base/logging.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/logging.h"
   6
   7 #if defined(OS_WIN)
   8 #include <io.h>
   9 #include <windows.h>
  10 typedef HANDLE FileHandle;
  11 typedef HANDLE MutexHandle;
  12 // Windows warns on using write().  It prefers _write().
  13 #define write(fd, buf, count) _write(fd, buf, static_cast<unsigned int>(count))
  14 // Windows doesn't define STDERR_FILENO.  Define it here.
  15 #define STDERR_FILENO 2
  16 #elif defined(OS_MACOSX)
  17 #include <mach/mach.h>
  18 #include <mach/mach_time.h>
  19 #include <mach-o/dyld.h>
  20 #elif defined(OS_POSIX)
  21 #if defined(OS_NACL)
  22 #include <sys/time.h> // timespec doesn't seem to be in <time.h>
  23 #else
  24 #include <sys/syscall.h>
  25 #endif
  26 #include <time.h>
  27 #endif
  28
  29 #if defined(OS_POSIX)
  30 #include <errno.h>
  31 #include <pthread.h>
  32 #include <stdlib.h>
  33 #include <stdio.h>
  34 #include <string.h>
  35 #include <unistd.h>
  36 #define MAX_PATH PATH_MAX
  37 typedef FILE* FileHandle;
  38 typedef pthread_mutex_t* MutexHandle;
  39 #endif
  40
  41 #include <algorithm>
  42 #include <cstring>
  43 #include <ctime>
  44 #include <iomanip>
  45 #include <ostream>
  46
  47 #include "base/base_switches.h"
  48 #include "base/command_line.h"
  49 #include "base/debug/debugger.h"
  50 #include "base/debug/stack_trace.h"
  51 #include "base/eintr_wrapper.h"
  52 #include "base/string_piece.h"
  53 #include "base/synchronization/lock_impl.h"
  54 #include "base/threading/platform_thread.h"
  55 #include "base/utf_string_conversions.h"
  56 #include "base/vlog.h"
  57 #if defined(OS_POSIX)
  58 #include "base/safe_strerror_posix.h"
  59 #endif
  60
  61 #if defined(OS_ANDROID)
  62 #include <android/log.h>
  63 #endif
  64
  65 namespace logging {
  66
  67 DcheckState g_dcheck_state = DISABLE_DCHECK_FOR_NON_OFFICIAL_RELEASE_BUILDS;
  68
  69 namespace {
  70
  71 VlogInfo* g_vlog_info = NULL;
  72 VlogInfo* g_vlog_info_prev = NULL;
  73
  74 const char* const log_severity_names[LOG_NUM_SEVERITIES] = {
  75   "INFO", "WARNING", "ERROR", "ERROR_REPORT", "FATAL" };
  76
  77 int min_log_level = 0;
  78
  79 // The default set here for logging_destination will only be used if
  80 // InitLogging is not called.  On Windows, use a file next to the exe;
  81 // on POSIX platforms, where it may not even be possible to locate the
  82 // executable on disk, use stderr.
  83 #if defined(OS_WIN)
  84 LoggingDestination logging_destination = LOG_ONLY_TO_FILE;
  85 #elif defined(OS_POSIX)
  86 LoggingDestination logging_destination = LOG_ONLY_TO_SYSTEM_DEBUG_LOG;
  87 #endif
  88
  89 // For LOG_ERROR and above, always print to stderr.
  90 const int kAlwaysPrintErrorLevel = LOG_ERROR;
  91
  92 // Which log file to use? This is initialized by InitLogging or
  93 // will be lazily initialized to the default value when it is
  94 // first needed.
  95 #if defined(OS_WIN)
  96 typedef std::wstring PathString;
  97 #else
  98 typedef std::string PathString;
  99 #endif
 100 PathString* log_file_name = NULL;
 101
 102 // this file is lazily opened and the handle may be NULL
 103 FileHandle log_file = NULL;
 104
 105 // what should be prepended to each message?
 106 bool log_process_id = false;
 107 bool log_thread_id = false;
 108 bool log_timestamp = true;
 109 bool log_tickcount = false;
 110
 111 // Should we pop up fatal debug messages in a dialog?
 112 bool show_error_dialogs = false;
 113
 114 // An assert handler override specified by the client to be called instead of
 115 // the debug message dialog and process termination.
 116 LogAssertHandlerFunction log_assert_handler = NULL;
 117 // An report handler override specified by the client to be called instead of
 118 // the debug message dialog.
 119 LogReportHandlerFunction log_report_handler = NULL;
 120 // A log message handler that gets notified of every log message we process.
 121 LogMessageHandlerFunction log_message_handler = NULL;
 122
 123 // Helper functions to wrap platform differences.
 124
 125 int32 CurrentProcessId() {
 126 #if defined(OS_WIN)
 127   return GetCurrentProcessId();
 128 #elif defined(OS_POSIX)
 129   return getpid();
 130 #endif
 131 }
 132
 133 uint64 TickCount() {
 134 #if defined(OS_WIN)
 135   return GetTickCount();
 136 #elif defined(OS_MACOSX)
 137   return mach_absolute_time();
 138 #elif defined(OS_NACL)
 139   // NaCl sadly does not have _POSIX_TIMERS enabled in sys/features.h
 140   // So we have to use clock() for now.
 141   return clock();
 142 #elif defined(OS_POSIX)
 143   struct timespec ts;
 144   clock_gettime(CLOCK_MONOTONIC, &ts);
 145
 146   uint64 absolute_micro =
 147     static_cast<int64>(ts.tv_sec) * 1000000 +
 148     static_cast<int64>(ts.tv_nsec) / 1000;
 149
 150   return absolute_micro;
 151 #endif
 152 }
 153
 154 void CloseFile(FileHandle log) {
 155 #if defined(OS_WIN)
 156   CloseHandle(log);
 157 #else
 158   fclose(log);
 159 #endif
 160 }
 161
 162 void DeleteFilePath(const PathString& log_name) {
 163 #if defined(OS_WIN)
 164   DeleteFile(log_name.c_str());
 165 #else
 166   unlink(log_name.c_str());
 167 #endif
 168 }
 169
 170 PathString GetDefaultLogFile() {
 171 #if defined(OS_WIN)
 172   // On Windows we use the same path as the exe.
 173   wchar_t module_name[MAX_PATH];
 174   GetModuleFileName(NULL, module_name, MAX_PATH);
 175
 176   PathString log_file = module_name;
 177   PathString::size_type last_backslash =
 178       log_file.rfind('\\', log_file.size());
 179   if (last_backslash != PathString::npos)
 180     log_file.erase(last_backslash + 1);
 181   log_file += L"debug.log";
 182   return log_file;
 183 #elif defined(OS_POSIX)
 184   // On other platforms we just use the current directory.
 185   return PathString("debug.log");
 186 #endif
 187 }
 188
 189 // This class acts as a wrapper for locking the logging files.
 190 // LoggingLock::Init() should be called from the main thread before any logging
 191 // is done. Then whenever logging, be sure to have a local LoggingLock
 192 // instance on the stack. This will ensure that the lock is unlocked upon
 193 // exiting the frame.
 194 // LoggingLocks can not be nested.
 195 class LoggingLock {
 196  public:
 197   LoggingLock() {
 198     LockLogging();
 199   }
 200
 201   ~LoggingLock() {
 202     UnlockLogging();
 203   }
 204
 205   static void Init(LogLockingState lock_log, const PathChar* new_log_file) {
 206     if (initialized)
 207       return;
 208     lock_log_file = lock_log;
 209     if (lock_log_file == LOCK_LOG_FILE) {
 210 #if defined(OS_WIN)
 211       if (!log_mutex) {
 212         std::wstring safe_name;
 213         if (new_log_file)
 214           safe_name = new_log_file;
 215         else
 216           safe_name = GetDefaultLogFile();
 217         // \ is not a legal character in mutex names so we replace \ with /
 218         std::replace(safe_name.begin(), safe_name.end(), '\\', '/');
 219         std::wstring t(L"Global\\");
 220         t.append(safe_name);
 221         log_mutex = ::CreateMutex(NULL, FALSE, t.c_str());
 222
 223         if (log_mutex == NULL) {
 224 #if DEBUG
 225           // Keep the error code for debugging
 226           int error = GetLastError();  // NOLINT
 227           base::debug::BreakDebugger();
 228 #endif
 229           // Return nicely without putting initialized to true.
 230           return;
 231         }
 232       }
 233 #endif
 234     } else {
 235       log_lock = new base::internal::LockImpl();
 236     }
 237     initialized = true;
 238   }
 239
 240  private:
 241   static void LockLogging() {
 242     if (lock_log_file == LOCK_LOG_FILE) {
 243 #if defined(OS_WIN)
 244       ::WaitForSingleObject(log_mutex, INFINITE);
 245       // WaitForSingleObject could have returned WAIT_ABANDONED. We don't
 246       // abort the process here. UI tests might be crashy sometimes,
 247       // and aborting the test binary only makes the problem worse.
 248       // We also don't use LOG macros because that might lead to an infinite
 249       // loop. For more info see http://crbug.com/18028.
 250 #elif defined(OS_POSIX)
 251       pthread_mutex_lock(&log_mutex);
 252 #endif
 253     } else {
 254       // use the lock
 255       log_lock->Lock();
 256     }
 257   }
 258
 259   static void UnlockLogging() {
 260     if (lock_log_file == LOCK_LOG_FILE) {
 261 #if defined(OS_WIN)
 262       ReleaseMutex(log_mutex);
 263 #elif defined(OS_POSIX)
 264       pthread_mutex_unlock(&log_mutex);
 265 #endif
 266     } else {
 267       log_lock->Unlock();
 268     }
 269   }
 270
 271   // The lock is used if log file locking is false. It helps us avoid problems
 272   // with multiple threads writing to the log file at the same time.  Use
 273   // LockImpl directly instead of using Lock, because Lock makes logging calls.
 274   static base::internal::LockImpl* log_lock;
 275
 276   // When we don't use a lock, we are using a global mutex. We need to do this
 277   // because LockFileEx is not thread safe.
 278 #if defined(OS_WIN)
 279   static MutexHandle log_mutex;
 280 #elif defined(OS_POSIX)
 281   static pthread_mutex_t log_mutex;
 282 #endif
 283
 284   static bool initialized;
 285   static LogLockingState lock_log_file;
 286 };
 287
 288 // static
 289 bool LoggingLock::initialized = false;
 290 // static
 291 base::internal::LockImpl* LoggingLock::log_lock = NULL;
 292 // static
 293 LogLockingState LoggingLock::lock_log_file = LOCK_LOG_FILE;
 294
 295 #if defined(OS_WIN)
 296 // static
 297 MutexHandle LoggingLock::log_mutex = NULL;
 298 #elif defined(OS_POSIX)
 299 pthread_mutex_t LoggingLock::log_mutex = PTHREAD_MUTEX_INITIALIZER;
 300 #endif
 301
 302 // Called by logging functions to ensure that debug_file is initialized
 303 // and can be used for writing. Returns false if the file could not be
 304 // initialized. debug_file will be NULL in this case.
 305 bool InitializeLogFileHandle() {
 306   if (log_file)
 307     return true;
 308
 309   if (!log_file_name) {
 310     // Nobody has called InitLogging to specify a debug log file, so here we
 311     // initialize the log file name to a default.
 312     log_file_name = new PathString(GetDefaultLogFile());
 313   }
 314
 315   if (logging_destination == LOG_ONLY_TO_FILE ||
 316       logging_destination == LOG_TO_BOTH_FILE_AND_SYSTEM_DEBUG_LOG) {
 317 #if defined(OS_WIN)
 318     log_file = CreateFile(log_file_name->c_str(), GENERIC_WRITE,
 319                           FILE_SHARE_READ | FILE_SHARE_WRITE, NULL,
 320                           OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
 321     if (log_file == INVALID_HANDLE_VALUE || log_file == NULL) {
 322       // try the current directory
 323       log_file = CreateFile(L".\\debug.log", GENERIC_WRITE,
 324                             FILE_SHARE_READ | FILE_SHARE_WRITE, NULL,
 325                             OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
 326       if (log_file == INVALID_HANDLE_VALUE || log_file == NULL) {
 327         log_file = NULL;
 328         return false;
 329       }
 330     }
 331     SetFilePointer(log_file, 0, 0, FILE_END);
 332 #elif defined(OS_POSIX)
 333     log_file = fopen(log_file_name->c_str(), "a");
 334     if (log_file == NULL)
 335       return false;
 336 #endif
 337   }
 338
 339   return true;
 340 }
 341
 342 }  // namespace
 343
 344
 345 bool BaseInitLoggingImpl(const PathChar* new_log_file,
 346                          LoggingDestination logging_dest,
 347                          LogLockingState lock_log,
 348                          OldFileDeletionState delete_old,
 349                          DcheckState dcheck_state) {
 350   g_dcheck_state = dcheck_state;
 351 // TODO(bbudge) Hook this up to NaCl logging.
 352 #if !defined(OS_NACL)
 353   CommandLine* command_line = CommandLine::ForCurrentProcess();
 354   // Don't bother initializing g_vlog_info unless we use one of the
 355   // vlog switches.
 356   if (command_line->HasSwitch(switches::kV) ||
 357       command_line->HasSwitch(switches::kVModule)) {
 358     // NOTE: If g_vlog_info has already been initialized, it might be in use
 359     // by another thread. Don't delete the old VLogInfo, just create a second
 360     // one. We keep track of both to avoid memory leak warnings.
 361     CHECK(!g_vlog_info_prev);
 362     g_vlog_info_prev = g_vlog_info;
 363
 364     g_vlog_info =
 365         new VlogInfo(command_line->GetSwitchValueASCII(switches::kV),
 366                      command_line->GetSwitchValueASCII(switches::kVModule),
 367                      &min_log_level);
 368   }
 369
 370   LoggingLock::Init(lock_log, new_log_file);
 371
 372   LoggingLock logging_lock;
 373
 374   if (log_file) {
 375     // calling InitLogging twice or after some log call has already opened the
 376     // default log file will re-initialize to the new options
 377     CloseFile(log_file);
 378     log_file = NULL;
 379   }
 380
 381   logging_destination = logging_dest;
 382
 383   // ignore file options if logging is disabled or only to system
 384   if (logging_destination == LOG_NONE ||
 385       logging_destination == LOG_ONLY_TO_SYSTEM_DEBUG_LOG)
 386     return true;
 387
 388   if (!log_file_name)
 389     log_file_name = new PathString();
 390   *log_file_name = new_log_file;
 391   if (delete_old == DELETE_OLD_LOG_FILE)
 392     DeleteFilePath(*log_file_name);
 393
 394   return InitializeLogFileHandle();
 395 #else
 396   return true;
 397 #endif  // !defined(OS_NACL)
 398 }
 399
 400 void SetMinLogLevel(int level) {
 401   min_log_level = std::min(LOG_ERROR_REPORT, level);
 402 }
 403
 404 int GetMinLogLevel() {
 405   return min_log_level;
 406 }
 407
 408 int GetVlogVerbosity() {
 409   return std::max(-1, LOG_INFO - GetMinLogLevel());
 410 }
 411
 412 int GetVlogLevelHelper(const char* file, size_t N) {
 413   DCHECK_GT(N, 0U);
 414   // Note: g_vlog_info may change on a different thread during startup
 415   // (but will always be valid or NULL).
 416   VlogInfo* vlog_info = g_vlog_info;
 417   return vlog_info ?
 418       vlog_info->GetVlogLevel(base::StringPiece(file, N - 1)) :
 419       GetVlogVerbosity();
 420 }
 421
 422 void SetLogItems(bool enable_process_id, bool enable_thread_id,
 423                  bool enable_timestamp, bool enable_tickcount) {
 424   log_process_id = enable_process_id;
 425   log_thread_id = enable_thread_id;
 426   log_timestamp = enable_timestamp;
 427   log_tickcount = enable_tickcount;
 428 }
 429
 430 void SetShowErrorDialogs(bool enable_dialogs) {
 431   show_error_dialogs = enable_dialogs;
 432 }
 433
 434 void SetLogAssertHandler(LogAssertHandlerFunction handler) {
 435   log_assert_handler = handler;
 436 }
 437
 438 void SetLogReportHandler(LogReportHandlerFunction handler) {
 439   log_report_handler = handler;
 440 }
 441
 442 void SetLogMessageHandler(LogMessageHandlerFunction handler) {
 443   log_message_handler = handler;
 444 }
 445
 446 LogMessageHandlerFunction GetLogMessageHandler() {
 447   return log_message_handler;
 448 }
 449
 450 // MSVC doesn't like complex extern templates and DLLs.
 451 #if !defined(COMPILER_MSVC)
 452 // Explicit instantiations for commonly used comparisons.
 453 template std::string* MakeCheckOpString<int, int>(
 454     const int&, const int&, const char* names);
 455 template std::string* MakeCheckOpString<unsigned long, unsigned long>(
 456     const unsigned long&, const unsigned long&, const char* names);
 457 template std::string* MakeCheckOpString<unsigned long, unsigned int>(
 458     const unsigned long&, const unsigned int&, const char* names);
 459 template std::string* MakeCheckOpString<unsigned int, unsigned long>(
 460     const unsigned int&, const unsigned long&, const char* names);
 461 template std::string* MakeCheckOpString<std::string, std::string>(
 462     const std::string&, const std::string&, const char* name);
 463 #endif
 464
 465 // Displays a message box to the user with the error message in it.
 466 // Used for fatal messages, where we close the app simultaneously.
 467 // This is for developers only; we don't use this in circumstances
 468 // (like release builds) where users could see it, since users don't
 469 // understand these messages anyway.
 470 void DisplayDebugMessageInDialog(const std::string& str) {
 471   if (str.empty())
 472     return;
 473
 474   if (!show_error_dialogs)
 475     return;
 476
 477 #if defined(OS_WIN)
 478   // For Windows programs, it's possible that the message loop is
 479   // messed up on a fatal error, and creating a MessageBox will cause
 480   // that message loop to be run. Instead, we try to spawn another
 481   // process that displays its command line. We look for "Debug
 482   // Message.exe" in the same directory as the application. If it
 483   // exists, we use it, otherwise, we use a regular message box.
 484   wchar_t prog_name[MAX_PATH];
 485   GetModuleFileNameW(NULL, prog_name, MAX_PATH);
 486   wchar_t* backslash = wcsrchr(prog_name, '\\');
 487   if (backslash)
 488     backslash[1] = 0;
 489   wcscat_s(prog_name, MAX_PATH, L"debug_message.exe");
 490
 491   std::wstring cmdline = UTF8ToWide(str);
 492   if (cmdline.empty())
 493     return;
 494
 495   STARTUPINFO startup_info;
 496   memset(&startup_info, 0, sizeof(startup_info));
 497   startup_info.cb = sizeof(startup_info);
 498
 499   PROCESS_INFORMATION process_info;
 500   if (CreateProcessW(prog_name, &cmdline[0], NULL, NULL, false, 0, NULL,
 501                      NULL, &startup_info, &process_info)) {
 502     WaitForSingleObject(process_info.hProcess, INFINITE);
 503     CloseHandle(process_info.hThread);
 504     CloseHandle(process_info.hProcess);
 505   } else {
 506     // debug process broken, let's just do a message box
 507     MessageBoxW(NULL, &cmdline[0], L"Fatal error",
 508                 MB_OK | MB_ICONHAND | MB_TOPMOST);
 509   }
 510 #else
 511   // We intentionally don't implement a dialog on other platforms.
 512   // You can just look at stderr.
 513 #endif
 514 }
 515
 516 #if defined(OS_WIN)
 517 LogMessage::SaveLastError::SaveLastError() : last_error_(::GetLastError()) {
 518 }
 519
 520 LogMessage::SaveLastError::~SaveLastError() {
 521   ::SetLastError(last_error_);
 522 }
 523 #endif  // defined(OS_WIN)
 524
 525 LogMessage::LogMessage(const char* file, int line, LogSeverity severity,
 526                        int ctr)
 527     : severity_(severity), file_(file), line_(line) {
 528   Init(file, line);
 529 }
 530
 531 LogMessage::LogMessage(const char* file, int line)
 532     : severity_(LOG_INFO), file_(file), line_(line) {
 533   Init(file, line);
 534 }
 535
 536 LogMessage::LogMessage(const char* file, int line, LogSeverity severity)
 537     : severity_(severity), file_(file), line_(line) {
 538   Init(file, line);
 539 }
 540
 541 LogMessage::LogMessage(const char* file, int line, std::string* result)
 542     : severity_(LOG_FATAL), file_(file), line_(line) {
 543   Init(file, line);
 544   stream_ << "Check failed: " << *result;
 545   delete result;
 546 }
 547
 548 LogMessage::LogMessage(const char* file, int line, LogSeverity severity,
 549                        std::string* result)
 550     : severity_(severity), file_(file), line_(line) {
 551   Init(file, line);
 552   stream_ << "Check failed: " << *result;
 553   delete result;
 554 }
 555
 556 LogMessage::~LogMessage() {
 557   // TODO(port): enable stacktrace generation on LOG_FATAL once backtrace are
 558   // working in Android.
 559 #if  !defined(NDEBUG) && !defined(OS_ANDROID) && !defined(OS_NACL)
 560   if (severity_ == LOG_FATAL) {
 561     // Include a stack trace on a fatal.
 562     base::debug::StackTrace trace;
 563     stream_ << std::endl;  // Newline to separate from log message.
 564     trace.OutputToStream(&stream_);
 565   }
 566 #endif
 567   stream_ << std::endl;
 568   std::string str_newline(stream_.str());
 569
 570   // Give any log message handler first dibs on the message.
 571   if (log_message_handler && log_message_handler(severity_, file_, line_,
 572           message_start_, str_newline)) {
 573     // The handler took care of it, no further processing.
 574     return;
 575   }
 576
 577   if (logging_destination == LOG_ONLY_TO_SYSTEM_DEBUG_LOG ||
 578       logging_destination == LOG_TO_BOTH_FILE_AND_SYSTEM_DEBUG_LOG) {
 579 #if defined(OS_WIN)
 580     OutputDebugStringA(str_newline.c_str());
 581 #elif defined(OS_ANDROID)
 582     android_LogPriority priority = ANDROID_LOG_UNKNOWN;
 583     switch (severity_) {
 584       case LOG_INFO:
 585         priority = ANDROID_LOG_INFO;
 586         break;
 587       case LOG_WARNING:
 588         priority = ANDROID_LOG_WARN;
 589         break;
 590       case LOG_ERROR:
 591       case LOG_ERROR_REPORT:
 592         priority = ANDROID_LOG_ERROR;
 593         break;
 594       case LOG_FATAL:
 595         priority = ANDROID_LOG_FATAL;
 596         break;
 597     }
 598     __android_log_write(priority, "chromium", str_newline.c_str());
 599 #endif
 600     fprintf(stderr, "%s", str_newline.c_str());
 601     fflush(stderr);
 602   } else if (severity_ >= kAlwaysPrintErrorLevel) {
 603     // When we're only outputting to a log file, above a certain log level, we
 604     // should still output to stderr so that we can better detect and diagnose
 605     // problems with unit tests, especially on the buildbots.
 606     fprintf(stderr, "%s", str_newline.c_str());
 607     fflush(stderr);
 608   }
 609
 610   // We can have multiple threads and/or processes, so try to prevent them
 611   // from clobbering each other's writes.
 612   // If the client app did not call InitLogging, and the lock has not
 613   // been created do it now. We do this on demand, but if two threads try
 614   // to do this at the same time, there will be a race condition to create
 615   // the lock. This is why InitLogging should be called from the main
 616   // thread at the beginning of execution.
 617   LoggingLock::Init(LOCK_LOG_FILE, NULL);
 618   // write to log file
 619   if (logging_destination != LOG_NONE &&
 620       logging_destination != LOG_ONLY_TO_SYSTEM_DEBUG_LOG) {
 621     LoggingLock logging_lock;
 622     if (InitializeLogFileHandle()) {
 623 #if defined(OS_WIN)
 624       SetFilePointer(log_file, 0, 0, SEEK_END);
 625       DWORD num_written;
 626       WriteFile(log_file,
 627                 static_cast<const void*>(str_newline.c_str()),
 628                 static_cast<DWORD>(str_newline.length()),
 629                 &num_written,
 630                 NULL);
 631 #else
 632       fprintf(log_file, "%s", str_newline.c_str());
 633       fflush(log_file);
 634 #endif
 635     }
 636   }
 637
 638   if (severity_ == LOG_FATAL) {
 639     // display a message or break into the debugger on a fatal error
 640     if (base::debug::BeingDebugged()) {
 641       base::debug::BreakDebugger();
 642     } else {
 643       if (log_assert_handler) {
 644         // make a copy of the string for the handler out of paranoia
 645         log_assert_handler(std::string(stream_.str()));
 646       } else {
 647         // Don't use the string with the newline, get a fresh version to send to
 648         // the debug message process. We also don't display assertions to the
 649         // user in release mode. The enduser can't do anything with this
 650         // information, and displaying message boxes when the application is
 651         // hosed can cause additional problems.
 652 #ifndef NDEBUG
 653         DisplayDebugMessageInDialog(stream_.str());
 654 #endif
 655         // Crash the process to generate a dump.
 656         base::debug::BreakDebugger();
 657       }
 658     }
 659   } else if (severity_ == LOG_ERROR_REPORT) {
 660     // We are here only if the user runs with --enable-dcheck in release mode.
 661     if (log_report_handler) {
 662       log_report_handler(std::string(stream_.str()));
 663     } else {
 664       DisplayDebugMessageInDialog(stream_.str());
 665     }
 666   }
 667 }
 668
 669 // writes the common header info to the stream
 670 void LogMessage::Init(const char* file, int line) {
 671   base::StringPiece filename(file);
 672   size_t last_slash_pos = filename.find_last_of("\\/");
 673   if (last_slash_pos != base::StringPiece::npos)
 674     filename.remove_prefix(last_slash_pos + 1);
 675
 676   // TODO(darin): It might be nice if the columns were fixed width.
 677
 678   stream_ <<  '[';
 679   if (log_process_id)
 680     stream_ << CurrentProcessId() << ':';
 681   if (log_thread_id)
 682     stream_ << base::PlatformThread::CurrentId() << ':';
 683   if (log_timestamp) {
 684     time_t t = time(NULL);
 685     struct tm local_time = {0};
 686 #if _MSC_VER >= 1400
 687     localtime_s(&local_time, &t);
 688 #else
 689     localtime_r(&t, &local_time);
 690 #endif
 691     struct tm* tm_time = &local_time;
 692     stream_ << std::setfill('0')
 693             << std::setw(2) << 1 + tm_time->tm_mon
 694             << std::setw(2) << tm_time->tm_mday
 695             << '/'
 696             << std::setw(2) << tm_time->tm_hour
 697             << std::setw(2) << tm_time->tm_min
 698             << std::setw(2) << tm_time->tm_sec
 699             << ':';
 700   }
 701   if (log_tickcount)
 702     stream_ << TickCount() << ':';
 703   if (severity_ >= 0)
 704     stream_ << log_severity_names[severity_];
 705   else
 706     stream_ << "VERBOSE" << -severity_;
 707
 708   stream_ << ":" << filename << "(" << line << ")] ";
 709
 710   message_start_ = stream_.tellp();
 711 }
 712
 713 #if defined(OS_WIN)
 714 // This has already been defined in the header, but defining it again as DWORD
 715 // ensures that the type used in the header is equivalent to DWORD. If not,
 716 // the redefinition is a compile error.
 717 typedef DWORD SystemErrorCode;
 718 #endif
 719
 720 SystemErrorCode GetLastSystemErrorCode() {
 721 #if defined(OS_WIN)
 722   return ::GetLastError();
 723 #elif defined(OS_POSIX)
 724   return errno;
 725 #else
 726 #error Not implemented
 727 #endif
 728 }
 729
 730 #if defined(OS_WIN)
 731 Win32ErrorLogMessage::Win32ErrorLogMessage(const char* file,
 732                                            int line,
 733                                            LogSeverity severity,
 734                                            SystemErrorCode err,
 735                                            const char* module)
 736     : err_(err),
 737       module_(module),
 738       log_message_(file, line, severity) {
 739 }
 740
 741 Win32ErrorLogMessage::Win32ErrorLogMessage(const char* file,
 742                                            int line,
 743                                            LogSeverity severity,
 744                                            SystemErrorCode err)
 745     : err_(err),
 746       module_(NULL),
 747       log_message_(file, line, severity) {
 748 }
 749
 750 Win32ErrorLogMessage::~Win32ErrorLogMessage() {
 751   const int error_message_buffer_size = 256;
 752   char msgbuf[error_message_buffer_size];
 753   DWORD flags = FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS;
 754   HMODULE hmod;
 755   if (module_) {
 756     hmod = GetModuleHandleA(module_);
 757     if (hmod) {
 758       flags |= FORMAT_MESSAGE_FROM_HMODULE;
 759     } else {
 760       // This makes a nested Win32ErrorLogMessage. It will have module_ of NULL
 761       // so it will not call GetModuleHandle, so recursive errors are
 762       // impossible.
 763       DPLOG(WARNING) << "Couldn't open module " << module_
 764           << " for error message query";
 765     }
 766   } else {
 767     hmod = NULL;
 768   }
 769   DWORD len = FormatMessageA(flags,
 770                              hmod,
 771                              err_,
 772                              0,
 773                              msgbuf,
 774                              sizeof(msgbuf) / sizeof(msgbuf[0]),
 775                              NULL);
 776   if (len) {
 777     while ((len > 0) &&
 778            isspace(static_cast<unsigned char>(msgbuf[len - 1]))) {
 779       msgbuf[--len] = 0;
 780     }
 781     stream() << ": " << msgbuf;
 782   } else {
 783     stream() << ": Error " << GetLastError() << " while retrieving error "
 784         << err_;
 785   }
 786 }
 787 #elif defined(OS_POSIX)
 788 ErrnoLogMessage::ErrnoLogMessage(const char* file,
 789                                  int line,
 790                                  LogSeverity severity,
 791                                  SystemErrorCode err)
 792     : err_(err),
 793       log_message_(file, line, severity) {
 794 }
 795
 796 ErrnoLogMessage::~ErrnoLogMessage() {
 797   stream() << ": " << safe_strerror(err_);
 798 }
 799 #endif  // OS_WIN
 800
 801 void CloseLogFile() {
 802   LoggingLock logging_lock;
 803
 804   if (!log_file)
 805     return;
 806
 807   CloseFile(log_file);
 808   log_file = NULL;
 809 }
 810
 811 void RawLog(int level, const char* message) {
 812   if (level >= min_log_level) {
 813     size_t bytes_written = 0;
 814     const size_t message_len = strlen(message);
 815     int rv;
 816     while (bytes_written < message_len) {
 817       rv = HANDLE_EINTR(
 818           write(STDERR_FILENO, message + bytes_written,
 819                 message_len - bytes_written));
 820       if (rv < 0) {
 821         // Give up, nothing we can do now.
 822         break;
 823       }
 824       bytes_written += rv;
 825     }
 826
 827     if (message_len > 0 && message[message_len - 1] != '\n') {
 828       do {
 829         rv = HANDLE_EINTR(write(STDERR_FILENO, "\n", 1));
 830         if (rv < 0) {
 831           // Give up, nothing we can do now.
 832           break;
 833         }
 834       } while (rv != 1);
 835     }
 836   }
 837
 838   if (level == LOG_FATAL)
 839     base::debug::BreakDebugger();
 840 }
 841
 842 // This was defined at the beginning of this file.
 843 #undef write
 844
 845 }  // namespace logging
 846
 847 std::ostream& operator<<(std::ostream& out, const wchar_t* wstr) {
 848   return out << WideToUTF8(std::wstring(wstr));
 849 }