How Can I Retrieve a Process Handle by Name in C ?

Retrieving Process Handle by Name in C

In C , you may encounter situations where you need to manipulate a process based on its name. For example, you might want to terminate a process known as "example.exe" without relying on window handles. This question delves into this specific scenario and presents a solution.

To retrieve the process handle by its name, we can leverage the Windows API functions CreateToolhelp32Snapshot and Process32Next. Here's a code snippet that demonstrates this approach:

#include <cstdio>
#include <windows.h>
#include <tlhelp32.h>

int main() {
  // Create a snapshot of running processes
  HANDLE snapshot = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);

  // Iterate over the processes
  PROCESSENTRY32 entry;
  entry.dwSize = sizeof(PROCESSENTRY32);
  if (Process32First(snapshot, &entry) == TRUE) {
    while (Process32Next(snapshot, &entry) == TRUE) {
      // Check if this is the process we want
      if (strcmp(entry.szExeFile, "example.exe") == 0) {
        // Open a handle to the process
        HANDLE hProcess = OpenProcess(PROCESS_ALL_ACCESS, FALSE, entry.th32ProcessID);
        // Perform desired operations on the process
        CloseHandle(hProcess);  // Close the handle
      }
    }
  }

  CloseHandle(snapshot);  // Close the snapshot handle
  return 0;
}

This solution will iterate through all running processes and compare their executable names with "example.exe". Once a match is found, a handle to that process is obtained and can be used to perform operations such as termination (via TerminateProcess).

Note: If you plan to use PROCESS_ALL_ACCESS in OpenProcess, you might need to elevate your process's privileges by enabling the SE_DEBUG_NAME privilege. Code to do this is shown below:

void EnableDebugPriv() {
  // Enable debug privilege
  HANDLE hToken;
  LUID luid;
  TOKEN_PRIVILEGES tkp;
  OpenProcessToken(GetCurrentProcess(), TOKEN_ADJUST_PRIVILEGES | TOKEN_QUERY, &hToken);
  LookupPrivilegeValue(NULL, SE_DEBUG_NAME, &luid);
  tkp.PrivilegeCount = 1;
  tkp.Privileges[0].Luid = luid;
  tkp.Privileges[0].Attributes = SE_PRIVILEGE_ENABLED;
  AdjustTokenPrivileges(hToken, false, &tkp, sizeof(tkp), NULL, NULL);
  CloseHandle(hToken);
}

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