Experimental Physics and
Industrial Control System

Eric Norum <[email protected]> · Fri, 10 Jul 2009 11:54:05 -0500

On Jul 10, 2009, at 11:08 AM, Mark Rivers wrote:

So it fails. The seg fault happens because the I/O is being done

without first calling iopl(3). If I modify the test_io.c program to

implement the call to iopl(3) then it works if I run it as root.

So on some systems executing iopl(3) and then calling execv() allows

I/O port access in the exec'd task, but on some systems it does not.

Any ideas why?

That's very strange.
The man page that I have for iopl explicitly states:
       Permissions are inherited by fork() and exec().

--
Eric Norum <[email protected]>
Advanced Photon Source
Argonne National Laboratory
(630) 252-4793

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System