How can I find the process id from the service name/handle in Delphi?

Question

I have the service name for a windows service in delphi, and I know how to get the handle from that as well. What I need to do is stop a service, and if the stop fails for some reason I need to kill the process associated with the service. The problem is that I have multiple services running from the same executable, so I can't use the executable name to kill the process. This means I need the process id to kill the proper associated process. How can I get this id or some way to kill the proper process from the service name or handle?

Answer 1

QueryServiceStatusEx?

Answer 2

Please note I have only accepted this solution so that a full delphi code solution is accepted, all due thanks to Jk though for pointing me on the correct path.

--

Ok, I've been able to figure out how to use the answer by Jk and have come up with this solution in delphi.

For reference, this is the link provided by Jk:

QueryServiceStatusEx

My Solution:

unit Demo;

interface

uses
  Windows, Forms, SysUtils,
  StdCtrls, WinSvc, Controls, Classes;

type

  //Form for basic demo usage
  TForm6 = class(TForm)
    Button1: TButton;
    Memo1: TMemo;
    procedure Button1Click(Sender: TObject);
  end;

  //Record defined for use as return buffer
  _SERVICE_STATUS_PROCESS = record
    dwServiceType: DWORD;
    dwCurrentState: DWORD;
    dwControlsAccepted: DWORD;
    dwWin32ExitCode: DWORD;
    dwServiceSpecificExitCode: DWORD;
    dwCheckPoint: DWORD;
    dwWaitHint: DWORD;
    dwProcessId: DWORD;
    dwServiceFlags: DWORD;
  end;
  //Function Prototype
  function QueryServiceStatusEx(
  SC_HANDLE: SC_Handle;
  SC_STATUS_TYPE: Cardinal;
  out lpBuffer: _SERVICE_STATUS_PROCESS;
  cbBufSize: DWORD;
  out pcbBytesNeeded: LPDWORD
  ): BOOL; stdcall;


  //internal setup function
  function GetPid(sService: String; sMachine: String = '') : Cardinal;
var
  Form6: TForm6;

implementation

{$R *.dfm}
const
  // windows api library
  advapi32 = 'advapi32.dll';
  //define the api call
  function QueryServiceStatusEx;   external advapi32 name 'QueryServiceStatusEx';

//for demo usage
procedure TForm6.Button1Click(Sender: TObject);
begin
  Memo1.Lines.Add(IntToStr(Integer(GetPid('Service'))))
end;


function GetPid(sService: String; sMachine: String = '') : Cardinal;
var
  schm,
  schs: SC_Handle;
  SC_STATUS_TYPE: Cardinal;
  lpBuffer: _SERVICE_STATUS_PROCESS;
  cbBufSize: DWORD;
  pcbBytesNeeded: LPDWORD;
begin
  //open the service manager  (defined in WinSvc)
  schm := OpenSCManager(PChar(sMachine), nil, SC_MANAGER_CONNECT);
  //set the status type to SC_STATUS_PROCESS_INFO
  //this is currently the only value supported
  SC_STATUS_TYPE := $00000000;
  //set the buffer size to the size of the record
  cbBufSize := sizeof(_SERVICE_STATUS_PROCESS);
  if (schm>0) then
  begin
    //grab the service handle
    schs := OpenService(schm, PChar(sService), SERVICE_QUERY_STATUS);
    if (schs>0) then
    begin
      //call the function
      QueryServiceStatusEx(
      schs,
      SC_STATUS_TYPE,
      lpBuffer,
      cbBufSize,
      pcbBytesNeeded);
      CloseServiceHandle(schs);
    end;
    CloseServiceHandle(schm);
  end;
  Result := lpBuffer.dwProcessId;
end;



end.

Please note that not all external naming and other necessities are included.

Answer 3

Or use DSiWin32 for many useful functions, including DSiGetProcessID. This code was written by StackOverflow user (and programmer) Gabr.

Here's the function, for your own reference. It will give you what you are looking for:

//Retrieves ID of the specified process. Requires Toolhelp API.
//  @returns False if ID cannot be retrieved. Check GetLastError - if it is 0, process
//       doesn't exist; otherwise it contains the Win32 error code.
//  @author  gabr
//  @since   2004-02-12
//
  function DSiGetProcessID(const processName: string; var processID: DWORD): boolean;
  var
    hSnapshot: THandle;
    procEntry: TProcessEntry32;
  begin
    Result := false;
    hSnapshot := CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
    if hSnapshot = 0 then
      Exit;
    try
      procEntry.dwSize := Sizeof(procEntry);
      if not Process32First(hSnapshot, procEntry) then
        Exit;
      repeat
        if AnsiSameText(procEntry.szExeFile, processName) then begin
          processID := procEntry.th32ProcessID;
          Result := true;
          break; // repeat
        end;
      until not Process32Next(hSnapshot, procEntry);
    finally DSiCloseHandleAndNull(hSnapshot); end;
  end; { DSiGetProcessID }