Unable to open /dev/io

[Malcolm Kay]

On Sun, 27 Jul 2003 07:19, Mark wrote:
> Earlier, I had asked a question on how to write a byte to the parallel
> port. And Daan Vreeken was kind enough to point me to a litle c-source that
> uses /dev/io.
>
> Unfortunately, as I just found out, when I raise kern.securelevel to 2
> (FreeBSD 4.7R), I can no longer open /dev/io for writing. :( That means I
> can no longer use this method; because there is no way I will allow my
> production server to run at kern.securelevel lower than 2. Which means I am
> back to square one. :(
>
> Sigh. Is there then no way to write a simple 0 or 1 to the parallel port,
> without compromizing the security of the server at large?
>

I also responded to your original enquiry suggesting that you might
also look at accessing the parallel port via /dev/ppi0 which can set the data
port using an ioctl() call -- man page ppi(4)

I believe this has less restrictions than /dev/io opening the whole device 
port area.

This might circumvent your problem.

> Thanks,
>
> - Mark
>

Malcolm Kay