Function vm_map_check_protection

freebsd/vm/vm_map.c:4050–4077

* vm_map_check_protection: * * Assert that the target map allows the specified privilege on the * entire address region given. The entire region must be allocated. * * WARNING! This code does not and should not check whether the * contents of the region is accessible. For example a smaller file * might be mapped into a larger address space. * * NOTE! This code is also called by munmap

 *	The map must be locked.  A read lock is sufficient.
 */
boolean_t
vm_map_check_protection(vm_map_t map, vm_offset_t start, vm_offset_t end,
			vm_prot_t protection)
{
	vm_map_entry_t entry;
	vm_map_entry_t tmp_entry;

	if (!vm_map_lookup_entry(map, start, &tmp_entry))
		return (FALSE);
	entry = tmp_entry;

	while (start < end) {
		/*
		 * No holes allowed!
		 */
		if (start < entry->start)
			return (FALSE);
		/*
		 * Check protection associated with entry.
		 */
		if ((entry->protection & protection) != protection)
			return (FALSE);
		/* go to next entry */
		start = entry->end;
		entry = vm_map_entry_succ(entry);
	}
	return (TRUE);
}

/*
 *