nptl: Add sendmmsg and recvmmsg cancellation tests

This patch adds cancellation tests for both sendmmsg and recvmmsg
syscalls.  Since for some system configuration (x86_64/i686 on
older kernels and non-Linux platforms), the tests are added as
two independent that report as unsupported if the syscall is not
presented.

Both new tests uses the already tst-cancel4.c code, which as moved
to a common tst-cancel4-common{.c,h} files.

Tested on x86_64 and i686.

	* nptl/Makefile (test): Add tst-cancel4_1 and tst-cancel4_2.
	* nptl/tst-cancel4-common.c: New file.
	* nptl/tst-cancel4-common.h: Likewise.
	* nptl/tst-cancel4.c: Move common definitions to
	tst-cancel4-common.{c,h} file.
	* nptl/tst-cancel4_1.c: New test.
	* nptl/tst-cancel4_2.c: New test.

1 files changed, 77 insertions, 0 deletions

diff --git a/nptl/tst-cancel4-common.h b/nptl/tst-cancel4-common.h
new file mode 100644
index 0000000000..e1683c435b
--- /dev/null
+++ b/nptl/tst-cancel4-common.h
@@ -0,0 +1,77 @@
+/* Common definition for tst-cancel4_* tests.
+
+   Copyright (C) 2016 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <pthread.h>
+
+/* Pipe descriptors.  */
+static int fds[2];
+
+/* Temporary file descriptor, to be closed after each round.  */
+static int tempfd = -1;
+static int tempfd2 = -1;
+/* Name of temporary file to be removed after each round.  */
+static char *tempfname;
+/* Temporary message queue.  */
+static int tempmsg = -1;
+
+/* Often used barrier for two threads.  */
+static pthread_barrier_t b2;
+
+/* The WRITE_BUFFER_SIZE value needs to be chosen such that if we set
+   the socket send buffer size to '1', a write of this size on that
+   socket will block.
+
+   The Linux kernel imposes a minimum send socket buffer size which
+   has changed over the years.  As of Linux 3.10 the value is:
+
+     2 * (2048 + SKB_DATA_ALIGN(sizeof(struct sk_buff)))
+
+   which is attempting to make sure that with standard MTUs,
+   TCP can always queue up at least 2 full sized packets.
+
+   Furthermore, there is logic in the socket send paths that
+   will allow one more packet (of any size) to be queued up as
+   long as some socket buffer space remains.   Blocking only
+   occurs when we try to queue up a new packet and the send
+   buffer space has already been fully consumed.
+
+   Therefore we must set this value to the largest possible value of
+   the formula above (and since it depends upon the size of "struct
+   sk_buff", it is dependent upon machine word size etc.) plus some
+   slack space.  */
+
+#define WRITE_BUFFER_SIZE 16384
+
+/* Cleanup handling test.  */
+static int cl_called;
+
+static void
+cl (void *arg)
+{
+  ++cl_called;
+}
+
+struct cancel_tests
+{
+  const char *name;
+  void *(*tf) (void *);
+  int nb;
+  int only_early;
+};
+#define ADD_TEST(name, nbar, early) { #name, tf_##name, nbar, early }