Identifying the CPU architecture type using C#

Question

I want to check which CPU architecture is the user running, is it i386 or X64 or AMD64. I want to do it in C#. I know i can try WMI or Registry. Is there any other way apart

Answer 1

Here is a piece of code that seems to work (based on P/Invoke); It allows to determine the CPU/Machine architecture, current process architecture and also a given binary file architecture (how it's been compiled):

    public enum Architecture
    {
        Unknown,
        x86,
        x64,
        arm64,
    }

    public static Architecture ProcessArchitecture
    {
        get
        {
            var si = new SYSTEM_INFO();
            GetSystemInfo(ref si);
            return GetArchitecture(ref si);
        }
    }

    public static Architecture MachineArchitecture
    {
        get
        {
            var si = new SYSTEM_INFO();
            GetNativeSystemInfo(ref si);
            return GetArchitecture(ref si);
        }
    }

    public static Architecture ReadFileArchitecture(string filePath)
    {
        if (filePath == null)
            throw new ArgumentNullException(nameof(filePath));

        using (var stream = File.OpenRead(filePath))
        {
            return ReadFileArchitecture(stream);
        }
    }

    // note .NET dll will come out as x86
    public static Architecture ReadFileArchitecture(Stream stream)
    {
        if (stream == null)
            throw new ArgumentNullException(nameof(stream));

        var length = stream.Length;
        if (length < 64)
            return Architecture.Unknown;

        var reader = new BinaryReader(stream);
        stream.Position = 60;
        var peHeaderPtr = reader.ReadUInt32();
        if (peHeaderPtr == 0)
        {
            peHeaderPtr = 128;
        }
        if (peHeaderPtr > length - 256)
            return Architecture.Unknown;

        stream.Position = peHeaderPtr;
        var peSignature = reader.ReadUInt32();
        if (peSignature != 0x00004550) // "PE"
            return Architecture.Unknown;

        var machine = reader.ReadUInt16();
        Architecture arch;
        switch (machine)
        {
            case IMAGE_FILE_MACHINE_AMD64:
                arch = Architecture.x64;
                break;

            case IMAGE_FILE_MACHINE_I386:
                arch = Architecture.x86;
                break;

            case IMAGE_FILE_MACHINE_ARM64:
                arch = Architecture.arm64;
                break;

            default:
                return Architecture.Unknown;
        }
        return arch;
    }

    private static Architecture GetArchitecture(ref SYSTEM_INFO si)
    {
        switch (si.wProcessorArchitecture)
        {
            case PROCESSOR_ARCHITECTURE_AMD64:
                return Architecture.x64;

            case PROCESSOR_ARCHITECTURE_ARM64:
                return Architecture.arm64;

            case PROCESSOR_ARCHITECTURE_INTEL:
                return Architecture.x86;

            default:
                throw new PlatformNotSupportedException();
        }
    }

    private const int PROCESSOR_ARCHITECTURE_AMD64 = 9;
    private const int PROCESSOR_ARCHITECTURE_INTEL = 0;
    private const int PROCESSOR_ARCHITECTURE_ARM64 = 12;
    private const int IMAGE_FILE_MACHINE_ARM64 = 0xAA64;
    private const int IMAGE_FILE_MACHINE_I386 = 0x14C;
    private const int IMAGE_FILE_MACHINE_AMD64 = 0x8664;

    [DllImport("kernel32")]
    private static extern void GetSystemInfo(ref SYSTEM_INFO lpSystemInfo);

    [DllImport("kernel32")]
    private static extern void GetNativeSystemInfo(ref SYSTEM_INFO lpSystemInfo);

    [StructLayout(LayoutKind.Sequential)]
    private struct SYSTEM_INFO
    {
        public short wProcessorArchitecture;
        public short wReserved;
        public int dwPageSize;
        public IntPtr lpMinimumApplicationAddress;
        public IntPtr lpMaximumApplicationAddress;
        public IntPtr dwActiveProcessorMask;
        public int dwNumberOfProcessors;
        public int dwProcessorType;
        public int dwAllocationGranularity;
        public short wProcessorLevel;
        public short wProcessorRevision;
    }

This code supports x86, x64 and arm64 architectures and Windows XP. In modern versions of .NET you have built-in functions in the System.Runtime.InteropServices.RuntimeInformation namespace.

Answer 2

How about this?

switch (typeof(string).Assembly.GetName().ProcessorArchitecture) {
    case System.Reflection.ProcessorArchitecture.X86:
        break;
    case System.Reflection.ProcessorArchitecture.Amd64:
        break;
    case System.Reflection.ProcessorArchitecture.Arm:
        break;
}

However case *.Arm: isn't tested yet.

Answer 3

Win32_Processor WMI Class will do the job. Use MgmtClassGen.exe to generate strongly-typed wrappers.

Answer 4

Depending on why you want to know, you might find that checking the size of the IntPtr structure is the easiest way.

Answer 5

You could ask the user perhaps?

Just kidding of course... I think WMI is what you would use for that. But maybe there is some other way as well?

If you go for WMI then LinqToWmi could be of use. I tried it out once, and it seemed pretty straight forward =) -> http://www.codeplex.com/linq2wmi

Answer 6

Here is my way:

If the operating system is Linux, pinvoke the libc-syscall uname, where you will have the processor in the Machine-field.

If the OS is Windows, check if System.IntPtr.Size * 8 = 64, then it's 64 bit. If it isn't 64-Bit, you check if IsWow64Process exists, and if it exists, and the process is Wow64, then it's x86-64, else it's x86-32.

This one is reliable.
Checking the processor-architecture environment variables is not.

Code:

namespace RamMonitorPrototype
{


    // https://stackoverflow.com/a/55202696/155077
    //[System.Runtime.InteropServices.StructLayout(System.Runtime.InteropServices.LayoutKind.Sequential)]
    //unsafe internal struct Utsname_internal
    //{
    //    public fixed byte sysname[65];
    //    public fixed byte nodename[65];
    //    public fixed byte release[65];
    //    public fixed byte version[65];
    //    public fixed byte machine[65];
    //    public fixed byte domainname[65];
    //}


    public class Utsname
    {
        public string SysName; // char[65]
        public string NodeName; // char[65]
        public string Release; // char[65]
        public string Version; // char[65]
        public string Machine; // char[65]
        public string DomainName; // char[65]

        public void Print()
        {
            System.Console.Write("SysName:\t");
            System.Console.WriteLine(this.SysName); // Linux 

            System.Console.Write("NodeName:\t");
            System.Console.WriteLine(this.NodeName); // System.Environment.MachineName

            System.Console.Write("Release:\t");
            System.Console.WriteLine(this.Release); // Kernel-version

            System.Console.Write("Version:\t");
            System.Console.WriteLine(this.Version); // #40~18.04.1-Ubuntu SMP Thu Nov 14 12:06:39 UTC 2019

            System.Console.Write("Machine:\t");
            System.Console.WriteLine(this.Machine); // x86_64

            System.Console.Write("DomainName:\t");
            System.Console.WriteLine(this.DomainName); // (none)
        }


    }


    // https://github.com/microsoft/referencesource/blob/master/System/compmod/microsoft/win32/UnsafeNativeMethods.cs
    // https://github.com/dotnet/corefx/blob/master/src/Common/src/CoreLib/System/Environment.Windows.cs
    public class DetermineOsBitness
    {
        private const string Kernel32 = "kernel32.dll";



        [System.Runtime.InteropServices.DllImport("libc", EntryPoint = "uname", CallingConvention = System.Runtime.InteropServices.CallingConvention.Cdecl)]
        private static extern int uname_syscall(System.IntPtr buf);

        // https://github.com/jpobst/Pinta/blob/master/Pinta.Core/Managers/SystemManager.cs
        public static Utsname Uname()
        {
            Utsname uts = null;
            System.IntPtr buf = System.IntPtr.Zero;

            buf = System.Runtime.InteropServices.Marshal.AllocHGlobal(8192);
            // This is a hacktastic way of getting sysname from uname ()
            if (uname_syscall(buf) == 0)
            {
                uts = new Utsname();
                uts.SysName = System.Runtime.InteropServices.Marshal.PtrToStringAnsi(buf);

                long bufVal = buf.ToInt64();
                uts.NodeName = System.Runtime.InteropServices.Marshal.PtrToStringAnsi(new System.IntPtr(bufVal + 1 * 65));
                uts.Release = System.Runtime.InteropServices.Marshal.PtrToStringAnsi(new System.IntPtr(bufVal + 2 * 65));
                uts.Version = System.Runtime.InteropServices.Marshal.PtrToStringAnsi(new System.IntPtr(bufVal + 3 * 65));
                uts.Machine = System.Runtime.InteropServices.Marshal.PtrToStringAnsi(new System.IntPtr(bufVal + 4 * 65));
                uts.DomainName = System.Runtime.InteropServices.Marshal.PtrToStringAnsi(new System.IntPtr(bufVal + 5 * 65));

                if (buf != System.IntPtr.Zero)
                    System.Runtime.InteropServices.Marshal.FreeHGlobal(buf);
            } // End if (uname_syscall(buf) == 0) 

            return uts;
        } // End Function Uname



        [System.Runtime.InteropServices.DllImport(Kernel32, CharSet = System.Runtime.InteropServices.CharSet.Auto, BestFitMapping = false)]
        [System.Runtime.Versioning.ResourceExposure(System.Runtime.Versioning.ResourceScope.Machine)]
        private static extern System.IntPtr GetModuleHandle(string modName);


        [System.Runtime.InteropServices.DllImport(Kernel32, CharSet = System.Runtime.InteropServices.CharSet.Ansi, BestFitMapping = false, SetLastError = true, ExactSpelling = true)]
        [System.Runtime.Versioning.ResourceExposure(System.Runtime.Versioning.ResourceScope.None)]
        private static extern System.IntPtr GetProcAddress(System.IntPtr hModule, string methodName);


        [System.Runtime.InteropServices.DllImport(Kernel32, SetLastError = true, CallingConvention = System.Runtime.InteropServices.CallingConvention.Winapi)]
        [return: System.Runtime.InteropServices.MarshalAs(System.Runtime.InteropServices.UnmanagedType.Bool)]
        private static extern bool IsWow64Process(
             [System.Runtime.InteropServices.In] Microsoft.Win32.SafeHandles.SafeHandleZeroOrMinusOneIsInvalid hProcess,
             [System.Runtime.InteropServices.Out, System.Runtime.InteropServices.MarshalAs(System.Runtime.InteropServices.UnmanagedType.Bool)] out bool wow64Process
        );


        [System.Security.SecurityCritical]
        private static bool DoesWin32MethodExist(string moduleName, string methodName)
        {
            System.IntPtr hModule = GetModuleHandle(moduleName);

            if (hModule == System.IntPtr.Zero)
            {
                System.Diagnostics.Debug.Assert(hModule != System.IntPtr.Zero, "GetModuleHandle failed.  Dll isn't loaded?");
                return false;
            }

            System.IntPtr functionPointer = GetProcAddress(hModule, methodName);
            return (functionPointer != System.IntPtr.Zero);
        }

        public static bool Is64BitOperatingSystem()
        {
            if (System.IntPtr.Size * 8 == 64)
                return true;

            if (!DoesWin32MethodExist(Kernel32, "IsWow64Process"))
                return false;

            bool isWow64;

            using(Microsoft.Win32.SafeHandles.SafeWaitHandle safeHandle = new Microsoft.Win32.SafeHandles.SafeWaitHandle(System.Diagnostics.Process.GetCurrentProcess().Handle, true))
            {
                IsWow64Process(safeHandle, out isWow64);
            }
            return isWow64;
        }

        // This doesn't work reliably
        public static string GetProcessorArchitecture()
        {
            string strProcessorArchitecture = null;

            try
            {
                strProcessorArchitecture = System.Convert.ToString(System.Environment.GetEnvironmentVariable("PROCESSOR_ARCHITECTURE"));

                switch (typeof(string).Assembly.GetName().ProcessorArchitecture)
                {
                    case System.Reflection.ProcessorArchitecture.X86:
                        strProcessorArchitecture = "x86";
                        break;
                    case System.Reflection.ProcessorArchitecture.Amd64:
                        strProcessorArchitecture = "x86";
                        break;
                    case System.Reflection.ProcessorArchitecture.Arm:
                        strProcessorArchitecture = "ARM";
                        break;
                }

                bool is64bit = !string.IsNullOrEmpty(System.Environment.GetEnvironmentVariable("PROCESSOR_ARCHITEW6432"));

                if (is64bit)
                    strProcessorArchitecture += "-64";
                else
                    strProcessorArchitecture += "-32";
            }
            catch (System.Exception ex)
            {
                strProcessorArchitecture = ex.Message;
            }

            return strProcessorArchitecture;
        } // End Function GetProcessorArchitecture


    }


}