/* $NetBSD: t_fifo.c,v 1.5 2021/10/02 18:39:15 thorpej Exp $ */

/*-
* Copyright (c) 2021 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Jason R. Thorpe.
*
* 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>
__COPYRIGHT("@(#) Copyright (c) 2021\
The NetBSD Foundation, inc. All rights reserved.");
__RCSID("$NetBSD: t_fifo.c,v 1.5 2021/10/02 18:39:15 thorpej Exp $");

#include <sys/event.h>
#include <sys/stat.h>

#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <inttypes.h>

#include <atf-c.h>

static const char       fifo_path[] = "fifo";

static void
fifo_support(void)
{
       errno = 0;
       if (mkfifo(fifo_path, 0600) == 0) {
               ATF_REQUIRE(unlink(fifo_path) == 0);
               return;
       }

       if (errno == EOPNOTSUPP) {
               atf_tc_skip("the kernel does not support FIFOs");
       } else {
               atf_tc_fail("mkfifo(2) failed");
       }
}

ATF_TC_WITH_CLEANUP(fifo);
ATF_TC_HEAD(fifo, tc)
{
       atf_tc_set_md_var(tc, "descr", "Checks EVFILT_WRITE on fifo");
}
ATF_TC_BODY(fifo, tc)
{
       const struct timespec to = { 0, 0 };
       struct kevent event[1];
       char *buf;
       int rfd, wfd, kq;
       long pipe_buf;

       fifo_support();

       ATF_REQUIRE(mkfifo(fifo_path, 0600) == 0);
       ATF_REQUIRE((rfd = open(fifo_path, O_RDONLY | O_NONBLOCK)) >= 0);
       ATF_REQUIRE((wfd = open(fifo_path, O_WRONLY | O_NONBLOCK)) >= 0);
       ATF_REQUIRE((kq = kqueue()) >= 0);

       /* Get the maximum atomic pipe write size. */
       pipe_buf = fpathconf(wfd, _PC_PIPE_BUF);
       ATF_REQUIRE(pipe_buf > 1);

       buf = malloc(pipe_buf);
       ATF_REQUIRE(buf != NULL);

       EV_SET(&event[0], wfd, EVFILT_WRITE, EV_ADD|EV_ENABLE, 0, 0, 0);
       ATF_REQUIRE(kevent(kq, event, 1, NULL, 0, NULL) == 0);

       /* We expect the FIFO to be writable. */
       ATF_REQUIRE(kevent(kq, NULL, 0, event, 1, &to) == 1);
       ATF_REQUIRE(event[0].ident == (uintptr_t)wfd);
       ATF_REQUIRE(event[0].filter == EVFILT_WRITE);

       /*
        * Write data into the FIFO until it is full, which is
        * defined as insufficient buffer space to hold the
        * maximum atomic pipe write size.
        */
       while (write(wfd, buf, pipe_buf) != -1) {
               continue;
       }
       ATF_REQUIRE(errno == EAGAIN);

       /* We expect the FIFO to no longer be writable. */
       ATF_REQUIRE(kevent(kq, NULL, 0, event, 1, &to) == 0);

       /* Read a single byte of data from the FIFO. */
       ATF_REQUIRE(read(rfd, buf, 1) == 1);

       /*
        * Because we have read only a single byte out, there will
        * be insufficient space for a pipe_buf-sized message, so
        * the FIFO should still not be writable.
        */
       ATF_REQUIRE(kevent(kq, NULL, 0, event, 1, &to) == 0);

       /*
        * Now read enough so that exactly pipe_buf space should be
        * available.  The FIFO should be writable after that.
        */
       ATF_REQUIRE(read(rfd, buf, pipe_buf - 1) == pipe_buf - 1);
       ATF_REQUIRE(kevent(kq, NULL, 0, event, 1, &to) == 1);
       ATF_REQUIRE(event[0].ident == (uintptr_t)wfd);
       ATF_REQUIRE(event[0].filter == EVFILT_WRITE);

       (void)close(wfd);
       (void)close(rfd);
       (void)close(kq);
}

ATF_TC_CLEANUP(fifo, tc)
{
       (void)unlink(fifo_path);
}

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

       return atf_no_error();
}