chrome_frame/update_launcher.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "chrome_frame/update_launcher.h"
   6
   7 #include <windows.h>
   8 #include <Shellapi.h>
   9
  10 #include "base/win/scoped_com_initializer.h"
  11 #include "google_update/google_update_idl.h"
  12
  13 namespace {
  14
  15 const wchar_t kChromeFrameGuid[] = L"{8BA986DA-5100-405E-AA35-86F34A02ACBF}";
  16
  17 const DWORD kLaunchFailureExitCode = 0xFF;
  18
  19 const wchar_t kUpdateCommandFlag[] = L"--update-cmd";
  20
  21 // Waits indefinitely for the provided process to exit. Returns the process's
  22 // exit code, or kLaunchFailureExitCode if an error occurs in the waiting.
  23 DWORD WaitForProcessExitCode(HANDLE handle) {
  24   DWORD exit_code = 0;
  25   return ((::WaitForSingleObject(handle, INFINITE) == WAIT_OBJECT_0) &&
  26           ::GetExitCodeProcess(handle, &exit_code)) ?
  27       exit_code : kLaunchFailureExitCode;
  28 }
  29
  30 }  // namespace
  31
  32 namespace update_launcher {
  33
  34 std::wstring GetUpdateCommandFromArguments(const wchar_t* command_line) {
  35   std::wstring command;
  36
  37   if (command_line != NULL) {
  38     int num_args = 0;
  39     wchar_t** args = NULL;
  40     args = ::CommandLineToArgvW(command_line, &num_args);
  41
  42     if (args) {
  43       if (num_args == 3 && _wcsicmp(args[1], kUpdateCommandFlag) == 0)
  44         command = args[2];
  45       ::LocalFree(args);
  46     }
  47   }
  48
  49   return command;
  50 }
  51
  52 // Because we do not have 'base' and all of its pretty RAII helpers, please
  53 // ensure that this function only ever contains a single 'return', in order
  54 // to reduce the chance of introducing a leak.
  55 DWORD LaunchUpdateCommand(const std::wstring& command) {
  56   DWORD exit_code = kLaunchFailureExitCode;
  57
  58   base::win::ScopedCOMInitializer com_initializer;
  59   if (com_initializer.succeeded()) {
  60     IProcessLauncher* ipl = NULL;
  61     HANDLE process = NULL;
  62
  63     HRESULT hr = ::CoCreateInstance(__uuidof(ProcessLauncherClass), NULL,
  64                                     CLSCTX_ALL, __uuidof(IProcessLauncher),
  65                                     reinterpret_cast<void**>(&ipl));
  66
  67     if (SUCCEEDED(hr)) {
  68       ULONG_PTR phandle = NULL;
  69       DWORD id = ::GetCurrentProcessId();
  70
  71       hr = ipl->LaunchCmdElevated(kChromeFrameGuid,
  72                                   command.c_str(), id, &phandle);
  73       if (SUCCEEDED(hr)) {
  74         process = reinterpret_cast<HANDLE>(phandle);
  75         exit_code = WaitForProcessExitCode(process);
  76       }
  77     }
  78
  79     if (process)
  80       ::CloseHandle(process);
  81     if (ipl)
  82       ipl->Release();
  83   }
  84
  85   return exit_code;
  86 }
  87
  88 }  // namespace process_launcher