TIOCCDTR (bug|feature)

[ka at spanky.UUCP]

Providing security is a major problem if you assume that your users
are required to cooperate but are avidly waiting to move in for the
kill the moment they find a hole in another user's security.  There
are capability based schemes which do relatively well at providing this,
but UNIX was designed more with environments like the Bell Labs in mind.

Barring a major re-design of the UNIX security mechanisms, you can
a) Forget about using write.  I prefer mail or a phone call anyway.
b) Make your terminal mode 620, and only talk to people in your group.

Preventing processes from doing a stty on a terminal other than the
control terminal doesn't really solve the problem since many terminals
are upset by various escape sequences, and it's just one more hack to
confuse people on sites that don't need it.
				Kenneth Almquist