Pre-load a program in VBScript for more efficient execution - vbscript

Question

I have a VBS script (compiled to an .exe, actually) that invokes another program (.exe) using the VBS Run instruction. My mainframe mentality tells me that it would be beneficial to pre-load this second program at the start of my script, so that it is available immediately when needed further down the line. Typically on mainframe, when appropriate, one would LOAD the program into memory at some point and then branch to it later.
Does this concept exist in VBS?
Thanks for any advice.

Answer 1

It is easy to start a program in a suspended state, but I have still not found a way to later resume the execution without a external tool (we need to call ResumeThread API). For this sample I have used the Windows SysInternal's PsSuspend tool to resume the process.
Option Explicit
Const SW_NORMAL = 1
Const CF_CREATE_SUSPENDED = 4
Const PROCESS_NAME = "Notepad.exe"
' Instantiate required objects
Dim wmi, shell
Set wmi = GetObject("winmgmts:{impersonationLevel=impersonate}!\\.\root\cimv2")
Set shell = WScript.CreateObject("WScript.Shell")
' Prepare the startup configuration for the process
' https://msdn.microsoft.com/en-us/library/aa394375%28v=vs.85%29.aspx
Dim startUp
Set startUp = wmi.Get("Win32_ProcessStartup").SpawnInstance_
With startUp
.ShowWindow = SW_NORMAL
.CreateFlags = CF_CREATE_SUSPENDED
End With
' Start the process
' https://msdn.microsoft.com/en-us/library/aa394372%28v=vs.85%29.aspx
Dim retCode, processID
retCode = wmi.Get("Win32_Process").Create( PROCESS_NAME, Null, startUp, processID )
If retCode <> 0 Then
Wscript.Echo "Process creation failed: " & retCode
WScript.Quit 1
End If
WScript.Echo "Process created with PID: " & processID
' Ask the OS to check for presence of our process
WScript.Echo shell.Exec("tasklist /fo:list /v /fi ""imagename eq " & PROCESS_NAME & """").StdOut.ReadAll()
' Wait (not required, just for testing)
WScript.Sleep 5000
' Resume the process - SysInternals pssuspend required
' https://technet.microsoft.com/en-us/sysinternals/pssuspend.aspx
Call shell.Run("pssuspend64.exe /accepteula -r " & processID, 0, False)
' Wait for the process to resume and show again the task list
WScript.Sleep 2000
WScript.Echo shell.Exec("tasklist /fo:list /v /fi ""imagename eq " & PROCESS_NAME & """").StdOut.ReadAll()