Build services as standalone executables

services/service_manager/runner/host/native_library_runner.cc

-// Copyright 2014 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 "services/service_manager/runner/host/native_library_runner.h"
-
-#include <stddef.h>
-
-#include "base/command_line.h"
-#include "base/files/file_path.h"
-#include "base/files/file_util.h"
-#include "base/logging.h"
-#include "mojo/edk/embedder/entrypoints.h"
-#include "mojo/public/c/system/thunks.h"
-
-namespace service_manager {
-
-namespace {
-
-template <typename Thunks>
-bool SetThunks(Thunks (*make_thunks)(),
-               const char* function_name,
-               base::NativeLibrary library) {
-  typedef size_t (*SetThunksFn)(const Thunks* thunks);
-  SetThunksFn set_thunks = reinterpret_cast<SetThunksFn>(
-      base::GetFunctionPointerFromNativeLibrary(library, function_name));
-  if (!set_thunks)
-    return false;
-  Thunks thunks = make_thunks();
-  size_t expected_size = set_thunks(&thunks);
-  if (expected_size > sizeof(Thunks)) {
-    LOG(ERROR) << "Invalid library: expected " << function_name
-               << " to return thunks of size: " << expected_size;
-    return false;
-  }
-  return true;
-}
-
-}  // namespace
-
-base::NativeLibrary LoadNativeLibrary(const base::FilePath& path) {
-  DVLOG(2) << "Loading Service in process from library: " << path.value();
-
-  base::NativeLibraryLoadError error;
-  base::NativeLibrary library = base::LoadNativeLibrary(path, &error);
-  LOG_IF(ERROR, !library)
-      << "Failed to load library (path: " << path.value()
-      << " reason: " << error.ToString() << ")";
-  return library;
-}
-
-bool RunServiceInNativeLibrary(base::NativeLibrary library,
-                               mojom::ServiceRequest request) {
-  // Tolerate |library| being null, to make life easier for callers.
-  if (!library)
-    return false;
-
-// Thunks aren't needed/used in component build, since the thunked methods
-// just live in their own dynamically loaded library.
-#if !defined(COMPONENT_BUILD)
-  if (!SetThunks(&mojo::edk::MakeSystemThunks, "MojoSetSystemThunks",
-                 library)) {
-    LOG(ERROR) << "MojoSetSystemThunks not found";
-    return false;
-  }
-
-#if !defined(OS_WIN)
-  // On Windows, initializing base::CommandLine with null parameters gets the
-  // process's command line from the OS. Other platforms need it to be passed
-  // in. This needs to be passed in before the service initializes the command
-  // line, which is done as soon as it loads.
-  typedef void (*InitCommandLineArgs)(int, const char* const*);
-  InitCommandLineArgs init_command_line_args =
-      reinterpret_cast<InitCommandLineArgs>(
-          base::GetFunctionPointerFromNativeLibrary(library,
-                                                    "InitCommandLineArgs"));
-  if (init_command_line_args) {
-    int argc = 0;
-    base::CommandLine* cmd_line = base::CommandLine::ForCurrentProcess();
-    const char** argv = new const char*[cmd_line->argv().size()];
-    for (auto& arg : cmd_line->argv())
-      argv[argc++] = arg.c_str();
-    init_command_line_args(argc, argv);
-  }
-#endif
-
-#endif  // !defined(COMPONENT_BUILD)
-
-  typedef MojoResult (*ServiceMainFunction)(MojoHandle);
-  ServiceMainFunction main_function = reinterpret_cast<ServiceMainFunction>(
-      base::GetFunctionPointerFromNativeLibrary(library, "ServiceMain"));
-  if (!main_function) {
-    LOG(ERROR) << "ServiceMain not found";
-    return false;
-  }
-  // |ServiceMain()| takes ownership of the service handle.
-  MojoHandle handle = request.PassMessagePipe().release().value();
-  MojoResult result = main_function(handle);
-  if (result != MOJO_RESULT_OK) {
-    LOG(ERROR) << "ServiceMain returned error (result: " << result << ")";
-  }
-  return true;
-}
-
-}  // namespace service_manager