/* $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();
}