IOPORT(8) BSD System Manager's Manual IOPORT(8)NAME
ioport - enable, disable, or display user level access to I/O ports
SYNOPSIS
ioport -a [iobase [count]]
ioport -d [iobase [count]]
ioport -e [iobase [count]]
ioport [-v] -m iobase count
ioport [-v] -u iobase count
DESCRIPTION
The ioport program displays or modifies the I/O port protection map.
This map can allow or disallow user level programs access to specific I/O
port address ranges. It is primarily useful in allowing the DOS compati-
bility system to access devices like the game port (joystick).
The three display modes, specified with the -a, -d, and -e flags, are es-
sentially identical; they show enabled and/or disabled ports as a range.
For instance, the output might look like this:
0x0000 - 0x03af : Disabled
0x03b0 - 0x03e7 : Enabled
0x03e8 - 0xffff : Disabled
In this case, all I/O ports except those in the middle range are inacces-
sible to user code. With the -a flag, all ports are displayed; the -d
and -e flags show only disabled or enabled ports, respectively. If no
iobase is given, scanning starts from port 0; if no count is given, scan-
ning continues to the end of the valid range (0xffff).
The map and unmap modes, specified with the -m (map) and -u (unmap)
flags, require the iobase and count arguments, and enable (-m) or disable
(-u) user level access to those ports. If the -v argument is supplied,
ioport will print a message stating the action it is about to perform.
In all cases, iobase and count can be specified in decimal, hexadecimal,
or octal.
HISTORY
The ioport command first appeared in BSD/OS and is currently under devel-
opment. It may not be present in future releases. The display modes are
modelled on code supplied by Jeff Kellem <composer@Beyond.Dreams.ORG>.
BSDI BSD/OS January 5, 1994 1