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libzmq/tests/test_zmq_ppoll_fd.cpp
E. G. Patrick Bos 36e4c9b474
add zmq_ppoll
zmq_ppoll mostly mimics zmq_poll behavior, except for the added feature of being able to specify a signal mask. Signals in this mask will be blocked during execution of zmq_ppoll. Switching of the process' active signal mask happens atomically with the actual poll call, so that no race conditions can occur. This behavior is useful when one wants to gracefully handle POSIX signals without race conditions. See e.g. the discussion below https://250bpm.com/blog:12/ for an explanation.

Also includes two new tests:
1. test_zmq_ppoll_fd does the same thing as test_zmq_poll_fd, demonstrating backwards compatibility with zmq_poll when used with a default signal mask.
2. test_zmq_ppoll_signals demonstrates the use of zmq_ppoll with a signal mask, blocking out SIGTERM everywhere except in zmq_ppoll, allowing to handle the signal in one place without having to worry about race conditions.
2021-09-24 11:04:20 +02:00

91 lines
2.8 KiB
C++

/*
Copyright (c) 2021 Contributors as noted in the AUTHORS file
This file is part of libzmq, the ZeroMQ core engine in C++.
libzmq is free software; you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License (LGPL) as published
by the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
As a special exception, the Contributors give you permission to link
this library with independent modules to produce an executable,
regardless of the license terms of these independent modules, and to
copy and distribute the resulting executable under terms of your choice,
provided that you also meet, for each linked independent module, the
terms and conditions of the license of that module. An independent
module is a module which is not derived from or based on this library.
If you modify this library, you must extend this exception to your
version of the library.
libzmq is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
License for more details.
You should have received a copy of the GNU Lesser General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "testutil.hpp"
#include "testutil_unity.hpp"
#include <string.h>
#ifndef _WIN32
#include <netdb.h>
#include <unistd.h>
#endif
SETUP_TEARDOWN_TESTCONTEXT
void test_ppoll_fd ()
{
#ifdef ZMQ_HAVE_PPOLL
int recv_socket = socket (AF_INET, SOCK_DGRAM, IPPROTO_UDP);
TEST_ASSERT_NOT_EQUAL (-1, recv_socket);
int flag = 1;
TEST_ASSERT_SUCCESS_ERRNO (
setsockopt (recv_socket, SOL_SOCKET, SO_REUSEADDR, &flag, sizeof (int)));
struct sockaddr_in saddr = bind_bsd_socket (recv_socket);
void *sb = test_context_socket (ZMQ_REP);
TEST_ASSERT_SUCCESS_ERRNO (zmq_bind (sb, "tcp://127.0.0.1:*"));
zmq_pollitem_t pollitems[] = {
{sb, 0, ZMQ_POLLIN, 0},
{NULL, recv_socket, ZMQ_POLLIN, 0},
};
int send_socket = socket (AF_INET, SOCK_DGRAM, IPPROTO_UDP);
TEST_ASSERT_NOT_EQUAL (-1, send_socket);
char buf[10];
memset (buf, 1, 10);
TEST_ASSERT_SUCCESS_ERRNO (sendto (
send_socket, buf, 10, 0, (struct sockaddr *) &saddr, sizeof (saddr)));
TEST_ASSERT_EQUAL (1, zmq_ppoll (pollitems, 2, 1, NULL));
TEST_ASSERT_BITS_LOW (ZMQ_POLLIN, pollitems[0].revents);
TEST_ASSERT_BITS_HIGH (ZMQ_POLLIN, pollitems[1].revents);
test_context_socket_close (sb);
close (send_socket);
close (recv_socket);
#else
TEST_IGNORE_MESSAGE ("libzmq without zmq_ppoll, ignoring test");
#endif // ZMQ_HAVE_PPOLL
}
int main ()
{
UNITY_BEGIN ();
RUN_TEST (test_ppoll_fd);
return UNITY_END ();
}