base: add SafeCopy.
Add a function that uses process_vm_readv on Linux to safely
dereference pointers without the risk of segfault.
Bug: http://b/30836730
Test: safe_copy_test on host
Change-Id: I10bafcffe2172e17b00f65455d1dd6a08aa631d7
diff --git a/runtime/base/safe_copy.h b/runtime/base/safe_copy.h
new file mode 100644
index 0000000..2eee212
--- /dev/null
+++ b/runtime/base/safe_copy.h
@@ -0,0 +1,30 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ART_RUNTIME_BASE_SAFE_COPY_H_
+#define ART_RUNTIME_BASE_SAFE_COPY_H_
+
+#include <sys/types.h>
+
+namespace art {
+
+// Safely dereference a pointer.
+// Returns -1 if safe copy isn't implemented on the platform, 0 if src is unreadable.
+ssize_t SafeCopy(void *dst, const void *src, size_t len);
+
+} // namespace art
+
+#endif // ART_RUNTIME_BASE_SAFE_COPY_H_