/* Bug 22786: test for buffer overflow in realpath.

   Copyright (C) 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/>.  */

/* This file must be run from within a directory called "stdlib".  */

#include <errno.h>

#include <limits.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <unistd.h>

#include <sys/stat.h>

#include <sys/types.h>

#include <support/check.h>

#include <support/support.h>

#include <support/temp_file.h>

#include <support/test-driver.h>

#include <libc-diag.h>

static int

do_test (void)

{

  const char *dir = support_create_temp_directory ("bz22786.");

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

  const size_t path_len = (size_t) INT_MAX + strlen (lnk) + 1;

  TEST_VERIFY_EXIT (symlink (".", lnk) == 0);

  DIAG_PUSH_NEEDS_COMMENT;

#if __GNUC_PREREQ (7, 0)

  /* GCC 7 warns about too-large allocations; here we need such

     allocation to succeed for the test to work.  */

  DIAG_IGNORE_NEEDS_COMMENT (7, "-Walloc-size-larger-than=");

#endif

  char *path = xmalloc (path_len);

  DIAG_POP_NEEDS_COMMENT;

  /* Construct very long path = "/tmp/bz22786.XXXX/symlink/aaaa....."  */

  char *p = mempcpy (path, lnk, strlen (lnk));

  *(p++) = '/';

  memset (p, 'a', path_len - (p - path) - 2);

  p[path_len - (p - path) - 1] = '\0';

  /* This call crashes before the fix for bz22786 on 32-bit platforms.  */

  p = realpath (path, NULL);

  if (p != NULL || errno != ENAMETOOLONG)

    {

      printf ("realpath: %s (%m)", p);

      return EXIT_FAILURE;

    }

  /* Cleanup.  */

  unlink (lnk);

  return 0;

}

#define TEST_FUNCTION do_test

#include <support/test-driver.c>