1// Copyright (c) 2006, Google Inc. 2// All rights reserved. 3// 4// Redistribution and use in source and binary forms, with or without 5// modification, are permitted provided that the following conditions are 6// met: 7// 8// * Redistributions of source code must retain the above copyright 9// notice, this list of conditions and the following disclaimer. 10// * Redistributions in binary form must reproduce the above 11// copyright notice, this list of conditions and the following disclaimer 12// in the documentation and/or other materials provided with the 13// distribution. 14// * Neither the name of Google Inc. nor the names of its 15// contributors may be used to endorse or promote products derived from 16// this software without specific prior written permission. 17// 18// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 19// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 20// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 21// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 22// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 23// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 24// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 28// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29// 30// ProtectedMemoryAllocator 31// 32// See the header file for documentation 33 34#include "protected_memory_allocator.h" 35#include <assert.h> 36 37//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 38ProtectedMemoryAllocator::ProtectedMemoryAllocator(vm_size_t pool_size) 39 : pool_size_(pool_size), 40 next_alloc_offset_(0), 41 valid_(false) { 42 43 kern_return_t result = vm_allocate(mach_task_self(), 44 &base_address_, 45 pool_size, 46 TRUE 47 ); 48 49 valid_ = (result == KERN_SUCCESS); 50 assert(valid_); 51} 52 53//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 54ProtectedMemoryAllocator::~ProtectedMemoryAllocator() { 55 vm_deallocate(mach_task_self(), 56 base_address_, 57 pool_size_ 58 ); 59} 60 61//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 62char *ProtectedMemoryAllocator::Allocate(vm_size_t bytes) { 63 if (valid_ && next_alloc_offset_ + bytes <= pool_size_) { 64 char *p = (char*)base_address_ + next_alloc_offset_; 65 next_alloc_offset_ += bytes; 66 return p; 67 } 68 69 return NULL; // ran out of memory in our allocation block 70} 71 72//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 73kern_return_t ProtectedMemoryAllocator::Protect() { 74 kern_return_t result = vm_protect(mach_task_self(), 75 base_address_, 76 pool_size_, 77 FALSE, 78 VM_PROT_READ); 79 80 return result; 81} 82 83//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 84kern_return_t ProtectedMemoryAllocator::Unprotect() { 85 kern_return_t result = vm_protect(mach_task_self(), 86 base_address_, 87 pool_size_, 88 FALSE, 89 VM_PROT_READ | VM_PROT_WRITE); 90 91 return result; 92} 93