This is inteded for to allow ifconfig to print various unstructured
information from an interface.
The data is returned from the kernel in ASCII form, see the comment in
if.h for some technicalities.
Canonical cut&paste example to be found in if_tun.c
Initial use:
Now tun* interfaces tell the PID of the process which opened them.
Future uses could be (volounteers welcome!):
Have ppp/slip interfaces tell which tty they use.
Make sync interfaces return their media state: red/yellow/blue
alarm, timeslot assignment and so on.
Make ethernets warn about missing heartbeats and/or cables
by bde, a few other tweaks to get the patch to apply cleanly again and
some improvements to the comments.
This change closes some fairly minor security holes associated with
F_SETOWN, fixes a few bugs, and removes some limitations that F_SETOWN
had on tty devices. For more details, see the description on the PR.
Because this patch increases the size of the proc and pgrp structures,
it is necessary to re-install the includes and recompile libkvm,
the vinum lkm, fstat, gcore, gdb, ipfilter, ps, top, and w.
PR: kern/7899
Reviewed by: bde, elvind
