LunaHook-mirror/LunaHook/engine32/Cage.cpp

#include "Cage.h"

bool Cage::attach_function()
{
  // https://vndb.org/v8381
  // 夢姿 ～ゆめのすがた～
  /*
  size_t __cdecl _mbslen(const unsigned __int8 *String)
{
const unsigned __int8 *v2; // eax
size_t i; // esi

if ( !dword_476AFC )
return strlen((const char *)String);
_lock(25);
v2 = String;
for ( i = 0; *v2; ++i )
{
if ( (byte_476C01[*v2] & 4) != 0 && !*++v2 )
break;
++v2;
}
_unlock(25);
return i;
}
  */
  /*
  .text:00451B0C                 mov     eax, [esp+8+String]
.text:00451B10                 pop     ecx
.text:00451B11                 xor     esi, esi
.text:00451B13
.text:00451B13 loc_451B13:                             ; CODE XREF: __mbslen+3D↓j
.text:00451B13                 mov     cl, [eax]
.text:00451B15                 test    cl, cl
.text:00451B17                 jz      short loc_451B2F
.text:00451B19                 movzx   ecx, cl
.text:00451B1C                 test    byte_476C01[ecx], 4
.text:00451B23                 jz      short loc_451B2B
.text:00451B25                 inc     eax
.text:00451B26                 cmp     byte ptr [eax], 0
.text:00451B29                 jz      short loc_451B2F
.text:00451B2B
.text:00451B2B loc_451B2B:                             ; CODE XREF: __mbslen+33↑j
.text:00451B2B                 inc     esi
.text:00451B2C                 inc     eax
.text:00451B2D                 jmp     short loc_451B13
  */
  BYTE check[] = {
      //clang-format off
      0x8B, 0x44, 0x24, 0x0C,
      0x59,
      0x33, 0xF6,
      0x8A, 0x08,
      0x84, 0xC9,
      0x74, 0x16,
      0x0F, 0xB6, 0xC9,
      0xF6, 0x81, XX4, 0x04,
      0x74, 0x06,
      0x40,
      0x80, 0x38, 0x00,
      0x74, 0x04,
      0x46,
      0x40,
      0xEB, 0xE4
      //clang-format on
  };
  auto addrx = MemDbg::findBytes(check, sizeof(check), processStartAddress, processStopAddress);
  if (!addrx)
    return false;
  addrx = MemDbg::findEnclosingAlignedFunction(addrx);
  if (!addrx)
    return 0;
  HookParam hp;
  hp.address = addrx;
  hp.type = USING_STRING;
  hp.offset = get_stack(1);
  return NewHook(hp, "Cage");
}