NAME
io —
I/O privilege file
DESCRIPTION
This device is
obsolete and is provided for compatibility purposes only; use
i386_iopl(2)
instead.
After opening
/dev/io for writing the process is granted full
I/O privileges; closing the returned file descriptor does
not result in revocation of these privileges. The new I/O
privileges can be useful in order to write userland programs that handle some
hardware directly.
The entire access control is handled by the file access permissions of
/dev/io, so care should be taken in granting rights for this
device.
I/O privilege on access to
/dev/io is only granted if the
kernel was built with the
COMPAT_10
option.
FILES
- /dev/io
-
SEE ALSO
mem(4)
HISTORY
The
io file appeared in
NetBSD 1.0
after it was in the kernel for some time.