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 //~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 38 ProtectedMemoryAllocator::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 //~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 54 ProtectedMemoryAllocator::~ProtectedMemoryAllocator() { 55 vm_deallocate(mach_task_self(), 56 base_address_, 57 pool_size_ 58 ); 59 } 60 61 //~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 62 char *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 //~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 73 kern_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 //~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 84 kern_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
