tests: check silent decoding of sendmmsg and recvmmsg syscalls

* tests/mmsg-silent.c: New file.
* tests/mmsg-silent.test: New test.
* tests/.gitignore: Add mmsg-silent.
* tests/Makefile.am (check_PROGRAMS): Likewise.
(DECODER_TESTS): Add mmsg-silent.test.
diff --git a/tests/.gitignore b/tests/.gitignore
index fa20bbd..06651bd 100644
--- a/tests/.gitignore
+++ b/tests/.gitignore
@@ -138,6 +138,7 @@
 mmap
 mmap64
 mmsg
+mmsg-silent
 mmsg_name
 mmsg_name-v
 mount
diff --git a/tests/Makefile.am b/tests/Makefile.am
index f32fc8b..59825de 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -194,6 +194,7 @@
 	mmap \
 	mmap64 \
 	mmsg \
+	mmsg-silent \
 	mmsg_name \
 	mmsg_name-v \
 	mount \
@@ -518,6 +519,7 @@
 	mmap.test \
 	mmap64.test \
 	mmsg.test \
+	mmsg-silent.test \
 	mmsg_name.test \
 	mmsg_name-v.test \
 	mount.test \
diff --git a/tests/mmsg-silent.c b/tests/mmsg-silent.c
new file mode 100644
index 0000000..47d0a50
--- /dev/null
+++ b/tests/mmsg-silent.c
@@ -0,0 +1,63 @@
+/*
+ * Check silent decoding of sendmmsg and recvmmsg syscalls.
+ *
+ * Copyright (c) 2016 Dmitry V. Levin <ldv@altlinux.org>
+ * 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.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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 "tests.h"
+#include <stdio.h>
+
+#include "msghdr.h"
+
+int
+main(void)
+{
+	int fds[2];
+	if (socketpair(AF_UNIX, SOCK_STREAM, 0, fds))
+		perror_msg_and_skip("socketpair");
+
+	char buf = 'A';
+	struct iovec iov = { .iov_base = &buf, .iov_len = sizeof(buf) };
+	struct mmsghdr mh = {
+		.msg_hdr = {
+			.msg_iov = &iov,
+			.msg_iovlen = 1
+		}
+	};
+
+	int rc = send_mmsg(fds[1], &mh, 1, MSG_DONTWAIT);
+	if (rc < 0)
+		perror_msg_and_skip("sendmmsg");
+	printf("sendmmsg(%d, %p, 1, MSG_DONTWAIT) = %d\n", fds[1], &mh, rc);
+
+	struct timespec t = { .tv_sec = 0, .tv_nsec = 12345678 };
+	rc = recv_mmsg(fds[0], &mh, 1, MSG_DONTWAIT, &t);
+	printf("recvmmsg(%d, %p, 1, MSG_DONTWAIT, %p) = %d\n",
+	       fds[0], &mh, &t, rc);
+
+	puts("+++ exited with 0 +++");
+	return 0;
+}
diff --git a/tests/mmsg-silent.test b/tests/mmsg-silent.test
new file mode 100755
index 0000000..775e0ad
--- /dev/null
+++ b/tests/mmsg-silent.test
@@ -0,0 +1,6 @@
+#!/bin/sh
+
+# Check silent decoding of sendmmsg and recvmmsg syscalls.
+
+. "${srcdir=.}/init.sh"
+run_strace_match_diff -a25 -e verbose=none -e trace=sendmmsg,recvmmsg