Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!utgpu!water!watnot!watmath!clyde!rutgers!brl-adm!seismo!rochester!ritcv!rocksvax!rocksanne!sunybcs!westpt!bill
From: bill@westpt.UUCP
Newsgroups: comp.unix.questions
Subject: Re: login gripes
Message-ID: <553@westpt.usma.edu>
Date: Tue, 31-Mar-87 11:15:01 EST
Article-I.D.: westpt.553
Posted: Tue Mar 31 11:15:01 1987
Date-Received: Sat, 4-Apr-87 09:34:02 EST
References: <8703231450.AA18626@ephemeral.ai.toronto.edu> <15831@sun.uucp>
Organization: US Military Academy, West Point, NY
Lines: 26
Summary: stdin <> /dev/tty

In article <15831@sun.uucp>, guy%gorodish@Sun.COM (Guy Harris) writes:
> >   Can't it turn echoing off right away so that when I am in a hurry the
> >   first few characters of my password don't end up on the screen?
> 
> 
> >   Why do these characters get ignored?
> 
> Because "getty" normally runs in RAW mode, while the password is
> collected in cooked mode.  When you switch to or from RAW mode,
> unread input is discarded.
> 

Actually what is happening is the password is taken in using a call to
the routine getpass() which reads directly from /dev/tty and not from
the stdin. So anything you typed before getting the Password: prompt
went to the stdin and is not available to that call. I can only assume
this was done to prevent anyone from spoofing login as to who is really
there. The echo goes away because reading from /dev/tty has nothing to do
with the current settings of stty. Another catch to this method is reads
and writes to/from /dev/tty cannot be redirected.


UUCP:      {philabs,phri}!westpt!bill        PHONE:     (914)446-7747
US SNAIL:  Martin Marietta Data Systems      RADIO:     KB3YV
           USMA, Bldg 600, Room 26           AX.25      KB3YV @ WA2RKN
           West Point, NY  10996