kc3-lang/gnulib/lib/vma-prot.c

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• Hash : 7b089321
  Author :
  Date : 2025-01-01T09:24:36
  

  maint: run 'make update-copyright'
  

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• lib/vma-prot.c

• /* Determine the protection of a virtual memory area.
     Copyright (C) 2024-2025 Free Software Foundation, Inc.
  
     This file is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published
     by the Free Software Foundation; either version 2 of the License,
     or (at your option) any later version.
  
     This file 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 General Public License for more details.
  
     You should have received a copy of the GNU General Public License
     along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  
  /* Written by Bruno Haible <bruno@clisp.org>, 2024.  */
  
  #include <config.h>
  
  /* Specification.  */
  #include "vma-prot.h"
  
  #include <stdint.h>
  
  struct locals
  {
    /* The common protections seen so far.  */
    unsigned int prot_so_far;
    /* The remaining address interval.
       remaining_start <= remaining_end-1.  */
    uintptr_t remaining_start;
    uintptr_t remaining_end;
  };
  
  static int
  callback (void *data, uintptr_t start, uintptr_t end, unsigned int flags)
  {
    struct locals *l = (struct locals *) data;
  
    if (start > l->remaining_start)
      {
        /* The interval [remaining_start, min (remaining_end, start)) is
           unmapped.  */
        l->prot_so_far = 0;
        return 1;
      }
    if (end - 1 < l->remaining_start)
      /* The interval [start,end) lies before [remaining_start,remaining_end).  */
      return 0;
    /* Here  start <= remaining_start <= remaining_end-1
       and            remaining_start <= end-1,
       hence start <= remaining_start <= min (end-1, remaining_end-1).
       So, the two intervals intersect.  */
    l->prot_so_far &= flags;
    if (l->prot_so_far == 0)
      return 1;
    if (l->remaining_end - 1 <= end - 1)
      /* Done.  */
      return 1;
    /* Trim the remaining address interval.  */
    l->remaining_start = end;
    return 0;
  }
  
  int
  get_vma_prot (void *start, size_t size)
  {
    uintptr_t start_address = (uintptr_t) start;
  
    struct locals l;
    l.prot_so_far = VMA_PROT_READ | VMA_PROT_WRITE | VMA_PROT_EXECUTE;
    l.remaining_start = start_address;
    l.remaining_end = start_address + size;
  
    if (l.remaining_end < l.remaining_start)
      /* Invalid arguments.  */
      return -1;
  
    if (l.remaining_end > l.remaining_start)
      {
        if (vma_iterate (callback, &l) < 0)
          return -1;
      }
    return l.prot_so_far;
  }
  

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