我有一个封装类,里面有一个公共方法,在程序集中。我想添加一个日志系统,但不幸的是,我没有源代码。于是我试图在特定的日志方法上重载这个方法,并在退出时调用原始方法。钩子函数已经正确地运作,但我无法获得任何类型的参数,或者至少我拿到了完全错误的东西。
我不能使用任何类型的注入或像PostSharp这样的库,所以我想知道这种事情是否可以在运行时以某种方式实现,还是我应该放弃?
为了给你更多细节,我将在下面粘贴一些代码片段:
我不能使用任何类型的注入或像PostSharp这样的库,所以我想知道这种事情是否可以在运行时以某种方式实现,还是我应该放弃?
为了给你更多细节,我将在下面粘贴一些代码片段:
public Hook(Delegate target, Delegate hook)
{
this.target = Marshal.GetFunctionPointerForDelegate(target);
targetDelegate = target;
this.hook = Marshal.GetFunctionPointerForDelegate(hook);
originalBytes = new byte[6];
Marshal.Copy(this.target, originalBytes, 0, 6);
byte[] hookPointerBytes = BitConverter.GetBytes(this.hook.ToInt32());
// Jump
newBytes = new byte[]
{
0x68, hookPointerBytes[0], hookPointerBytes[1], hookPointerBytes[2], hookPointerBytes[3], 0xC3
};
}
public object CallOriginal(params object[] args)
{
// Remove the patch
Uninstall();
// Invoke the original method
object ret = targetDelegate.DynamicInvoke(args);
// Re-apply the patch
Install();
return ret;
}
public sealed class Foo
{
public void DoSomething(Int32 value1)
{
// and here I am getting value1 = -1919988997
Console.WriteLine(value1);
}
}
class Program
{
[UnmanagedFunctionPointer(CallingConvention.Cdecl)]
public delegate void DoSomethingDelegate(Int32 value1);
private static DoSomethingDelegate Original { get; set; }
private static DoSomethingDelegate Hooked { get; set; }
private static HookManager _hookManager;
public static void DoSomething(Int32 value1)
{
// This is called as well after foo.DoSomething but value1 is 251934152
Console.WriteLine("Hooked DoSomething: " + value1) ;
var hook = _hook["DoSomethingHook"];
// Call the original Foo.DoSomething
hook.CallOriginal(value1);
}
static void Main(string[] args)
{
RuntimeHelpers.PrepareMethod(typeof(Foo).GetMethod("DoSomething").MethodHandle);
_hookManager = new HookManager();
var originalPointer = typeof(Foo).GetMethod("DoSomething").MethodHandle.GetFunctionPointer();
Original = (DoSomethingDelegate)Marshal.GetDelegateForFunctionPointer(originalPointer, typeof(DoSomethingDelegate));
Hooked = DoSomething;
_hookManager.Add(Original, Hooked, "DoSomethingHook");
// Call Hook method, HookManager it is just an extended dictionary...
_hookManager.InstallAll();
var foo = new Foo();
// Calling the original method here with 1
foo.DoSomething(1);
Console.ReadLine();
}
}