/* Test the xreadlink function.

   Copyright (C) 2017-2018 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 <errno.h>

#include <fcntl.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <support/check.h>

#include <support/support.h>

#include <support/temp_file.h>

#include <support/xunistd.h>

static int

do_test (void)

{

  char *dir = support_create_temp_directory ("tst-xreadlink-");

  char *symlink_name = xasprintf ("%s/symlink", dir);

  add_temp_file (symlink_name);

  /* The limit 10000 is arbitrary and simply there to prevent an

     attempt to exhaust all available disk space.  */

  for (int size = 1; size < 10000; ++size)

    {

      char *contents = xmalloc (size + 1);

      for (int i = 0; i < size; ++i)

        contents[i] = 'a' + (rand () % 26);

      contents[size] = '\0';

      if (symlink (contents, symlink_name) != 0)

        {

          if (errno == ENAMETOOLONG)

            {

              printf ("info: ENAMETOOLONG failure at %d bytes\n", size);

              free (contents);

              break;

            }

          FAIL_EXIT1 ("symlink (%d bytes): %m", size);

        }

      char *readlink_result = xreadlink (symlink_name);

      TEST_VERIFY (strcmp (readlink_result, contents) == 0);

      free (readlink_result);

      xunlink (symlink_name);

      free (contents);

    }

  /* Create an empty file to suppress the temporary file deletion

     warning.  */

  xclose (xopen (symlink_name, O_WRONLY | O_CREAT, 0));

  free (symlink_name);

  free (dir);

  return 0;

}

#include <support/test-driver.c>