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2004-10-19 Roland McGrath <roland@frob.com>
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	* sysdeps/mach/readonly-area.c: New file.
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Roland McGrath committed Oct 20, 2004
1 parent 356e414 commit 604208c
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57 changes: 57 additions & 0 deletions sysdeps/mach/readonly-area.c
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/* Test if a memory region is wholly unwritable. Mach version.
Copyright (C) 2004 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, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */

#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;
}

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