* Copyright (c) 2021 The NetBSD Foundation, Inc.

/* $NetBSD: t_empty.c,v 1.2 2024/08/23 07:13:50 rin Exp $ */

/*-
* Copyright (c) 2021 The NetBSD Foundation, Inc.
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``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 FOUNDATION OR CONTRIBUTORS
* 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 <sys/cdefs.h>
__RCSID("$NetBSD: t_empty.c,v 1.2 2024/08/23 07:13:50 rin Exp $");

#include <sys/event.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <sys/types.h>

#include <netinet/in.h>

#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

#include <atf-c.h>

static void
test_empty(int readfd, int writefd, bool is_tcp)
{
struct timespec ts = { 0, 0 };
struct kevent event;
int kq, error, sndbufsize;
char buf[1024] = { 0 };
ssize_t rv;

ATF_REQUIRE((kq = kqueue()) >= 0);

EV_SET(&event, writefd, EVFILT_EMPTY, EV_ADD, 0, 0, NULL);
ATF_REQUIRE(kevent(kq, &event, 1, NULL, 0, NULL) == 0);

/* Check that EMPTY is true. */
memset(&event, 0, sizeof(event));
ATF_REQUIRE(kevent(kq, NULL, 0, &event, 1, &ts) == 1);
ATF_REQUIRE(event.ident == (uintptr_t)writefd);
ATF_REQUIRE(event.filter == EVFILT_EMPTY);

if (is_tcp) {
/*
* Get the write socket buffer size so that we can set
* the read socket buffer size to something larger
* later on.
*/
socklen_t slen = sizeof(sndbufsize);
ATF_REQUIRE(getsockopt(writefd, SOL_SOCKET,
SO_SNDBUF, &sndbufsize, &slen) == 0);

/*
* Set the receive buffer size to 1, slamming shut
* the TCP receive window, thus trapping all of the
* data in the sender's queue.
*/
int val = 1;
ATF_REQUIRE(setsockopt(readfd, SOL_SOCKET,
SO_RCVBUF, &val, sizeof(val)) == 0);
}

/* Write until the write buffer is full. */
for (rv = 0; rv != -1;) {
rv = write(writefd, buf, sizeof(buf));
error = errno;
ATF_REQUIRE(rv > 0 || (rv == -1 && error == EAGAIN));
}

/* Check that EMPTY is false. */
ATF_REQUIRE(kevent(kq, NULL, 0, &event, 1, &ts) == 0);

if (is_tcp) {
/*
* Set the receive buffer size to something larger than
* the sender's send buffer.
*/
int val = sndbufsize + 128;
ATF_REQUIRE(setsockopt(readfd, SOL_SOCKET,
SO_RCVBUF, &val, sizeof(val)) == 0);
}

/* Read all of the data that's available. */
for (rv = 0; rv != -1;) {
rv = read(readfd, buf, sizeof(buf));
error = errno;
ATF_REQUIRE(rv > 0 || (rv == -1 && error == EAGAIN));
}

/*
* Check that EMPTY is true. Check a few times (TCP might
* not drain immediately).
*/
if (is_tcp) {
for (rv = 0; rv < 5; rv++) {
if (kevent(kq, NULL, 0, &event, 1, &ts) == 1) {
break;
}
}
sleep(1);
}
memset(&event, 0, sizeof(event));
ATF_REQUIRE(kevent(kq, NULL, 0, &event, 1, &ts) == 1);
ATF_REQUIRE(event.ident == (uintptr_t)writefd);
ATF_REQUIRE(event.filter == EVFILT_EMPTY);
}

ATF_TC(sock_tcp);
ATF_TC_HEAD(sock_tcp, tc)
{
atf_tc_set_md_var(tc, "descr",
"Test EVFILT_EMPTY with TCP sockets.");
}

ATF_TC_BODY(sock_tcp, tc)
{
int readsock, writesock;
socklen_t slen;

ATF_REQUIRE((readsock =
socket(PF_INET, SOCK_STREAM | SOCK_NONBLOCK, IPPROTO_TCP)) != -1);
ATF_REQUIRE((writesock =
socket(PF_INET, SOCK_STREAM | SOCK_NONBLOCK, IPPROTO_TCP)) != -1);

struct sockaddr_in sin = {
.sin_len = sizeof(sin),
.sin_family = AF_INET,
.sin_port = 0, /* no need to swap 0 */
.sin_addr = { .s_addr = htonl(INADDR_LOOPBACK) },
};
ATF_REQUIRE(bind(readsock, (struct sockaddr *)&sin,
sizeof(sin)) == 0);
ATF_REQUIRE(listen(readsock, 1) == 0);
slen = sizeof(sin);
ATF_REQUIRE(getsockname(readsock, (struct sockaddr *)&sin, &slen) == 0);

ATF_REQUIRE_ERRNO(EINPROGRESS,
connect(writesock, (struct sockaddr *)&sin, sizeof(sin)) == -1);

/* XXX Avoid race between connect(2) and accept(2). */
sleep(1);

slen = sizeof(sin);
ATF_REQUIRE((readsock = accept(readsock, (struct sockaddr *)&sin,
&slen)) != -1);

test_empty(readsock, writesock, true);
}

ATF_TP_ADD_TCS(tp)
{
ATF_TP_ADD_TC(tp, sock_tcp);

return atf_no_error();
}