嘗試關閉SSL套接字時使用boost asio 1.64的分段錯誤（SIGSEGV）

Question

我不明白如何關閉boost::asio ssl套接字。 我已經嘗試了幾種方法，但是總會在某些時候出現Segmentation fault 。

我一直在閱讀以下文章來解決這種情況： boost asio ssl async_shutdown總是以錯誤結束嗎？

具體來說，我正在嘗試實施

甲方發起shutdown（）並等待乙方以shutdown（）響應

請注意，客戶端和服務器都在localhost中運行。

下面是客戶端代碼：

typedef boost::asio::ssl::stream<boost::asio::ip::tcp::socket> SSLSocket;

MyClass::MyClass(const std::string &url,
    const std::string &port) throw() :
    m_socket(NULL), m_url(url), m_port(port), m_isConnected(false)
{
}

void MyClass::disconnect()
{
  // See the section "the disconnect method"
}

bool MyClass::tryConnect() throw()
{ 
  boost::asio::io_service ioService;
  boost::asio::ssl::context ctx(boost::asio::ssl::context::sslv23);
  m_socket = new SSLSocket(ioService, ctx);

  tcp::resolver resolver(ioService);
  tcp::resolver::query query(m_url, m_port);

  tcp::resolver::iterator end;
  tcp::resolver::iterator endpoint_iterator = resolver.resolve(query);

  boost::system::error_code error = boost::asio::error::host_not_found;
  boost::asio::connect(m_socket->lowest_layer(), endpoint_iterator, error);

  if(endpoint_iterator == end || error)
  {
    m_isConnected = false;
  }
  else
  {
    m_socket->set_verify_mode(boost::asio::ssl::verify_none);
    m_socket->handshake(SSLSocket::client);

    m_isConnected = true;
  }

  return m_isConnected;
}

void MyClass::write(const std::string &message)
{
  boost::asio::write(*m_socket, boost::asio::buffer(message));
}

std::string MyClass::readUntil(const std::string &until)
{
  boost::asio::read_until(*m_socket, response, until);
  ...
  return response;
}

int main()
{
  MyClass mc(...);

  while(true)
  {
    bool connected = mc.isConnected();

    if(!connected)
    {
      connected = mc.tryConnect();
    }

    if(connected)
    {
      mc.send(...);
      std::string resp = mc.readUntil(...);
      mc.disconnect();
    }
  }
}

斷開方法

我已閱讀評論中鏈接的帖子，並且更新了ssl服務器和客戶端。 現在，他們兩個都執行shutdown()操作以正確關閉ssl連接，但是關閉套接字時我仍然出錯。

我已經更新了disconnect()方法（它總是在程序崩潰的地方），如下所示：

...
boost::asio::ssl::stream<boost::asio::ip::tcp::socket> *m_socket;
...
void MyClass::disconnect()
{
  // Shutdown the connection
  // TODO is this the correct way to close a boost asio socket?
  if(m_socket != NULL)
  {
    std::cout << "shutting down the socket, thread = " <<
        pthread_self() << std::endl;

    // I have checked that the thread is always the same, so the problem 
    // is not related with race conditions or similar.

    boost::system::error_code ec;
    m_socket->lowest_layer().shutdown(
        boost::asio::ip::tcp::socket::shutdown_both, ec);

    std::cout <<
        "Shut down, err = " << ec << ", " <<
        "Category: " << ec.category().name() << std::endl;

    if(!ec)
    {
      std::cout << "closing the socket, thread = " <<
         pthread_self() << std::endl;

      if(m_socket->lowest_layer().is_open())
      {
        m_socket->lowest_layer().close(ec);
      }

      std::cout <<
        "Socket closed, err = " << ec << ", " <<  "Category: " <<
        ec.category().name() << std::endl;

      if(!ec)
      {
        std::cout << "Deleting socket... " << std::endl;
        delete m_socket;
        m_socket = NULL;
        std::cout << "Socket deleted" << std::endl;
      }
    }
  }

  m_isConnected = false;
}

錯誤回溯

bkactrace（來自斷開連接方法）在這里：

#0  0x4158114f in boost::system::error_code::operator=<boost::asio::error::basic_errors> (this=0x1d, val=boost::asio::error::operation_aborted)
    at .../include/boost/system/error_code.hpp:344
#1  0x41587308 in boost::asio::detail::epoll_reactor::deregister_descriptor (this=0x46463045, descriptor=27, descriptor_data=@0x812ef14: 0x8151ea8, 
    closing=true) at .../include/boost/asio/detail/impl/epoll_reactor.ipp:351
#2  0x41588550 in boost::asio::detail::reactive_socket_service_base::close (this=0x812efbc, impl=..., ec=...)
    at .../include/boost/asio/detail/impl/reactive_socket_service_base.ipp:104
#3  0x415885da in boost::asio::stream_socket_service<boost::asio::ip::tcp>::close (this=0x812efa8, impl=..., ec=...)
    at .../include/boost/asio/stream_socket_service.hpp:174
#4  0x41588630 in boost::asio::basic_socket<boost::asio::ip::tcp, boost::asio::stream_socket_service<boost::asio::ip::tcp> >::close (this=0x812ef08, ec=...)
    at .../include/boost/asio/basic_socket.hpp:385
#5  0x41576383 in MyClass::disconnect (this=0x80a6f58) at ...

檢查frame 1 ，可以看出boost正在產生的錯誤是boost::asio::error::operation_aborted;

另外，使用gdb和simetimes運行進程時，我看到以下斷言失敗 ：

pthread_mutex_lock.c:312: __pthread_mutex_lock_full: Assertion `(-(e)) != 3 || !robust' failed.

Answer 1

我發現了問題。

我正在用以下方法打開套接字：

void connect()
{
  ...
  boost::asio::io_service m_ioService
  ...
  m_sock = new SSLSocket(m_ioService, ...)
}

當connect方法返回時， m_ioService不在范圍內，因此由於ioService被刪除，套接字崩潰。 注意， m_ioService是通過引用傳遞的，此外，它是不可復制的。