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glibc  2.9
readonly-area.c
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00001 /* Test if a memory region is wholly unwritable.  Mach version.
00002    Copyright (C) 2004 Free Software Foundation, Inc.
00003    This file is part of the GNU C Library.
00004 
00005    The GNU C Library is free software; you can redistribute it and/or
00006    modify it under the terms of the GNU Lesser General Public
00007    License as published by the Free Software Foundation; either
00008    version 2.1 of the License, or (at your option) any later version.
00009 
00010    The GNU C Library is distributed in the hope that it will be useful,
00011    but WITHOUT ANY WARRANTY; without even the implied warranty of
00012    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00013    Lesser General Public License for more details.
00014 
00015    You should have received a copy of the GNU Lesser General Public
00016    License along with the GNU C Library; if not, write to the Free
00017    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
00018    02111-1307 USA.  */
00019 
00020 #include <stdlib.h>
00021 #include <stdint.h>
00022 #include <mach.h>
00023 
00024 /* Return 1 if the whole area PTR .. PTR+SIZE is not writable.
00025    Return -1 if it is writable.  */
00026 
00027 int
00028 __readonly_area (const char *ptr, size_t size)
00029 {
00030   vm_address_t region_address = (uintptr_t) ptr;
00031   vm_size_t region_length = size;
00032   vm_prot_t protection;
00033   vm_prot_t max_protection;
00034   vm_inherit_t inheritance;
00035   boolean_t is_shared;
00036   mach_port_t object_name;
00037   vm_offset_t offset;
00038 
00039   while (__vm_region (__mach_task_self (),
00040                     &region_address, &region_length,
00041                     &protection, &max_protection, &inheritance, &is_shared,
00042                     &object_name, &offset) == KERN_SUCCESS
00043         && region_address <= (uintptr_t) ptr)
00044     {
00045       region_address += region_length;
00046       if (region_address < (uintptr_t) ptr)
00047        continue;
00048 
00049       if (protection & VM_PROT_WRITE)
00050        return -1;
00051 
00052       if (region_address - (uintptr_t) ptr >= size)
00053        break;
00054     }
00055 
00056   return 1;
00057 }