DebugActiveProcess API in delphi

[C++]

Hello i've been reading up on some APIs and I came accross this api. I was trying to code a small debugger from it that attaches itself to a process but it seems a bit difficult to implement. Found some examples but they are not coded in delphi. Can anyone show a delphi example on how to use to attach to process? (DebugActiveProcess)

[C++]

I was thinking to get handle of process by using findwindow api then OpenProcess with DebugActiveProcess api but it doesn't find handle. 

[Hero]

3 hours ago, C++ said:

I was thinking to get handle of process by using findwindow api then OpenProcess with DebugActiveProcess api but it doesn't find handle. 

I'm not quite sure I followed. When you have a window handle, you use the following api to get the process identifier: GetWindowThreadProcessId. Naturally you provide this process identifier as an argument when you call DebugActiveProcess or OpenProcess.

Edited February 9, 2018 by Hero

[C++]

2 hours ago, Hero said:

I'm not quite sure I followed. When you have a window handle, you use the following api to get the process identifier: GetWindowThreadProcessId. Naturally you provide this process identifier as an argument when you call DebugActiveProcess or OpenProcess.

I overlooked and corrected. Sorry was not fully clear of the information provided. Now here's the main problem why I was assuming I was not getting handle. After I got handle of process and to enter a debug loop. Process got stuck here  WaitForDebugEvent(De,  INFINITE);  and never passes there. Even if I manually close target. It still hangs at WaitForDebugEvent(De,  INFINITE); . If I created the process everything runs perfectly fine but trying to attach to a process that is already running with api DebugActiveProcess, everything hangs at WaitForDebugEvent . As I stated  even when closing the target. My program is still there hanging at WaitForDebugEvent(De, INFINITE);

 

I even tried openprocess with all 3 of these flags 

//PROCESS_ALL_ACCESS,
//DEBUG_PROCESS,
//DEBUG_ONLY_THIS_PROCESS,

Shows found process but still hangs at WaitForDebugEvent(De, INFINITE);

 

I also PM you with my code to see also what I did

I hope I made it clearer 

[C++]

 I figured it out. It was my mistake sorry.  If you check my code you will also see my mistake . Thanks again for help really appreciate it. 

Edited February 9, 2018 by C++
Slight correction

[Usieh]

In Delphi, you can use the DebugActiveProcess function from the Windows API https://tech-stack.com/blog/what-is-an-api/ to attach to a process and debug it. Here's a simple example of how to use it:
program DebuggingExample;

{$APPTYPE CONSOLE}

uses
  Windows,
  SysUtils;

var
  ProcessID: DWORD;

begin
  try
    // Prompt the user for the process ID to attach to
    Write('Enter the Process ID to attach to: ');
    ReadLn(ProcessID);

    // Attach to the specified process
    if DebugActiveProcess(ProcessID) then
    begin
      Writeln('Attached to process ', ProcessID);
      // You can now use debugging functionality here
      // For example, you can set breakpoints and handle debugging events
      // See the Windows API documentation for more details on debugging functions
      // ...

      // Wait for the user to press Enter before detaching
      Write('Press Enter to detach...');
      ReadLn;

      // Detach from the process
      DebugActiveProcessStop(ProcessID);
      Writeln('Detached from process ', ProcessID);
    end
    else
    begin
      Writeln('Failed to attach to process ', ProcessID);
    end;
  except
    on E: Exception do
      Writeln(E.ClassName, ': ', E.Message);
  end;
end.

This Delphi code will prompt the user to enter the Process ID of the target process to which you want to attach for debugging. It then uses DebugActiveProcess to attach to the specified process. You can add your debugging logic inside the attached block, such as setting breakpoints and handling debugging events.

Make sure you have the necessary privileges to attach to another process for debugging. You may need to run your Delphi application as an administrator to do so. Additionally, be cautious when debugging other processes, as it can have unintended consequences.

[Guruhardoi7]

Sir how I can scan  own process memory for a patten in delphi?