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From: wescott@Columbia.NCR.COM (Mike Wescott)
Newsgroups: comp.sys.ncr
Subject: Re: /bin/login wierdness, m'aidez
Message-ID: <2248@sauron.Columbia.NCR.COM>
Date: 27 Jul 90 00:22:04 GMT
References: <1633@ssbn.WLK.COM>
Sender: news@sauron.Columbia.NCR.COM
Reply-To: wescott@micky.Columbia.NCR.COM (Mike Wescott)
Distribution: na
Organization: E&M-Columbia, NCR Corp, W Columbia, SC
Lines: 28

In article <1633@ssbn.WLK.COM> bill@ssbn.WLK.COM (Bill Kennedy) writes:
> I wrote a program that
> goes out and manipulates a tty port and uses the modem's result codes
> to set the baud rate and then exec to either /etc/getty or a credit
> authorization terminal program.

[...]

> On the Tower I get to getty OK (according to ps) and when I type in
> my login ID I get to login bill (according to ps) but I never get
> prompted for a password, it just replies login incorrect and prompts
> for login again.

/bin/login can't open /dev/tty to get the password so password checking
fails and you get "login incorrect" without even lifting a finger. The
most likely reason /dev/tty can't be opened is that there isn't one. /dev/tty
is supposed to be the controlling terminal and in this case /bin/login does
not have one.  A process acquires a controlling terminal when:
	1) it inherits one from its parent
	2) or it is a process group leader (setpgrp called or parent is init)
		and it opens a tty which has no associated process group
		and the process has no controlling terminal already

Check out the tty field on a "ps -ef" for the getty or login, if it has
a "?" then there is no controlling tty.
--
	-Mike Wescott
	 mike.wescott@ncrcae.Columbia.NCR.COM