4 files changed, 798 insertions, 0 deletions

diff --git a/tests/sys/fifo/Makefile b/tests/sys/fifo/Makefile
index 602bf1ed29403..ea67241f4b9a5 100644
--- a/tests/sys/fifo/Makefile
+++ b/tests/sys/fifo/Makefile
@@ -4,6 +4,7 @@ TESTSDIR=	${TESTSBASE}/sys/fifo
 
 PLAIN_TESTS_C+=	fifo_create
 PLAIN_TESTS_C+=	fifo_io
+ATF_TESTS_C+=	fifo_kqueue
 PLAIN_TESTS_C+=	fifo_misc
 PLAIN_TESTS_C+=	fifo_open
 
diff --git a/tests/sys/fifo/fifo_kqueue.c b/tests/sys/fifo/fifo_kqueue.c
new file mode 100644
index 0000000000000..a2ddafd62eae3
--- /dev/null
+++ b/tests/sys/fifo/fifo_kqueue.c
@@ -0,0 +1,430 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+ *
+ * Copyright (c) 2020 Jan Kokemüller
+ *
+ * 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 AUTHOR 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 AUTHOR 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>
+__FBSDID("$FreeBSD$");
+
+#include <sys/param.h>
+#include <sys/event.h>
+#include <sys/stat.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <poll.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include <unistd.h>
+
+#include <atf-c.h>
+
+ATF_TC_WITHOUT_HEAD(fifo_kqueue__writes);
+ATF_TC_BODY(fifo_kqueue__writes, tc)
+{
+	int p[2] = { -1, -1 };
+
+	ATF_REQUIRE(mkfifo("testfifo", 0600) == 0);
+
+	ATF_REQUIRE((p[0] = open("testfifo",
+	    O_RDONLY | O_CLOEXEC | O_NONBLOCK)) >= 0);
+	ATF_REQUIRE((p[1] = open("testfifo",
+	    O_WRONLY | O_CLOEXEC | O_NONBLOCK)) >= 0);
+
+	int kq = kqueue();
+	ATF_REQUIRE(kq >= 0);
+
+	struct kevent kev[32];
+	EV_SET(&kev[0], p[1], EVFILT_WRITE, EV_ADD | EV_CLEAR, 0, 0, 0);
+	EV_SET(&kev[1], p[1], EVFILT_READ, EV_ADD | EV_CLEAR, 0, 0, 0);
+
+	ATF_REQUIRE(kevent(kq, kev, 2, NULL, 0, NULL) == 0);
+
+	/* A new writer should immediately get a EVFILT_WRITE event. */
+
+	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev),
+	    &(struct timespec) { 0, 0 }) == 1);
+	ATF_REQUIRE(kev[0].ident == (uintptr_t)p[1]);
+	ATF_REQUIRE(kev[0].filter == EVFILT_WRITE);
+	ATF_REQUIRE(kev[0].flags == EV_CLEAR);
+	ATF_REQUIRE(kev[0].fflags == 0);
+	ATF_REQUIRE(kev[0].data == 16384);
+	ATF_REQUIRE(kev[0].udata == 0);
+
+	/* Filling up the pipe should make the EVFILT_WRITE disappear. */
+
+	char c = 0;
+	ssize_t r;
+	while ((r = write(p[1], &c, 1)) == 1) {
+	}
+	ATF_REQUIRE(r < 0);
+	ATF_REQUIRE(errno == EAGAIN || errno == EWOULDBLOCK);
+
+	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev),
+	    &(struct timespec) { 0, 0 }) == 0);
+
+	/* Reading (PIPE_BUF - 1) bytes will not trigger a EVFILT_WRITE yet. */
+
+	for (int i = 0; i < PIPE_BUF - 1; ++i) {
+		ATF_REQUIRE(read(p[0], &c, 1) == 1);
+	}
+
+	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev),
+	    &(struct timespec) { 0, 0 }) == 0);
+
+	/* Reading one additional byte triggers the EVFILT_WRITE. */
+
+	ATF_REQUIRE(read(p[0], &c, 1) == 1);
+
+	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev),
+	    &(struct timespec) { 0, 0 }) == 1);
+	ATF_REQUIRE(kev[0].ident == (uintptr_t)p[1]);
+	ATF_REQUIRE(kev[0].filter == EVFILT_WRITE);
+	ATF_REQUIRE(kev[0].flags == EV_CLEAR);
+	ATF_REQUIRE(kev[0].fflags == 0);
+	ATF_REQUIRE(kev[0].data == PIPE_BUF);
+	ATF_REQUIRE(kev[0].udata == 0);
+
+	/*
+	 * Reading another byte triggers the EVFILT_WRITE again with a changed
+	 * 'data' field.
+	 */
+
+	ATF_REQUIRE(read(p[0], &c, 1) == 1);
+
+	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev),
+	    &(struct timespec) { 0, 0 }) == 1);
+	ATF_REQUIRE(kev[0].ident == (uintptr_t)p[1]);
+	ATF_REQUIRE(kev[0].filter == EVFILT_WRITE);
+	ATF_REQUIRE(kev[0].flags == EV_CLEAR);
+	ATF_REQUIRE(kev[0].fflags == 0);
+	ATF_REQUIRE(kev[0].data == PIPE_BUF + 1);
+	ATF_REQUIRE(kev[0].udata == 0);
+
+	/*
+	 * Closing the read end should make a EV_EOF appear but leave the 'data'
+	 * field unchanged.
+	 */
+
+	ATF_REQUIRE(close(p[0]) == 0);
+
+	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev), NULL) == 1);
+	ATF_REQUIRE(kev[0].ident == (uintptr_t)p[1]);
+	ATF_REQUIRE(kev[0].filter == EVFILT_WRITE);
+	ATF_REQUIRE(kev[0].flags == (EV_CLEAR | EV_EOF));
+	ATF_REQUIRE(kev[0].fflags == 0);
+	ATF_REQUIRE(kev[0].data == PIPE_BUF + 1);
+	ATF_REQUIRE(kev[0].udata == 0);
+
+	ATF_REQUIRE(close(kq) == 0);
+	ATF_REQUIRE(close(p[1]) == 0);
+}
+
+ATF_TC_WITHOUT_HEAD(fifo_kqueue__connecting_reader);
+ATF_TC_BODY(fifo_kqueue__connecting_reader, tc)
+{
+	int p[2] = { -1, -1 };
+
+	ATF_REQUIRE(mkfifo("testfifo", 0600) == 0);
+
+	ATF_REQUIRE((p[0] = open("testfifo",
+	    O_RDONLY | O_CLOEXEC | O_NONBLOCK)) >= 0);
+	ATF_REQUIRE((p[1] = open("testfifo",
+	    O_WRONLY | O_CLOEXEC | O_NONBLOCK)) >= 0);
+
+	int kq = kqueue();
+	ATF_REQUIRE(kq >= 0);
+
+	struct kevent kev[32];
+	EV_SET(&kev[0], p[1], EVFILT_WRITE, EV_ADD | EV_CLEAR, 0, 0, 0);
+	EV_SET(&kev[1], p[1], EVFILT_READ, EV_ADD | EV_CLEAR, 0, 0, 0);
+
+	ATF_REQUIRE(kevent(kq, kev, 2, NULL, 0, NULL) == 0);
+
+	/* A new writer should immediately get a EVFILT_WRITE event. */
+
+	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev),
+	    &(struct timespec) { 0, 0 }) == 1);
+	ATF_REQUIRE(kev[0].ident == (uintptr_t)p[1]);
+	ATF_REQUIRE(kev[0].filter == EVFILT_WRITE);
+	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev),
+	    &(struct timespec) { 0, 0 }) == 0);
+
+	/*
+	 * Filling the pipe, reading (PIPE_BUF + 1) bytes, then closing the
+	 * read end leads to a EVFILT_WRITE with EV_EOF set.
+	 */
+
+	char c = 0;
+	ssize_t r;
+	while ((r = write(p[1], &c, 1)) == 1) {
+	}
+	ATF_REQUIRE(r < 0);
+	ATF_REQUIRE(errno == EAGAIN || errno == EWOULDBLOCK);
+
+	for (int i = 0; i < PIPE_BUF + 1; ++i) {
+		ATF_REQUIRE(read(p[0], &c, 1) == 1);
+	}
+
+	ATF_REQUIRE(close(p[0]) == 0);
+
+	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev), NULL) == 1);
+	ATF_REQUIRE(kev[0].filter == EVFILT_WRITE);
+	ATF_REQUIRE((kev[0].flags & EV_EOF) != 0);
+	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev),
+	    &(struct timespec) { 0, 0 }) == 0);
+
+	/* Opening the reader again must trigger the EVFILT_WRITE. */
+
+	ATF_REQUIRE((p[0] = open("testfifo",
+	    O_RDONLY | O_CLOEXEC | O_NONBLOCK)) >= 0);
+
+	r = kevent(kq, NULL, 0, kev, nitems(kev), &(struct timespec) { 1, 0 });
+	ATF_REQUIRE(r == 1);
+	ATF_REQUIRE(kev[0].ident == (uintptr_t)p[1]);
+	ATF_REQUIRE(kev[0].filter == EVFILT_WRITE);
+	ATF_REQUIRE(kev[0].flags == EV_CLEAR);
+	ATF_REQUIRE(kev[0].fflags == 0);
+	ATF_REQUIRE(kev[0].data == PIPE_BUF + 1);
+	ATF_REQUIRE(kev[0].udata == 0);
+	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev),
+	    &(struct timespec) { 0, 0 }) == 0);
+
+	ATF_REQUIRE(close(kq) == 0);
+	ATF_REQUIRE(close(p[0]) == 0);
+	ATF_REQUIRE(close(p[1]) == 0);
+}
+
+ATF_TC_WITHOUT_HEAD(fifo_kqueue__reads);
+ATF_TC_BODY(fifo_kqueue__reads, tc)
+{
+	int p[2] = { -1, -1 };
+
+	ATF_REQUIRE(mkfifo("testfifo", 0600) == 0);
+
+	ATF_REQUIRE((p[0] = open("testfifo",
+	    O_RDONLY | O_CLOEXEC | O_NONBLOCK)) >= 0);
+	ATF_REQUIRE((p[1] = open("testfifo",
+	    O_WRONLY | O_CLOEXEC | O_NONBLOCK)) >= 0);
+
+	/* Check that EVFILT_READ behaves sensibly on a FIFO reader. */
+
+	char c = 0;
+	ssize_t r;
+	while ((r = write(p[1], &c, 1)) == 1) {
+	}
+	ATF_REQUIRE(r < 0);
+	ATF_REQUIRE(errno == EAGAIN || errno == EWOULDBLOCK);
+
+	for (int i = 0; i < PIPE_BUF + 1; ++i) {
+		ATF_REQUIRE(read(p[0], &c, 1) == 1);
+	}
+
+	int kq = kqueue();
+	ATF_REQUIRE(kq >= 0);
+
+	struct kevent kev[32];
+	EV_SET(&kev[0], p[0], EVFILT_READ, EV_ADD | EV_CLEAR, 0, 0, 0);
+
+	ATF_REQUIRE(kevent(kq, kev, 1, NULL, 0, NULL) == 0);
+
+	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev),
+	    &(struct timespec) { 0, 0 }) == 1);
+	ATF_REQUIRE(kev[0].ident == (uintptr_t)p[0]);
+	ATF_REQUIRE(kev[0].filter == EVFILT_READ);
+	ATF_REQUIRE(kev[0].flags == EV_CLEAR);
+	ATF_REQUIRE(kev[0].fflags == 0);
+	ATF_REQUIRE(kev[0].data == 65023);
+	ATF_REQUIRE(kev[0].udata == 0);
+
+	while ((r = read(p[0], &c, 1)) == 1) {
+	}
+	ATF_REQUIRE(r < 0);
+	ATF_REQUIRE(errno == EAGAIN || errno == EWOULDBLOCK);
+
+	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev),
+	    &(struct timespec) { 0, 0 }) == 0);
+
+	ATF_REQUIRE(close(kq) == 0);
+	ATF_REQUIRE(close(p[0]) == 0);
+	ATF_REQUIRE(close(p[1]) == 0);
+}
+
+ATF_TC_WITHOUT_HEAD(fifo_kqueue__read_eof_wakeups);
+ATF_TC_BODY(fifo_kqueue__read_eof_wakeups, tc)
+{
+	int p[2] = { -1, -1 };
+
+	ATF_REQUIRE(mkfifo("testfifo", 0600) == 0);
+
+	ATF_REQUIRE((p[0] = open("testfifo",
+	    O_RDONLY | O_CLOEXEC | O_NONBLOCK)) >= 0);
+	ATF_REQUIRE((p[1] = open("testfifo",
+	    O_WRONLY | O_CLOEXEC | O_NONBLOCK)) >= 0);
+
+	int kq = kqueue();
+	ATF_REQUIRE(kq >= 0);
+
+	struct kevent kev[32];
+
+	EV_SET(&kev[0], p[0], EVFILT_READ, EV_ADD | EV_CLEAR, 0, 0, 0);
+	ATF_REQUIRE(kevent(kq, kev, 1, NULL, 0, NULL) == 0);
+
+	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev),
+	    &(struct timespec) { 0, 0 }) == 0);
+
+	/*
+	 * Closing the writer must trigger a EVFILT_READ edge with EV_EOF set.
+	 */
+
+	ATF_REQUIRE(close(p[1]) == 0);
+
+	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev),
+	    &(struct timespec) { 0, 0 }) == 1);
+	ATF_REQUIRE(kev[0].ident == (uintptr_t)p[0]);
+	ATF_REQUIRE(kev[0].filter == EVFILT_READ);
+	ATF_REQUIRE(kev[0].flags == (EV_EOF | EV_CLEAR));
+	ATF_REQUIRE(kev[0].fflags == 0);
+	ATF_REQUIRE(kev[0].data == 0);
+	ATF_REQUIRE(kev[0].udata == 0);
+
+	/*
+	 * Trying to read from a closed pipe should not trigger EVFILT_READ
+	 * edges.
+	 */
+
+	char c;
+	ATF_REQUIRE(read(p[0], &c, 1) == 0);
+
+	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev),
+	    &(struct timespec) { 0, 0 }) == 0);
+
+	ATF_REQUIRE(close(kq) == 0);
+	ATF_REQUIRE(close(p[0]) == 0);
+}
+
+ATF_TC_WITHOUT_HEAD(fifo_kqueue__read_eof_state_when_reconnecting);
+ATF_TC_BODY(fifo_kqueue__read_eof_state_when_reconnecting, tc)
+{
+	int p[2] = { -1, -1 };
+
+	ATF_REQUIRE(mkfifo("testfifo", 0600) == 0);
+
+	ATF_REQUIRE((p[0] = open("testfifo",
+	    O_RDONLY | O_CLOEXEC | O_NONBLOCK)) >= 0);
+	ATF_REQUIRE((p[1] = open("testfifo",
+	    O_WRONLY | O_CLOEXEC | O_NONBLOCK)) >= 0);
+
+	int kq = kqueue();
+	ATF_REQUIRE(kq >= 0);
+
+	struct kevent kev[32];
+
+	EV_SET(&kev[0], p[0], EVFILT_READ, EV_ADD | EV_CLEAR, 0, 0, 0);
+	ATF_REQUIRE(kevent(kq, kev, 1, NULL, 0, NULL) == 0);
+
+	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev),
+	    &(struct timespec) { 0, 0 }) == 0);
+
+	/*
+	 * Closing the writer must trigger a EVFILT_READ edge with EV_EOF set.
+	 */
+
+	ATF_REQUIRE(close(p[1]) == 0);
+
+	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev),
+	    &(struct timespec) { 0, 0 }) == 1);
+	ATF_REQUIRE(kev[0].ident == (uintptr_t)p[0]);
+	ATF_REQUIRE(kev[0].filter == EVFILT_READ);
+	ATF_REQUIRE(kev[0].flags == (EV_EOF | EV_CLEAR));
+	ATF_REQUIRE(kev[0].fflags == 0);
+	ATF_REQUIRE(kev[0].data == 0);
+	ATF_REQUIRE(kev[0].udata == 0);
+
+	/* A new reader shouldn't see the EOF flag. */
+
+	{
+		int new_reader;
+		ATF_REQUIRE((new_reader = open("testfifo",
+		    O_RDONLY | O_CLOEXEC | O_NONBLOCK)) >= 0);
+
+		int new_kq = kqueue();
+		ATF_REQUIRE(new_kq >= 0);
+
+		struct kevent new_kev[32];
+		EV_SET(&new_kev[0], new_reader, EVFILT_READ, EV_ADD | EV_CLEAR,
+		    0, 0, 0);
+		ATF_REQUIRE(kevent(new_kq, new_kev, 1, NULL, 0, NULL) == 0);
+
+		ATF_REQUIRE(kevent(new_kq, NULL, 0, new_kev, nitems(new_kev),
+		    &(struct timespec) { 0, 0 }) == 0);
+
+		ATF_REQUIRE(close(new_kq) == 0);
+		ATF_REQUIRE(close(new_reader) == 0);
+	}
+
+	/*
+	 * Simply reopening the writer does not trigger the EVFILT_READ again --
+	 * EV_EOF should be cleared, but there is no data yet so the filter
+	 * does not trigger.
+	 */
+
+	ATF_REQUIRE((p[1] = open("testfifo",
+	    O_WRONLY | O_CLOEXEC | O_NONBLOCK)) >= 0);
+
+	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev),
+	    &(struct timespec) { 0, 0 }) == 0);
+
+	/* Writing a byte should trigger a EVFILT_READ. */
+
+	char c = 0;
+	ATF_REQUIRE(write(p[1], &c, 1) == 1);
+
+	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev),
+	    &(struct timespec) { 0, 0 }) == 1);
+	ATF_REQUIRE(kev[0].ident == (uintptr_t)p[0]);
+	ATF_REQUIRE(kev[0].filter == EVFILT_READ);
+	ATF_REQUIRE(kev[0].flags == EV_CLEAR);
+	ATF_REQUIRE(kev[0].fflags == 0);
+	ATF_REQUIRE(kev[0].data == 1);
+	ATF_REQUIRE(kev[0].udata == 0);
+
+	ATF_REQUIRE(close(kq) == 0);
+	ATF_REQUIRE(close(p[0]) == 0);
+	ATF_REQUIRE(close(p[1]) == 0);
+}
+
+ATF_TP_ADD_TCS(tp)
+{
+	ATF_TP_ADD_TC(tp, fifo_kqueue__writes);
+	ATF_TP_ADD_TC(tp, fifo_kqueue__connecting_reader);
+	ATF_TP_ADD_TC(tp, fifo_kqueue__reads);
+	ATF_TP_ADD_TC(tp, fifo_kqueue__read_eof_wakeups);
+	ATF_TP_ADD_TC(tp, fifo_kqueue__read_eof_state_when_reconnecting);
+
+	return atf_no_error();
+}
diff --git a/tests/sys/kern/pipe/Makefile b/tests/sys/kern/pipe/Makefile
index bcd2d070cc8b6..193676465aa3b 100644
--- a/tests/sys/kern/pipe/Makefile
+++ b/tests/sys/kern/pipe/Makefile
@@ -5,6 +5,7 @@ TESTSDIR=	${TESTSBASE}/sys/kern/pipe
 PLAIN_TESTS_C+= big_pipe_test
 PLAIN_TESTS_C+= pipe_fstat_bug_test
 PLAIN_TESTS_C+= pipe_ino_test
+ATF_TESTS_C+=   pipe_kqueue_test
 PLAIN_TESTS_C+= pipe_overcommit1_test
 PLAIN_TESTS_C+= pipe_overcommit2_test
 PLAIN_TESTS_C+= pipe_reverse2_test
diff --git a/tests/sys/kern/pipe/pipe_kqueue_test.c b/tests/sys/kern/pipe/pipe_kqueue_test.c
new file mode 100644
index 0000000000000..8b644e75e3988
--- /dev/null
+++ b/tests/sys/kern/pipe/pipe_kqueue_test.c
@@ -0,0 +1,366 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+ *
+ * Copyright (c) 2020 Jan Kokemüller
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/param.h>
+#include <sys/event.h>
+#include <sys/stat.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <poll.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include <unistd.h>
+
+#include <atf-c.h>
+
+ATF_TC_WITHOUT_HEAD(pipe_kqueue__write_end);
+ATF_TC_BODY(pipe_kqueue__write_end, tc)
+{
+	int p[2] = { -1, -1 };
+
+	ATF_REQUIRE(pipe2(p, O_CLOEXEC | O_NONBLOCK) == 0);
+	ATF_REQUIRE(p[0] >= 0);
+	ATF_REQUIRE(p[1] >= 0);
+
+	int kq = kqueue();
+	ATF_REQUIRE(kq >= 0);
+
+	struct kevent kev[32];
+	EV_SET(&kev[0], p[1], EVFILT_WRITE, EV_ADD | EV_CLEAR, 0, 0, 0);
+
+	ATF_REQUIRE(kevent(kq, kev, 1, NULL, 0, NULL) == 0);
+
+	/* Test that EVFILT_WRITE behaves sensibly on the write end. */
+
+	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev),
+	    &(struct timespec) { 0, 0 }) == 1);
+	ATF_REQUIRE(kev[0].ident == (uintptr_t)p[1]);
+	ATF_REQUIRE(kev[0].filter == EVFILT_WRITE);
+	ATF_REQUIRE(kev[0].flags == EV_CLEAR);
+	ATF_REQUIRE(kev[0].fflags == 0);
+	ATF_REQUIRE(kev[0].data == 16384);
+	ATF_REQUIRE(kev[0].udata == 0);
+
+	/* Filling up the pipe should make the EVFILT_WRITE disappear. */
+
+	char c = 0;
+	ssize_t r;
+	while ((r = write(p[1], &c, 1)) == 1) {
+	}
+	ATF_REQUIRE(r < 0);
+	ATF_REQUIRE(errno == EAGAIN || errno == EWOULDBLOCK);
+
+	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev),
+	    &(struct timespec) { 0, 0 }) == 0);
+
+	/* Reading (PIPE_BUF - 1) bytes will not trigger a EVFILT_WRITE yet. */
+
+	for (int i = 0; i < PIPE_BUF - 1; ++i) {
+		ATF_REQUIRE(read(p[0], &c, 1) == 1);
+	}
+
+	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev),
+	    &(struct timespec) { 0, 0 }) == 0);
+
+	/* Reading one additional byte triggers the EVFILT_WRITE. */
+
+	ATF_REQUIRE(read(p[0], &c, 1) == 1);
+
+	r = kevent(kq, NULL, 0, kev, nitems(kev), &(struct timespec) { 0, 0 });
+	ATF_REQUIRE(r == 1);
+	ATF_REQUIRE(kev[0].ident == (uintptr_t)p[1]);
+	ATF_REQUIRE(kev[0].filter == EVFILT_WRITE);
+	ATF_REQUIRE(kev[0].flags == EV_CLEAR);
+	ATF_REQUIRE(kev[0].fflags == 0);
+	ATF_REQUIRE(kev[0].data == PIPE_BUF);
+	ATF_REQUIRE(kev[0].udata == 0);
+
+	/*
+	 * Reading another byte triggers the EVFILT_WRITE again with a changed
+	 * 'data' field.
+	 */
+
+	ATF_REQUIRE(read(p[0], &c, 1) == 1);
+
+	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev),
+	    &(struct timespec) { 0, 0 }) == 1);
+	ATF_REQUIRE(kev[0].ident == (uintptr_t)p[1]);
+	ATF_REQUIRE(kev[0].filter == EVFILT_WRITE);
+	ATF_REQUIRE(kev[0].flags == EV_CLEAR);
+	ATF_REQUIRE(kev[0].fflags == 0);
+	ATF_REQUIRE(kev[0].data == PIPE_BUF + 1);
+	ATF_REQUIRE(kev[0].udata == 0);
+
+	/*
+	 * Closing the read end should make a EV_EOF appear but leave the 'data'
+	 * field unchanged.
+	 */
+
+	ATF_REQUIRE(close(p[0]) == 0);
+
+	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev),
+	    &(struct timespec) { 0, 0 }) == 1);
+	ATF_REQUIRE(kev[0].ident == (uintptr_t)p[1]);
+	ATF_REQUIRE(kev[0].filter == EVFILT_WRITE);
+	ATF_REQUIRE(kev[0].flags == (EV_CLEAR | EV_EOF | EV_ONESHOT));
+	ATF_REQUIRE(kev[0].fflags == 0);
+	ATF_REQUIRE(kev[0].data == PIPE_BUF + 1);
+	ATF_REQUIRE(kev[0].udata == 0);
+
+	ATF_REQUIRE(close(kq) == 0);
+	ATF_REQUIRE(close(p[1]) == 0);
+}
+
+ATF_TC_WITHOUT_HEAD(pipe_kqueue__closed_read_end);
+ATF_TC_BODY(pipe_kqueue__closed_read_end, tc)
+{
+	int p[2] = { -1, -1 };
+
+	ATF_REQUIRE(pipe2(p, O_CLOEXEC | O_NONBLOCK) == 0);
+	ATF_REQUIRE(p[0] >= 0);
+	ATF_REQUIRE(p[1] >= 0);
+
+	ATF_REQUIRE(close(p[0]) == 0);
+
+	int kq = kqueue();
+	ATF_REQUIRE(kq >= 0);
+
+	struct kevent kev[32];
+	EV_SET(&kev[0], p[1], EVFILT_READ, EV_ADD | EV_CLEAR | EV_RECEIPT, /**/
+	    0, 0, 0);
+	EV_SET(&kev[1], p[1], EVFILT_WRITE, EV_ADD | EV_CLEAR | EV_RECEIPT, /**/
+	    0, 0, 0);
+
+	/*
+	 * Trying to register EVFILT_WRITE when the pipe is closed leads to an
+	 * EPIPE error.
+	 */
+
+	ATF_REQUIRE(kevent(kq, kev, 2, kev, 2, NULL) == 2);
+	ATF_REQUIRE((kev[0].flags & EV_ERROR) != 0);
+	ATF_REQUIRE(kev[0].data == 0);
+	ATF_REQUIRE((kev[1].flags & EV_ERROR) != 0);
+	ATF_REQUIRE(kev[1].data == EPIPE);
+
+	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev),
+	    &(struct timespec) { 0, 0 }) == 1);
+	ATF_REQUIRE(kev[0].ident == (uintptr_t)p[1]);
+	ATF_REQUIRE(kev[0].filter == EVFILT_READ);
+	ATF_REQUIRE(kev[0].flags == (EV_EOF | EV_CLEAR | EV_RECEIPT));
+	ATF_REQUIRE(kev[0].fflags == 0);
+	ATF_REQUIRE(kev[0].data == 0);
+	ATF_REQUIRE(kev[0].udata == 0);
+
+	ATF_REQUIRE(close(kq) == 0);
+	ATF_REQUIRE(close(p[1]) == 0);
+}
+
+ATF_TC_WITHOUT_HEAD(pipe_kqueue__closed_read_end_register_before_close);
+ATF_TC_BODY(pipe_kqueue__closed_read_end_register_before_close, tc)
+{
+	int p[2] = { -1, -1 };
+
+	ATF_REQUIRE(pipe2(p, O_CLOEXEC | O_NONBLOCK) == 0);
+	ATF_REQUIRE(p[0] >= 0);
+	ATF_REQUIRE(p[1] >= 0);
+
+	int kq = kqueue();
+	ATF_REQUIRE(kq >= 0);
+
+	struct kevent kev[32];
+	EV_SET(&kev[0], p[1], EVFILT_READ, EV_ADD | EV_CLEAR | EV_RECEIPT, /**/
+	    0, 0, 0);
+	EV_SET(&kev[1], p[1], EVFILT_WRITE, EV_ADD | EV_CLEAR | EV_RECEIPT, /**/
+	    0, 0, 0);
+
+	/*
+	 * Registering EVFILT_WRITE before the pipe is closed leads to a
+	 * EVFILT_WRITE event with EV_EOF set.
+	 */
+
+	ATF_REQUIRE(kevent(kq, kev, 2, kev, 2, NULL) == 2);
+	ATF_REQUIRE((kev[0].flags & EV_ERROR) != 0);
+	ATF_REQUIRE(kev[0].data == 0);
+	ATF_REQUIRE((kev[1].flags & EV_ERROR) != 0);
+	ATF_REQUIRE(kev[1].data == 0);
+
+	ATF_REQUIRE(close(p[0]) == 0);
+
+	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev),
+	    &(struct timespec) { 0, 0 }) == 2);
+	{
+		ATF_REQUIRE(kev[0].ident == (uintptr_t)p[1]);
+		ATF_REQUIRE(kev[0].filter == EVFILT_WRITE);
+		ATF_REQUIRE(kev[0].flags ==
+		    (EV_EOF | EV_CLEAR | EV_ONESHOT | EV_RECEIPT));
+		ATF_REQUIRE(kev[0].fflags == 0);
+		ATF_REQUIRE(kev[0].data == 16384);
+		ATF_REQUIRE(kev[0].udata == 0);
+	}
+	{
+		ATF_REQUIRE(kev[1].ident == (uintptr_t)p[1]);
+		ATF_REQUIRE(kev[1].filter == EVFILT_READ);
+		ATF_REQUIRE(kev[1].flags == (EV_EOF | EV_CLEAR | EV_RECEIPT));
+		ATF_REQUIRE(kev[1].fflags == 0);
+		ATF_REQUIRE(kev[1].data == 0);
+		ATF_REQUIRE(kev[1].udata == 0);
+	}
+
+	ATF_REQUIRE(close(kq) == 0);
+	ATF_REQUIRE(close(p[1]) == 0);
+}
+
+ATF_TC_WITHOUT_HEAD(pipe_kqueue__closed_write_end);
+ATF_TC_BODY(pipe_kqueue__closed_write_end, tc)
+{
+	int p[2] = { -1, -1 };
+
+	ATF_REQUIRE(pipe2(p, O_CLOEXEC | O_NONBLOCK) == 0);
+	ATF_REQUIRE(p[0] >= 0);
+	ATF_REQUIRE(p[1] >= 0);
+
+	char c = 0;
+	ssize_t r;
+	while ((r = write(p[1], &c, 1)) == 1) {
+	}
+	ATF_REQUIRE(r < 0);
+	ATF_REQUIRE(errno == EAGAIN || errno == EWOULDBLOCK);
+
+	ATF_REQUIRE(close(p[1]) == 0);
+
+	int kq = kqueue();
+	ATF_REQUIRE(kq >= 0);
+
+	struct kevent kev[32];
+	EV_SET(&kev[0], p[0], EVFILT_READ, EV_ADD | EV_CLEAR | EV_RECEIPT, /**/
+	    0, 0, 0);
+	EV_SET(&kev[1], p[0], EVFILT_WRITE, EV_ADD | EV_CLEAR | EV_RECEIPT, /**/
+	    0, 0, 0);
+
+	/*
+	 * Trying to register EVFILT_WRITE when the pipe is closed leads to an
+	 * EPIPE error.
+	 */
+
+	ATF_REQUIRE(kevent(kq, kev, 2, kev, 2, NULL) == 2);
+	ATF_REQUIRE((kev[0].flags & EV_ERROR) != 0);
+	ATF_REQUIRE(kev[0].data == 0);
+	ATF_REQUIRE((kev[1].flags & EV_ERROR) != 0);
+	ATF_REQUIRE(kev[1].data == EPIPE);
+
+	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev),
+	    &(struct timespec) { 0, 0 }) == 1);
+	ATF_REQUIRE(kev[0].ident == (uintptr_t)p[0]);
+	ATF_REQUIRE(kev[0].filter == EVFILT_READ);
+	ATF_REQUIRE(kev[0].flags == (EV_EOF | EV_CLEAR | EV_RECEIPT));
+	ATF_REQUIRE(kev[0].fflags == 0);
+	ATF_REQUIRE(kev[0].data == 65536);
+	ATF_REQUIRE(kev[0].udata == 0);
+
+	ATF_REQUIRE(close(kq) == 0);
+	ATF_REQUIRE(close(p[0]) == 0);
+}
+
+ATF_TC_WITHOUT_HEAD(pipe_kqueue__closed_write_end_register_before_close);
+ATF_TC_BODY(pipe_kqueue__closed_write_end_register_before_close, tc)
+{
+	int p[2] = { -1, -1 };
+
+	ATF_REQUIRE(pipe2(p, O_CLOEXEC | O_NONBLOCK) == 0);
+	ATF_REQUIRE(p[0] >= 0);
+	ATF_REQUIRE(p[1] >= 0);
+
+	int kq = kqueue();
+	ATF_REQUIRE(kq >= 0);
+
+	struct kevent kev[32];
+	EV_SET(&kev[0], p[0], EVFILT_READ, EV_ADD | EV_CLEAR | EV_RECEIPT, /**/
+	    0, 0, 0);
+	EV_SET(&kev[1], p[0], EVFILT_WRITE, EV_ADD | EV_CLEAR | EV_RECEIPT, /**/
+	    0, 0, 0);
+
+	/*
+	 * Registering EVFILT_WRITE before the pipe is closed leads to a
+	 * EVFILT_WRITE event with EV_EOF set.
+	 */
+
+	ATF_REQUIRE(kevent(kq, kev, 2, kev, 2, NULL) == 2);
+	ATF_REQUIRE((kev[0].flags & EV_ERROR) != 0);
+	ATF_REQUIRE(kev[0].data == 0);
+	ATF_REQUIRE((kev[1].flags & EV_ERROR) != 0);
+	ATF_REQUIRE(kev[1].data == 0);
+
+	char c = 0;
+	ssize_t r;
+	while ((r = write(p[1], &c, 1)) == 1) {
+	}
+	ATF_REQUIRE(r < 0);
+	ATF_REQUIRE(errno == EAGAIN || errno == EWOULDBLOCK);
+
+	ATF_REQUIRE(close(p[1]) == 0);
+
+	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev),
+	    &(struct timespec) { 0, 0 }) == 2);
+	{
+		ATF_REQUIRE(kev[0].ident == (uintptr_t)p[0]);
+		ATF_REQUIRE(kev[0].filter == EVFILT_WRITE);
+		ATF_REQUIRE(kev[0].flags ==
+		    (EV_EOF | EV_CLEAR | EV_ONESHOT | EV_RECEIPT));
+		ATF_REQUIRE(kev[0].fflags == 0);
+		ATF_REQUIRE(kev[0].data == 4096 ||
+		    kev[0].data == 512 /* on FreeBSD 11.3 */);
+		ATF_REQUIRE(kev[0].udata == 0);
+	}
+	{
+		ATF_REQUIRE(kev[1].ident == (uintptr_t)p[0]);
+		ATF_REQUIRE(kev[1].filter == EVFILT_READ);
+		ATF_REQUIRE(kev[1].flags == (EV_EOF | EV_CLEAR | EV_RECEIPT));
+		ATF_REQUIRE(kev[1].fflags == 0);
+		ATF_REQUIRE(kev[1].data == 65536);
+		ATF_REQUIRE(kev[1].udata == 0);
+	}
+
+	ATF_REQUIRE(close(kq) == 0);
+	ATF_REQUIRE(close(p[0]) == 0);
+}
+
+ATF_TP_ADD_TCS(tp)
+{
+	ATF_TP_ADD_TC(tp, pipe_kqueue__write_end);
+	ATF_TP_ADD_TC(tp, pipe_kqueue__closed_read_end);
+	ATF_TP_ADD_TC(tp, pipe_kqueue__closed_read_end_register_before_close);
+	ATF_TP_ADD_TC(tp, pipe_kqueue__closed_write_end);
+	ATF_TP_ADD_TC(tp, pipe_kqueue__closed_write_end_register_before_close);
+
+	return atf_no_error();
+}