code for encrypting sensitive tcmalloc metadata

third_party/tcmalloc/chromium/src/metadata_encode.h

-// Copyright (c) 2008, Google Inc.
+// Copyright (c) 2011, 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.
 
 // ---
-// Author: Ken Ashcraft <opensource@google.com>
+// Author: Rebecca Shapiro
+//
+// Here lies code that aids in encoding allocator metadata.  Because
+// some, but not all operating systems provide metadata encoding
+// facilities, this header file is used to determine which encoding
+// implementation gets included in the build.
 
-#include "static_vars.h"
-#include <stddef.h>                     // for NULL
-#include <new>                          // for operator new
-#include "internal_logging.h"  // for CHECK_CONDITION
-#include "sampler.h"           // for Sampler
+
+#ifndef TCMALLOC_METADATA_ENCODE_H_
+#define TCMALLOC_METADATA_ENCODE_H_
+
+#include "config.h"
+#ifdef HAVE_STDINT_H
+#include <stdint.h>                     // for uintptr_t
+#endif
+
+#include "config_hardening.h"
+#ifndef TCMALLOC_SPAN_ENCODE
+#include "metadata_encode_disabled.h"
+#else
+#ifdef OS_WIN
+#include "metadata_encode_disabled.h"
+#else // TCMALLOC_SPAN_ENCODE and not OS_WIN.
+#include "metadata_encode_posix.h"
+#endif // OS_WIN
+#endif // TCMALLOC_SPAN_ENCODE
 
 namespace tcmalloc {
 
-SpinLock Static::pageheap_lock_(SpinLock::LINKER_INITIALIZED);
-SizeMap Static::sizemap_;
-CentralFreeListPadded Static::central_cache_[kNumClasses];
-PageHeapAllocator<Span> Static::span_allocator_;
-PageHeapAllocator<StackTrace> Static::stacktrace_allocator_;
-Span Static::sampled_objects_;
-PageHeapAllocator<StackTraceTable::Bucket> Static::bucket_allocator_;
-StackTrace* Static::growth_stacks_ = NULL;
-char Static::pageheap_memory_[sizeof(PageHeap)];
-
-void Static::InitStaticVars() {
-  sizemap_.Init();
-  span_allocator_.Init();
-  span_allocator_.New(); // Reduce cache conflicts
-  span_allocator_.New(); // Reduce cache conflicts
-  stacktrace_allocator_.Init();
-  bucket_allocator_.Init();
-  // Do a bit of sanitizing: make sure central_cache is aligned properly
-  CHECK_CONDITION((sizeof(central_cache_[0]) % 64) == 0);
-  for (int i = 0; i < kNumClasses; ++i) {
-    central_cache_[i].Init(i);
-  }
-  new ((void*)pageheap_memory_) PageHeap;
-  DLL_Init(&sampled_objects_);
-  Sampler::InitStatics();
+template <typename T>
+inline T EncodePtr(T ptr){
+  return reinterpret_cast<T>(
+      EncodeUintptr(reinterpret_cast<uintptr_t>(ptr)));
 }
 
-}  // namespace tcmalloc
+template <typename T>
+inline T DecodePtr(T ptr){
+  return reinterpret_cast<T>(
+      DecodeUintptr(reinterpret_cast<uintptr_t>(ptr)));
+}
+
+}
+
+#endif // TCMALLOC_METADATA_ENCODE_H_