1  /* Copyright (C) 1991-2023 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 <assert.h>
      19  #include <errno.h>
      20  #include <stdio.h>
      21  #include <string.h>
      22  #include <sys/param.h>
      23  
      24  
      25  /* Fill buf with a string describing the errno code in ERRNUM.  */
      26  int
      27  __xpg_strerror_r (int errnum, char *buf, size_t buflen)
      28  {
      29    const char *estr = __strerror_r (errnum, buf, buflen);
      30  
      31    /* We know that __strerror_r returns buf (with a dynamically computed
      32       string) if errnum is invalid, otherwise it returns a string whose
      33       storage has indefinite extent.  */
      34    if (estr == buf)
      35      return EINVAL;
      36    else
      37      {
      38        size_t estrlen = strlen (estr);
      39  
      40        /* Terminate the string in any case.  */
      41        if (buflen > 0)
      42  	*((char *) __mempcpy (buf, estr, MIN (buflen - 1, estrlen))) = '\0';
      43  
      44        return buflen <= estrlen ? ERANGE : 0;
      45      }
      46  }