#include <windows.h>
#include <tlhelp32.h>
#include <stdio.h>
#include <wchar.h>

DWORD GetProcessIdByName(const wchar_t* name);
void ListProcessThreads(DWORD owner_pid);

int main() {
  DWORD pid = GetProcessIdByName(L"Gw2.exe");
  if (pid == 0) return 1;

  ListProcessThreads(pid);
  return 0;
}

DWORD GetProcessIdByName(const wchar_t* name) {
  HANDLE process_snapshot;
  PROCESSENTRY32 process_entry;

  process_snapshot = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
  if(process_snapshot == INVALID_HANDLE_VALUE) return 0;

  process_entry.dwSize = sizeof(PROCESSENTRY32);

  if(!Process32First(process_snapshot, &process_entry)) return 0;

  do {
    if (wcscmp(process_entry.szExeFile, name) == 0) {
      CloseHandle(process_snapshot);
      return process_entry.th32ProcessID;
    }
  } while(Process32Next( process_snapshot, &process_entry));

  CloseHandle(process_snapshot);
  return 0;
}

void PrintTIB(DWORD thread_id) {
  HANDLE thread_handle = OpenThread(THREAD_GET_CONTEXT | THREAD_QUERY_INFORMATION, FALSE, thread_id);
  if (thread_handle == NULL) return;

  SuspendThread(thread_handle);

  CONTEXT context;
  context.ContextFlags = CONTEXT_SEGMENTS;
  if (!GetThreadContext(thread_handle, &context)) {
    CloseHandle(thread_handle);
    return;
  }

  LDT_ENTRY ldtSel;
  if (!GetThreadSelectorEntry(thread_handle, context.SegFs, &ldtSel)) return;

  ResumeThread(thread_handle);

  DWORD fs_base = (ldtSel.HighWord.Bits.BaseHi << 24 ) | ( ldtSel.HighWord.Bits.BaseMid << 16 ) | ( ldtSel.BaseLow );
  fwprintf(stdout, L"[i] FS:[0] (TIB) is @ 0x%08X\n", fs_base);
}

void ListProcessThreads(DWORD owner_pid) {
  HANDLE thread_snapshot = INVALID_HANDLE_VALUE;
  THREADENTRY32 thread_entry;

  thread_snapshot = CreateToolhelp32Snapshot( TH32CS_SNAPTHREAD, 0 );
  if(thread_snapshot == INVALID_HANDLE_VALUE) return;

  thread_entry.dwSize = sizeof(THREADENTRY32);

  if(!Thread32First(thread_snapshot, &thread_entry )) return;

  do {
    if (thread_entry.th32OwnerProcessID == owner_pid) {
      fwprintf(stdout, L"[i] thread_id = %d \n", thread_entry.th32ThreadID);
      PrintTIB(thread_entry.th32ThreadID);
    }
  } while(Thread32Next(thread_snapshot, &thread_entry ));

  CloseHandle(thread_snapshot);
}