Issue 202: reviewed by Waylonis

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@205 4c0a9323-5329-0410-9bdc-e9ce6186880e

src/client/mac/handler/protected_memory_allocator.cc

@@ -0,0 +1,92 @@
+// 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(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;
+}