support/tst-xreadlink.c

   1 /* Test the xreadlink function.
   2    Copyright (C) 2017-2018 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <errno.h>
  20 #include <fcntl.h>
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24 #include <support/check.h>
  25 #include <support/support.h>
  26 #include <support/temp_file.h>
  27 #include <support/xunistd.h>
  28
  29 static int
  30 do_test (void)
  31 {
  32   char *dir = support_create_temp_directory ("tst-xreadlink-");
  33   char *symlink_name = xasprintf ("%s/symlink", dir);
  34   add_temp_file (symlink_name);
  35
  36   /* The limit 10000 is arbitrary and simply there to prevent an
  37      attempt to exhaust all available disk space.  */
  38   for (int size = 1; size < 10000; ++size)
  39     {
  40       char *contents = xmalloc (size + 1);
  41       for (int i = 0; i < size; ++i)
  42         contents[i] = 'a' + (rand () % 26);
  43       contents[size] = '\0';
  44       if (symlink (contents, symlink_name) != 0)
  45         {
  46           if (errno == ENAMETOOLONG)
  47             {
  48               printf ("info: ENAMETOOLONG failure at %d bytes\n", size);
  49               free (contents);
  50               break;
  51             }
  52           FAIL_EXIT1 ("symlink (%d bytes): %m", size);
  53         }
  54
  55       char *readlink_result = xreadlink (symlink_name);
  56       TEST_VERIFY (strcmp (readlink_result, contents) == 0);
  57       free (readlink_result);
  58       xunlink (symlink_name);
  59       free (contents);
  60     }
  61
  62   /* Create an empty file to suppress the temporary file deletion
  63      warning.  */
  64   xclose (xopen (symlink_name, O_WRONLY | O_CREAT, 0));
  65
  66   free (symlink_name);
  67   free (dir);
  68
  69   return 0;
  70 }
  71
  72 #include <support/test-driver.c>