/*

   This Source Code Form is subject to the terms of the Mozilla Public

   License, v. 2.0. If a copy of the MPL was not distributed with this

   file, You can obtain one at http://mozilla.org/MPL/2.0/.

   Copyright (C) 2010-2011 Michael Möller <mmoeller@openhardwaremonitor.org>

 */

 using System;

 using System.IO;

 using System.Reflection;

 using System.Runtime.InteropServices;

 using System.Security.AccessControl;

 using System.Threading;

 using System.Text;

 namespace OpenHardwareMonitor.Hardware {

   internal static class Ring0 {

     private static KernelDriver driver;

     private static string fileName;

     private static Mutex isaBusMutex;

     private static readonly StringBuilder report = new StringBuilder();

     private const uint OLS_TYPE = 40000;

     private static IOControlCode

       IOCTL_OLS_GET_REFCOUNT = new IOControlCode(OLS_TYPE, 0x801,

         IOControlCode.Access.Any),

       IOCTL_OLS_GET_DRIVER_VERSION = new IOControlCode(OLS_TYPE, 0x800,

         IOControlCode.Access.Any),

       IOCTL_OLS_READ_MSR = new IOControlCode(OLS_TYPE, 0x821,

         IOControlCode.Access.Any),

       IOCTL_OLS_WRITE_MSR = new IOControlCode(OLS_TYPE, 0x822, 

         IOControlCode.Access.Any),

       IOCTL_OLS_READ_IO_PORT_BYTE = new IOControlCode(OLS_TYPE, 0x833,

         IOControlCode.Access.Read),

       IOCTL_OLS_WRITE_IO_PORT_BYTE = new IOControlCode(OLS_TYPE, 0x836, 

         IOControlCode.Access.Write),

       IOCTL_OLS_READ_PCI_CONFIG = new IOControlCode(OLS_TYPE, 0x851, 

         IOControlCode.Access.Read),

       IOCTL_OLS_WRITE_PCI_CONFIG = new IOControlCode(OLS_TYPE, 0x852,

         IOControlCode.Access.Write),

       IOCTL_OLS_READ_MEMORY = new IOControlCode(OLS_TYPE, 0x841,

         IOControlCode.Access.Read);

     private static string GetTempFileName() {

       // try to get a file in the temporary folder

       try {

         return Path.GetTempFileName();        

       } catch (IOException) { 

           // some I/O exception

         } 

         catch (UnauthorizedAccessException) { 

           // we do not have the right to create a file in the temp folder

         }

         catch (NotSupportedException) {

           // invalid path format of the TMP system environment variable

         }

       // if this failed, we try to create one in the application folder

       string fileName = Path.ChangeExtension(

         Assembly.GetExecutingAssembly().Location, ".sys");

       try {

         using (FileStream stream = File.Create(fileName)) {

           return fileName;

         }        

       } catch (IOException) { } 

         catch (UnauthorizedAccessException) { }

       return null;

     }

     private static bool ExtractDriver(string fileName) {

       string resourceName = "OpenHardwareMonitor.Hardware." +

         (IntPtr.Size == 4 ? "WinRing0.sys" : "WinRing0x64.sys");

       string[] names =

         Assembly.GetExecutingAssembly().GetManifestResourceNames();

       byte[] buffer = null;

       for (int i = 0; i < names.Length; i++) {

         if (names[i].Replace('\\', '.') == resourceName) {

           using (Stream stream = Assembly.GetExecutingAssembly().

             GetManifestResourceStream(names[i])) 

           {

               buffer = new byte[stream.Length];

               stream.Read(buffer, 0, buffer.Length);

           }

         }

       }

       if (buffer == null)

         return false;

       try {

         using (FileStream target = new FileStream(fileName, FileMode.Create)) {

           target.Write(buffer, 0, buffer.Length);

         }

       } catch (IOException) { 

         // for example there is not enough space on the disk

         return false; 

       }

       return true;

     }

     public static void Open() {

       // no implementation for unix systems

       int p = (int)Environment.OSVersion.Platform;

       if ((p == 4) || (p == 128))

         return;  

       if (driver != null)

         return;

       // clear the current report

       report.Length = 0;

       driver = new KernelDriver("WinRing0_1_2_0");

       driver.Open();

       if (!driver.IsOpen) {

         // driver is not loaded, try to reinstall and open

         driver.Delete();

         fileName = GetTempFileName();

         if (fileName != null && ExtractDriver(fileName)) {

           if (driver.Install(fileName)) {

             driver.Open();

             if (!driver.IsOpen) {

               driver.Delete();

               report.AppendLine("Status: Opening driver failed");

             }

           } else {

             report.AppendLine("Status: Installing driver \"" +

               fileName + "\" failed" +

               (File.Exists(fileName) ? " and file exists" : ""));

             report.AppendLine();

             report.Append("Exception: " + Marshal.GetExceptionForHR(

               Marshal.GetHRForLastWin32Error()).Message);

           }

         } else {

           report.AppendLine("Status: Extracting driver failed");

         }

         try {

           // try to delte the driver file

           if (File.Exists(fileName))

             File.Delete(fileName);

           fileName = null;

         } catch (IOException) { } 

           catch (UnauthorizedAccessException) { }

       }

       if (!driver.IsOpen) 

         driver = null;

       string mutexName = "Global\\Access_ISABUS.HTP.Method";

       try {

         isaBusMutex = new Mutex(false, mutexName);

       } catch (UnauthorizedAccessException) {

         try {

           isaBusMutex = Mutex.OpenExisting(mutexName, MutexRights.Synchronize);

         } catch { }

       }

     }

     public static bool IsOpen {

       get { return driver != null; }

     }

     public static void Close() {

       if (driver == null)

         return;

       uint refCount = 0;

       driver.DeviceIOControl(IOCTL_OLS_GET_REFCOUNT, null, ref refCount);

       driver.Close();

       if (refCount <= 1)

         driver.Delete();

       driver = null;

       if (isaBusMutex != null) {

         isaBusMutex.Close();

         isaBusMutex = null;

       }

       // try to delete temporary driver file again if failed during open

       if (fileName != null && File.Exists(fileName)) {

         try {

           File.Delete(fileName);

           fileName = null;

         } catch (IOException) { } 

           catch (UnauthorizedAccessException) { }

       }

     }

     public static string GetReport() {

       if (report.Length > 0) {

         StringBuilder r = new StringBuilder();

         r.AppendLine("Ring0");

         r.AppendLine();

         r.Append(report);

         r.AppendLine();

         return r.ToString();

       } else

         return null;

     }

     public static bool WaitIsaBusMutex(int millisecondsTimeout) {

       if (isaBusMutex == null)

         return true;

       try {

         return isaBusMutex.WaitOne(millisecondsTimeout, false);

       } catch (AbandonedMutexException) { return false; } 

         catch (InvalidOperationException) { return false; }

     }

     public static void ReleaseIsaBusMutex() {

       if (isaBusMutex == null)

         return;

       isaBusMutex.ReleaseMutex();

     }

     public static bool Rdmsr(uint index, out uint eax, out uint edx) {

       if (driver == null) {

         eax = 0;

         edx = 0;

         return false;

       }

       ulong buffer = 0;

       bool result = driver.DeviceIOControl(IOCTL_OLS_READ_MSR, index,

         ref buffer);

       edx = (uint)((buffer >> 32) & 0xFFFFFFFF);

       eax = (uint)(buffer & 0xFFFFFFFF);

       return result;

     }

     public static bool RdmsrTx(uint index, out uint eax, out uint edx,

       ulong threadAffinityMask) 

     {

       ulong mask = ThreadAffinity.Set(threadAffinityMask);

       bool result = Rdmsr(index, out eax, out edx);

       ThreadAffinity.Set(mask);

       return result;

     }

     [StructLayout(LayoutKind.Sequential, Pack = 1)]

     private struct WrmsrInput {

       public uint Register;

       public ulong Value;

     }

     public static bool Wrmsr(uint index, uint eax, uint edx) {

       if (driver == null)

         return false;

       WrmsrInput input = new WrmsrInput();

       input.Register = index;

       input.Value = ((ulong)edx << 32) | eax;

       return driver.DeviceIOControl(IOCTL_OLS_WRITE_MSR, input);

     }

     public static byte ReadIoPort(uint port) {

       if (driver == null)

         return 0;

       uint value = 0;

       driver.DeviceIOControl(IOCTL_OLS_READ_IO_PORT_BYTE, port, ref value);

       return (byte)(value & 0xFF);

     }

     [StructLayout(LayoutKind.Sequential, Pack = 1)]

     private struct WriteIoPortInput {

       public uint PortNumber;

       public byte Value;

     }

     public static void WriteIoPort(uint port, byte value) {

       if (driver == null)

         return;

       WriteIoPortInput input = new WriteIoPortInput();

       input.PortNumber = port;

       input.Value = value;

       driver.DeviceIOControl(IOCTL_OLS_WRITE_IO_PORT_BYTE, input);

     }

     public const uint InvalidPciAddress = 0xFFFFFFFF;

     public static uint GetPciAddress(byte bus, byte device, byte function) {

       return

         (uint)(((bus & 0xFF) << 8) | ((device & 0x1F) << 3) | (function & 7));

     }

     [StructLayout(LayoutKind.Sequential, Pack = 1)]

     private struct ReadPciConfigInput {

       public uint PciAddress;

       public uint RegAddress;

     }

     public static bool ReadPciConfig(uint pciAddress, uint regAddress, 

       out uint value) 

     {

       if (driver == null || (regAddress & 3) != 0) {

         value = 0;

         return false;

       }

       ReadPciConfigInput input = new ReadPciConfigInput();

       input.PciAddress = pciAddress;

       input.RegAddress = regAddress;

       value = 0;

       return driver.DeviceIOControl(IOCTL_OLS_READ_PCI_CONFIG, input, 

         ref value);

     }

     [StructLayout(LayoutKind.Sequential, Pack = 1)]

     private struct WritePciConfigInput {

       public uint PciAddress;

       public uint RegAddress;

       public uint Value;

     }

     public static bool WritePciConfig(uint pciAddress, uint regAddress, 

       uint value) 

     {

       if (driver == null || (regAddress & 3) != 0)

         return false;

       WritePciConfigInput input = new WritePciConfigInput();

       input.PciAddress = pciAddress;

       input.RegAddress = regAddress;

       input.Value = value;

       return driver.DeviceIOControl(IOCTL_OLS_WRITE_PCI_CONFIG, input);

     }

     [StructLayout(LayoutKind.Sequential, Pack = 1)]

     private struct ReadMemoryInput {

       public ulong address;

       public uint unitSize;

       public uint count;

     }

     public static bool ReadMemory<T>(ulong address, ref T buffer) {

       if (driver == null) {

         return false;

       }

       ReadMemoryInput input = new ReadMemoryInput();

       input.address = address;

       input.unitSize = 1;

       input.count = (uint)Marshal.SizeOf(buffer);

       return driver.DeviceIOControl(IOCTL_OLS_READ_MEMORY, input,

         ref buffer);

     }

   }

 }