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From: dvv@hq.demos.su (Dmitry V. Volodin)
Newsgroups: comp.unix.xenix.sco
Subject: Re: How do you use ungetty?
Message-ID: <1990Sep3.165541.10480@hq.demos.su>
Date: 3 Sep 90 16:55:41 GMT
References: <5540@minyos.xx.rmit.oz>
Reply-To: dvv@hq.demos.su (Dmitry V. Volodin)
Organization: DEMOS, Moscow, USSR
Lines: 64

In article <5540@minyos.xx.rmit.oz> s892024@minyos.xx.rmit.oz (Richard Muirden [G.A.]) writes:
>Hi, this is rather desperate!
>
>I need to diable getty running on /dev/tty1A while making a call out
>with a specialised dialer (ie: not uucp/cu) which is done automatically
>every morning. thus I want to rerun getty when the call has finished
>to reenable calls on that line.  
>
>I believe that ungetty is what I need but there is **nothing** in the 
>docs about it. I am running SCO Xenix/386 2.3.2
>
>Any help wanted/needed and apprieciated!! :-)
>
1) You should create /usr/spool/uucp/LCK..tty??? (LOWERCASE tty e.g. tty1a)!
2) You should do a trick with open/ioctl on the line (a piece of code
   from /usr/lib/uucp/dialHA24.c ):

--------- CUT ---------
	/* ........ */

	/*
	 *  Must open with O_NDELAY set or the open may hang.
	 */
	if ((fd = open(acu, O_RDWR | O_NDELAY)) < 0) {
		fprintf(stderr, "dial: Can't open device: %s\n", acu);
		exit(RC_FAIL | RCE_OPEN | retcode);
	}
	/*
	 * set line for no echo and correct speed.
	 * We will issue commands to the Hayes 2400 at the highest possible
	 * baud rate to encourage connection at the highest baud rate.
	 * If hanging up, issue commands at 2400 to enable auto answer
	 * at 2400.
	 */
	signal(SIGINT, abort);
	errflag = ioctl(fd, TCGETA, &term);
	term.c_cflag &= ~(CBAUD | HUPCL);
	term.c_cflag |= CLOCAL | (hflag ? (B2400|HUPCL) : highbaud);
	term.c_lflag &= ~ECHO;
	term.c_cc[VMIN] = '\1';
	term.c_cc[VTIME] = '\0';
	errflag = ioctl(fd, TCSETA, &term);
	if (errflag) {
		char buf[16];
		DEBUG(1, "dial: ioctl error on %s", acu);
		DEBUG(1, " errno=%d\n", errno);
		cleanup(RC_FAIL | RCE_IOCTL | retcode);
	}
	/*
	 *  Reopen line with clocal so we can talk without carrier present
	 */
	c = fd;
/*!!!!*/if ((fd = open(acu, O_RDWR)) < 0) {
		fprintf(stderr, "dial: Can't open device local: %s\n", acu);
		exit(RC_FAIL | RCE_OPEN | retcode);
	}
	close(c);
--------- CUT ---------
Note the line marked /*!!!!*/. getty wakes up from waiting CD in this
particular moment and, finding /usr/spool/uucp/LCK..tty???, goes sleep
until this lock file is gone.


Dima <dvv@hq.demos.su> or <dvv%hq.demos.su@fuug.fi>