Move content::MakeSharedMemorySegmentViaIPC into its own file

content/common/child_process_sandbox_support_impl_shm_linux.cc

+// Copyright (c) 2011 The Chromium Authors. All rights reserved.

[jam, 2011/12/14 01:14:28]

child_process_sandbox_support_impl_shm_linux.cc is (like the original file) not
very informative (that name means nothing to me). can we pick something more
sane? also, this should have its own header, to make it look like less of a
workaround for a build problem.

actually, looking at this more, there's only one caller of this in the nacl
code. why not just put this file in it directly and avoid this new file
altogether?

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/global_descriptors_posix.h"
+#include "base/pickle.h"
+#include "content/common/child_process_sandbox_support_impl_linux.h"
+#include "content/common/chrome_descriptors.h"
+#include "content/common/sandbox_methods_linux.h"
+#include "content/common/unix_domain_socket_posix.h"
+
+static int GetSandboxFD() {
+  return kSandboxIPCChannel + base::GlobalDescriptors::kBaseDescriptor;

[jam, 2011/12/14 01:14:28]

we shouldn't duplicate this, can we share it somehow?

+}
+
+namespace content {
+
+int MakeSharedMemorySegmentViaIPC(size_t length, bool executable) {
+  Pickle request;
+  request.WriteInt(LinuxSandbox::METHOD_MAKE_SHARED_MEMORY_SEGMENT);
+  request.WriteUInt32(length);
+  request.WriteBool(executable);
+  uint8_t reply_buf[10];
+  int result_fd;
+  ssize_t result = UnixDomainSocket::SendRecvMsg(GetSandboxFD(),
+                                                 reply_buf, sizeof(reply_buf),
+                                                 &result_fd, request);
+  if (result == -1)
+    return -1;
+  return result_fd;
+}
+
+}  // namespace content