Squashed 'libs/protobuf/' content from commit fcd3b9a85

git-subtree-dir: libs/protobuf
git-subtree-split: fcd3b9a85ef36e46643dc30176cea1a7ad62e02b

ruby/ext/google/protobuf_c/wrap_memcpy.c

@@ -0,0 +1,52 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2017 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// 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.
+
+#include <string.h>
+
+// On x86-64 Linux with glibc, we link against the 2.2.5 version of memcpy so
+// that we avoid depending on the 2.14 version of the symbol. This way,
+// distributions that are using pre-2.14 versions of glibc can successfully use
+// the gem we distribute
+// (https://github.com/protocolbuffers/protobuf/issues/2783).
+//
+// This wrapper is enabled by passing the linker flags -Wl,-wrap,memcpy in
+// extconf.rb.
+#ifdef __linux__
+#if defined(__x86_64__) && defined(__GNU_LIBRARY__)
+__asm__(".symver memcpy,memcpy@GLIBC_2.2.5");
+void *__wrap_memcpy(void *dest, const void *src, size_t n) {
+  return memcpy(dest, src, n);
+}
+#else
+void *__wrap_memcpy(void *dest, const void *src, size_t n) {
+  return memmove(dest, src, n);
+}
+#endif
+#endif