Fix p{readv,writev}{64} consolidation implementation

This patch fixes the p{readv,writev}{64} consolidation implementation
from commits 4e77815 and af5fdf5.  Different from pread/pwrite
implementation, preadv/pwritev implementation does not require
__ALIGNMENT_ARG because kernel syscall prototypes define
the high and low part of the off_t, if it is the case, directly
(different from pread/pwrite where the architecture ABI for passing
64-bit values must be in consideration for passsing the arguments).

It also adds some basic tests for preadv/pwritev.

Tested on x86_64, i686, and armhf.

	* misc/Makefile (tests): Add tst-preadvwritev and tst-preadvwritev64.
	* misc/tst-preadvwritev.c: New file.
	* misc/tst-preadvwritev64.c: Likewise.
	* sysdeps/unix/sysv/linux/preadv.c (preadv): Remove SYSCALL_LL{64}
	usage.
	* sysdeps/unix/sysv/linux/preadv64.c (preadv64): Likewise.
	* sysdeps/unix/sysv/linux/pwritev.c (pwritev): Likewise.
	* sysdeps/unix/sysv/linux/pwritev64.c (pwritev64): Likewise.
	* sysdeps/unix/sysv/linux/sysdep.h (LO_HI_LONG): New macro.

1 files changed, 114 insertions, 0 deletions

diff --git a/misc/tst-preadvwritev.c b/misc/tst-preadvwritev.c
new file mode 100644
index 0000000000..08deecca11
--- /dev/null
+++ b/misc/tst-preadvwritev.c
@@ -0,0 +1,114 @@
+/* Tests for preadv and pwritev.
+   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 <sys/uio.h>
+
+/* Allow testing of the 64-bit versions as well.  */
+#ifndef PREADV
+# define PREADV  preadv
+# define PWRITEV pwritev
+#endif
+
+static void do_prepare (void);
+static int do_test (void);
+#define PREPARE(argc, argv)     do_prepare ()
+#define TEST_FUNCTION           do_test ()
+#include "../test-skeleton.c"
+
+static char *temp_filename;
+static int temp_fd;
+
+void
+do_prepare (void)
+{
+  temp_fd = create_temp_file ("tst-PREADVwritev.", &temp_filename);
+  if (temp_fd == -1)
+    {
+      printf ("cannot create temporary file: %m\n");
+      exit (1);
+    }
+}
+
+#define FAIL(str) \
+  do { printf ("error: %s (line %d)\n", str, __LINE__); return 1; } while (0)
+
+int
+do_test (void)
+{
+  struct iovec iov[2];
+  ssize_t ret;
+
+  char buf1[32];
+  char buf2[64];
+
+  memset (buf1, 0xf0, sizeof buf1);
+  memset (buf2, 0x0f, sizeof buf2);
+
+  memset (iov, 0, sizeof iov);
+  iov[0].iov_base = buf1;
+  iov[0].iov_len = sizeof buf1;
+  iov[1].iov_base = buf2;
+  iov[1].iov_len = sizeof buf2;
+
+  ret = PWRITEV (temp_fd, iov, 2, 0);
+  if (ret == -1)
+    FAIL ("first PWRITEV returned -1");
+  if (ret != (sizeof buf1 + sizeof buf2))
+    FAIL ("first PWRITEV returned an unexpected value");
+
+  ret = PWRITEV (temp_fd, iov, 2, sizeof buf1 + sizeof buf2);
+  if (ret == -1)
+    FAIL ("second PWRITEV returned -1");
+  if (ret != (sizeof buf1 + sizeof buf2))
+    FAIL ("second PWRITEV returned an unexpected value");
+
+  char buf3[32];
+  char buf4[64];
+
+  memset (buf3, 0x0f, sizeof buf3);
+  memset (buf4, 0xf0, sizeof buf4);
+
+  iov[0].iov_base = buf3;
+  iov[0].iov_len = sizeof buf3;
+  iov[1].iov_base = buf4;
+  iov[1].iov_len = sizeof buf4;
+
+  ret = PREADV (temp_fd, iov, 2, 0);
+  if (ret == -1)
+    FAIL ("first PREADV returned -1");
+  if (ret != (sizeof buf3 + sizeof buf4))
+    FAIL ("first PREADV returned an unexpected value");
+
+  if (memcmp (buf1, buf3, sizeof buf1) != 0)
+    FAIL ("first buffer from first PREADV different than expected");
+  if (memcmp (buf2, buf4, sizeof buf2) != 0)
+    FAIL ("second buffer from first PREADV different than expected");
+
+  ret = PREADV (temp_fd, iov, 2, sizeof buf3 + sizeof buf4);
+  if (ret == -1)
+    FAIL ("second PREADV returned -1");
+  if (ret != (sizeof buf3 + sizeof buf4))
+    FAIL ("second PREADV returned an unexpected value");
+
+  if (memcmp (buf1, buf3, sizeof buf1) != 0)
+    FAIL ("first buffer from second PREADV different than expected");
+  if (memcmp (buf2, buf4, sizeof buf2) != 0)
+    FAIL ("second buffer from second PREADV different than expected");
+
+  return 0;
+}