[Gameluner]

You can make it with files.

Код:

stock pName(playerid)
{
    new n[25];
    GetPlayerName(playerid,n,sizeof(n));
    return n;
}

CMD:whiteadd(playerid,params[])
{
    new player,string[50];
    if(sscanf(params,"u",player)) return SendClientMessage(playerid,-1,"Usage: /whiteadd [PlayerNick/PlayerID]");
    if(!IsPlayerConnected(player) || player == INVALID_PLAYER_ID) return SendClientMessage(playerid,-1,"Player is not connected);
    format(string,50,"Whitelist/%s.ini",pName(player));
    new File:LogFile = fopen(string,io_read);
    fclose(LogFile);
    return 1;
}

public OnPlayerConnect(playerid)
{
    new string[50];
    format(string,50,"Whitelist/%s.ini",pName(player));
    if(!fexist(string))
    {
        Kick(playerid);
    }
    else
    {}
    return 1;
}

This should work.