Creating a pexe content handler to translate and run pexes.

mojo/nacl/nonsfi/irt_pnacl_translator_link.cc

+// Copyright 2015 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 <fcntl.h>
+
+#include "base/files/file_util.h"
+#include "base/logging.h"
+#include "mojo/nacl/nonsfi/irt_mojo_nonsfi.h"
+#include "mojo/public/cpp/bindings/string.h"
+#include "mojo/public/cpp/bindings/strong_binding.h"
+#include "mojo/public/cpp/utility/run_loop.h"
+#include "native_client/src/untrusted/irt/irt_dev.h"
+#include "services/nacl/pnacl_link.mojom.h"
+
+namespace {
+
+class PexeLinkerImpl : public mojo::nacl::PexeLinker {
+ public:
+  PexeLinkerImpl(mojo::ScopedMessagePipeHandle handle,
+                 int (*func)(int nexe_fd, const int* obj_file_fds,

[Mark Seaborn, 2015/10/27 17:30:20]

It might be worth typedef'ing this in this file to avoid repetition.

[Sean Klein, 2015/10/28 17:02:41]

Done.

+                             int obj_file_fd_count))
+      : func_(func), strong_binding_(this, handle.Pass()) {}
+  void PexeLink(const mojo::String& object_file_name,
+                const mojo::Callback<void(mojo::String)>& callback)
+      override {
+    // Create a temporary .nexe file which will be the result of calling our
+    // linker.
+    base::FilePath nexe_file_name;
+    if (!CreateTemporaryFile(&nexe_file_name))
+      LOG(FATAL) << "Could not create temporary nexe file";
+    int nexe_file_fd = open(nexe_file_name.value().c_str(), O_RDWR);
+    if (nexe_file_fd < 0)
+      LOG(FATAL) << "Could not create temp file for linked nexe";
+
+    // Open our temporary object file. Additionally, unlink it, since it is a
+    // temporary file that is no longer needed after it is opened.
+    size_t obj_file_fd_count = 1;
+    int obj_file_fds[] = { open(object_file_name.get().c_str(), O_RDONLY) };

[Mark Seaborn, 2015/10/27 17:30:20]

Can you use "int obj_file_fds = open(...)" here too?

[Sean Klein, 2015/10/28 17:02:41]

Done.

+    if (unlink(object_file_name.get().c_str()))
+      LOG(FATAL) << "Could not unlink temporary object file";
+    if (obj_file_fds[0] < 0)
+      LOG(FATAL) << "Could not open object file";
+
+    if (func_(nexe_file_fd, obj_file_fds, obj_file_fd_count))
+      LOG(FATAL) << "Error calling func on object file";
+
+    // Return the name of the nexe file.
+    callback.Run(mojo::String(nexe_file_name.value()));
+  }
+ private:
+  int (*func_)(int nexe_fd, const int* obj_file_fds, int obj_file_fd_count);
+  mojo::StrongBinding<mojo::nacl::PexeLinker> strong_binding_;
+};
+
+void ServeLinkRequest(int (*func)(int nexe_fd,
+                                  const int* obj_file_fds,
+                                  int obj_file_fd_count)) {
+  // Acquire the handle -- this is our mechanism to contact the
+  // content handler which called us.
+  MojoHandle handle;
+  nacl::MojoGetInitialHandle(&handle);
+
+  // Convert the MojoHandle into a ScopedMessagePipeHandle, and use that to
+  // implement the PexeLinker interface.
+  PexeLinkerImpl impl(
+      mojo::ScopedMessagePipeHandle(mojo::MessagePipeHandle(handle)).Pass(),
+      func);
+  mojo::RunLoop::current()->RunUntilIdle();
+}
+
+}  // namespace anonymous
+
+namespace nacl {
+
+const struct nacl_irt_private_pnacl_translator_link
+    nacl_irt_private_pnacl_translator_link = {
+  ServeLinkRequest
+};
+
+}  // namespace nacl