/* Test if a memory region is wholly unwritable.  Mach version.

   Copyright (C) 2004-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or

   modify it under the terms of the GNU Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library 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

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with the GNU C Library; if not, see

   <http://www.gnu.org/licenses/>.  */

#include <stdlib.h>

#include <stdint.h>

#include <mach.h>

/* Return 1 if the whole area PTR .. PTR+SIZE is not writable.

   Return -1 if it is writable.  */

int

__readonly_area (const char *ptr, size_t size)

{

  vm_address_t region_address = (uintptr_t) ptr;

  vm_size_t region_length = size;

  vm_prot_t protection;

  vm_prot_t max_protection;

  vm_inherit_t inheritance;

  boolean_t is_shared;

  mach_port_t object_name;

  vm_offset_t offset;

  while (__vm_region (__mach_task_self (),

		      &region_address, &region_length,

		      &protection, &max_protection, &inheritance, &is_shared,

		      &object_name, &offset) == KERN_SUCCESS

	 && region_address <= (uintptr_t) ptr)

    {

      region_address += region_length;

      if (region_address < (uintptr_t) ptr)

	continue;

      if (protection & VM_PROT_WRITE)

	return -1;

      if (region_address - (uintptr_t) ptr >= size)

	break;

    }

  return 1;

}