sysdeps/mach/readonly-area.c

   1 /* Test if a memory region is wholly unwritable.  Mach version.
   2    Copyright (C) 2004 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, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <stdlib.h>
  21 #include <stdint.h>
  22 #include <mach.h>
  23
  24 /* Return 1 if the whole area PTR .. PTR+SIZE is not writable.
  25    Return -1 if it is writable.  */
  26
  27 int
  28 __readonly_area (const char *ptr, size_t size)
  29 {
  30   vm_address_t region_address = (uintptr_t) ptr;
  31   vm_size_t region_length = size;
  32   vm_prot_t protection;
  33   vm_prot_t max_protection;
  34   vm_inherit_t inheritance;
  35   boolean_t is_shared;
  36   mach_port_t object_name;
  37   vm_offset_t offset;
  38
  39   while (__vm_region (__mach_task_self (),
  40                       &region_address, &region_length,
  41                       &protection, &max_protection, &inheritance, &is_shared,
  42                       &object_name, &offset) == KERN_SUCCESS
  43          && region_address <= (uintptr_t) ptr)
  44     {
  45       region_address += region_length;
  46       if (region_address < (uintptr_t) ptr)
  47         continue;
  48
  49       if (protection & VM_PROT_WRITE)
  50         return -1;
  51
  52       if (region_address - (uintptr_t) ptr >= size)
  53         break;
  54     }
  55
  56   return 1;
  57 }