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// Copyright (c) 2006, Google Inc.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
// ProtectedMemoryAllocator
//
// See the header file for documentation
#include "protected_memory_allocator.h"
#include <assert.h>
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
ProtectedMemoryAllocator::ProtectedMemoryAllocator(vm_size_t pool_size)
: pool_size_(pool_size),
next_alloc_offset_(0),
valid_(false) {
kern_return_t result = vm_allocate(mach_task_self(),
&base_address_,
pool_size,
TRUE
);
valid_ = (result == KERN_SUCCESS);
assert(valid_);
}
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
ProtectedMemoryAllocator::~ProtectedMemoryAllocator() {
vm_deallocate(mach_task_self(),
base_address_,
pool_size_
);
}
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
char *ProtectedMemoryAllocator::Allocate(vm_size_t bytes) {
if (valid_ && next_alloc_offset_ + bytes <= pool_size_) {
char *p = (char*)base_address_ + next_alloc_offset_;
next_alloc_offset_ += bytes;
return p;
}
return NULL; // ran out of memory in our allocation block
}
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
kern_return_t ProtectedMemoryAllocator::Protect() {
kern_return_t result = vm_protect(mach_task_self(),
base_address_,
pool_size_,
FALSE,
VM_PROT_READ);
return result;
}
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
kern_return_t ProtectedMemoryAllocator::Unprotect() {
kern_return_t result = vm_protect(mach_task_self(),
base_address_,
pool_size_,
FALSE,
VM_PROT_READ | VM_PROT_WRITE);
return result;
}