bytes_written,
                 message_len - bytes_written));
       if (rv < 0) {
         // Give up, nothing we can do now.
         break;
       }
       bytes_written += rv;
     }

     if (message_len > 0 && message[message_len - 1] != '\n') {
       do {
         rv = HANDLE_EINTR(write(STDERR_FILENO, "\n", 1));
         if (rv < 0) {
           // Give up, nothing we can do now.
           break;
         }
       } while (rv != 1);
     }
   }

   if (level == LOG_FATAL)
     base::debug::BreakDebugger();
 }

 // This was defined at the beginning of this file.
 #undef write

 #if defined(OS_WIN)
 std::wstring GetLogFileFullPath() {
   if (log_file_name)
     return *log_file_name;
   return std::wstring();
 }
 #endif

 }  // namespace logging

 std::ostream& std::operator<<(std::ostream& out, const wchar_t* wstr) {
   return out << base::WideToUTF8(std::wstring(wstr));
 }