Utils.c

#include "Utils.h"

BOOLEAN CheckMask(CHAR8* base, CHAR8* pattern, CHAR8* mask)
{
	for (; *mask; ++base, ++pattern, ++mask)
		if (*mask == 'x' && *base != *pattern)
			return FALSE;

	return TRUE;
}

VOID* FindPattern(CHAR8* base, UINTN size, CHAR8* pattern, CHAR8* mask)
{
	size -= AsciiStrLen(mask);
	for (UINTN i = 0; i <= size; ++i)
	{
		VOID* addr = &base[i];
		if (CheckMask(addr, pattern, mask))
			return addr;
	}
	return NULL;
}

VOID* GetExport(UINT8* ModuleBase, CHAR8* export)
{
	EFI_IMAGE_DOS_HEADER* dosHeaders = (EFI_IMAGE_DOS_HEADER*)ModuleBase;
	if (dosHeaders->e_magic != EFI_IMAGE_DOS_SIGNATURE)
		return NULL;

	EFI_IMAGE_NT_HEADERS64* ntHeaders = (EFI_IMAGE_NT_HEADERS64*)(ModuleBase + dosHeaders->e_lfanew);
	UINT32 exportsRva = ntHeaders->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_EXPORT].VirtualAddress;
	EFI_IMAGE_EXPORT_DIRECTORY* exports = (EFI_IMAGE_EXPORT_DIRECTORY*)(ModuleBase + exportsRva);
	UINT32* nameRva = (UINT32*)(ModuleBase + exports->AddressOfNames);

	for (UINT32 i = 0; i < exports->NumberOfNames; ++i)
	{
		CHAR8* func = (CHAR8*)(ModuleBase + nameRva[i]);
		if (AsciiStrCmp(func, export) == 0)
		{
			UINT32* funcRva = (UINT32*)(ModuleBase + exports->AddressOfFunctions);
			UINT16* ordinalRva = (UINT16*)(ModuleBase + exports->AddressOfNameOrdinals);
			return (VOID*)(((UINT64)ModuleBase) + funcRva[ordinalRva[i]]);
		}
	}
	return NULL;
}

VOID MemCopy(VOID* dest, VOID* src, UINTN size) 
{
	for (UINT8* d = dest, *s = src; size--; *d++ = *s++);
}