/* Copyright (C) 2011-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   Contributed by Ryan S. Arnold <rsa@us.ibm.com>, 2011.

   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 <fcntl.h>

#include <limits.h>

#include <paths.h>

#include <stdio.h>

#include <stdint.h>

#include <stdlib.h>

#include <unistd.h>

#include <sys/uio.h>

/* The purpose of this test is to verify that the INTERNAL_[V]SYSCALL_NCS

   macros on 64-bit platforms don't cast the return type to (int) which would

   erroneously sign extend the return value should the high bit of the bottom

   half of the word be '1'.  */

#if 0

/* Used to test the non power-of-2 code path.  */

#undef IOV_MAX

#define IOV_MAX 1000

#endif

/* writev() should report that it has written EXPECTED number of bytes.  */

#define EXPECTED ((size_t) INT32_MAX + 1)

static int

do_test (void)

{

  struct iovec iv[IOV_MAX];

  /* POSIX doesn't guarantee that IOV_MAX is pow of 2 but we're optimistic.  */

  size_t bufsz = EXPECTED / IOV_MAX;

  size_t bufrem = EXPECTED % IOV_MAX;

  /* If there's a remainder then IOV_MAX probably isn't a power of 2 and we

     need to make bufsz bigger so that the last iovec, iv[IOV_MAX-1], is free

     for the remainder.  */

  if (bufrem)

    {

      bufsz = bufsz + 1;

      bufrem = EXPECTED - (bufsz * (IOV_MAX - 1));

    }

  /* We writev to /dev/null since we're just testing writev's return value.  */

  int fd = open (_PATH_DEVNULL, O_WRONLY);

  if (fd == -1)

    {

      printf ("Unable to open /dev/null for writing.\n");

      return -1;

    }

  iv[0].iov_base = malloc (bufsz);

  if (iv[0].iov_base == NULL)

    {

      printf ("malloc (%zu) failed.\n", bufsz);

      close (fd);

      return -1;

    }

  iv[0].iov_len = bufsz;

  /* We optimistically presume that there isn't a remainder and set all iovec

     instances to the same base and len as the first instance.  */

  for (int i = 1; i < IOV_MAX; i++)

    {

      /* We don't care what the data is so reuse the allocation from iv[0];  */

      iv[i].iov_base = iv[0].iov_base;

      iv[i].iov_len = iv[0].iov_len;

    }

  /* If there is a remainder then we correct the last iov_len.  */

  if (bufrem)

    iv[IOV_MAX - 1].iov_len = bufrem;

  /* Write junk to /dev/null with the writev syscall in order to get a return

     of INT32_MAX+1 bytes to verify that the INTERNAL_SYSCALL wrappers aren't

     mangling the result if the signbit of a 32-bit number is set.  */

  ssize_t ret = writev (fd, iv, IOV_MAX);

  free (iv[0].iov_base);

  close (fd);

  if (ret != (ssize_t) EXPECTED)

    {

#ifdef ARTIFICIAL_LIMIT

      if (ret != (ssize_t) ARTIFICIAL_LIMIT)

#endif

	{

	  printf ("writev() return value: %zd != EXPECTED: %zd\n",

		  ret, EXPECTED);

	  return 1;

	}

    }

  return 0;

}

/* Time enough for a large writev syscall to complete.  */

#define TIMEOUT 20

#define TEST_FUNCTION do_test ()

#include "../test-skeleton.c"