Csh hacking -- having problems...

[The Grey Wolf]

[ .globl    _newsfood, 512; ]

I'm doing a major upgrade to the Berkeley C shell (no flames, please;
I speak csh and sh fluently and have different uses for each one).  One
of the things I am implementing is a "push" builtin, which is supposed
to simply fork() and create an exact duplicate of the shell on top of itself.

In the older version of this shell (to which I have regrettably lost the
source), we used to do this for extended alterations of environment without
having to restart the damn thing (i.e. aliases and shell variables were
preserved).  It was easier than throwing it into a ( subshell ), and we
needed the interaction.

Now, never mind *why* I want to do this when there might be other solutions...
When the push command is entered, the following set of events occurs (assume
all necessary variables):

dopush()
{
    switch (fork()) {
    case -1:	/* error */
	setname("push");
	bferr("Couldn't fork!");
	return (1);
    case 0:	/* child */
	/* set $$ = getpid() */
	/* set process group to $$ */
	/* set tty process group to $$ */
	/* increment push level */
	return(0);
    default:	/* parent */
	wait(&exitstat);
	/* reset process group */
	/* reset terminal process group */
	return(exitstat);
    }
}

Now, the push() occurs fine (it forks and does all the necessary stuff).
HOWEVER:  As soon as I hit an interrupt, the pushed shell prints a prompt,
exits, and the original shell prints a prompt.

The thing that's confusing is that I don't know why the pushed shell is only
catching the interrupt once and then giving up.  It seems as though the
parent shell also gets the interrupt (which I didn't think would happen if
the process group gets reset).  I thought Berkeley signal handlers reset
themselves...?

This is a Pyramid running OSx 5.0b, under the BSD universe (essentially
BSD 4.2-and-a-half).
-- 
thought:  I ain't so damb dumn! | Your brand new kernel just dump core on you
war: Invalid argument           | And fsck can't find root inode 2
                                | Don't worry -- be happy...
...!{ucbvax,acad,uunet,amdahl,pyramid}!unisoft!greywolf