Suspend Process in C#

Suspend Process in C#

Here's my suggestion:

 [Flags]
    public enum ThreadAccess : int
    {
      TERMINATE = (0x0001),
      SUSPEND_RESUME = (0x0002),
      GET_CONTEXT = (0x0008),
      SET_CONTEXT = (0x0010),
      SET_INFORMATION = (0x0020),
      QUERY_INFORMATION = (0x0040),
      SET_THREAD_TOKEN = (0x0080),
      IMPERSONATE = (0x0100),
      DIRECT_IMPERSONATION = (0x0200)
    }

    [DllImport("kernel32.dll")]
    static extern IntPtr OpenThread(ThreadAccess dwDesiredAccess, bool bInheritHandle, uint dwThreadId);
    [DllImport("kernel32.dll")]
    static extern uint SuspendThread(IntPtr hThread);
    [DllImport("kernel32.dll")]
    static extern int ResumeThread(IntPtr hThread);
    [DllImport("kernel32", CharSet = CharSet.Auto,SetLastError = true)]
    static extern bool CloseHandle(IntPtr handle);


private static void SuspendProcess(int pid)
{
  var process = Process.GetProcessById(pid); // throws exception if process does not exist

  foreach (ProcessThread pT in process.Threads)
  {
    IntPtr pOpenThread = OpenThread(ThreadAccess.SUSPEND_RESUME, false, (uint)pT.Id);

    if (pOpenThread == IntPtr.Zero)
    {
      continue;
    }

    SuspendThread(pOpenThread);

    CloseHandle(pOpenThread);
  }
}

public static void ResumeProcess(int pid)
{
  var process = Process.GetProcessById(pid);

  if (process.ProcessName == string.Empty)
    return;

  foreach (ProcessThread pT in process.Threads)
  {
    IntPtr pOpenThread = OpenThread(ThreadAccess.SUSPEND_RESUME, false, (uint)pT.Id);

    if (pOpenThread == IntPtr.Zero)
    {
      continue;
    }

    var suspendCount = 0;
    do
    {
      suspendCount = ResumeThread(pOpenThread);
    } while (suspendCount > 0);

    CloseHandle(pOpenThread);
  }
}

How to check if a process is suspended? - Not not responding

Having established that the thread is waiting via it's ThreadState, you can examine the WaitReason property of the ProcessThread and see if that says it's Suspended.

Obviously, there are timing issues with performing tests such as these, since the other process is outside of your control.

How to create suspended process from c# without P/Invoke?

The only way to do this is with CreateProcess. The .net Process class does not offer the functionality. Either p/invoke CreateProcess or use a mixed mode C++/CLI assembly to call the same.

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