/*
  
  Version: MPL 1.1/GPL 2.0/LGPL 2.1

  The contents of this file are subject to the Mozilla Public License Version
  1.1 (the "License"); you may not use this file except in compliance with
  the License. You may obtain a copy of the License at
 
  http://www.mozilla.org/MPL/

  Software distributed under the License is distributed on an "AS IS" basis,
  WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  for the specific language governing rights and limitations under the License.

  The Original Code is the Open Hardware Monitor code.

  The Initial Developer of the Original Code is 
  Michael Möller <m.moeller@gmx.ch>.
  Portions created by the Initial Developer are Copyright (C) 2010
  the Initial Developer. All Rights Reserved.

  Contributor(s):

  Alternatively, the contents of this file may be used under the terms of
  either the GNU General Public License Version 2 or later (the "GPL"), or
  the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
  in which case the provisions of the GPL or the LGPL are applicable instead
  of those above. If you wish to allow use of your version of this file only
  under the terms of either the GPL or the LGPL, and not to allow others to
  use your version of this file under the terms of the MPL, indicate your
  decision by deleting the provisions above and replace them with the notice
  and other provisions required by the GPL or the LGPL. If you do not delete
  the provisions above, a recipient may use your version of this file under
  the terms of any one of the MPL, the GPL or the LGPL.
 
*/

using System;
using System.IO;
using System.Runtime.InteropServices;
using System.Security.AccessControl;
using Microsoft.Win32.SafeHandles;

namespace OpenHardwareMonitor.Hardware {
  internal class KernelDriver {

    private string id;

    private SafeFileHandle device; 
    
    public KernelDriver(string id) {
      this.id = id;
    }
   
    public bool Install(string path) {
      IntPtr manager = NativeMethods.OpenSCManager(null, null,
        ServiceControlManagerAccessRights.SC_MANAGER_ALL_ACCESS);

      if (manager == IntPtr.Zero)
        return false;

      IntPtr service = NativeMethods.CreateService(manager, id, id,
        ServiceAccessRights.SERVICE_ALL_ACCESS,
        ServiceType.SERVICE_KERNEL_DRIVER, StartType.SERVICE_DEMAND_START,
        ErrorControl.SERVICE_ERROR_NORMAL, path, null, null, null, null,
        null);

      if (service == IntPtr.Zero) {
        if (Marshal.GetHRForLastWin32Error() == ERROR_SERVICE_EXISTS)
          service = NativeMethods.OpenService(manager, id,
            ServiceAccessRights.SERVICE_ALL_ACCESS);
        else
          return false;
      }

      if (!NativeMethods.StartService(service, 0, null)) {
        if (Marshal.GetHRForLastWin32Error() != ERROR_SERVICE_ALREADY_RUNNING)
          return false;
      }

      NativeMethods.CloseServiceHandle(service);
      NativeMethods.CloseServiceHandle(manager);
      
      try {
        // restrict the driver access to system (SY) and builtin admins (BA)
        // TODO: replace with a call to IoCreateDeviceSecure in the driver
        FileSecurity fileSecurity = File.GetAccessControl(@"\\.\" + id);
        fileSecurity.SetSecurityDescriptorSddlForm(
          "O:BAG:SYD:(A;;FA;;;SY)(A;;FA;;;BA)");
        File.SetAccessControl(@"\\.\" + id, fileSecurity);
      } catch { }
      
      return true;
    }

    public bool Open() {
      device = new SafeFileHandle(NativeMethods.CreateFile(@"\\.\" + id,
        FileAccess.GENERIC_READ | FileAccess.GENERIC_WRITE, 0, IntPtr.Zero,
        CreationDisposition.OPEN_EXISTING, FileAttributes.FILE_ATTRIBUTE_NORMAL,
        IntPtr.Zero), true);

      if (device.IsInvalid) {
        device.Close();
        device.Dispose();
        device = null;
      }

      return device != null;
    }

    public bool IsOpen {
      get { return device != null; }
    }

    public bool DeviceIOControl(IOControlCode ioControlCode, object inBuffer) {
      if (device == null)
        return false;

      uint bytesReturned;
      bool b = NativeMethods.DeviceIoControl(device, ioControlCode,
        inBuffer, inBuffer == null ? 0 : (uint)Marshal.SizeOf(inBuffer),
        null, 0, out bytesReturned, IntPtr.Zero);
      return b;
    }

    public bool DeviceIOControl<T>(IOControlCode ioControlCode, object inBuffer, 
      ref T outBuffer) 
    {
      if (device == null)
        return false;

      object boxedOutBuffer = outBuffer;
      uint bytesReturned;
      bool b = NativeMethods.DeviceIoControl(device, ioControlCode,
        inBuffer, inBuffer == null ? 0 : (uint)Marshal.SizeOf(inBuffer),
        boxedOutBuffer, (uint)Marshal.SizeOf(boxedOutBuffer),
        out bytesReturned, IntPtr.Zero);
      outBuffer = (T)boxedOutBuffer;
      return b;
    }

    public void Close() {
      if (device != null) {
        device.Close();
        device.Dispose();
        device = null;
      }
    }

    public bool Delete() {
      IntPtr manager = NativeMethods.OpenSCManager(null, null,
      ServiceControlManagerAccessRights.SC_MANAGER_ALL_ACCESS);

      if (manager == IntPtr.Zero)
        return false;      

      IntPtr service = NativeMethods.OpenService(manager, id,
        ServiceAccessRights.SERVICE_ALL_ACCESS);

      if (service == IntPtr.Zero)
        return true;

      ServiceStatus status = new ServiceStatus();
      NativeMethods.ControlService(service, ServiceControl.SERVICE_CONTROL_STOP, 
        ref status);

      NativeMethods.DeleteService(service);

      NativeMethods.CloseServiceHandle(service);
      NativeMethods.CloseServiceHandle(manager);
      
      return true;
    }

    private enum ServiceAccessRights : uint {
      SERVICE_ALL_ACCESS = 0xF01FF
    }

    private enum ServiceControlManagerAccessRights : uint {
      SC_MANAGER_ALL_ACCESS = 0xF003F
    }

    private enum ServiceType : uint {
      SERVICE_KERNEL_DRIVER = 1,
      SERVICE_FILE_SYSTEM_DRIVER = 2
    }

    private enum StartType : uint {
      SERVICE_BOOT_START = 0,
      SERVICE_SYSTEM_START = 1,
      SERVICE_AUTO_START = 2,
      SERVICE_DEMAND_START = 3,
      SERVICE_DISABLED = 4
    }

    private enum ErrorControl : uint {
      SERVICE_ERROR_IGNORE = 0,
      SERVICE_ERROR_NORMAL = 1,
      SERVICE_ERROR_SEVERE = 2,
      SERVICE_ERROR_CRITICAL = 3
    }

    private enum ServiceControl : uint {
      SERVICE_CONTROL_STOP = 1,
      SERVICE_CONTROL_PAUSE = 2,
      SERVICE_CONTROL_CONTINUE = 3,
      SERVICE_CONTROL_INTERROGATE = 4,
      SERVICE_CONTROL_SHUTDOWN = 5,
      SERVICE_CONTROL_PARAMCHANGE = 6,
      SERVICE_CONTROL_NETBINDADD = 7,
      SERVICE_CONTROL_NETBINDREMOVE = 8,
      SERVICE_CONTROL_NETBINDENABLE = 9,
      SERVICE_CONTROL_NETBINDDISABLE = 10,
      SERVICE_CONTROL_DEVICEEVENT = 11,
      SERVICE_CONTROL_HARDWAREPROFILECHANGE = 12,
      SERVICE_CONTROL_POWEREVENT = 13,
      SERVICE_CONTROL_SESSIONCHANGE = 14
    }

    [StructLayout(LayoutKind.Sequential, Pack = 1)]
    private struct ServiceStatus {
      public uint dwServiceType;
      public uint dwCurrentState;
      public uint dwControlsAccepted;
      public uint dwWin32ExitCode;
      public uint dwServiceSpecificExitCode;
      public uint dwCheckPoint;
      public uint dwWaitHint;
    }

    private enum FileAccess : uint {
      GENERIC_READ = 0x80000000,
      GENERIC_WRITE = 0x40000000
    }

    private enum CreationDisposition : uint {
      CREATE_NEW = 1,
      CREATE_ALWAYS = 2,
      OPEN_EXISTING = 3,
      OPEN_ALWAYS = 4,
      TRUNCATE_EXISTING = 5
    }

    private enum FileAttributes : uint {
      FILE_ATTRIBUTE_NORMAL = 0x80
    }

    private const int
      ERROR_SERVICE_EXISTS = unchecked((int)0x80070431),
      ERROR_SERVICE_ALREADY_RUNNING = unchecked((int)0x80070420);

    private static class NativeMethods {
      private const string ADVAPI = "advapi32.dll";
      private const string KERNEL = "kernel32.dll";

      [DllImport(ADVAPI, CallingConvention = CallingConvention.Winapi)]
      public static extern IntPtr OpenSCManager(string machineName,
        string databaseName, ServiceControlManagerAccessRights dwAccess);

      [DllImport(ADVAPI, CallingConvention = CallingConvention.Winapi)]
      [return: MarshalAs(UnmanagedType.Bool)]
      public static extern bool CloseServiceHandle(IntPtr hSCObject);

      [DllImport(ADVAPI, CallingConvention = CallingConvention.Winapi,
        SetLastError = true)]
      public static extern IntPtr CreateService(IntPtr hSCManager,
        string lpServiceName, string lpDisplayName, 
        ServiceAccessRights dwDesiredAccess, ServiceType dwServiceType,
        StartType dwStartType, ErrorControl dwErrorControl,
        string lpBinaryPathName, string lpLoadOrderGroup, string lpdwTagId,
        string lpDependencies, string lpServiceStartName, string lpPassword);

      [DllImport(ADVAPI, CallingConvention = CallingConvention.Winapi,
        SetLastError = true)]
      public static extern IntPtr OpenService(IntPtr hSCManager,
        string lpServiceName, ServiceAccessRights dwDesiredAccess);

      [DllImport(ADVAPI, CallingConvention = CallingConvention.Winapi,
        SetLastError = true)]
      [return: MarshalAs(UnmanagedType.Bool)]
      public static extern bool DeleteService(IntPtr hService);

      [DllImport(ADVAPI, CallingConvention = CallingConvention.Winapi,
        SetLastError = true)]
      [return: MarshalAs(UnmanagedType.Bool)]
      public static extern bool StartService(IntPtr hService, 
        uint dwNumServiceArgs, string[] lpServiceArgVectors);

      [DllImport(ADVAPI, CallingConvention = CallingConvention.Winapi,
        SetLastError = true)]
      [return: MarshalAs(UnmanagedType.Bool)]
      public static extern bool ControlService(IntPtr hService,
        ServiceControl dwControl, ref ServiceStatus lpServiceStatus);

      [DllImport(KERNEL, CallingConvention = CallingConvention.Winapi)]
      public static extern bool DeviceIoControl(SafeFileHandle device,
        IOControlCode ioControlCode, 
        [MarshalAs(UnmanagedType.AsAny)] [In] object inBuffer, 
        uint inBufferSize,
        [MarshalAs(UnmanagedType.AsAny)] [Out] object outBuffer,
        uint nOutBufferSize, out uint bytesReturned, IntPtr overlapped);

      [DllImport(KERNEL, CallingConvention = CallingConvention.Winapi, 
        SetLastError = true)]
      public static extern IntPtr CreateFile(string lpFileName,
        FileAccess dwDesiredAccess, uint dwShareMode, 
        IntPtr lpSecurityAttributes, CreationDisposition dwCreationDisposition, 
        FileAttributes dwFlagsAndAttributes, IntPtr hTemplateFile);
    }
  }
}