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/thirdparty/breakpad/client/mac/handler/protected_memory_allocator.cc

http://github.com/tomahawk-player/tomahawk
C++ | 92 lines | 44 code | 11 blank | 37 comment | 3 complexity | 935f02d105434a544c91a5ef50c3db9b MD5 | raw file
 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}