1  /* Copyright (C) 2005-2023 Free Software Foundation, Inc.
       2     This file is part of the GNU C Library.
       3  
       4     The GNU C Library is free software; you can redistribute it and/or
       5     modify it under the terms of the GNU Lesser General Public
       6     License as published by the Free Software Foundation; either
       7     version 2.1 of the License, or (at your option) any later version.
       8  
       9     The GNU C Library is distributed in the hope that it will be useful,
      10     but WITHOUT ANY WARRANTY; without even the implied warranty of
      11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      12     Lesser General Public License for more details.
      13  
      14     You should have received a copy of the GNU Lesser General Public
      15     License along with the GNU C Library; if not, see
      16     <https://www.gnu.org/licenses/>.  */
      17  
      18  #include <limits.h>
      19  #include <stdlib.h>
      20  #include <string.h>
      21  #include <unistd.h>
      22  
      23  
      24  char *
      25  __realpath_chk (const char *buf, char *resolved, size_t resolvedlen)
      26  {
      27  #ifdef PATH_MAX
      28    if (resolvedlen < PATH_MAX)
      29      __chk_fail ();
      30  
      31    return __realpath (buf, resolved);
      32  #else
      33    long int pathmax =__pathconf (buf, _PC_PATH_MAX);
      34    if (pathmax != -1)
      35      {
      36        /* We do have a fixed limit.  */
      37        if (resolvedlen < pathmax)
      38  	__chk_fail ();
      39  
      40        return __realpath (buf, resolved);
      41      }
      42  
      43    /* Since there is no fixed limit we check whether the size is large
      44       enough.  */
      45    char *res = __realpath (buf, NULL);
      46    if (res != NULL)
      47      {
      48        size_t actlen = strlen (res) + 1;
      49        if (actlen > resolvedlen)
      50  	__chk_fail ();
      51  
      52        memcpy (resolved, res, actlen);
      53        free (res);
      54        res = resolved;
      55      }
      56  
      57    return res;
      58  #endif
      59  }