[英]Dynamically Append Code to a method .Net-Core
I'm interested in dynamically appending code in .Net-Core.我对在 .Net-Core 中动态附加代码很感兴趣。 Note: This is for education purposes only.
注意:这仅用于教育目的。
Currently I have a class which swaps methods:目前我有一个交换方法的类:
public static void Inject<TTarget, TInject>(string targetFuncName, string injectFuncName)
{
MethodInfo methodToReplace = typeof(TTarget).GetMethod(targetFuncName, BindingFlags.Instance | BindingFlags.Static | BindingFlags.NonPublic | BindingFlags.Public);
MethodInfo methodToInject = typeof(TInject).GetMethod(injectFuncName, BindingFlags.Instance | BindingFlags.Static | BindingFlags.NonPublic | BindingFlags.Public);
RuntimeHelpers.PrepareMethod(methodToReplace.MethodHandle);
RuntimeHelpers.PrepareMethod(methodToInject.MethodHandle);
unsafe
{
if (IntPtr.Size == 4)
{
int* inj = (int*)methodToInject.MethodHandle.Value.ToPointer() + 2;
int* tar = (int*)methodToReplace.MethodHandle.Value.ToPointer() + 2;
#if DEBUG
Console.WriteLine("\nVersion x86 Debug\n");
byte* injInst = (byte*)*inj;
byte* tarInst = (byte*)*tar;
int* injSrc = (int*)(injInst + 1);
int* tarSrc = (int*)(tarInst + 1);
*tarSrc = (((int)injInst + 5) + *injSrc) - ((int)tarInst + 5);
#else
Console.WriteLine("\nVersion x86 Release\n");
*tar = *inj;
#endif
}
else
{
long* inj = (long*)methodToInject.MethodHandle.Value.ToPointer() + 1;
long* tar = (long*)methodToReplace.MethodHandle.Value.ToPointer() + 1;
#if DEBUG
Console.WriteLine("\nVersion x64 Debug\n");
byte* injInst = (byte*)*inj;
byte* tarInst = (byte*)*tar;
int* injSrc = (int*)(injInst + 1);
int* tarSrc = (int*)(tarInst + 1);
*tarSrc = (((int)injInst + 5) + *injSrc) - ((int)tarInst + 5);
#else
Console.WriteLine("\nVersion x64 Release\n");
*tar = *inj;
#endif
}
}
}
This Code swaps the method fine, However, if you're debugging it seems like to original code is never hit.此代码很好地交换了方法,但是,如果您正在调试,则似乎永远不会命中原始代码。 Instead I would like to swap the return statements from the method bytes and replace it with a jump statement to another function with the same parameters.
相反,我想交换方法字节中的返回语句,并将其替换为跳转到具有相同参数的另一个函数的语句。
However, .Net Core doesn't currently support the MethodRental.SwapMethodBody
How Can dynamically append code to the end of a function?但是,.Net Core 目前不支持
MethodRental.SwapMethodBody
如何将代码动态附加到函数的末尾?
I figured out a cheat way to do it.我想出了一个作弊的方法来做到这一点。 I haven't written all the code yet but I'll explain in pseudo code
我还没有写完所有的代码,但我会用伪代码来解释
Say we have a method:假设我们有一个方法:
public class ValuesController: ControllerBase
{
[HttpGet("Seven")]
public int Seven(string id)
{
return 7;
}
}
We want to swap it with another method我们想用另一种方法交换它
public int Eight(int retValue)
{
return retValue + 1;
}
We can generate a Func in a dynamic assembly.我们可以在动态程序集中生成一个 Func。 Which looks like so:
看起来像这样:
public int Dummy(string id)
{}
public int DummyFuncContainer(string id)
{
var result = Dummy(id);
return Eight(result);
}
Then all you need to do is.然后你需要做的就是。
Swap the Dummy()
method with the func we want Seven()
and then we swap Seven()
(Which is now pointing at Dummy()
) with DummyFuncContainer()
.用我们想要的函数
Seven()
交换Dummy()
方法,然后用DummyFuncContainer()
交换Seven()
(现在指向Dummy()
DummyFuncContainer()
。
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