/// <summary>
/// Dynamically lookup a function in the dll via kernel32!GetProcAddress.
/// </summary>
/// <param name="functionName">raw name of the function in the export table.</param>
/// <returns>null if function is not found. Else a delegate to the unmanaged function.</returns>
/// <remarks>GetProcAddress results are valid as long as the dll is not yet unloaded. This
/// is very very dangerous to use since you need to ensure that the dll is not unloaded
/// until after you're done with any objects implemented by the dll. For example, if you
/// get a delegate that then gets an IUnknown implemented by this dll,
/// you can not dispose this library until that IUnknown is collected. Else, you may free
/// the library and then the CLR may call release on that IUnknown and it will crash.</remarks>
public TDelegate GetUnmanagedFunction <TDelegate>(string functionName) where TDelegate : class
{
using (AnsiString str = new AnsiString(functionName))
{
IntPtr functionPtr;
NtStatus result = Win32.LdrGetProcedureAddress(this, str.Buffer, 0, out functionPtr);
// Failure is a common case, especially for adaptive code.
if (result.IsError())
{
//result.ReturnException().Log();
return(null);
}
Delegate function = Marshal.GetDelegateForFunctionPointer(functionPtr, typeof(TDelegate));
// Ideally, we'd just make the constraint on TDelegate be
// System.Delegate, but compiler error CS0702 (constrained can't be System.Delegate)
// prevents that. So we make the constraint system.object and do the cast from object-->TDelegate.
object o = function;
return((TDelegate)o);
}
}
public IntPtr GetProcedure(int procedureNumber)
{
IntPtr functionPtr;
NtStatus result = Win32.LdrGetProcedureAddress(this, IntPtr.Zero, procedureNumber, out functionPtr);
return(functionPtr);
}
public IntPtr GetProcedure(string procedureName)
{
AnsiString str = new AnsiString(procedureName);
{
IntPtr functionPtr = IntPtr.Zero;
NtStatus result = Win32.LdrGetProcedureAddress(this, functionPtr, 0, out functionPtr);
return(functionPtr);
}
}
public static IntPtr GetProcedure(IntPtr dllHandle, string procedureName)
{
IntPtr handle;
using (AnsiString str = new AnsiString(procedureName))
{
Win32.LdrGetProcedureAddress(dllHandle, str.Buffer, 0, out handle).ThrowIf();
}
return(handle);
}
