浅谈Linux系统中的异常堆栈跟踪的简单实现

/*** 用于将backtrace_symbols函数所返回的字符串解析成对应的函数名，便于理解* 头文件  cxxabi.h* 名字空间	abi* @param mangled_name A NUL-terminated character string containing the name to be demangled.* @param output_buffer  A region of memory, allocated with malloc, of *length bytes, into which the demangled name is stored. If output_buffer is not long enough, it is expanded using realloc. *     output_buffer may instead be NULL; in that case, the demangled name is placed in a region of memory allocated with malloc. * @param length  If length is non-NULL, the length of the buffer containing the demangled name is placed in *length.* @param status  *status is set to one of the following values:*        0: The demangling operation succeeded.*       -1: A memory allocation failiure occurred.*       -2: Mangled_name is not a valid name under the C++ ABI mangling rules.*       -3: One of the arguments is invalid.*/char *__cxa_demangle (const char *mangled_name, char *output_buffer, size_t *length, int *status);

#define MAX_FRAMES 100void GetStackTrace (std::string* stack){  void* addresses[MAX_FRAMES];  int size = backtrace (addresses, MAX_FRAMES);  std::unique_ptr<char*, void(*)(void*)> symbols {    backtrace_symbols (addresses, size),    std::free  };  for (int i = 0; i < size; ++i) {    stack->append (symbols.get()[i]);    stack->append ("/n");  }}void TestFunc (std::string& stack, int value){  while (--value);  GetStackTrace (&stack);}int main(int argc, char* argv[]){  std::string stack;  TestFunc (stack, 5);  std::cout << stack << std::endl;  return 0;}

void DemangleSymbol (std::string* symbol){  size_t size = 0;  int status = -4;  char temp[256] = {'/0'};  //first, try to demangle a c++ name  if (1 == sscanf (symbol->c_str (), "%*[^(]%*[^_]%[^)+]", temp)) {    std::unique_ptr<char, void(*)(void*)> demangled {      abi::__cxa_demangle (temp, NULL, &size, &status),      std::free    };    if (demangled.get ()) {      symbol->clear ();      symbol->append (demangled.get ());      return;    }  }  //if that didn't work, try to get a regular c symbol  if (1 == sscanf(symbol->c_str (), "%255s", temp)) {    symbol->clear ();    symbol->append (temp);  }}void GetStackTrace (std::string* stack){  void* addresses[MAX_FRAMES];  int size = backtrace (addresses, MAX_FRAMES);  std::unique_ptr<char*, void(*)(void*)> symbols {    backtrace_symbols (addresses, size),    std::free  };  for (int i = 0; i < size; ++i) {    std::string demangled (symbols.get()[i]);    DemangleSymbol (&demangled);    stack->append (demangled);    stack->append ("/n");  }}

// The prefix used for mangled symbols, per the Itanium C++ ABI:// http://www.codesourcery.com/cxx-abi/abi.html#manglingconst char kMangledSymbolPrefix[] = "_Z";// Characters that can be used for symbols, generated by Ruby:// (('a'..'z').to_a+('A'..'Z').to_a+('0'..'9').to_a + ['_']).joinconst char kSymbolCharacters[] = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_";// Demangles C++ symbols in the given text. Example:// "out/Debug/base_unittests(_ZN10StackTraceC1Ev+0x20) [0x817778c]"// =>// "out/Debug/base_unittests(StackTrace::StackTrace()+0x20) [0x817778c]"void DemangleSymbol (std::string* symbol){  std::string::size_type search_from = 0;  while (search_from < symbol->size ()) {    // Look for the start of a mangled symbol from search_from    std::string::size_type mangled_start = symbol->find (kMangledSymbolPrefix, search_from);    if (mangled_start == std::string::npos) {      break; // Mangled symbol not found    }    // Look for the end of the mangled symbol    std::string::size_type mangled_end = symbol->find_first_not_of (kSymbolCharacters, mangled_start);    if (mangled_end == std::string::npos) {      mangled_end = symbol->size ();    }    std::string mangled_symbol = std::move (symbol->substr (mangled_start, mangled_end - mangled_start));    // Try to demangle the mangled symbol candidate    int status = -4; // some arbitrary value to eliminate the compiler warning    std::unique_ptr<char, void(*)(void*)> demangled_symbol {      abi::__cxa_demangle (mangled_symbol.c_str (), nullptr, 0, &status),      std::free    };    // 0 Demangling is success    if (0 == status) {      // Remove the mangled symbol      symbol->erase (mangled_start, mangled_end - mangled_start);      // Insert the demangled symbol      symbol->insert (mangled_start, demangled_symbol.get ());      // Next time, we will start right after the demangled symbol      search_from = mangled_start + strlen (demangled_symbol.get ());    }    else {      // Failed to demangle. Retry after the "_Z" we just found      search_from = mangled_start + 2;    }  }}