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