tests: add a test for shutdown(2) on a datagram socket

2 files changed, 113 insertions, 0 deletions

diff --git a/tests/sys/kern/Makefile b/tests/sys/kern/Makefile
index 308cfd22a0ec..143c13297585 100644
--- a/tests/sys/kern/Makefile
+++ b/tests/sys/kern/Makefile
@@ -26,6 +26,7 @@ ATF_TESTS_C+=	ptrace_test
 TEST_METADATA.ptrace_test+=		timeout="15"
 ATF_TESTS_C+=	reaper
 ATF_TESTS_C+=	sched_affinity
+ATF_TESTS_C+=	shutdown_dgram
 ATF_TESTS_C+=	sigaltstack
 ATF_TESTS_C+=	sigwait
 ATF_TESTS_C+=	socket_accept
@@ -75,6 +76,7 @@ LIBADD.unix_seqpacket_test+=		pthread
 LIBADD.kcov+=				pthread
 CFLAGS.ktls_test+=			-DOPENSSL_API_COMPAT=0x10100000L
 LIBADD.ktls_test+=			crypto util
+LIBADD.shutdown_dgram+=			pthread
 LIBADD.socket_msg_waitall+=		pthread
 LIBADD.sendfile_helper+=		pthread
 LIBADD.fdgrowtable_test+=		util pthread kvm procstat
diff --git a/tests/sys/kern/shutdown_dgram.c b/tests/sys/kern/shutdown_dgram.c
new file mode 100644
index 000000000000..04382d14f48f
--- /dev/null
+++ b/tests/sys/kern/shutdown_dgram.c
@@ -0,0 +1,111 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2024 Gleb Smirnoff <glebius@FreeBSD.org>
+ *
+ * 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/socket.h>
+#include <sys/un.h>
+#include <assert.h>
+#include <errno.h>
+#include <pthread.h>
+#include <unistd.h>
+#include <netinet/in.h>
+
+#include <atf-c.h>
+
+/*
+ * shutdown(2) on SOCK_DGRAM shall return ENOTCONN per POSIX.  However, there
+ * is historical behavior of the shutdown(2) also unblocking any ongoing
+ * recv(2) syscall on the socket.  It is known that some programs rely on this
+ * behavior, but exact list of problems isn't known.  Neither we know if the
+ * "feature" is required on PF_UNIX sockets or on PF_INET/INET6 sockets or
+ * on both kinds.  Feel free to improve this comment if you know any details.
+ *
+ * List of relevant commits, bug reports and reviews:
+ * 63649db04205
+ * https://reviews.freebsd.org/D10351
+ * b114aa79596c (regresses)
+ * https://reviews.freebsd.org/D3039 (regresses)
+ * kern/84761 c5cff17017f9 aada5cccd878
+ */
+
+
+static void *
+blocking_thread(void *arg)
+{
+	int *s = arg;
+	char buf[1];
+	int error, rv;
+
+	rv = recv(*s, buf, sizeof(buf), 0);
+	error = (rv == -1) ? errno : 0;
+
+	return ((void *)(uintptr_t)error);
+}
+
+static void
+shutdown_thread(int s)
+{
+	pthread_t t;
+	int rv;
+
+	ATF_REQUIRE(pthread_create(&t, NULL, blocking_thread, &s) == 0);
+	usleep(1000);
+	ATF_REQUIRE(shutdown(s, SHUT_RD) == -1);
+	ATF_REQUIRE(errno == ENOTCONN);
+	ATF_REQUIRE(pthread_join(t, (void *)&rv) == 0);
+	ATF_REQUIRE(rv == 0);
+	close(s);
+}
+
+ATF_TC_WITHOUT_HEAD(unblock);
+ATF_TC_BODY(unblock, tc)
+{
+	static const struct sockaddr_un sun = {
+		.sun_family = AF_LOCAL,
+		.sun_len = sizeof(sun),
+		.sun_path = "shutdown-dgram-test-sock",
+	};
+	int s;
+
+	ATF_REQUIRE((s = socket(PF_UNIX, SOCK_DGRAM, 0)) >= 0);
+	ATF_REQUIRE(bind(s, (struct sockaddr *)&sun, sizeof(sun)) == 0);
+	shutdown_thread(s);
+
+	static const struct sockaddr_in sin = {
+		.sin_family = AF_INET,
+		.sin_len = sizeof(sin),
+	};
+	ATF_REQUIRE((s = socket(PF_INET, SOCK_DGRAM, 0)) >= 0);
+	ATF_REQUIRE(bind(s, (struct sockaddr *)&sin, sizeof(sin)) == 0);
+	shutdown_thread(s);
+}
+
+ATF_TP_ADD_TCS(tp)
+{
+	ATF_TP_ADD_TC(tp, unblock);
+
+	return (atf_no_error());
+}