1  /* Hardware capability support for run-time dynamic loader.  String splitting.
       2     Copyright (C) 2020-2023 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 <dl-hwcaps.h>
      20  #include <stdbool.h>
      21  #include <string.h>
      22  
      23  _Bool
      24  _dl_hwcaps_split (struct dl_hwcaps_split *s)
      25  {
      26    if (s->segment == NULL)
      27      return false;
      28  
      29    /* Skip over the previous segment.   */
      30    s->segment += s->length;
      31  
      32    /* Consume delimiters.  This also avoids returning an empty
      33       segment.  */
      34    while (*s->segment == ':')
      35      ++s->segment;
      36    if (*s->segment == '\0')
      37      return false;
      38  
      39    /* This could use strchrnul, but we would have to link the function
      40       into ld.so for that.  */
      41    const char *colon = strchr (s->segment, ':');
      42    if (colon == NULL)
      43      s->length = strlen (s->segment);
      44    else
      45      s->length = colon - s->segment;
      46    return true;
      47  }
      48  
      49  _Bool
      50  _dl_hwcaps_split_masked (struct dl_hwcaps_split_masked *s)
      51  {
      52    while (true)
      53      {
      54        if (!_dl_hwcaps_split (&s->split))
      55          return false;
      56        bool active = s->bitmask & 1;
      57        s->bitmask >>= 1;
      58        if (active && _dl_hwcaps_contains (s->mask,
      59                                           s->split.segment, s->split.length))
      60          return true;
      61      }
      62  }
      63  
      64  _Bool
      65  _dl_hwcaps_contains (const char *hwcaps, const char *name, size_t name_length)
      66  {
      67    if (hwcaps == NULL)
      68      return true;
      69  
      70    struct dl_hwcaps_split split;
      71    _dl_hwcaps_split_init (&split, hwcaps);
      72    while (_dl_hwcaps_split (&split))
      73      if (split.length == name_length
      74          && memcmp (split.segment, name, name_length) == 0)
      75        return true;
      76    return false;
      77  }