1  /* Classify a domain name for IDNA purposes.
       2     Copyright (C) 2018-2023 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     <https://www.gnu.org/licenses/>.  */
      18  
      19  #include <errno.h>
      20  #include <inet/net-internal.h>
      21  #include <stdbool.h>
      22  #include <string.h>
      23  #include <wchar.h>
      24  
      25  enum idna_name_classification
      26  __idna_name_classify (const char *name)
      27  {
      28    mbstate_t mbs;
      29    memset (&mbs, 0, sizeof (mbs));
      30    const char *p = name;
      31    const char *end = p + strlen (p) + 1;
      32    bool nonascii = false;
      33    bool backslash = false;
      34    while (true)
      35      {
      36        wchar_t wc;
      37        size_t result = mbrtowc (&wc, p, end - p, &mbs);
      38        if (result == 0)
      39          /* NUL terminator was reached.  */
      40          break;
      41        else if (result == (size_t) -2)
      42          /* Incomplete trailing multi-byte character.  This is an
      43             encoding error because we received the full name.  */
      44          return idna_name_encoding_error;
      45        else if (result == (size_t) -1)
      46          {
      47            /* Other error, including EILSEQ.  */
      48            if (errno == EILSEQ)
      49              return idna_name_encoding_error;
      50            else if (errno == ENOMEM)
      51              return idna_name_memory_error;
      52            else
      53              return idna_name_error;
      54          }
      55        else
      56          {
      57            /* A wide character was decoded.  */
      58            p += result;
      59            if (wc == L'\\')
      60              backslash = true;
      61            else if (wc > 127)
      62              nonascii = true;
      63          }
      64      }
      65  
      66    if (nonascii)
      67      {
      68        if (backslash)
      69          return idna_name_nonascii_backslash;
      70        else
      71          return idna_name_nonascii;
      72      }
      73    else
      74      return idna_name_ascii;
      75  }