Well,
I think Hijack should warn you that it read only part of the file, because as IR maps get larger and more complex it may well be possible to have a config.ini longer than 4 or 8k either deliberately or accidentally.

The only question is, how should Mark warn you? via the serial port message like he does with bad IR translations?
Or via a pop-up menu (or both).

I'd prefer both methods.

I don't think we have to get too clever with stat()ing the file etc - all that needs to be done is compare the number of bytes the read() call returns, compared to the block size/max amount amount of bytes requested -
if they are the same then you either have a exact sized config.ini (in which case I'd like to know before I add anything else to it), or I have a file thats larger than the amount I read - as a read will normally return less than what you request if the file is smaller than the amount you requested.

In either case (exactly 4 or 8K file or >4 or 8K file) its time for a warning.

You could also popup a warning/log a message on the serial port - if config.ini appears to be close to the maximum size without exceeding it.
Not sure I'd want a popup warning about this though.