BOOL WINAPI DetourEnumerateExports()

in src/modules.cpp [461:541]
70 lines of code
16 McCabe index (conditional complexity)

BOOL WINAPI DetourEnumerateExports(_In_ HMODULE hModule,
                                   _In_opt_ PVOID pContext,
                                   _In_ PF_DETOUR_ENUMERATE_EXPORT_CALLBACK pfExport)
{
    if (pfExport == NULL) {
        SetLastError(ERROR_INVALID_PARAMETER);
        return FALSE;
    }

    PIMAGE_DOS_HEADER pDosHeader = (PIMAGE_DOS_HEADER)hModule;
    if (hModule == NULL) {
        pDosHeader = (PIMAGE_DOS_HEADER)GetModuleHandleW(NULL);
    }

    __try {
#pragma warning(suppress:6011) // GetModuleHandleW(NULL) never returns NULL.
        if (pDosHeader->e_magic != IMAGE_DOS_SIGNATURE) {
            SetLastError(ERROR_BAD_EXE_FORMAT);
            return NULL;
        }

        PIMAGE_NT_HEADERS pNtHeader = (PIMAGE_NT_HEADERS)((PBYTE)pDosHeader +
                                                          pDosHeader->e_lfanew);
        if (pNtHeader->Signature != IMAGE_NT_SIGNATURE) {
            SetLastError(ERROR_INVALID_EXE_SIGNATURE);
            return FALSE;
        }
        if (pNtHeader->FileHeader.SizeOfOptionalHeader == 0) {
            SetLastError(ERROR_EXE_MARKED_INVALID);
            return FALSE;
        }

        PIMAGE_EXPORT_DIRECTORY pExportDir
            = (PIMAGE_EXPORT_DIRECTORY)
            RvaAdjust(pDosHeader,
                      pNtHeader->OptionalHeader
                      .DataDirectory[IMAGE_DIRECTORY_ENTRY_EXPORT].VirtualAddress);

        if (pExportDir == NULL) {
            SetLastError(ERROR_EXE_MARKED_INVALID);
            return FALSE;
        }

        PBYTE pExportDirEnd = (PBYTE)pExportDir + pNtHeader->OptionalHeader
            .DataDirectory[IMAGE_DIRECTORY_ENTRY_EXPORT].Size;
        PDWORD pdwFunctions = (PDWORD)RvaAdjust(pDosHeader, pExportDir->AddressOfFunctions);
        PDWORD pdwNames = (PDWORD)RvaAdjust(pDosHeader, pExportDir->AddressOfNames);
        PWORD pwOrdinals = (PWORD)RvaAdjust(pDosHeader, pExportDir->AddressOfNameOrdinals);

        for (DWORD nFunc = 0; nFunc < pExportDir->NumberOfFunctions; nFunc++) {
            PBYTE pbCode = (pdwFunctions != NULL)
                ? (PBYTE)RvaAdjust(pDosHeader, pdwFunctions[nFunc]) : NULL;
            PCHAR pszName = NULL;

            // if the pointer is in the export region, then it is a forwarder.
            if (pbCode > (PBYTE)pExportDir && pbCode < pExportDirEnd) {
                pbCode = NULL;
            }

            for (DWORD n = 0; n < pExportDir->NumberOfNames; n++) {
                if (pwOrdinals[n] == nFunc) {
                    pszName = (pdwNames != NULL)
                        ? (PCHAR)RvaAdjust(pDosHeader, pdwNames[n]) : NULL;
                    break;
                }
            }
            ULONG nOrdinal = pExportDir->Base + nFunc;

            if (!pfExport(pContext, nOrdinal, pszName, pbCode)) {
                break;
            }
        }
        SetLastError(NO_ERROR);
        return TRUE;
    }
    __except(GetExceptionCode() == EXCEPTION_ACCESS_VIOLATION ?
             EXCEPTION_EXECUTE_HANDLER : EXCEPTION_CONTINUE_SEARCH) {
        SetLastError(ERROR_EXE_MARKED_INVALID);
        return NULL;
    }
}