swapped thread suspend/resume technique with undocumented NtProcessSu…

…spend/NtProcessResume

psutil/_psutil_windows.c

@@ -1144,8 +1144,9 @@ psutil_proc_cwd(PyObject *self, PyObject *args) {
 /*
  * Resume or suspends a process
  */
-int
-psutil_proc_suspend_or_resume(DWORD pid, int suspend) {
+// [POSSIBLE BUG]: Thread suspending is bad, 'cause programs can use their own thread suspending as a part of internal logic
+// And it's slow: https://github.com/mridgers/clink/issues/420
+int psutil_proc_suspend_or_resume_threads(DWORD pid, int suspend) {
     // a huge thanks to http://www.codeproject.com/KB/threads/pausep.aspx
     HANDLE hThreadSnap = NULL;
     HANDLE hThread;
@@ -1208,6 +1209,48 @@ psutil_proc_suspend_or_resume(DWORD pid, int suspend) {
     return TRUE;
 }
 
+// Special XP/2003 stuff
+int psutil_proc_suspend_or_resume(DWORD pid, int suspend)
+{
+    HANDLE hProcess = NULL;
+
+	typedef LONG (NTAPI *NtSuspendProcess)(IN HANDLE ProcessHandle);
+	typedef LONG (NTAPI *NtResumeProcess)(IN HANDLE ProcessHandle);
+	NtSuspendProcess pfnNtSuspendProcess = (NtSuspendProcess)GetProcAddress(GetModuleHandle("ntdll"), "NtSuspendProcess");
+    NtResumeProcess pfnNtResumeProcess = (NtResumeProcess)GetProcAddress(GetModuleHandle("ntdll"), "NtResumeProcess");
+    if (!pfnNtSuspendProcess || !pfnNtResumeProcess) {
+        PyErr_SetFromWindowsErr(0);
+        return FALSE;
+    }
+
+	if (pid == 0) {
+        AccessDenied("");
+        return FALSE;
+    }
+
+    hProcess = OpenProcess(PROCESS_SUSPEND_RESUME, FALSE, pid);
+    if (hProcess == INVALID_HANDLE_VALUE) {
+        PyErr_SetFromWindowsErr(0);
+        return FALSE;
+    }
+
+    if (suspend == 1) {
+        if (pfnNtSuspendProcess(hProcess) == (DWORD) - 1) {
+            PyErr_SetFromWindowsErr(0);
+			CloseHandle(hProcess);
+            return FALSE;
+        }
+    } else {
+        if (pfnNtResumeProcess(hProcess) == (DWORD) - 1) {
+            PyErr_SetFromWindowsErr(0);
+			CloseHandle(hProcess);
+            return FALSE;
+        }
+    }
+
+    CloseHandle(hProcess);
+    return TRUE;
+}
 
 static PyObject *
 psutil_proc_suspend(PyObject *self, PyObject *args) {