学步园

使用IsWow64Process可以检测当前进程是否运行在WOW64环境下(WOW64 is the x86 emulator that allows Win32-based applications to run on 64-bit Windows),有些人也把它用来检测CPU位数(这用法是错误的)
在MSDN上也有这个函数的使用方法,当然我还是写了个,注意的是IsWow64Process第一个参数是一个有QUERY权限的进程句柄.

BOOL IsWow64Current()
{
	FARPROC fnIsWow64Process;
	BOOL bIsWow64;


	bIsWow64 = FALSE;
	fnIsWow64Process = GetProcAddress(GetModuleHandle(TEXT("kernel32.dll")), "IsWow64Process");


	if(fnIsWow64Process)
		if(((BOOL (WINAPI *)(HANDLE, PBOOL))fnIsWow64Process)(GetCurrentProcess(), &bIsWow64))
			return bIsWow64;
	return FALSE;
}

嗯哼~那么来看看IsWow64Process的实现吧~

KERNELBASE!IsWow64Process:
759f8c8e 8bff            mov     edi,edi
759f8c90 55              push    ebp
759f8c91 8bec            mov     ebp,esp
759f8c93 56              push    esi
759f8c94 6a00            push    0 //ReturnLength
759f8c96 6a04            push    4 //ProcessInformationLength
759f8c98 8d4508          lea     eax,[ebp+8]
759f8c9b 50              push    eax //ProcessInformation
759f8c9c 6a1a            push    1Ah    //ProcessInformationClass::ProcessWow64Information
759f8c9e ff7508          push    dword ptr [ebp+8] //ProcessHandle
759f8ca1 ff1528109f75    call    dword ptr [KERNELBASE!_imp__NtQueryInformationProcess (759f1028)]
759f8ca7 8bf0            mov     esi,eax
759f8ca9 85f6            test    esi,esi ;NtQueryInformationProcess失败
759f8cab 0f8c35170200    jl      KERNELBASE!IsWow64Process+0x1f (75a1a3e6)


KERNELBASE!IsWow64Process+0x27:
759f8cb1 8b4d0c          mov     ecx,dword ptr [ebp+0Ch]
759f8cb4 33c0            xor     eax,eax
759f8cb6 394508          cmp     dword ptr [ebp+8],eax
759f8cb9 0f95c0          setne   al
759f8cbc 8901            mov     dword ptr [ecx],eax //把结果放在第二个参数的指向


KERNELBASE!IsWow64Process+0x34:
759f8cbe 33c0            xor     eax,eax
759f8cc0 85f6            test    esi,esi
759f8cc2 0f9dc0          setge   al //return (esi >= 0);
759f8cc5 5e              pop     esi
759f8cc6 5d              pop     ebp
759f8cc7 c20800          ret     8


KERNELBASE!IsWow64Process+0x1f:
75a1a3e6 56              push    esi
75a1a3e7 e8b9c7fdff      call    KERNELBASE!BaseSetLastNTError (759f6ba5)
75a1a3ec e9cde8fdff      jmp     KERNELBASE!IsWow64Process+0x34 (759f8cbe)

于是乎~很简单实现了IsWow64Process(顺便学会set指令怎么用了)