Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!auspex!guy
From: guy@auspex.auspex.com (Guy Harris)
Newsgroups: comp.soft-sys.andrew
Subject: Re: Typescript under SunOS 4.1?
Message-ID: <3987@auspex.auspex.com>
Date: 30 Aug 90 23:43:14 GMT
References: <3974@auspex.auspex.com> <MaqjA2cB0KGWM9OCk4@holmes.parc.xerox.com>
Organization: Auspex Systems, Santa Clara
Lines: 83

>Sounds to me like the right thing to try is to rebuild under 4.1.  I'll
>try that and report back.

Well, I finally dragged our 4.1 documentation out of its box.  Starting
on page 52 of the SunOS 4.1 Release Manual, there's a discussion of the
changes to the controlling terminal stuff in 4.1.

It notes that the following BSD-flavored code should cause "/dev/ttya"
to become the process's controlling terminal:

	if ((fd = open("/dev/tty", O_WRONLY)) != -1) {
		(void) ioctl(fd, TIOCNOTTY, 0);
		(void) close(fd);
	}
	(void) setpgrp(0, 0);
	fd = open("/dev/ttya", O_RDWR);

and that the following code might *not* do so:

	if ((fd = open("/dev/tty", O_WRONLY)) != -1) {
		(void) ioctl(fd, TIOCNOTTY, 0);
		(void) close(fd);
	}
	fd = open("/dev/ttya", O_RDWR);

because, while in 4.xBSD, the TIOCNOTTY "ioctl" will zero out the
process's process group, it will not do so in SunOS 4.1.

Now, the code in ".../atk/typescript/tscript.c" that releases the
controlling tty is, for non-HP-UX systems:

    {
	int fd;

	(void)signal(SIGTTOU,SIG_IGN);    /* For handling signals when changing the window size */

	fd = open ("/dev/tty", O_RDWR);
	if (fd >= 0) {
	    ioctl (fd, TIOCNOTTY, 0);
	    close (fd);
	}
#if SY_AIX221
 	else {
 	    ioctl(0, TIOCNOTTY,	0); /* might help when /dev/tty is hosed */
 	    setpgrp();
 	}
#else
        else
            setpgrp(0, 0);
#endif
      }

The astute reader will note that this is similar to the second section
of code - the one that the documentation says won't work.

Given that in 4.xBSD TIOCNOTTY will set the process group to 0, it
appears that it would be harmless to change the code to:

    {
	int fd;

	(void)signal(SIGTTOU,SIG_IGN);    /* For handling signals when changing the window size */

	fd = open ("/dev/tty", O_RDWR);
	if (fd >= 0) {
	    ioctl (fd, TIOCNOTTY, 0);
	    close (fd);
	}
#if SY_AIX221
 	else {
 	    ioctl(0, TIOCNOTTY,	0); /* might help when /dev/tty is hosed */
 	    setpgrp();
 	}
#else
        setpgrp(0, 0);
#endif
      }

so that the "setpgrp(0, 0)" is *always* done.  This should probably be
tried both on a SunOS 4.1 system, and on some non-HP-UX, non-AIX
systems, to see if it works on both systems.  If so, the change should
be put in (no #ifdefs for SunOS 4.1, please, if it works both on SunOS
4.1 and other systems; the code has enough #ifdefs already).