auto_start_helper.cpp

#include "pch.h"
#include "auto_start_helper.h"

#include <Lmcons.h>

#include <comdef.h>
#include <taskschd.h>
#pragma comment(lib, "taskschd.lib")
#pragma comment(lib, "comsupp.lib")

#include <Shlobj.h>

// Helper macros from wix.
// TODO: use "s" and "..." parameters to report errors from these functions.
#define ExitOnFailure(x,s,...)   if (FAILED(x)) { goto LExit; }
#define ExitWithLastError(x,s,...) { DWORD Dutil_er = ::GetLastError(); x = HRESULT_FROM_WIN32(Dutil_er); if (!FAILED(x)) { x = E_FAIL; }  goto LExit; }
#define ExitFunction()        { goto LExit; }


const DWORD USERNAME_DOMAIN_LEN = DNLEN + UNLEN + 2; // Domain Name + '\' + User Name + '\0'
const DWORD USERNAME_LEN = UNLEN + 1; // User Name + '\0'


bool enable_auto_start_task_for_this_user() {
  HRESULT hr = S_OK;

  WCHAR username_domain[USERNAME_DOMAIN_LEN];
  WCHAR username[USERNAME_LEN];

  std::wstring wstrTaskName;

  ITaskService *pService = NULL;
  ITaskFolder *pTaskFolder = NULL;
  ITaskDefinition *pTask = NULL;
  IRegistrationInfo *pRegInfo = NULL;
  ITaskSettings *pSettings = NULL;
  ITriggerCollection *pTriggerCollection = NULL;
  IRegisteredTask *pRegisteredTask = NULL;

  // ------------------------------------------------------
  // Get the Domain/Username for the trigger.
  if (!GetEnvironmentVariable(L"USERNAME", username, USERNAME_LEN)) {
    ExitWithLastError(hr, "Getting username failed: %x", hr);
  }
  if (!GetEnvironmentVariable(L"USERDOMAIN", username_domain, USERNAME_DOMAIN_LEN)) {
    ExitWithLastError(hr, "Getting the user's domain failed: %x", hr);
  }
  wcscat_s(username_domain, L"\\");
  wcscat_s(username_domain, username);

  // Task Name.
  wstrTaskName = L"Autorun for ";
  wstrTaskName += username;

  // Get the executable path passed to the custom action.
  WCHAR wszExecutablePath[MAX_PATH];
  GetModuleFileName(NULL, wszExecutablePath, MAX_PATH);

  // ------------------------------------------------------
  // Create an instance of the Task Service.
  hr = CoCreateInstance(CLSID_TaskScheduler,
    NULL,
    CLSCTX_INPROC_SERVER,
    IID_ITaskService,
    (void**)&pService);
  ExitOnFailure(hr, "Failed to create an instance of ITaskService: %x", hr);

  // Connect to the task service.
  hr = pService->Connect(_variant_t(), _variant_t(),
    _variant_t(), _variant_t());
  ExitOnFailure(hr, "ITaskService::Connect failed: %x", hr);

  // ------------------------------------------------------
  // Get the PowerToys task folder. Creates it if it doesn't exist.
  hr = pService->GetFolder(_bstr_t(L"\\PowerToys"), &pTaskFolder);
  if (FAILED(hr)) {
    // Folder doesn't exist. Get the Root folder and create the PowerToys subfolder.
    ITaskFolder *pRootFolder = NULL;
    hr = pService->GetFolder(_bstr_t(L"\\"), &pRootFolder);
    ExitOnFailure(hr, "Cannot get Root Folder pointer: %x", hr);
    hr = pRootFolder->CreateFolder(_bstr_t(L"\\PowerToys"), _variant_t(L""), &pTaskFolder);
    if (FAILED(hr)) {
      pRootFolder->Release();
      ExitOnFailure(hr, "Cannot create PowerToys task folder: %x", hr);
    }
  }

  // If the task exists, just enable it.
  {
    IRegisteredTask *pExistingRegisteredTask = NULL;
    hr=pTaskFolder->GetTask(_bstr_t(wstrTaskName.c_str()), &pExistingRegisteredTask);
    if (SUCCEEDED(hr)) {
      // Task exists, try enabling it.
      hr = pExistingRegisteredTask->put_Enabled(VARIANT_TRUE);
      pExistingRegisteredTask->Release();
      if (SUCCEEDED(hr)) {
        // Function enable. Sounds like a success.
        ExitFunction();
      }
    }
  }

  // Create the task builder object to create the task.
  hr = pService->NewTask(0, &pTask);
  ExitOnFailure(hr, "Failed to create a task definition: %x", hr);

  // ------------------------------------------------------
  // Get the registration info for setting the identification.
  hr = pTask->get_RegistrationInfo(&pRegInfo);
  ExitOnFailure(hr, "Cannot get identification pointer: %x", hr);
  hr = pRegInfo->put_Author(_bstr_t(username_domain));
  ExitOnFailure(hr, "Cannot put identification info: %x", hr);

  // ------------------------------------------------------
  // Create the settings for the task
  hr = pTask->get_Settings(&pSettings);
  ExitOnFailure(hr, "Cannot get settings pointer: %x", hr);

  hr = pSettings->put_StartWhenAvailable(VARIANT_FALSE);
  ExitOnFailure(hr, "Cannot put_StartWhenAvailable setting info: %x", hr);
  hr = pSettings->put_StopIfGoingOnBatteries(VARIANT_FALSE);
  ExitOnFailure(hr, "Cannot put_StopIfGoingOnBatteries setting info: %x", hr);
  hr = pSettings->put_ExecutionTimeLimit(_bstr_t(L"PT0S")); //Unlimited
  ExitOnFailure(hr, "Cannot put_ExecutionTimeLimit setting info: %x", hr);
  hr = pSettings->put_DisallowStartIfOnBatteries(VARIANT_FALSE);
  ExitOnFailure(hr, "Cannot put_DisallowStartIfOnBatteries setting info: %x", hr);

  // ------------------------------------------------------
  // Get the trigger collection to insert the logon trigger.
  hr = pTask->get_Triggers(&pTriggerCollection);
  ExitOnFailure(hr, "Cannot get trigger collection: %x", hr);

  // Add the logon trigger to the task.
  {
    ITrigger *pTrigger = NULL;
    ILogonTrigger *pLogonTrigger = NULL;
    hr = pTriggerCollection->Create(TASK_TRIGGER_LOGON, &pTrigger);
    ExitOnFailure(hr, "Cannot create the trigger: %x", hr);

    hr = pTrigger->QueryInterface(
      IID_ILogonTrigger, (void**)&pLogonTrigger);
    pTrigger->Release();
    ExitOnFailure(hr, "QueryInterface call failed for ILogonTrigger: %x", hr);

    hr = pLogonTrigger->put_Id(_bstr_t(L"Trigger1"));

    // Timing issues may make explorer not be started when the task runs.
    // Add a little delay to mitigate this.
    hr = pLogonTrigger->put_Delay(_bstr_t(L"PT03S"));

    // Define the user. The task will execute when the user logs on.
    // The specified user must be a user on this computer.
    hr = pLogonTrigger->put_UserId(_bstr_t(username_domain));
    pLogonTrigger->Release();
    ExitOnFailure(hr, "Cannot add user ID to logon trigger: %x", hr);
  }

  // ------------------------------------------------------
  // Add an Action to the task. This task will execute the path passed to this custom action.
  {
    IActionCollection *pActionCollection = NULL;
    IAction *pAction = NULL;
    IExecAction *pExecAction = NULL;

    // Get the task action collection pointer.
    hr = pTask->get_Actions(&pActionCollection);
    ExitOnFailure(hr, "Cannot get Task collection pointer: %x", hr);

    // Create the action, specifying that it is an executable action.
    hr = pActionCollection->Create(TASK_ACTION_EXEC, &pAction);
    pActionCollection->Release();
    ExitOnFailure(hr, "Cannot create the action: %x", hr);

    // QI for the executable task pointer.
    hr = pAction->QueryInterface(
      IID_IExecAction, (void**)&pExecAction);
    pAction->Release();
    ExitOnFailure(hr, "QueryInterface call failed for IExecAction: %x", hr);

    // Set the path of the executable to PowerToys (passed as CustomActionData).
    hr = pExecAction->put_Path(_bstr_t(wszExecutablePath));
    pExecAction->Release();
    ExitOnFailure(hr, "Cannot set path of executable: %x", hr);
  }

  // ------------------------------------------------------
  // Create the principal for the task
  {
    IPrincipal *pPrincipal = NULL;
    hr = pTask->get_Principal(&pPrincipal);
    ExitOnFailure(hr, "Cannot get principal pointer: %x", hr);

    // Set up principal information:
    hr = pPrincipal->put_Id(_bstr_t(L"Principal1"));

    hr = pPrincipal->put_UserId(_bstr_t(username_domain));

    hr = pPrincipal->put_LogonType(TASK_LOGON_INTERACTIVE_TOKEN);

    // Run the task with the highest available privileges.
    if (IsUserAnAdmin()) {
      hr = pPrincipal->put_RunLevel(_TASK_RUNLEVEL::TASK_RUNLEVEL_HIGHEST);
    } else {
      hr = pPrincipal->put_RunLevel(_TASK_RUNLEVEL::TASK_RUNLEVEL_LUA);
    }
    pPrincipal->Release();
    ExitOnFailure(hr, "Cannot put principal run level: %x", hr);
  }
  // ------------------------------------------------------
  //  Save the task in the PowerToys folder.
  hr = pTaskFolder->RegisterTaskDefinition(
    _bstr_t(wstrTaskName.c_str()),
    pTask,
    TASK_CREATE_OR_UPDATE,
    _variant_t(username_domain),
    _variant_t(),
    TASK_LOGON_INTERACTIVE_TOKEN,
    _variant_t(L""),
    &pRegisteredTask);
  ExitOnFailure(hr, "Error saving the Task : %x", hr);

LExit:
  if (pService) pService->Release();
  if (pTaskFolder) pTaskFolder->Release();
  if (pTask) pTask->Release();
  if (pRegInfo) pRegInfo->Release();
  if (pSettings) pSettings->Release();
  if (pTriggerCollection) pTriggerCollection->Release();
  if (pRegisteredTask) pRegisteredTask->Release();

  return(SUCCEEDED(hr));
}

bool disable_auto_start_task_for_this_user() {
  HRESULT hr = S_OK;

  WCHAR username[USERNAME_LEN];
  std::wstring wstrTaskName;

  ITaskService *pService = NULL;
  ITaskFolder *pTaskFolder = NULL;

  // ------------------------------------------------------
  // Get the Username for the task.
  if (!GetEnvironmentVariable(L"USERNAME", username, USERNAME_LEN)) {
    ExitWithLastError(hr, "Getting username failed: %x", hr);
  }

  // Task Name.
  wstrTaskName = L"Autorun for ";
  wstrTaskName += username;

  // ------------------------------------------------------
  // Create an instance of the Task Service.
  hr = CoCreateInstance(CLSID_TaskScheduler,
    NULL,
    CLSCTX_INPROC_SERVER,
    IID_ITaskService,
    (void**)&pService);
  ExitOnFailure(hr, "Failed to create an instance of ITaskService: %x", hr);

  // Connect to the task service.
  hr = pService->Connect(_variant_t(), _variant_t(),
    _variant_t(), _variant_t());
  ExitOnFailure(hr, "ITaskService::Connect failed: %x", hr);

  // ------------------------------------------------------
  // Get the PowerToys task folder.
  hr = pService->GetFolder(_bstr_t(L"\\PowerToys"), &pTaskFolder);
  if (FAILED(hr)) {
    // Folder doesn't exist. No need to disable a non-existing task.
    hr = S_OK;
    ExitFunction();
  }

  // ------------------------------------------------------
  // If the task exists, disable.
  {
    IRegisteredTask *pExistingRegisteredTask = NULL;
    hr = pTaskFolder->GetTask(_bstr_t(wstrTaskName.c_str()), &pExistingRegisteredTask);
    if (SUCCEEDED(hr)) {
      // Task exists, try disabling it.
      hr = pExistingRegisteredTask->put_Enabled(VARIANT_FALSE);
      pExistingRegisteredTask->Release();
      if (SUCCEEDED(hr)) {
        // Function disable. Sounds like a success.
        ExitFunction();
      }
    }
  }

LExit:
  if (pService) pService->Release();
  if (pTaskFolder) pTaskFolder->Release();

  return(SUCCEEDED(hr));
}

bool is_auto_start_task_active_for_this_user(){
  HRESULT hr = S_OK;

  WCHAR username[USERNAME_LEN];
  std::wstring wstrTaskName;

  ITaskService *pService = NULL;
  ITaskFolder *pTaskFolder = NULL;

  // ------------------------------------------------------
  // Get the Username for the task.
  if (!GetEnvironmentVariable(L"USERNAME", username, USERNAME_LEN)) {
    ExitWithLastError(hr, "Getting username failed: %x", hr);
  }

  // Task Name.
  wstrTaskName = L"Autorun for ";
  wstrTaskName += username;

  // ------------------------------------------------------
  // Create an instance of the Task Service.
  hr = CoCreateInstance(CLSID_TaskScheduler,
    NULL,
    CLSCTX_INPROC_SERVER,
    IID_ITaskService,
    (void**)&pService);
  ExitOnFailure(hr, "Failed to create an instance of ITaskService: %x", hr);

  // Connect to the task service.
  hr = pService->Connect(_variant_t(), _variant_t(),
    _variant_t(), _variant_t());
  ExitOnFailure(hr, "ITaskService::Connect failed: %x", hr);

  // ------------------------------------------------------
  // Get the PowerToys task folder.
  hr = pService->GetFolder(_bstr_t(L"\\PowerToys"), &pTaskFolder);
  ExitOnFailure(hr, "ITaskFolder doesn't exist: %x", hr);

  // ------------------------------------------------------
  // If the task exists, disable.
  {
    IRegisteredTask *pExistingRegisteredTask = NULL;
    hr = pTaskFolder->GetTask(_bstr_t(wstrTaskName.c_str()), &pExistingRegisteredTask);
    if (SUCCEEDED(hr)) {
      // Task exists, get its value.
      VARIANT_BOOL is_enabled;
      hr = pExistingRegisteredTask->get_Enabled(&is_enabled);
      pExistingRegisteredTask->Release();
      if (SUCCEEDED(hr)) {
        // Got the value. Return it.
        hr = (is_enabled == VARIANT_TRUE) ? S_OK : E_FAIL; // Fake success or fail to return the value.
        ExitFunction();
      }
    }
  }

LExit:
  if (pService) pService->Release();
  if (pTaskFolder) pTaskFolder->Release();

  return(SUCCEEDED(hr));

}