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 <stdio.h>
  33 #include <stdlib.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/alias.h"
  50 #include "base/debug/debugger.h"
  51 #include "base/debug/stack_trace.h"
  52 #include "base/posix/eintr_wrapper.h"
  53 #include "base/strings/string_piece.h"
  54 #include "base/strings/utf_string_conversions.h"
  55 #include "base/synchronization/lock_impl.h"
  56 #include "base/threading/platform_thread.h"
  57 #include "base/vlog.h"
  58 #if defined(OS_POSIX)
  59 #include "base/safe_strerror_posix.h"
  60 #endif
  61
  62 #if defined(OS_ANDROID)
  63 #include <android/log.h>
  64 #endif
  65
  66 namespace logging {
  67
  68 DcheckState g_dcheck_state = DISABLE_DCHECK_FOR_NON_OFFICIAL_RELEASE_BUILDS;
  69
  70 DcheckState get_dcheck_state() {
  71   return g_dcheck_state;
  72 }
  73
  74 void set_dcheck_state(DcheckState state) {
  75   g_dcheck_state = state;
  76 }
  77
  78 namespace {
  79
  80 VlogInfo* g_vlog_info = NULL;
  81 VlogInfo* g_vlog_info_prev = NULL;
  82
  83 const char* const log_severity_names[LOG_NUM_SEVERITIES] = {
  84   "INFO", "WARNING", "ERROR", "ERROR_REPORT", "FATAL" };
  85
  86 const char* log_severity_name(int severity)
  87 {
  88   if (severity >= 0 && severity < LOG_NUM_SEVERITIES)
  89     return log_severity_names[severity];
  90   return "UNKNOWN";
  91 }
  92
  93 int min_log_level = 0;
  94
  95 LoggingDestination logging_destination = LOG_DEFAULT;
  96
  97 // For LOG_ERROR and above, always print to stderr.
  98 const int kAlwaysPrintErrorLevel = LOG_ERROR;
  99
 100 // Which log file to use? This is initialized by InitLogging or
 101 // will be lazily initialized to the default value when it is
 102 // first needed.
 103 #if defined(OS_WIN)
 104 typedef std::wstring PathString;
 105 #else
 106 typedef std::string PathString;
 107 #endif
 108 PathString* log_file_name = NULL;
 109
 110 // this file is lazily opened and the handle may be NULL
 111 FileHandle log_file = NULL;
 112
 113 // what should be prepended to each message?
 114 bool log_process_id = false;
 115 bool log_thread_id = false;
 116 bool log_timestamp = true;
 117 bool log_tickcount = false;
 118
 119 // Should we pop up fatal debug messages in a dialog?
 120 bool show_error_dialogs = false;
 121
 122 // An assert handler override specified by the client to be called instead of
 123 // the debug message dialog and process termination.
 124 LogAssertHandlerFunction log_assert_handler = NULL;
 125 // An report handler override specified by the client to be called instead of
 126 // the debug message dialog.
 127 LogReportHandlerFunction log_report_handler = NULL;
 128 // A log message handler that gets notified of every log message we process.
 129 LogMessageHandlerFunction log_message_handler = NULL;
 130
 131 // Helper functions to wrap platform differences.
 132
 133 int32 CurrentProcessId() {
 134 #if defined(OS_WIN)
 135   return GetCurrentProcessId();
 136 #elif defined(OS_POSIX)
 137   return getpid();
 138 #endif
 139 }
 140
 141 uint64 TickCount() {
 142 #if defined(OS_WIN)
 143   return GetTickCount();
 144 #elif defined(OS_MACOSX)
 145   return mach_absolute_time();
 146 #elif defined(OS_NACL)
 147   // NaCl sadly does not have _POSIX_TIMERS enabled in sys/features.h
 148   // So we have to use clock() for now.
 149   return clock();
 150 #elif defined(OS_POSIX)
 151   struct timespec ts;
 152   clock_gettime(CLOCK_MONOTONIC, &ts);
 153
 154   uint64 absolute_micro =
 155     static_cast<int64>(ts.tv_sec) * 1000000 +
 156     static_cast<int64>(ts.tv_nsec) / 1000;
 157
 158   return absolute_micro;
 159 #endif
 160 }
 161
 162 void DeleteFilePath(const PathString& log_name) {
 163 #if defined(OS_WIN)
 164   DeleteFile(log_name.c_str());
 165 #elif defined (OS_NACL)
 166   // Do nothing; unlink() isn't supported on NaCl.
 167 #else
 168   unlink(log_name.c_str());
 169 #endif
 170 }
 171
 172 PathString GetDefaultLogFile() {
 173 #if defined(OS_WIN)
 174   // On Windows we use the same path as the exe.
 175   wchar_t module_name[MAX_PATH];
 176   GetModuleFileName(NULL, module_name, MAX_PATH);
 177
 178   PathString log_file = module_name;
 179   PathString::size_type last_backslash =
 180       log_file.rfind('\\', log_file.size());
 181   if (last_backslash != PathString::npos)
 182     log_file.erase(last_backslash + 1);
 183   log_file += L"debug.log";
 184   return log_file;
 185 #elif defined(OS_POSIX)
 186   // On other platforms we just use the current directory.
 187   return PathString("debug.log");
 188 #endif
 189 }
 190
 191 // This class acts as a wrapper for locking the logging files.
 192 // LoggingLock::Init() should be called from the main thread before any logging
 193 // is done. Then whenever logging, be sure to have a local LoggingLock
 194 // instance on the stack. This will ensure that the lock is unlocked upon
 195 // exiting the frame.
 196 // LoggingLocks can not be nested.
 197 class LoggingLock {
 198  public:
 199   LoggingLock() {
 200     LockLogging();
 201   }
 202
 203   ~LoggingLock() {
 204     UnlockLogging();
 205   }
 206
 207   static void Init(LogLockingState lock_log, const PathChar* new_log_file) {
 208     if (initialized)
 209       return;
 210     lock_log_file = lock_log;
 211     if (lock_log_file == LOCK_LOG_FILE) {
 212 #if defined(OS_WIN)
 213       if (!log_mutex) {
 214         std::wstring safe_name;
 215         if (new_log_file)
 216           safe_name = new_log_file;
 217         else
 218           safe_name = GetDefaultLogFile();
 219         // \ is not a legal character in mutex names so we replace \ with /
 220         std::replace(safe_name.begin(), safe_name.end(), '\\', '/');
 221         std::wstring t(L"Global\\");
 222         t.append(safe_name);
 223         log_mutex = ::CreateMutex(NULL, FALSE, t.c_str());
 224
 225         if (log_mutex == NULL) {
 226 #if DEBUG
 227           // Keep the error code for debugging
 228           int error = GetLastError();  // NOLINT
 229           base::debug::BreakDebugger();
 230 #endif
 231           // Return nicely without putting initialized to true.
 232           return;
 233         }
 234       }
 235 #endif
 236     } else {
 237       log_lock = new base::internal::LockImpl();
 238     }
 239     initialized = true;
 240   }
 241
 242  private:
 243   static void LockLogging() {
 244     if (lock_log_file == LOCK_LOG_FILE) {
 245 #if defined(OS_WIN)
 246       ::WaitForSingleObject(log_mutex, INFINITE);
 247       // WaitForSingleObject could have returned WAIT_ABANDONED. We don't
 248       // abort the process here. UI tests might be crashy sometimes,
 249       // and aborting the test binary only makes the problem worse.
 250       // We also don't use LOG macros because that might lead to an infinite
 251       // loop. For more info see http://crbug.com/18028.
 252 #elif defined(OS_POSIX)
 253       pthread_mutex_lock(&log_mutex);
 254 #endif
 255     } else {
 256       // use the lock
 257       log_lock->Lock();
 258     }
 259   }
 260
 261   static void UnlockLogging() {
 262     if (lock_log_file == LOCK_LOG_FILE) {
 263 #if defined(OS_WIN)
 264       ReleaseMutex(log_mutex);
 265 #elif defined(OS_POSIX)
 266       pthread_mutex_unlock(&log_mutex);
 267 #endif
 268     } else {
 269       log_lock->Unlock();
 270     }
 271   }
 272
 273   // The lock is used if log file locking is false. It helps us avoid problems
 274   // with multiple threads writing to the log file at the same time.  Use
 275   // LockImpl directly instead of using Lock, because Lock makes logging calls.
 276   static base::internal::LockImpl* log_lock;
 277
 278   // When we don't use a lock, we are using a global mutex. We need to do this
 279   // because LockFileEx is not thread safe.
 280 #if defined(OS_WIN)
 281   static MutexHandle log_mutex;
 282 #elif defined(OS_POSIX)
 283   static pthread_mutex_t log_mutex;
 284 #endif
 285
 286   static bool initialized;
 287   static LogLockingState lock_log_file;
 288 };
 289
 290 // static
 291 bool LoggingLock::initialized = false;
 292 // static
 293 base::internal::LockImpl* LoggingLock::log_lock = NULL;
 294 // static
 295 LogLockingState LoggingLock::lock_log_file = LOCK_LOG_FILE;
 296
 297 #if defined(OS_WIN)
 298 // static
 299 MutexHandle LoggingLock::log_mutex = NULL;
 300 #elif defined(OS_POSIX)
 301 pthread_mutex_t LoggingLock::log_mutex = PTHREAD_MUTEX_INITIALIZER;
 302 #endif
 303
 304 // Called by logging functions to ensure that debug_file is initialized
 305 // and can be used for writing. Returns false if the file could not be
 306 // initialized. debug_file will be NULL in this case.
 307 bool InitializeLogFileHandle() {
 308   if (log_file)
 309     return true;
 310
 311   if (!log_file_name) {
 312     // Nobody has called InitLogging to specify a debug log file, so here we
 313     // initialize the log file name to a default.
 314     log_file_name = new PathString(GetDefaultLogFile());
 315   }
 316
 317   if ((logging_destination & LOG_TO_FILE) != 0) {
 318 #if defined(OS_WIN)
 319     log_file = CreateFile(log_file_name->c_str(), GENERIC_WRITE,
 320                           FILE_SHARE_READ | FILE_SHARE_WRITE, NULL,
 321                           OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
 322     if (log_file == INVALID_HANDLE_VALUE || log_file == NULL) {
 323       // try the current directory
 324       log_file = CreateFile(L".\\debug.log", GENERIC_WRITE,
 325                             FILE_SHARE_READ | FILE_SHARE_WRITE, NULL,
 326                             OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
 327       if (log_file == INVALID_HANDLE_VALUE || log_file == NULL) {
 328         log_file = NULL;
 329         return false;
 330       }
 331     }
 332     SetFilePointer(log_file, 0, 0, FILE_END);
 333 #elif defined(OS_POSIX)
 334     log_file = fopen(log_file_name->c_str(), "a");
 335     if (log_file == NULL)
 336       return false;
 337 #endif
 338   }
 339
 340   return true;
 341 }
 342
 343 void CloseFile(FileHandle log) {
 344 #if defined(OS_WIN)
 345   CloseHandle(log);
 346 #else
 347   fclose(log);
 348 #endif
 349 }
 350
 351 void CloseLogFileUnlocked() {
 352   if (!log_file)
 353     return;
 354
 355   CloseFile(log_file);
 356   log_file = NULL;
 357 }
 358
 359 }  // namespace
 360
 361 LoggingSettings::LoggingSettings()
 362     : logging_dest(LOG_DEFAULT),
 363       log_file(NULL),
 364       lock_log(LOCK_LOG_FILE),
 365       delete_old(APPEND_TO_OLD_LOG_FILE),
 366       dcheck_state(DISABLE_DCHECK_FOR_NON_OFFICIAL_RELEASE_BUILDS) {}
 367
 368 bool BaseInitLoggingImpl(const LoggingSettings& settings) {
 369 #if defined(OS_NACL)
 370   // Can log only to the system debug log.
 371   CHECK_EQ(settings.logging_dest & ~LOG_TO_SYSTEM_DEBUG_LOG, 0);
 372 #endif
 373   g_dcheck_state = settings.dcheck_state;
 374   CommandLine* command_line = CommandLine::ForCurrentProcess();
 375   // Don't bother initializing g_vlog_info unless we use one of the
 376   // vlog switches.
 377   if (command_line->HasSwitch(switches::kV) ||
 378       command_line->HasSwitch(switches::kVModule)) {
 379     // NOTE: If g_vlog_info has already been initialized, it might be in use
 380     // by another thread. Don't delete the old VLogInfo, just create a second
 381     // one. We keep track of both to avoid memory leak warnings.
 382     CHECK(!g_vlog_info_prev);
 383     g_vlog_info_prev = g_vlog_info;
 384
 385     g_vlog_info =
 386         new VlogInfo(command_line->GetSwitchValueASCII(switches::kV),
 387                      command_line->GetSwitchValueASCII(switches::kVModule),
 388                      &min_log_level);
 389   }
 390
 391   logging_destination = settings.logging_dest;
 392
 393   // ignore file options unless logging to file is set.
 394   if ((logging_destination & LOG_TO_FILE) == 0)
 395     return true;
 396
 397   LoggingLock::Init(settings.lock_log, settings.log_file);
 398   LoggingLock logging_lock;
 399
 400   // Calling InitLogging twice or after some log call has already opened the
 401   // default log file will re-initialize to the new options.
 402   CloseLogFileUnlocked();
 403
 404   if (!log_file_name)
 405     log_file_name = new PathString();
 406   *log_file_name = settings.log_file;
 407   if (settings.delete_old == DELETE_OLD_LOG_FILE)
 408     DeleteFilePath(*log_file_name);
 409
 410   return InitializeLogFileHandle();
 411 }
 412
 413 void SetMinLogLevel(int level) {
 414   min_log_level = std::min(LOG_ERROR_REPORT, level);
 415 }
 416
 417 int GetMinLogLevel() {
 418   return min_log_level;
 419 }
 420
 421 int GetVlogVerbosity() {
 422   return std::max(-1, LOG_INFO - GetMinLogLevel());
 423 }
 424
 425 int GetVlogLevelHelper(const char* file, size_t N) {
 426   DCHECK_GT(N, 0U);
 427   // Note: g_vlog_info may change on a different thread during startup
 428   // (but will always be valid or NULL).
 429   VlogInfo* vlog_info = g_vlog_info;
 430   return vlog_info ?
 431       vlog_info->GetVlogLevel(base::StringPiece(file, N - 1)) :
 432       GetVlogVerbosity();
 433 }
 434
 435 void SetLogItems(bool enable_process_id, bool enable_thread_id,
 436                  bool enable_timestamp, bool enable_tickcount) {
 437   log_process_id = enable_process_id;
 438   log_thread_id = enable_thread_id;
 439   log_timestamp = enable_timestamp;
 440   log_tickcount = enable_tickcount;
 441 }
 442
 443 void SetShowErrorDialogs(bool enable_dialogs) {
 444   show_error_dialogs = enable_dialogs;
 445 }
 446
 447 void SetLogAssertHandler(LogAssertHandlerFunction handler) {
 448   log_assert_handler = handler;
 449 }
 450
 451 void SetLogReportHandler(LogReportHandlerFunction handler) {
 452   log_report_handler = handler;
 453 }
 454
 455 void SetLogMessageHandler(LogMessageHandlerFunction handler) {
 456   log_message_handler = handler;
 457 }
 458
 459 LogMessageHandlerFunction GetLogMessageHandler() {
 460   return log_message_handler;
 461 }
 462
 463 // MSVC doesn't like complex extern templates and DLLs.
 464 #if !defined(COMPILER_MSVC)
 465 // Explicit instantiations for commonly used comparisons.
 466 template std::string* MakeCheckOpString<int, int>(
 467     const int&, const int&, const char* names);
 468 template std::string* MakeCheckOpString<unsigned long, unsigned long>(
 469     const unsigned long&, const unsigned long&, const char* names);
 470 template std::string* MakeCheckOpString<unsigned long, unsigned int>(
 471     const unsigned long&, const unsigned int&, const char* names);
 472 template std::string* MakeCheckOpString<unsigned int, unsigned long>(
 473     const unsigned int&, const unsigned long&, const char* names);
 474 template std::string* MakeCheckOpString<std::string, std::string>(
 475     const std::string&, const std::string&, const char* name);
 476 #endif
 477
 478 // Displays a message box to the user with the error message in it.
 479 // Used for fatal messages, where we close the app simultaneously.
 480 // This is for developers only; we don't use this in circumstances
 481 // (like release builds) where users could see it, since users don't
 482 // understand these messages anyway.
 483 void DisplayDebugMessageInDialog(const std::string& str) {
 484   if (str.empty())
 485     return;
 486
 487   if (!show_error_dialogs)
 488     return;
 489
 490 #if defined(OS_WIN)
 491   // For Windows programs, it's possible that the message loop is
 492   // messed up on a fatal error, and creating a MessageBox will cause
 493   // that message loop to be run. Instead, we try to spawn another
 494   // process that displays its command line. We look for "Debug
 495   // Message.exe" in the same directory as the application. If it
 496   // exists, we use it, otherwise, we use a regular message box.
 497   wchar_t prog_name[MAX_PATH];
 498   GetModuleFileNameW(NULL, prog_name, MAX_PATH);
 499   wchar_t* backslash = wcsrchr(prog_name, '\\');
 500   if (backslash)
 501     backslash[1] = 0;
 502   wcscat_s(prog_name, MAX_PATH, L"debug_message.exe");
 503
 504   std::wstring cmdline = base::UTF8ToWide(str);
 505   if (cmdline.empty())
 506     return;
 507
 508   STARTUPINFO startup_info;
 509   memset(&startup_info, 0, sizeof(startup_info));
 510   startup_info.cb = sizeof(startup_info);
 511
 512   PROCESS_INFORMATION process_info;
 513   if (CreateProcessW(prog_name, &cmdline[0], NULL, NULL, false, 0, NULL,
 514                      NULL, &startup_info, &process_info)) {
 515     WaitForSingleObject(process_info.hProcess, INFINITE);
 516     CloseHandle(process_info.hThread);
 517     CloseHandle(process_info.hProcess);
 518   } else {
 519     // debug process broken, let's just do a message box
 520     MessageBoxW(NULL, &cmdline[0], L"Fatal error",
 521                 MB_OK | MB_ICONHAND | MB_TOPMOST);
 522   }
 523 #else
 524   // We intentionally don't implement a dialog on other platforms.
 525   // You can just look at stderr.
 526 #endif
 527 }
 528
 529 #if defined(OS_WIN)
 530 LogMessage::SaveLastError::SaveLastError() : last_error_(::GetLastError()) {
 531 }
 532
 533 LogMessage::SaveLastError::~SaveLastError() {
 534   ::SetLastError(last_error_);
 535 }
 536 #endif  // defined(OS_WIN)
 537
 538 LogMessage::LogMessage(const char* file, int line, LogSeverity severity,
 539                        int ctr)
 540     : severity_(severity), file_(file), line_(line) {
 541   Init(file, line);
 542 }
 543
 544 LogMessage::LogMessage(const char* file, int line)
 545     : severity_(LOG_INFO), file_(file), line_(line) {
 546   Init(file, line);
 547 }
 548
 549 LogMessage::LogMessage(const char* file, int line, LogSeverity severity)
 550     : severity_(severity), file_(file), line_(line) {
 551   Init(file, line);
 552 }
 553
 554 LogMessage::LogMessage(const char* file, int line, std::string* result)
 555     : severity_(LOG_FATAL), file_(file), line_(line) {
 556   Init(file, line);
 557   stream_ << "Check failed: " << *result;
 558   delete result;
 559 }
 560
 561 LogMessage::LogMessage(const char* file, int line, LogSeverity severity,
 562                        std::string* result)
 563     : severity_(severity), file_(file), line_(line) {
 564   Init(file, line);
 565   stream_ << "Check failed: " << *result;
 566   delete result;
 567 }
 568
 569 LogMessage::~LogMessage() {
 570 #if !defined(NDEBUG) && !defined(OS_NACL)
 571   if (severity_ == LOG_FATAL) {
 572     // Include a stack trace on a fatal.
 573     base::debug::StackTrace trace;
 574     stream_ << std::endl;  // Newline to separate from log message.
 575     trace.OutputToStream(&stream_);
 576   }
 577 #endif
 578   stream_ << std::endl;
 579   std::string str_newline(stream_.str());
 580
 581   // Give any log message handler first dibs on the message.
 582   if (log_message_handler &&
 583       log_message_handler(severity_, file_, line_,
 584                           message_start_, str_newline)) {
 585     // The handler took care of it, no further processing.
 586     return;
 587   }
 588
 589   if ((logging_destination & LOG_TO_SYSTEM_DEBUG_LOG) != 0) {
 590 #if defined(OS_WIN)
 591     OutputDebugStringA(str_newline.c_str());
 592 #elif defined(OS_ANDROID)
 593     android_LogPriority priority =
 594         (severity_ < 0) ? ANDROID_LOG_VERBOSE : ANDROID_LOG_UNKNOWN;
 595     switch (severity_) {
 596       case LOG_INFO:
 597         priority = ANDROID_LOG_INFO;
 598         break;
 599       case LOG_WARNING:
 600         priority = ANDROID_LOG_WARN;
 601         break;
 602       case LOG_ERROR:
 603       case LOG_ERROR_REPORT:
 604         priority = ANDROID_LOG_ERROR;
 605         break;
 606       case LOG_FATAL:
 607         priority = ANDROID_LOG_FATAL;
 608         break;
 609     }
 610     __android_log_write(priority, "chromium", str_newline.c_str());
 611 #endif
 612     fprintf(stderr, "%s", str_newline.c_str());
 613     fflush(stderr);
 614   } else if (severity_ >= kAlwaysPrintErrorLevel) {
 615     // When we're only outputting to a log file, above a certain log level, we
 616     // should still output to stderr so that we can better detect and diagnose
 617     // problems with unit tests, especially on the buildbots.
 618     fprintf(stderr, "%s", str_newline.c_str());
 619     fflush(stderr);
 620   }
 621
 622   // write to log file
 623   if ((logging_destination & LOG_TO_FILE) != 0) {
 624     // We can have multiple threads and/or processes, so try to prevent them
 625     // from clobbering each other's writes.
 626     // If the client app did not call InitLogging, and the lock has not
 627     // been created do it now. We do this on demand, but if two threads try
 628     // to do this at the same time, there will be a race condition to create
 629     // the lock. This is why InitLogging should be called from the main
 630     // thread at the beginning of execution.
 631     LoggingLock::Init(LOCK_LOG_FILE, NULL);
 632     LoggingLock logging_lock;
 633     if (InitializeLogFileHandle()) {
 634 #if defined(OS_WIN)
 635       SetFilePointer(log_file, 0, 0, SEEK_END);
 636       DWORD num_written;
 637       WriteFile(log_file,
 638                 static_cast<const void*>(str_newline.c_str()),
 639                 static_cast<DWORD>(str_newline.length()),
 640                 &num_written,
 641                 NULL);
 642 #else
 643       fprintf(log_file, "%s", str_newline.c_str());
 644       fflush(log_file);
 645 #endif
 646     }
 647   }
 648
 649   if (severity_ == LOG_FATAL) {
 650     // Ensure the first characters of the string are on the stack so they
 651     // are contained in minidumps for diagnostic purposes.
 652     char str_stack[1024];
 653     str_newline.copy(str_stack, arraysize(str_stack));
 654     base::debug::Alias(str_stack);
 655
 656     // display a message or break into the debugger on a fatal error
 657     if (base::debug::BeingDebugged()) {
 658       base::debug::BreakDebugger();
 659     } else {
 660       if (log_assert_handler) {
 661         // make a copy of the string for the handler out of paranoia
 662         log_assert_handler(std::string(stream_.str()));
 663       } else {
 664         // Don't use the string with the newline, get a fresh version to send to
 665         // the debug message process. We also don't display assertions to the
 666         // user in release mode. The enduser can't do anything with this
 667         // information, and displaying message boxes when the application is
 668         // hosed can cause additional problems.
 669 #ifndef NDEBUG
 670         DisplayDebugMessageInDialog(stream_.str());
 671 #endif
 672         // Crash the process to generate a dump.
 673         base::debug::BreakDebugger();
 674       }
 675     }
 676   } else if (severity_ == LOG_ERROR_REPORT) {
 677     // We are here only if the user runs with --enable-dcheck in release mode.
 678     if (log_report_handler) {
 679       log_report_handler(std::string(stream_.str()));
 680     } else {
 681       DisplayDebugMessageInDialog(stream_.str());
 682     }
 683   }
 684 }
 685
 686 // writes the common header info to the stream
 687 void LogMessage::Init(const char* file, int line) {
 688   base::StringPiece filename(file);
 689   size_t last_slash_pos = filename.find_last_of("\\/");
 690   if (last_slash_pos != base::StringPiece::npos)
 691     filename.remove_prefix(last_slash_pos + 1);
 692
 693   // TODO(darin): It might be nice if the columns were fixed width.
 694
 695   stream_ <<  '[';
 696   if (log_process_id)
 697     stream_ << CurrentProcessId() << ':';
 698   if (log_thread_id)
 699     stream_ << base::PlatformThread::CurrentId() << ':';
 700   if (log_timestamp) {
 701     time_t t = time(NULL);
 702     struct tm local_time = {0};
 703 #if _MSC_VER >= 1400
 704     localtime_s(&local_time, &t);
 705 #else
 706     localtime_r(&t, &local_time);
 707 #endif
 708     struct tm* tm_time = &local_time;
 709     stream_ << std::setfill('0')
 710             << std::setw(2) << 1 + tm_time->tm_mon
 711             << std::setw(2) << tm_time->tm_mday
 712             << '/'
 713             << std::setw(2) << tm_time->tm_hour
 714             << std::setw(2) << tm_time->tm_min
 715             << std::setw(2) << tm_time->tm_sec
 716             << ':';
 717   }
 718   if (log_tickcount)
 719     stream_ << TickCount() << ':';
 720   if (severity_ >= 0)
 721     stream_ << log_severity_name(severity_);
 722   else
 723     stream_ << "VERBOSE" << -severity_;
 724
 725   stream_ << ":" << filename << "(" << line << ")] ";
 726
 727   message_start_ = stream_.tellp();
 728 }
 729
 730 #if defined(OS_WIN)
 731 // This has already been defined in the header, but defining it again as DWORD
 732 // ensures that the type used in the header is equivalent to DWORD. If not,
 733 // the redefinition is a compile error.
 734 typedef DWORD SystemErrorCode;
 735 #endif
 736
 737 SystemErrorCode GetLastSystemErrorCode() {
 738 #if defined(OS_WIN)
 739   return ::GetLastError();
 740 #elif defined(OS_POSIX)
 741   return errno;
 742 #else
 743 #error Not implemented
 744 #endif
 745 }
 746
 747 #if defined(OS_WIN)
 748 Win32ErrorLogMessage::Win32ErrorLogMessage(const char* file,
 749                                            int line,
 750                                            LogSeverity severity,
 751                                            SystemErrorCode err,
 752                                            const char* module)
 753     : err_(err),
 754       module_(module),
 755       log_message_(file, line, severity) {
 756 }
 757
 758 Win32ErrorLogMessage::Win32ErrorLogMessage(const char* file,
 759                                            int line,
 760                                            LogSeverity severity,
 761                                            SystemErrorCode err)
 762     : err_(err),
 763       module_(NULL),
 764       log_message_(file, line, severity) {
 765 }
 766
 767 Win32ErrorLogMessage::~Win32ErrorLogMessage() {
 768   const int error_message_buffer_size = 256;
 769   char msgbuf[error_message_buffer_size];
 770   DWORD flags = FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS;
 771   HMODULE hmod;
 772   if (module_) {
 773     hmod = GetModuleHandleA(module_);
 774     if (hmod) {
 775       flags |= FORMAT_MESSAGE_FROM_HMODULE;
 776     } else {
 777       // This makes a nested Win32ErrorLogMessage. It will have module_ of NULL
 778       // so it will not call GetModuleHandle, so recursive errors are
 779       // impossible.
 780       DPLOG(WARNING) << "Couldn't open module " << module_
 781           << " for error message query";
 782     }
 783   } else {
 784     hmod = NULL;
 785   }
 786   DWORD len = FormatMessageA(flags,
 787                              hmod,
 788                              err_,
 789                              0,
 790                              msgbuf,
 791                              sizeof(msgbuf) / sizeof(msgbuf[0]),
 792                              NULL);
 793   if (len) {
 794     while ((len > 0) &&
 795            isspace(static_cast<unsigned char>(msgbuf[len - 1]))) {
 796       msgbuf[--len] = 0;
 797     }
 798     stream() << ": " << msgbuf;
 799   } else {
 800     stream() << ": Error " << GetLastError() << " while retrieving error "
 801         << err_;
 802   }
 803   // We're about to crash (CHECK). Put |err_| on the stack (by placing it in a
 804   // field) and use Alias in hopes that it makes it into crash dumps.
 805   DWORD last_error = err_;
 806   base::debug::Alias(&last_error);
 807 }
 808 #elif defined(OS_POSIX)
 809 ErrnoLogMessage::ErrnoLogMessage(const char* file,
 810                                  int line,
 811                                  LogSeverity severity,
 812                                  SystemErrorCode err)
 813     : err_(err),
 814       log_message_(file, line, severity) {
 815 }
 816
 817 ErrnoLogMessage::~ErrnoLogMessage() {
 818   stream() << ": " << safe_strerror(err_);
 819 }
 820 #endif  // OS_WIN
 821
 822 void CloseLogFile() {
 823   LoggingLock logging_lock;
 824   CloseLogFileUnlocked();
 825 }
 826
 827 void RawLog(int level, const char* message) {
 828   if (level >= min_log_level) {
 829     size_t bytes_written = 0;
 830     const size_t message_len = strlen(message);
 831     int rv;
 832     while (bytes_written < message_len) {
 833       rv = HANDLE_EINTR(
 834           write(STDERR_FILENO, message + bytes_written,
 835                 message_len - bytes_written));
 836       if (rv < 0) {
 837         // Give up, nothing we can do now.
 838         break;
 839       }
 840       bytes_written += rv;
 841     }
 842
 843     if (message_len > 0 && message[message_len - 1] != '\n') {
 844       do {
 845         rv = HANDLE_EINTR(write(STDERR_FILENO, "\n", 1));
 846         if (rv < 0) {
 847           // Give up, nothing we can do now.
 848           break;
 849         }
 850       } while (rv != 1);
 851     }
 852   }
 853
 854   if (level == LOG_FATAL)
 855     base::debug::BreakDebugger();
 856 }
 857
 858 // This was defined at the beginning of this file.
 859 #undef write
 860
 861 #if defined(OS_WIN)
 862 std::wstring GetLogFileFullPath() {
 863   if (log_file_name)
 864     return *log_file_name;
 865   return std::wstring();
 866 }
 867 #endif
 868
 869 }  // namespace logging
 870
 871 std::ostream& operator<<(std::ostream& out, const wchar_t* wstr) {
 872   return out << base::WideToUTF8(std::wstring(wstr));
 873 }