| // Copyright (c) 2012 The Chromium Authors. All rights reserved. | 
 | // Use of this source code is governed by a BSD-style license that can be | 
 | // found in the LICENSE file. | 
 |  | 
 | #include "base/debug/stack_trace.h" | 
 |  | 
 | #include <windows.h> | 
 | #include <dbghelp.h> | 
 |  | 
 | #include <iostream> | 
 |  | 
 | #include "base/basictypes.h" | 
 | #include "base/logging.h" | 
 | #include "base/memory/singleton.h" | 
 | #include "base/process/launch.h" | 
 | #include "base/strings/string_util.h" | 
 | #include "base/synchronization/lock.h" | 
 | #include "base/win/windows_version.h" | 
 |  | 
 | namespace base { | 
 | namespace debug { | 
 |  | 
 | namespace { | 
 |  | 
 | // Previous unhandled filter. Will be called if not NULL when we intercept an | 
 | // exception. Only used in unit tests. | 
 | LPTOP_LEVEL_EXCEPTION_FILTER g_previous_filter = NULL; | 
 |  | 
 | // Prints the exception call stack. | 
 | // This is the unit tests exception filter. | 
 | long WINAPI StackDumpExceptionFilter(EXCEPTION_POINTERS* info) { | 
 |   debug::StackTrace(info).Print(); | 
 |   if (g_previous_filter) | 
 |     return g_previous_filter(info); | 
 |   return EXCEPTION_CONTINUE_SEARCH; | 
 | } | 
 |  | 
 | FilePath GetExePath() { | 
 |   wchar_t system_buffer[MAX_PATH]; | 
 |   GetModuleFileName(NULL, system_buffer, MAX_PATH); | 
 |   system_buffer[MAX_PATH - 1] = L'\0'; | 
 |   return FilePath(system_buffer); | 
 | } | 
 |  | 
 | // SymbolContext is a threadsafe singleton that wraps the DbgHelp Sym* family | 
 | // of functions.  The Sym* family of functions may only be invoked by one | 
 | // thread at a time.  SymbolContext code may access a symbol server over the | 
 | // network while holding the lock for this singleton.  In the case of high | 
 | // latency, this code will adversely affect performance. | 
 | // | 
 | // There is also a known issue where this backtrace code can interact | 
 | // badly with breakpad if breakpad is invoked in a separate thread while | 
 | // we are using the Sym* functions.  This is because breakpad does now | 
 | // share a lock with this function.  See this related bug: | 
 | // | 
 | //   http://code.google.com/p/google-breakpad/issues/detail?id=311 | 
 | // | 
 | // This is a very unlikely edge case, and the current solution is to | 
 | // just ignore it. | 
 | class SymbolContext { | 
 |  public: | 
 |   static SymbolContext* GetInstance() { | 
 |     // We use a leaky singleton because code may call this during process | 
 |     // termination. | 
 |     return | 
 |       Singleton<SymbolContext, LeakySingletonTraits<SymbolContext> >::get(); | 
 |   } | 
 |  | 
 |   // Returns the error code of a failed initialization. | 
 |   DWORD init_error() const { | 
 |     return init_error_; | 
 |   } | 
 |  | 
 |   // For the given trace, attempts to resolve the symbols, and output a trace | 
 |   // to the ostream os.  The format for each line of the backtrace is: | 
 |   // | 
 |   //    <tab>SymbolName[0xAddress+Offset] (FileName:LineNo) | 
 |   // | 
 |   // This function should only be called if Init() has been called.  We do not | 
 |   // LOG(FATAL) here because this code is called might be triggered by a | 
 |   // LOG(FATAL) itself. Also, it should not be calling complex code that is | 
 |   // extensible like PathService since that can in turn fire CHECKs. | 
 |   void OutputTraceToStream(const void* const* trace, | 
 |                            size_t count, | 
 |                            std::ostream* os) { | 
 |     base::AutoLock lock(lock_); | 
 |  | 
 |     for (size_t i = 0; (i < count) && os->good(); ++i) { | 
 |       const int kMaxNameLength = 256; | 
 |       DWORD_PTR frame = reinterpret_cast<DWORD_PTR>(trace[i]); | 
 |  | 
 |       // Code adapted from MSDN example: | 
 |       // http://msdn.microsoft.com/en-us/library/ms680578(VS.85).aspx | 
 |       ULONG64 buffer[ | 
 |         (sizeof(SYMBOL_INFO) + | 
 |           kMaxNameLength * sizeof(wchar_t) + | 
 |           sizeof(ULONG64) - 1) / | 
 |         sizeof(ULONG64)]; | 
 |       memset(buffer, 0, sizeof(buffer)); | 
 |  | 
 |       // Initialize symbol information retrieval structures. | 
 |       DWORD64 sym_displacement = 0; | 
 |       PSYMBOL_INFO symbol = reinterpret_cast<PSYMBOL_INFO>(&buffer[0]); | 
 |       symbol->SizeOfStruct = sizeof(SYMBOL_INFO); | 
 |       symbol->MaxNameLen = kMaxNameLength - 1; | 
 |       BOOL has_symbol = SymFromAddr(GetCurrentProcess(), frame, | 
 |                                     &sym_displacement, symbol); | 
 |  | 
 |       // Attempt to retrieve line number information. | 
 |       DWORD line_displacement = 0; | 
 |       IMAGEHLP_LINE64 line = {}; | 
 |       line.SizeOfStruct = sizeof(IMAGEHLP_LINE64); | 
 |       BOOL has_line = SymGetLineFromAddr64(GetCurrentProcess(), frame, | 
 |                                            &line_displacement, &line); | 
 |  | 
 |       // Output the backtrace line. | 
 |       (*os) << "\t"; | 
 |       if (has_symbol) { | 
 |         (*os) << symbol->Name << " [0x" << trace[i] << "+" | 
 |               << sym_displacement << "]"; | 
 |       } else { | 
 |         // If there is no symbol information, add a spacer. | 
 |         (*os) << "(No symbol) [0x" << trace[i] << "]"; | 
 |       } | 
 |       if (has_line) { | 
 |         (*os) << " (" << line.FileName << ":" << line.LineNumber << ")"; | 
 |       } | 
 |       (*os) << "\n"; | 
 |     } | 
 |   } | 
 |  | 
 |  private: | 
 |   friend struct DefaultSingletonTraits<SymbolContext>; | 
 |  | 
 |   SymbolContext() : init_error_(ERROR_SUCCESS) { | 
 |     // Initializes the symbols for the process. | 
 |     // Defer symbol load until they're needed, use undecorated names, and | 
 |     // get line numbers. | 
 |     SymSetOptions(SYMOPT_DEFERRED_LOADS | | 
 |                   SYMOPT_UNDNAME | | 
 |                   SYMOPT_LOAD_LINES); | 
 |     if (!SymInitialize(GetCurrentProcess(), NULL, TRUE)) { | 
 |       init_error_ = GetLastError(); | 
 |       // TODO(awong): Handle error: SymInitialize can fail with | 
 |       // ERROR_INVALID_PARAMETER. | 
 |       // When it fails, we should not call debugbreak since it kills the current | 
 |       // process (prevents future tests from running or kills the browser | 
 |       // process). | 
 |       DLOG(ERROR) << "SymInitialize failed: " << init_error_; | 
 |       return; | 
 |     } | 
 |  | 
 |     init_error_ = ERROR_SUCCESS; | 
 |  | 
 |     // When transferring the binaries e.g. between bots, path put | 
 |     // into the executable will get off. To still retrieve symbols correctly, | 
 |     // add the directory of the executable to symbol search path. | 
 |     // All following errors are non-fatal. | 
 |     const size_t kSymbolsArraySize = 1024; | 
 |     scoped_ptr<wchar_t[]> symbols_path(new wchar_t[kSymbolsArraySize]); | 
 |  | 
 |     // Note: The below function takes buffer size as number of characters, | 
 |     // not number of bytes! | 
 |     if (!SymGetSearchPathW(GetCurrentProcess(), | 
 |                            symbols_path.get(), | 
 |                            kSymbolsArraySize)) { | 
 |       DLOG(WARNING) << "SymGetSearchPath failed: "; | 
 |       return; | 
 |     } | 
 |  | 
 |     std::wstring new_path(std::wstring(symbols_path.get()) + | 
 |                           L";" + GetExePath().DirName().value()); | 
 |     if (!SymSetSearchPathW(GetCurrentProcess(), new_path.c_str())) { | 
 |       DLOG(WARNING) << "SymSetSearchPath failed."; | 
 |       return; | 
 |     } | 
 |   } | 
 |  | 
 |   DWORD init_error_; | 
 |   base::Lock lock_; | 
 |   DISALLOW_COPY_AND_ASSIGN(SymbolContext); | 
 | }; | 
 |  | 
 | }  // namespace | 
 |  | 
 | bool EnableInProcessStackDumping() { | 
 |   // Add stack dumping support on exception on windows. Similar to OS_POSIX | 
 |   // signal() handling in process_util_posix.cc. | 
 |   g_previous_filter = SetUnhandledExceptionFilter(&StackDumpExceptionFilter); | 
 |   RouteStdioToConsole(); | 
 |   return true; | 
 | } | 
 |  | 
 | // Disable optimizations for the StackTrace::StackTrace function. It is | 
 | // important to disable at least frame pointer optimization ("y"), since | 
 | // that breaks CaptureStackBackTrace() and prevents StackTrace from working | 
 | // in Release builds (it may still be janky if other frames are using FPO, | 
 | // but at least it will make it further). | 
 | #if defined(COMPILER_MSVC) | 
 | #pragma optimize("", off) | 
 | #endif | 
 |  | 
 | StackTrace::StackTrace() { | 
 |   // When walking our own stack, use CaptureStackBackTrace(). | 
 |   count_ = CaptureStackBackTrace(0, arraysize(trace_), trace_, NULL); | 
 | } | 
 |  | 
 | #if defined(COMPILER_MSVC) | 
 | #pragma optimize("", on) | 
 | #endif | 
 |  | 
 | StackTrace::StackTrace(const EXCEPTION_POINTERS* exception_pointers) { | 
 |   // StackWalk64() may modify context record passed to it, so we will | 
 |   // use a copy. | 
 |   CONTEXT context_record = *exception_pointers->ContextRecord; | 
 |   InitTrace(&context_record); | 
 | } | 
 |  | 
 | StackTrace::StackTrace(const CONTEXT* context) { | 
 |   // StackWalk64() may modify context record passed to it, so we will | 
 |   // use a copy. | 
 |   CONTEXT context_record = *context; | 
 |   InitTrace(&context_record); | 
 | } | 
 |  | 
 | void StackTrace::InitTrace(CONTEXT* context_record) { | 
 |   // When walking an exception stack, we need to use StackWalk64(). | 
 |   count_ = 0; | 
 |   // Initialize stack walking. | 
 |   STACKFRAME64 stack_frame; | 
 |   memset(&stack_frame, 0, sizeof(stack_frame)); | 
 | #if defined(_WIN64) | 
 |   int machine_type = IMAGE_FILE_MACHINE_AMD64; | 
 |   stack_frame.AddrPC.Offset = context_record->Rip; | 
 |   stack_frame.AddrFrame.Offset = context_record->Rbp; | 
 |   stack_frame.AddrStack.Offset = context_record->Rsp; | 
 | #else | 
 |   int machine_type = IMAGE_FILE_MACHINE_I386; | 
 |   stack_frame.AddrPC.Offset = context_record->Eip; | 
 |   stack_frame.AddrFrame.Offset = context_record->Ebp; | 
 |   stack_frame.AddrStack.Offset = context_record->Esp; | 
 | #endif | 
 |   stack_frame.AddrPC.Mode = AddrModeFlat; | 
 |   stack_frame.AddrFrame.Mode = AddrModeFlat; | 
 |   stack_frame.AddrStack.Mode = AddrModeFlat; | 
 |   while (StackWalk64(machine_type, | 
 |                      GetCurrentProcess(), | 
 |                      GetCurrentThread(), | 
 |                      &stack_frame, | 
 |                      context_record, | 
 |                      NULL, | 
 |                      &SymFunctionTableAccess64, | 
 |                      &SymGetModuleBase64, | 
 |                      NULL) && | 
 |          count_ < arraysize(trace_)) { | 
 |     trace_[count_++] = reinterpret_cast<void*>(stack_frame.AddrPC.Offset); | 
 |   } | 
 |  | 
 |   for (size_t i = count_; i < arraysize(trace_); ++i) | 
 |     trace_[i] = NULL; | 
 | } | 
 |  | 
 | void StackTrace::Print() const { | 
 |   OutputToStream(&std::cerr); | 
 | } | 
 |  | 
 | void StackTrace::OutputToStream(std::ostream* os) const { | 
 |   SymbolContext* context = SymbolContext::GetInstance(); | 
 |   DWORD error = context->init_error(); | 
 |   if (error != ERROR_SUCCESS) { | 
 |     (*os) << "Error initializing symbols (" << error | 
 |           << ").  Dumping unresolved backtrace:\n"; | 
 |     for (size_t i = 0; (i < count_) && os->good(); ++i) { | 
 |       (*os) << "\t" << trace_[i] << "\n"; | 
 |     } | 
 |   } else { | 
 |     (*os) << "Backtrace:\n"; | 
 |     context->OutputTraceToStream(trace_, count_, os); | 
 |   } | 
 | } | 
 |  | 
 | }  // namespace debug | 
 | }  // namespace base |