I need to check whether a program (xyz.exe) is running, but only for the current user. Whatever method is used cannot require elevated rights, and has to run fast (so WMI is out).
Process.GetProcessesByName("xyz") returns results for "xyz" for all logged in users... but I only care about the current user.
Ideas?
Use the current process SessionId to filter the list of processes:
public static bool IsProcessRunningSameSession(string processName)
{
var currentSessionID = Process.GetCurrentProcess().SessionId;
return Process.GetProcessesByName(processName).Where(p => p.SessionId == currentSessionID).Any();
}
I found the answer here: http://dotbay.blogspot.com/2009/06/finding-owner-of-process-in-c.html
I'll copy/paste it in case that blog ever goes by-by.
////
// 'WindowsIdentity' Extension Method Demo:
// Enumerate all running processes with their associated Windows Identity
////
foreach (var p in Process.GetProcesses())
{
string processName;
try
{
processName = p.WindowsIdentity().Name;
}
catch (Exception ex)
{
processName = ex.Message; // Probably "Access is denied"
}
Console.WriteLine(p.ProcessName + " (" + processName + ")");
}
Here's the corresponding class:
//-----------------------------------------------------------------------
// <copyright file="ProcessExtensions.cs" company="DockOfTheBay">
// http://www.dotbay.be
// </copyright>
// <summary>Defines the ProcessExtensions class.</summary>
//-----------------------------------------------------------------------
namespace DockOfTheBay
{
using System;
using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Security.Principal;
/// <summary>
/// Extension Methods for the System.Diagnostics.Process Class.
/// </summary>
public static class ProcessExtensions
{
/// <summary>
/// Required to query an access token.
/// </summary>
private static uint TOKEN_QUERY = 0x0008;
/// <summary>
/// Returns the WindowsIdentity associated to a Process
/// </summary>
/// <param name="process">The Windows Process.</param>
/// <returns>The WindowsIdentity of the Process.</returns>
/// <remarks>Be prepared for 'Access Denied' Exceptions</remarks>
public static WindowsIdentity WindowsIdentity(this Process process)
{
IntPtr ph = IntPtr.Zero;
WindowsIdentity wi = null;
try
{
OpenProcessToken(process.Handle, TOKEN_QUERY, out ph);
wi = new WindowsIdentity(ph);
}
catch (Exception)
{
throw;
}
finally
{
if (ph != IntPtr.Zero)
{
CloseHandle(ph);
}
}
return wi;
}
[DllImport("advapi32.dll", SetLastError = true)]
private static extern bool OpenProcessToken(IntPtr processHandle, uint desiredAccess, out IntPtr tokenHandle);
[DllImport("kernel32.dll", SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
private static extern bool CloseHandle(IntPtr hObject);
}
}
Here's the complete program. It's a CommandLine C# application. It's ugly and has no comments. But it works. You feed it the name of an EXE (including the path), it checks to see if it's already running, and if not, starts it.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.IO;
using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Security.Principal;
namespace SingleRun
{
class Program
{
static void Main(string[] args)
{
string path = "";
var prog = "";
if (args.Length == 0) {
MessageBox.Show("Please include a program to start.\n\nExample: \nSingleRun.exe \"C:\\Program Files\\Windows NT\\Accessories\\wordpad.exe\"", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
System.Environment.Exit(1);
}else{
path = args[0];
if (!File.Exists(path)) {
MessageBox.Show("\"" + path + "\" does not exist.\nPlease check the location.\nAnything with spaces in it needs to be inside double-quotes.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
System.Environment.Exit(1);
}else{
var splits = path.Split('\\');
prog = splits[splits.Length - 1];
foreach (var p in Process.GetProcessesByName(prog.Replace(".exe",""))) {
string processOwner;
try {
processOwner = p.WindowsIdentity().Name;
}
catch (Exception ex) {
processOwner = ex.Message; // Probably "Access is denied"
}
if (processOwner.Contains(Environment.UserName)) {
MessageBox.Show("Program already running with PID " + p.Id, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
System.Environment.Exit(1);
}
}
Process newProcess = Process.Start(path);
Console.WriteLine("Launching " + prog + " with PID: " + newProcess.Id);
}
}
}
}
/// <summary>
/// Extension Methods for the System.Diagnostics.Process Class.
/// </summary>
public static class ProcessExtensions {
/// <summary>
/// Required to query an access token.
/// </summary>
private static uint TOKEN_QUERY = 0x0008;
/// <summary>
/// Returns the WindowsIdentity associated to a Process
/// </summary>
/// <param name="process">The Windows Process.</param>
/// <returns>The WindowsIdentity of the Process.</returns>
/// <remarks>Be prepared for 'Access Denied' Exceptions</remarks>
public static WindowsIdentity WindowsIdentity(this Process process) {
IntPtr ph = IntPtr.Zero;
WindowsIdentity wi = null;
try {
OpenProcessToken(process.Handle, TOKEN_QUERY, out ph);
wi = new WindowsIdentity(ph);
}
catch (Exception) {
throw;
}
finally {
if (ph != IntPtr.Zero) {
CloseHandle(ph);
}
}
return wi;
}
[DllImport("advapi32.dll", SetLastError = true)]
private static extern bool OpenProcessToken(IntPtr processHandle, uint desiredAccess, out IntPtr tokenHandle);
[DllImport("kernel32.dll", SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
private static extern bool CloseHandle(IntPtr hObject);
}
}
Works fine code above. But if you want only know if current user see the opened app: If the process is not form current user, you have already an exception if you try to get the handle. So, you can do it much more simple with this extention:
public static bool ProcessAccessibleForCurrentUser(this Process process)
{
try
{
var ptr = process.Handle;
return true;
}
catch
{
return false;
}
}
