我有两个线程,mainThread
和 recvThread
。
在 recvThread
上,我调用了 SSL_read(ssl, readBuffer, sizeof(readBuffer))
。这会阻塞线程,直到接收到数据。
然后,在 mainThread
上,我被告知需要发送一些数据。因此,我调用了 SSL_write(ssl, someData, sizeof(someData))
。
有时,这工作正常。其他时候,这会失败并出现奇怪的内部错误消息。我的猜测是,当在同一 ssl
上下文中发生 SSL_read 时,我无法调用 SSL_write。这对我来说很有意义,但我该如何解决呢?
我是否让 recvThread
做类似的事情:
SSL * ssl;
std::string data;
boost::mutex dataMutex;
while (recvThreadShouldBeRunning) {
char readBuffer[100];
auto nRead = SSL_read(ssl, readBuffer, sizeof(readBuffer)); //Non-blocking call to SSL_read.
// Do something with nRead (handle errors, use data)
{
auto dataLock = boost::unique_lock<boost::mutex>(dataMutex);
if (data.length() > 0)
{
SSL_write(ssl, data.c_str(), data.length());
}
}
sleep(50);
}
然后当我需要发送一些东西时...
{
auto dataLock = boost::unique_lock<boost::mutex>(dataMutex);
data = "some data";
}
这似乎可行,但我认为这对我的问题来说是一个相当丑陋的解决方案。有没有办法以某种方式SSL_lock()
SSL_wait_on_data()
SSL_unlock()
?或者这是解决问题的最佳方法?
解决这类问题的标准方法是什么?
感谢您的宝贵时间。
最佳答案
文档中的引述似乎包含了答案:
OpenSSL can safely be used in multi-threaded applications provided that at least two callback functions are set, locking_function and threadid_func.
locking_function(int mode, int n, const char *file, int line)
is needed to perform locking on shared data structures. (Note that OpenSSL uses a number of global data structures that will be implicitly shared whenever multiple threads use OpenSSL.) Multi-threaded applications will crash at random if it is not set.
locking_function()
must be able to handle up toCRYPTO_num_locks()
different mutex locks. It sets the n-th lock ifmode
&CRYPTO_LOCK
, and releases it otherwise.
file
andline
are the file number of the function setting the lock. They can be useful for debugging.
The example of using the locking-related functions (github) :
crypto/threads/mttest.c shows examples of the callback functions on Solaris, Irix and Win32.
关于c++ - SSL 读取和 SSL 同时写入,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/21527206/