/*
 * Copyright (c) 2014-2015 Dmitry V. Levin <ldv@altlinux.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <assert.h>
#include <stddef.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/wait.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

int main(void)
{
	static const char data[] = "data";
	const size_t size = sizeof(data) - 1;
	struct sockaddr_in addr;
	socklen_t len = sizeof(addr);
	pid_t pid;

	memset(&addr, 0, sizeof(addr));
	addr.sin_family = AF_INET;
	addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);

	close(0);
	close(1);

	if (socket(PF_INET, SOCK_STREAM, 0)) {
		perror("socket");
		return 77;
	}
	if (bind(0, (struct sockaddr *) &addr, len)) {
		perror("bind");
		return 77;
	}
	assert(listen(0, 5) == 0);

	memset(&addr, 0, sizeof(addr));
	assert(getsockname(0, (struct sockaddr *) &addr, &len) == 0);

	assert((pid = fork()) >= 0);

	if (pid) {
		char buf[sizeof(data)];
		int status;

		assert(accept(0, (struct sockaddr *) &addr, &len) == 1);
		assert(close(0) == 0);
		assert(recv(1, buf, sizeof(buf), MSG_WAITALL) == (int) size);
		assert(waitpid(pid, &status, 0) == pid);
		assert(status == 0);
		assert(close(1) == 0);
	} else {
		assert(close(0) == 0);
		assert(socket(PF_INET, SOCK_STREAM, 0) == 0);
		assert(connect(0, (struct sockaddr *) &addr, len) == 0);
		assert(send(0, data, size, MSG_DONTROUTE) == (int) size);
		assert(close(0) == 0);
	}

	return 0;
}