Question

I want my C++ program to scan for processes and when a certain file.exe is running, I want my program to do something (irrelevant here). Could you help me with this task?

I found something on the internet. Is this ok ?

CreateMutex(NULL, FALSE, NAMEofTHEprocess_exe);
if (GetLastError() == ERROR_ALREADY_EXISTS)return 0;

Can I use it in my program? I dont know what the Mutex is.

Answer 1

Here’s a basic enumeration of running processes in Windows:

#define  WINVER      0x0500
#define _WIN32_WINNT 0x0500
#define  PSAPI_VERSION    1
#include <windows.h>
#include <tchar.h>
#include <psapi.h>
#include <sddl.h>

void ListProcesses()
{
  DWORD aProcesses[1024], cbNeeded, cProcesses;
  MEMORYSTATUSEX statex;

  statex.dwLength = sizeof(statex);

  ::GlobalMemoryStatusEx(&statex);

  ::EnumProcesses(aProcesses, sizeof(aProcesses), &cbNeeded);
  cProcesses = cbNeeded / sizeof(DWORD);

  for (size_t i = 0; i < cProcesses; ++i)
    if(aProcesses[i] != 0)
      std::cout << "PID: " << aProcesses[i] << ", Name: " << getProcessNameByID(aProcesses[i]) << std::endl;
}

You can use the final name look-up with getProcessNameByID to make a decision. Here’s the code for getProcessPathNameByID:

#include <tchar.h>

std::string getProcessNameByHandle(HANDLE hProcess)
{
  if (NULL == hProcess)
    return "<unknown>";

  TCHAR szProcessName[MAX_PATH] = TEXT("<unknown>");
  HMODULE hMod;
  DWORD cbNeeded;

  if (::EnumProcessModules(hProcess, &hMod, sizeof(hMod), &cbNeeded))
    ::GetModuleBaseName(hProcess, hMod, szProcessName, sizeof(szProcessName)/sizeof(TCHAR));

  return std::string(szProcessName);
}

std::string getProcessNameByID(DWORD processID)
{
  HANDLE      hProcess = ::OpenProcess(PROCESS_QUERY_INFORMATION | PROCESS_VM_READ, FALSE, processID);
  std::string result   = getProcessNameByHandle(hProcess);
  ::CloseHandle(hProcess);

  return result;
}