Re: Review Request 50936: Kept poll socket alive during 'send()' continuations.

[Greg Mann]

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This is an automatically generated e-mail. To reply, visit:
https://reviews.apache.org/r/50936/
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(Updated Aug. 9, 2016, 9:56 p.m.)


Review request for mesos, Benjamin Mahler, Joseph Wu, and Vinod Kone.


Bugs: MESOS-5988
    https://issues.apache.org/jira/browse/MESOS-5988


Repository: mesos


Description (updated)
-------

Currently, the poll socket implementation doesn't keep
the socket alive after `PollSocketImpl.send(data, length)`
passes execution off to a continuation. This patch passes
a shared pointer of the socket implementation along to the
continuation, keeping the socket alive.


Diffs
-----

  3rdparty/libprocess/src/poll_socket.cpp 
d14dd1ae210e112b917329803dfb09d98386b966 

Diff: https://reviews.apache.org/r/50936/diff/


Testing
-------

I was able to expose the poll socket bug with the following test case. It 
triggers a "Bad file descriptor" error after 100-200 repetitions on my OSX 
machine. After applying this patch, I can run the test thousands of times with 
no failures:

```
TEST(HTTPTest, ClosedSocketFailure)
{
  const Try<Socket> server_create = Socket::create();
  ASSERT_SOME(server_create);

  Socket server = server_create.get();
  LOG(INFO) << "*** server fd: " << server.get();

  Future<size_t> sent;
  Future<Socket> _socket;

  string data;
  for (auto i = 0; i < 26000; i++) {
    data += "abcdefghijklmnopqrstuvwxyz0123456789abcdefghijklmnopqrstuvwxyz012";
  }
  const char* data_cstr = data.c_str();

  {
    const Try<Socket> client_create = Socket::create();
    ASSERT_SOME(client_create);

    Socket client = client_create.get();
    LOG(INFO) << "*** client fd: " << client.get();

    const Try<Nothing> listen = server.listen(5);
    ASSERT_SOME(listen);

    const Try<Address> server_address = server.address();
    ASSERT_SOME(server_address);

    _socket = server.accept();

    const Future<Nothing> connect = client.connect(server_address.get());

    // Wait for the server to have accepted the client connection.
    AWAIT_ASSERT_READY(_socket);
    Socket socket = _socket.get(); // TODO(jmlvanre): Remove const copy.

    // Verify that the client also views the connection as established.
    AWAIT_ASSERT_READY(connect);

    // Send a message from the client to the server.
    sent = client.send(data_cstr, data.size());
    LOG(INFO) << "*** exiting scope";
  }

  AWAIT_READY(sent);

  LOG(INFO) << "*** exiting test case";
}
```


Thanks,

Greg Mann