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Support for private methods added.
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@halllo
halllo committed Dec 11, 2013
1 parent 33c3827 commit f45b028
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Showing 7 changed files with 460 additions and 355 deletions.
362 changes: 181 additions & 181 deletions MReplace/MethodReplaceLogic.cs
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Expand Up @@ -5,199 +5,199 @@

namespace MReplace
{
/// <summary>
/// by Ziad Elmalki (http://www.codeproject.com/Articles/37549/CLR-Injection-Runtime-Method-Replacer)
/// </summary>
public static class MethodReplaceLogic
{
public static object ReplaceWith(this MethodBase dest, MethodBase source)
{
if (!MethodSignaturesEqual(source, dest))
{
throw new ArgumentException("The method signatures are not the same.", "source");
}
return ReplaceMethod(GetMethodAddress(source), dest);
}
/// <summary>
/// by Ziad Elmalki (http://www.codeproject.com/Articles/37549/CLR-Injection-Runtime-Method-Replacer)
/// </summary>
public static class MethodReplaceLogic
{
public static object ReplaceWith(this MethodBase dest, MethodBase source)
{
if (!MethodSignaturesEqual(source, dest))
{
throw new ArgumentException("The method signatures are not the same.", "source");
}
return ReplaceMethod(GetMethodAddress(source), dest);
}

internal static object ReplaceMethod(IntPtr srcAdr, MethodBase dest)
{
IntPtr destAdr = GetMethodAddress(dest);
object oldPointer;
unsafe
{
if (IntPtr.Size == 8)
{
ulong* d = (ulong*)destAdr.ToPointer();
oldPointer = *d;
*d = *((ulong*)srcAdr.ToPointer());
}
else
{
uint* d = (uint*)destAdr.ToPointer();
oldPointer = *d;
*d = *((uint*)srcAdr.ToPointer());
}
}
return oldPointer;
}
internal static object ReplaceMethod(IntPtr srcAdr, MethodBase dest)
{
IntPtr destAdr = GetMethodAddress(dest);
object oldPointer;
unsafe
{
if (IntPtr.Size == 8)
{
ulong* d = (ulong*)destAdr.ToPointer();
oldPointer = *d;
*d = *((ulong*)srcAdr.ToPointer());
}
else
{
uint* d = (uint*)destAdr.ToPointer();
oldPointer = *d;
*d = *((uint*)srcAdr.ToPointer());
}
}
return oldPointer;
}

internal static object ReplaceMethodBack(MethodBase dest, object oldPointer)
{
IntPtr destAdr = GetMethodAddress(dest);
unsafe
{
if (IntPtr.Size == 8)
{
ulong* d = (ulong*)destAdr.ToPointer();
*d = (ulong)oldPointer;
}
else
{
uint* d = (uint*)destAdr.ToPointer();
*d = (uint)oldPointer;
}
}
return oldPointer;
}
internal static object ReplaceMethodBack(MethodBase dest, object oldPointer)
{
IntPtr destAdr = GetMethodAddress(dest);
unsafe
{
if (IntPtr.Size == 8)
{
ulong* d = (ulong*)destAdr.ToPointer();
*d = (ulong)oldPointer;
}
else
{
uint* d = (uint*)destAdr.ToPointer();
*d = (uint)oldPointer;
}
}
return oldPointer;
}

private static IntPtr GetMethodAddress(MethodBase method)
{
if ((method is DynamicMethod))
{
return GetDynamicMethodAddress(method);
}
private static IntPtr GetMethodAddress(MethodBase method)
{
if ((method is DynamicMethod))
{
return GetDynamicMethodAddress(method);
}

// Prepare the method so it gets jited
RuntimeHelpers.PrepareMethod(method.MethodHandle);
// Prepare the method so it gets jited
RuntimeHelpers.PrepareMethod(method.MethodHandle);

// If 3.5 sp1 or greater than we have a different layout in memory.
if (IsNet20Sp2OrGreater())
{
return GetMethodAddress20SP2(method);
}
// If 3.5 sp1 or greater than we have a different layout in memory.
if (IsNet20Sp2OrGreater())
{
return GetMethodAddress20SP2(method);
}

unsafe
{
// Skip these
const int skip = 10;
unsafe
{
// Skip these
const int skip = 10;

// Read the method index.
UInt64* location = (UInt64*)(method.MethodHandle.Value.ToPointer());
int index = (int)(((*location) >> 32) & 0xFF);
// Read the method index.
UInt64* location = (UInt64*)(method.MethodHandle.Value.ToPointer());
int index = (int)(((*location) >> 32) & 0xFF);

if (IntPtr.Size == 8)
{
// Get the method table
ulong* classStart = (ulong*)method.DeclaringType.TypeHandle.Value.ToPointer();
ulong* address = classStart + index + skip;
return new IntPtr(address);
}
else
{
// Get the method table
uint* classStart = (uint*)method.DeclaringType.TypeHandle.Value.ToPointer();
uint* address = classStart + index + skip;
return new IntPtr(address);
}
}
}
if (IntPtr.Size == 8)
{
// Get the method table
ulong* classStart = (ulong*)method.DeclaringType.TypeHandle.Value.ToPointer();
ulong* address = classStart + index + skip;
return new IntPtr(address);
}
else
{
// Get the method table
uint* classStart = (uint*)method.DeclaringType.TypeHandle.Value.ToPointer();
uint* address = classStart + index + skip;
return new IntPtr(address);
}
}
}

private static IntPtr GetDynamicMethodAddress(MethodBase method)
{
unsafe
{
byte* ptr = (byte*)GetDynamicMethodRuntimeHandle(method).ToPointer();
if (IsNet20Sp2OrGreater())
{
if (IntPtr.Size == 8)
{
ulong* address = (ulong*)ptr;
address = (ulong*)*(address + 5);
return new IntPtr(address + 12);
}
else
{
uint* address = (uint*)ptr;
address = (uint*)*(address + 5);
return new IntPtr(address + 12);
}
}
else
{
if (IntPtr.Size == 8)
{
ulong* address = (ulong*)ptr;
address += 6;
return new IntPtr(address);
}
else
{
uint* address = (uint*)ptr;
address += 6;
return new IntPtr(address);
}
}
}
}
private static IntPtr GetDynamicMethodAddress(MethodBase method)
{
unsafe
{
byte* ptr = (byte*)GetDynamicMethodRuntimeHandle(method).ToPointer();
if (IsNet20Sp2OrGreater())
{
if (IntPtr.Size == 8)
{
ulong* address = (ulong*)ptr;
address = (ulong*)*(address + 5);
return new IntPtr(address + 12);
}
else
{
uint* address = (uint*)ptr;
address = (uint*)*(address + 5);
return new IntPtr(address + 12);
}
}
else
{
if (IntPtr.Size == 8)
{
ulong* address = (ulong*)ptr;
address += 6;
return new IntPtr(address);
}
else
{
uint* address = (uint*)ptr;
address += 6;
return new IntPtr(address);
}
}
}
}

private static IntPtr GetDynamicMethodRuntimeHandle(MethodBase method)
{
if (method is DynamicMethod)
{
FieldInfo fieldInfo = typeof(DynamicMethod).GetField("m_method", BindingFlags.NonPublic | BindingFlags.Instance);
return ((RuntimeMethodHandle)fieldInfo.GetValue(method)).Value;
}
return method.MethodHandle.Value;
}
private static IntPtr GetDynamicMethodRuntimeHandle(MethodBase method)
{
if (method is DynamicMethod)
{
FieldInfo fieldInfo = typeof(DynamicMethod).GetField("m_method", BindingFlags.NonPublic | BindingFlags.Instance);
return ((RuntimeMethodHandle)fieldInfo.GetValue(method)).Value;
}
return method.MethodHandle.Value;
}

private static IntPtr GetMethodAddress20SP2(MethodBase method)
{
unsafe
{
return new IntPtr(((int*)method.MethodHandle.Value.ToPointer() + 2));
}
}
private static IntPtr GetMethodAddress20SP2(MethodBase method)
{
unsafe
{
return new IntPtr(((int*)method.MethodHandle.Value.ToPointer() + 2));
}
}

private static bool MethodSignaturesEqual(MethodBase x, MethodBase y)
{
if (x.CallingConvention != y.CallingConvention)
{
return false;
}
Type returnX = GetMethodReturnType(x), returnY = GetMethodReturnType(y);
if (returnX != returnY)
{
return false;
}
ParameterInfo[] xParams = x.GetParameters(), yParams = y.GetParameters();
if (xParams.Length != yParams.Length)
{
return false;
}
for (int i = 0; i < xParams.Length; i++)
{
if (xParams[i].ParameterType != yParams[i].ParameterType)
{
return false;
}
}
return true;
}
private static bool MethodSignaturesEqual(MethodBase x, MethodBase y)
{
if (x.CallingConvention != y.CallingConvention)
{
return false;
}
Type returnX = GetMethodReturnType(x), returnY = GetMethodReturnType(y);
if (returnX != returnY)
{
return false;
}
ParameterInfo[] xParams = x.GetParameters(), yParams = y.GetParameters();
if (xParams.Length != yParams.Length)
{
return false;
}
for (int i = 0; i < xParams.Length; i++)
{
if (xParams[i].ParameterType != yParams[i].ParameterType)
{
return false;
}
}
return true;
}

private static Type GetMethodReturnType(MethodBase method)
{
MethodInfo methodInfo = method as MethodInfo;
if (methodInfo == null)
{
// Constructor info.
throw new ArgumentException("Unsupported MethodBase : " + method.GetType().Name, "method");
}
return methodInfo.ReturnType;
}
private static Type GetMethodReturnType(MethodBase method)
{
MethodInfo methodInfo = method as MethodInfo;
if (methodInfo == null)
{
// Constructor info.
throw new ArgumentException("Unsupported MethodBase : " + method.GetType().Name, "method");
}
return methodInfo.ReturnType;
}

private static bool IsNet20Sp2OrGreater()
{
return Environment.Version.Major > 2;
}
}
private static bool IsNet20Sp2OrGreater()
{
return Environment.Version.Major > 2;
}
}
}

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