delphi - Determine the parent process of the current app

Question

I wrote this utility (exe) which can be called from within this host application. And I'd prefer it that the utility can only be called from the host application. Running it from the outside or a different host should terminate the utility immediately.

Is there a way to find out which process launched my utility?

Thanks for the replies.

Answer 1

You can use the CreateToolhelp32Snapshot function to enumerate the running process list and then the Process32First function to get the th32ParentProcessID which is the identifier of the process that created this process (its parent process).

See this example .

uses
  Psapi,
  Windows,
  tlhelp32,
  SysUtils;

function GetTheParentProcessFileName(): String;
const
  BufferSize = 4096;
var
  HandleSnapShot  : THandle;
  EntryParentProc : TProcessEntry32;
  CurrentProcessId: DWORD;
  HandleParentProc: THandle;
  ParentProcessId : DWORD;
  ParentProcessFound  : Boolean;
  ParentProcPath      : String;

begin
  ParentProcessFound := False;
  HandleSnapShot := CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);   //enumerate the process
  if HandleSnapShot <> INVALID_HANDLE_VALUE then
  begin
    EntryParentProc.dwSize := SizeOf(EntryParentProc);
    if Process32First(HandleSnapShot, EntryParentProc) then    //find the first process
    begin
      CurrentProcessId := GetCurrentProcessId(); //get the id of the current process
      repeat
        if EntryParentProc.th32ProcessID = CurrentProcessId then
        begin
          ParentProcessId := EntryParentProc.th32ParentProcessID; //get the id of the parent process
          HandleParentProc := OpenProcess(PROCESS_QUERY_INFORMATION or PROCESS_VM_READ, False, ParentProcessId);
          if HandleParentProc <> 0 then
          begin
              ParentProcessFound := True;
              SetLength(ParentProcPath, BufferSize);
              GetModuleFileNameEx(HandleParentProc, 0, PChar(ParentProcPath),BufferSize);
              ParentProcPath := PChar(ParentProcPath);
              CloseHandle(HandleParentProc);
          end;
          break;
        end;
      until not Process32Next(HandleSnapShot, EntryParentProc);
    end;
    CloseHandle(HandleSnapShot);
  end;

  if ParentProcessFound then
    Result := ParentProcPath
  else
    Result := '';
end;