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 "google_update/google_update_idl.h"
  11
  12 namespace {
  13
  14 const wchar_t kChromeFrameGuid[] = L"{8BA986DA-5100-405E-AA35-86F34A02ACBF}";
  15
  16 const DWORD kLaunchFailureExitCode = 0xFF;
  17
  18 const wchar_t kUpdateCommandFlag[] = L"--update-cmd";
  19
  20 // Waits indefinitely for the provided process to exit. Returns the process's
  21 // exit code, or kLaunchFailureExitCode if an error occurs in the waiting.
  22 DWORD WaitForProcessExitCode(HANDLE handle) {
  23   DWORD exit_code = 0;
  24
  25   DWORD wait_result = ::WaitForSingleObject(handle, INFINITE);
  26
  27   if (wait_result == WAIT_OBJECT_0 && ::GetExitCodeProcess(handle, &exit_code))
  28     return exit_code;
  29
  30   return kLaunchFailureExitCode;
  31 }
  32
  33 }  // namespace
  34
  35 namespace update_launcher {
  36
  37 std::wstring GetUpdateCommandFromArguments(const wchar_t* command_line) {
  38   std::wstring command;
  39
  40   if (command_line != NULL) {
  41     int num_args = 0;
  42     wchar_t** args = NULL;
  43     args = ::CommandLineToArgvW(command_line, &num_args);
  44
  45     if (args) {
  46       if (num_args == 3 && _wcsicmp(args[1], kUpdateCommandFlag) == 0)
  47         command = args[2];
  48       ::LocalFree(args);
  49     }
  50   }
  51
  52   return command;
  53 }
  54
  55 // Because we do not have 'base' and all of its pretty RAII helpers, please
  56 // ensure that this function only ever contains a single 'return', in order
  57 // to reduce the chance of introducing a leak.
  58 DWORD LaunchUpdateCommand(const std::wstring& command) {
  59   DWORD exit_code = kLaunchFailureExitCode;
  60
  61   HRESULT hr = ::CoInitialize(NULL);
  62
  63   if (SUCCEEDED(hr)) {
  64     IProcessLauncher* ipl = NULL;
  65     HANDLE process = NULL;
  66
  67     hr = ::CoCreateInstance(__uuidof(ProcessLauncherClass), NULL,
  68                             CLSCTX_ALL, __uuidof(IProcessLauncher),
  69                             reinterpret_cast<void**>(&ipl));
  70
  71     if (SUCCEEDED(hr)) {
  72       ULONG_PTR phandle = NULL;
  73       DWORD id = ::GetCurrentProcessId();
  74
  75       hr = ipl->LaunchCmdElevated(kChromeFrameGuid,
  76                                   command.c_str(), id, &phandle);
  77       if (SUCCEEDED(hr)) {
  78         process = reinterpret_cast<HANDLE>(phandle);
  79         exit_code = WaitForProcessExitCode(process);
  80       }
  81     }
  82
  83     if (process)
  84       ::CloseHandle(process);
  85     if (ipl)
  86       ipl->Release();
  87
  88     ::CoUninitialize();
  89   }
  90
  91   return exit_code;
  92 }
  93
  94 }  // namespace process_launcher