1 files changed, 62 insertions, 0 deletions
diff --git a/security/sandbox/chromium/base/memory/platform_shared_memory_region.cc b/security/sandbox/chromium/base/memory/platform_shared_memory_region.cc
new file mode 100644
index 0000000000..45647925b3
--- /dev/null
+++ b/security/sandbox/chromium/base/memory/platform_shared_memory_region.cc
@@ -0,0 +1,62 @@
+// Copyright 2018 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/memory/platform_shared_memory_region.h"
+
+#include "base/memory/shared_memory_mapping.h"
+#include "base/numerics/checked_math.h"
+
+namespace base {
+namespace subtle {
+
+// static
+PlatformSharedMemoryRegion PlatformSharedMemoryRegion::CreateWritable(
+    size_t size) {
+  return Create(Mode::kWritable, size);
+}
+
+// static
+PlatformSharedMemoryRegion PlatformSharedMemoryRegion::CreateUnsafe(
+    size_t size) {
+  return Create(Mode::kUnsafe, size);
+}
+
+PlatformSharedMemoryRegion::PlatformSharedMemoryRegion() = default;
+PlatformSharedMemoryRegion::PlatformSharedMemoryRegion(
+    PlatformSharedMemoryRegion&& other) = default;
+PlatformSharedMemoryRegion& PlatformSharedMemoryRegion::operator=(
+    PlatformSharedMemoryRegion&& other) = default;
+PlatformSharedMemoryRegion::~PlatformSharedMemoryRegion() = default;
+
+PlatformSharedMemoryRegion::ScopedPlatformHandle
+PlatformSharedMemoryRegion::PassPlatformHandle() {
+  return std::move(handle_);
+}
+
+bool PlatformSharedMemoryRegion::MapAt(off_t offset,
+                                       size_t size,
+                                       void** memory,
+                                       size_t* mapped_size) const {
+  if (!IsValid())
+    return false;
+
+  if (size == 0)
+    return false;
+
+  size_t end_byte;
+  if (!CheckAdd(offset, size).AssignIfValid(&end_byte) || end_byte > size_) {
+    return false;
+  }
+
+  bool success = MapAtInternal(offset, size, memory, mapped_size);
+  if (success) {
+    DCHECK_EQ(
+        0U, reinterpret_cast<uintptr_t>(*memory) & (kMapMinimumAlignment - 1));
+  }
+
+  return success;
+}
+
+}  // namespace subtle
+}  // namespace base