using DotNetDetour;
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using System;
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using System.Collections;
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using System.Collections.Generic;
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using UnityEngine;
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using System.Linq;
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namespace MonoHook
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{
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public unsafe abstract class CodePatcher
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{
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public bool isValid { get; protected set; }
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protected void* _pTarget, _pReplace, _pProxy;
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protected int _jmpCodeSize;
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protected byte[] _targetHeaderBackup;
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public CodePatcher(IntPtr target, IntPtr replace, IntPtr proxy, int jmpCodeSize)
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{
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_pTarget = target.ToPointer();
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_pReplace = replace.ToPointer();
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_pProxy = proxy.ToPointer();
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_jmpCodeSize = jmpCodeSize;
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}
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public void ApplyPatch()
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{
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BackupHeader();
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EnableAddrModifiable();
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PatchTargetMethod();
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PatchProxyMethod();
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FlushICache();
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}
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public void RemovePatch()
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{
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if (_targetHeaderBackup == null)
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return;
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EnableAddrModifiable();
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RestoreHeader();
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FlushICache();
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}
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protected void BackupHeader()
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{
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if (_targetHeaderBackup != null)
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return;
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uint requireSize = LDasm.SizeofMinNumByte(_pTarget, _jmpCodeSize);
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_targetHeaderBackup = new byte[requireSize];
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fixed (void* ptr = _targetHeaderBackup)
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HookUtils.MemCpy(ptr, _pTarget, _targetHeaderBackup.Length);
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}
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protected void RestoreHeader()
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{
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if (_targetHeaderBackup == null)
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return;
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HookUtils.MemCpy_Jit(_pTarget, _targetHeaderBackup);
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}
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protected void PatchTargetMethod()
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{
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byte[] buff = GenJmpCode(_pTarget, _pReplace);
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HookUtils.MemCpy_Jit(_pTarget, buff);
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}
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protected void PatchProxyMethod()
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{
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if (_pProxy == null)
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return;
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// copy target's code to proxy
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HookUtils.MemCpy_Jit(_pProxy, _targetHeaderBackup);
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// jmp to target's new position
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long jmpFrom = (long)_pProxy + _targetHeaderBackup.Length;
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long jmpTo = (long)_pTarget + _targetHeaderBackup.Length;
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byte[] buff = GenJmpCode((void*)jmpFrom, (void*)jmpTo);
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HookUtils.MemCpy_Jit((void*)jmpFrom, buff);
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}
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protected void FlushICache()
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{
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HookUtils.FlushICache(_pTarget, _targetHeaderBackup.Length);
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HookUtils.FlushICache(_pProxy, _targetHeaderBackup.Length * 2);
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}
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protected abstract byte[] GenJmpCode(void* jmpFrom, void* jmpTo);
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#if ENABLE_HOOK_DEBUG
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protected string PrintAddrs()
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{
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if (IntPtr.Size == 4)
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return $"target:0x{(uint)_pTarget:x}, replace:0x{(uint)_pReplace:x}, proxy:0x{(uint)_pProxy:x}";
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else
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return $"target:0x{(ulong)_pTarget:x}, replace:0x{(ulong)_pReplace:x}, proxy:0x{(ulong)_pProxy:x}";
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}
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#endif
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private void EnableAddrModifiable()
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{
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HookUtils.SetAddrFlagsToRWX(new IntPtr(_pTarget), _targetHeaderBackup.Length);
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HookUtils.SetAddrFlagsToRWX(new IntPtr(_pProxy), _targetHeaderBackup.Length + _jmpCodeSize);
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}
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}
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public unsafe class CodePatcher_x86 : CodePatcher
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{
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protected static readonly byte[] s_jmpCode = new byte[] // 5 bytes
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{
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0xE9, 0x00, 0x00, 0x00, 0x00, // jmp $val ; $val = $dst - $src - 5
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};
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public CodePatcher_x86(IntPtr target, IntPtr replace, IntPtr proxy) : base(target, replace, proxy, s_jmpCode.Length) { }
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protected override unsafe byte[] GenJmpCode(void* jmpFrom, void* jmpTo)
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{
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byte[] ret = new byte[s_jmpCode.Length];
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int val = (int)jmpTo - (int)jmpFrom - 5;
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fixed(void * p = &ret[0])
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{
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byte* ptr = (byte*)p;
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*ptr = 0xE9;
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int* pOffset = (int*)(ptr + 1);
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*pOffset = val;
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}
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return ret;
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}
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}
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/// <summary>
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/// x64下2G 内的跳转
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/// </summary>
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public unsafe class CodePatcher_x64_near : CodePatcher_x86 // x64_near pathcer code is same to x86
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{
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public CodePatcher_x64_near(IntPtr target, IntPtr replace, IntPtr proxy) : base(target, replace, proxy) { }
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}
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/// <summary>
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/// x64下距离超过2G的跳转
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/// </summary>
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public unsafe class CodePatcher_x64_far : CodePatcher
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{
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protected static readonly byte[] s_jmpCode = new byte[] // 12 bytes
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{
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// 由于 rax 会被函数作为返回值修改，并且不会被做为参数使用，因此修改是安全的
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0x48, 0xB8, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // mov rax, <jmpTo>
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0x50, // push rax
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0xC3 // ret
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};
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//protected static readonly byte[] s_jmpCode2 = new byte[] // 14 bytes
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//{
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// 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // <jmpTo>
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// 0xFF, 0x25, 0xF2, 0xFF, 0xFF, 0xFF // jmp [rip - 0xe]
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//};
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public CodePatcher_x64_far(IntPtr target, IntPtr replace, IntPtr proxy) : base(target, replace, proxy, s_jmpCode.Length) { }
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protected override unsafe byte[] GenJmpCode(void* jmpFrom, void* jmpTo)
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{
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byte[] ret = new byte[s_jmpCode.Length];
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fixed (void* p = &ret[0])
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{
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byte* ptr = (byte*)p;
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*ptr++ = 0x48;
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*ptr++ = 0xB8;
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*(long*)ptr = (long)jmpTo;
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ptr += 8;
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*ptr++ = 0x50;
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*ptr++ = 0xC3;
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}
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return ret;
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}
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}
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public unsafe class CodePatcher_arm32_near : CodePatcher
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{
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private static readonly byte[] s_jmpCode = new byte[] // 4 bytes
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{
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0x00, 0x00, 0x00, 0xEA, // B $val ; $val = (($dst - $src) / 4 - 2) & 0x1FFFFFF
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};
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public CodePatcher_arm32_near(IntPtr target, IntPtr replace, IntPtr proxy) : base(target, replace, proxy, s_jmpCode.Length)
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{
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if (Math.Abs((long)target - (long)replace) >= ((1 << 25) - 1))
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throw new ArgumentException("address offset of target and replace must less than ((1 << 25) - 1)");
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#if ENABLE_HOOK_DEBUG
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Debug.Log($"CodePatcher_arm32_near: {PrintAddrs()}");
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#endif
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}
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protected override unsafe byte[] GenJmpCode(void* jmpFrom, void* jmpTo)
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{
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byte[] ret = new byte[s_jmpCode.Length];
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int val = ((int)jmpTo - (int)jmpFrom) / 4 - 2;
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fixed (void* p = &ret[0])
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{
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byte* ptr = (byte*)p;
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*ptr++ = (byte)val;
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*ptr++ = (byte)(val >> 8);
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*ptr++ = (byte)(val >> 16);
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*ptr++ = 0xEA;
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}
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return ret;
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}
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}
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public unsafe class CodePatcher_arm32_far : CodePatcher
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{
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private static readonly byte[] s_jmpCode = new byte[] // 8 bytes
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{
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0x04, 0xF0, 0x1F, 0xE5, // LDR PC, [PC, #-4]
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0x00, 0x00, 0x00, 0x00, // $val
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};
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public CodePatcher_arm32_far(IntPtr target, IntPtr replace, IntPtr proxy) : base(target, replace, proxy, s_jmpCode.Length)
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{
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if (Math.Abs((long)target - (long)replace) < ((1 << 25) - 1))
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throw new ArgumentException("address offset of target and replace must larger than ((1 << 25) - 1), please use InstructionModifier_arm32_near instead");
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#if ENABLE_HOOK_DEBUG
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Debug.Log($"CodePatcher_arm32_far: {PrintAddrs()}");
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#endif
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}
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protected override unsafe byte[] GenJmpCode(void* jmpFrom, void* jmpTo)
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{
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byte[] ret = new byte[s_jmpCode.Length];
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fixed (void* p = &ret[0])
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{
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uint* ptr = (uint*)p;
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*ptr++ = 0xE51FF004;
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*ptr = (uint)jmpTo;
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}
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return ret;
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}
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}
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/// <summary>
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/// arm64 下 ±128MB 范围内的跳转
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/// </summary>
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public unsafe class CodePatcher_arm64_near : CodePatcher
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{
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private static readonly byte[] s_jmpCode = new byte[] // 4 bytes
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{
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/*
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* from 0x14 to 0x17 is B opcode
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* offset bits is 26
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* https://developer.arm.com/documentation/ddi0596/2021-09/Base-Instructions/B--Branch-
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*/
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0x00, 0x00, 0x00, 0x14, // B $val ; $val = (($dst - $src)/4) & 7FFFFFF
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};
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public CodePatcher_arm64_near(IntPtr target, IntPtr replace, IntPtr proxy) : base(target, replace, proxy, s_jmpCode.Length)
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{
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if (Math.Abs((long)target - (long)replace) >= ((1 << 26) - 1) * 4)
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throw new ArgumentException("address offset of target and replace must less than (1 << 26) - 1) * 4");
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#if ENABLE_HOOK_DEBUG
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Debug.Log($"CodePatcher_arm64: {PrintAddrs()}");
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#endif
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}
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protected override unsafe byte[] GenJmpCode(void* jmpFrom, void* jmpTo)
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{
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byte[] ret = new byte[s_jmpCode.Length];
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int val = (int)((long)jmpTo - (long)jmpFrom) / 4;
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fixed (void* p = &ret[0])
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{
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byte* ptr = (byte*)p;
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*ptr++ = (byte)val;
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*ptr++ = (byte)(val >> 8);
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*ptr++ = (byte)(val >> 16);
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byte last = (byte)(val >> 24);
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last &= 0b11;
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last |= 0x14;
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*ptr = last;
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}
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return ret;
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}
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}
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/// <summary>
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/// arm64 远距离跳转
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/// </summary>
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public unsafe class CodePatcher_arm64_far : CodePatcher
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{
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private static readonly byte[] s_jmpCode = new byte[] // 20 bytes(字节数过多，太危险了，不建议使用)
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{
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/*
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* ADR: https://developer.arm.com/documentation/ddi0596/2021-09/Base-Instructions/ADR--Form-PC-relative-address-
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* BR: https://developer.arm.com/documentation/ddi0596/2021-09/Base-Instructions/BR--Branch-to-Register-
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*/
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0x6A, 0x00, 0x00, 0x10, // ADR X10, #C
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0x4A, 0x01, 0x40, 0xF9, // LDR X10, [X10,#0]
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0x40, 0x01, 0x1F, 0xD6, // BR X10
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 // $dst
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};
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public CodePatcher_arm64_far(IntPtr target, IntPtr replace, IntPtr proxy, int jmpCodeSize) : base(target, replace, proxy, jmpCodeSize)
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{
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}
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protected override unsafe byte[] GenJmpCode(void* jmpFrom, void* jmpTo)
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{
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throw new NotImplementedException();
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}
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}
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}
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