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 <iostream>
+
+#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 "native_client/src/untrusted/irt/irt_dev.h"
+
+void serve_link_request(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);
+
+  // Read / Wait until we can get the object file name.
+  MojoResult result;
+  char object_file_name[PATH_MAX];
+  uint32_t path_size = sizeof(object_file_name);
+  do {
+    result = MojoReadMessage(handle,
+                             object_file_name,
+                             &path_size,
+                             nullptr,
+                             nullptr,
+                             MOJO_READ_MESSAGE_FLAG_NONE);
+    if (result == MOJO_RESULT_SHOULD_WAIT) {
+      result = MojoWait(handle,
+                        MOJO_HANDLE_SIGNAL_READABLE,
+                        MOJO_DEADLINE_INDEFINITE,
+                        nullptr);
+      if (result != MOJO_RESULT_OK)
+        LOG(FATAL) << "Pexe linker could not wait for object file name";
+    } else {
+      break;
+    }
+  } while (true);
+  if (result != MOJO_RESULT_OK)
+    LOG(FATAL) << "Pexe linker could not read object file name";
+  object_file_name[path_size] = '\0';
+
+  // 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, O_RDONLY) };
+  if (unlink(object_file_name))
+    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";
+
+  // Give the name of the resultant nexe back to the content handler
+  // so it may be launched.
+  result = MojoWriteMessage(handle,
+                            nexe_file_name.value().c_str(),
+                            nexe_file_name.value().size(),
+                            nullptr,
+                            0,
+                            MOJO_WRITE_MESSAGE_FLAG_NONE);
+
+  if (result != MOJO_RESULT_OK)
+    LOG(FATAL) << "Could not write message to content handler: " << result;
+}
+
+const struct nacl_irt_private_pnacl_translator_link
+    nacl_irt_private_pnacl_translator_link = {
+  serve_link_request
+};