base/wmi_util.h

   1 // Copyright (c) 2006-2008 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 // WMI (Windows Management and Instrumentation) is a big, complex, COM-based
   6 // API that can be used to perform all sorts of things. Sometimes is the best
   7 // way to accomplish something under windows but its lack of an approachable
   8 // C++ interface prevents its use. This collection of fucntions is a step in
   9 // that direction.
  10 // There are two classes; WMIUtil and WMIProcessUtil. The first
  11 // one contain generic helpers and the second one contains the only
  12 // functionality that is needed right now which is to use WMI to launch a
  13 // process.
  14 // To use any function on this header you must call CoInitialize or
  15 // CoInitializeEx beforehand.
  16 //
  17 // For more information about WMI programming:
  18 // http://msdn2.microsoft.com/en-us/library/aa384642(VS.85).aspx
  19
  20 #ifndef BASE_WMI_UTIL_H__
  21 #define BASE_WMI_UTIL_H__
  22
  23 #include <string>
  24 #include <wbemidl.h>
  25
  26 class WMIUtil {
  27  public:
  28   // Creates an instance of the WMI service connected to the local computer and
  29   // returns its COM interface. If 'set-blanket' is set to true, the basic COM
  30   // security blanket is applied to the returned interface. This is almost
  31   // always desirable unless you set the parameter to false and apply a custom
  32   // COM security blanket.
  33   // Returns true if succeeded and 'wmi_services': the pointer to the service.
  34   // When done with the interface you must call Release();
  35   static bool CreateLocalConnection(bool set_blanket,
  36                                     IWbemServices** wmi_services);
  37
  38   // Creates a WMI method using from a WMI class named 'class_name' that
  39   // contains a method named 'method_name'. Only WMI classes that are CIM
  40   // classes can be created using this function.
  41   // Returns true if succeeded and 'class_instance' returns a pointer to the
  42   // WMI method that you can fill with parameter values using SetParameter.
  43   // When done with the interface you must call Release();
  44   static bool CreateClassMethodObject(IWbemServices* wmi_services,
  45                                       const std::wstring& class_name,
  46                                       const std::wstring& method_name,
  47                                       IWbemClassObject** class_instance);
  48
  49   // Fills a single parameter given an instanced 'class_method'. Returns true
  50   // if operation succeeded. When all the parameters are set the method can
  51   // be executed using IWbemServices::ExecMethod().
  52   static bool SetParameter(IWbemClassObject* class_method,
  53                            const std::wstring& parameter_name,
  54                            VARIANT* parameter);
  55 };
  56
  57 // This class contains functionality of the WMI class 'Win32_Process'
  58 // more info: http://msdn2.microsoft.com/en-us/library/aa394372(VS.85).aspx
  59 class WMIProcessUtil {
  60  public:
  61   // Creates a new process from 'command_line'. The advantage over CreateProcess
  62   // is that it allows you to always break out from a Job object that the caller
  63   // is attached to even if the Job object flags prevent that.
  64   // Returns true and the process id in process_id if the process is launched
  65   // successful. False otherwise.
  66   // Note that a fully qualified path must be specified in most cases unless
  67   // the program is not in the search path of winmgmt.exe.
  68   // Processes created this way are children of wmiprvse.exe and run with the
  69   // caller credentials.
  70   static bool Launch(const std::wstring& command_line, int* process_id);
  71 };
  72
  73 #endif  // BASE_WMI_UTIL_H__