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