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我正在实现一个使用boost::asio实现TLS连接库的类。boost :: asio io_service :: run_one导致分段错误
我只实现同步操作，其中一些接受超时。 我实现使用deadline_timer和io_service.run_one超时方法，如在本实施例中说明：http://www.boost.org/doc/libs/1_45_0/doc/html/boost_asio/example/timeouts/async_tcp_client.cpp
我的问题是与从插座读取准确“n”个字节，并接受一个超时作为参数的方法。问题是io_service.run_one()正在筹集SIGSEV，我不知道为什么。下面是代码（这是这么长时间，但我不知道有什么别的更好的办法来解释这一点）：
代码
下面是参与测试的方法，我执行：
void CMDRboostConnection::check_deadline()
{
// Check whether the deadline has passed. We compare the deadline against
// the current time since a new asynchronous operation may have moved the
// deadline before this actor had a chance to run.
if (m_timeoutOpsTimer->expires_at() <= boost::asio::deadline_timer::traits_type::now())
{
// TODO do I need to cancel async operations?
m_timeoutOpsErrorCode = boost::asio::error::timed_out;
// There is no longer an active deadline. The expiry is set to positive
// infinity so that the actor takes no action until a new deadline is set.
m_timeoutOpsTimer->expires_at(boost::posix_time::pos_infin);
}
// Put the actor back to sleep.
m_timeoutOpsTimer->async_wait(
boost::bind(&CMDRboostConnection::check_deadline, this));
}
bool CMDRboostConnection::connect()
{
// TODO: This method already throws an exception, it should be void.
DEBUG("Connecting to " + m_url + " : " + m_port);
try
{
// If the socket is already connected, disconnect it before
// opening a new conneciont.
if (isConnected())
{
disconnect();
}
m_socket = new SSLSocket(m_ioService, m_context);
tcp::resolver resolver(m_ioService);
tcp::resolver::query query(m_url, m_port);
tcp::resolver::iterator end;
tcp::resolver::iterator endpoint_iterator = resolver.resolve(query);
boost::asio::connect(m_socket->lowest_layer(), resolver.resolve(query));
if (endpoint_iterator == end)
{
DEBUG("Endpoint cannot be resolved, disconnecting...");
disconnect();
}
else
{
m_timeoutOpsTimer = new boost::asio::deadline_timer(m_ioService);
m_timeoutOpsTimer->expires_at(boost::posix_time::pos_infin);
// Start the persistent actor that checks for deadline expiry.
check_deadline();
DEBUG("Endpoint resolved, performing handshake");
m_socket->set_verify_mode(boost::asio::ssl::verify_none);
m_socket->handshake(SSLSocket::client);
DEBUG("Handshake done, connected to " + m_url + " : " + m_port);
m_isConnected = true;
}
}
catch (boost::system::system_error &err)
{
disconnect();
throw;
}
return m_isConnected;
}
std::streambuf& CMDRboostConnection::readNBytes(int n, unsigned int timeout)
{
try
{
if(!isConnected())
{
std::string err = "Cannot read, not connected";
ERROR(err);
throw std::logic_error(err);
}
if(n == 0)
{
return m_buffer;
}
m_timeoutOpsTimer->expires_from_now(
boost::posix_time::milliseconds(timeout));
m_timeoutOpsErrorCode = boost::asio::error::would_block;
boost::asio::async_read(
*m_socket,
m_buffer,
boost::asio::transfer_exactly(n),
boost::bind(
&CMDRboostConnection::timoutOpsCallback,
this,
boost::asio::placeholders::error,
boost::asio::placeholders::bytes_transferred)
);
do
{
m_ioService.run_one();
} while (m_timeoutOpsErrorCode == boost::asio::error::would_block);
if(m_timeoutOpsErrorCode)
{
throw boost::system::system_error(m_timeoutOpsErrorCode);
}
return m_buffer;
}
catch(boost::system::system_error &err)
{
ERROR("Timeout reached trying to read a message");
disconnect();
throw;
}
}
void CMDRboostConnection::disconnect()
{
try
{
DEBUG("Disconnecting...");
if(isConnected())
{
m_socket->shutdown();
DEBUG("Closing socket...");
m_socket->lowest_layer().close();
if(m_socket != NULL)
{
delete m_socket;
m_socket = NULL;
}
}
if(m_timeoutOpsTimer != NULL)
{
delete m_timeoutOpsTimer;
m_timeoutOpsTimer = NULL;
}
DEBUG("Disconnection performed properly");
m_isConnected = false;
}
catch (boost::system::system_error &err)
{
ERROR("Exception thrown, error = " << err.code() <<
", category: " << err.code().category().name() << std::endl);
m_isConnected = false;
throw;
}
}
测试
下面是我运行测试方法测试：
TEST(CMDRboostConnection, readNbytesTimeoutDoesNotMakeTheProgramCrashWhenTmeout)
{
std::auto_ptr<CMDR::SSL::ICMDRsslConnection> m_connection =
std::auto_ptr<CMDR::SSL::ICMDRsslConnection>(
new CMDR::SSL::CMDRboostConnection("localhost", "9999"));
unsigned int sleepInterval = 0; // seconds
unsigned int timeout = 10; // milliseconds
unsigned int numIterations = 10;
std::string msg("delay 500000"); // microseconds
if(!m_connection->isConnected())
{
m_connection->connect();
}
for(unsigned int i = 0; i < numIterations; i++)
{
if(!m_connection->isConnected())
{
m_connection->connect();
}
ASSERT_NO_THROW(m_connection->write(msg));
ASSERT_THROW (
m_connection->readNBytes(msg.size(), timeout),
boost::system::system_error);
ASSERT_FALSE(m_connection->isConnected());
ASSERT_NO_THROW(m_connection->connect());
sleep(sleepInterval);
}
}
问题
在上面的测试中，第一次循环迭代成功，也就是第一次调用方法readNBytes时，它工作（按预期引发异常）。第二次执行时，会引发SIGSEV。
编辑
我执行等来测试其他功能上面的测试。我意识到，如果我只执行上述测试，它就可以工作。但是，如果我另外执行它，那么程序会崩溃，并提到SIGSEV。
这是导致问题的测试之一：
TEST(CMDRboostConnection, canConnectDisconnect)
{
std::auto_ptr<CMDR::SSL::ICMDRsslConnection> m_connection =
std::auto_ptr<CMDR::SSL::ICMDRsslConnection>(
new CMDR::SSL::CMDRboostConnection("localhost", "9999"));
unsigned int sleepInterval = 0; // seconds
unsigned int timeout = 1000; // milliseconds
unsigned int numIterations = 10;
std::string msg("normally");
if(!m_connection->isConnected())
{
ASSERT_NO_THROW (m_connection->connect());
}
for(unsigned int i = 0; i < numIterations; i++)
{
ASSERT_NO_THROW(m_connection->disconnect());
sleep(sleepInterval);
ASSERT_NO_THROW(m_connection->connect());
}
}
总之，如果我执行上述两种测试，第一个崩溃。但是如果我只执行第一个，它就会起作用。
编辑2 修正了评论中提到的错误。
我可以'现在既不使用C++ 11也不使用智能ptrs，但是我意识到我的原始ptrs比'auto_ptr' – Dan