proc on q

[utzoo!decvax!ucbvax!ihnss!cbosg!harpo!chico!duke!reed!valer]

/*
 *	This program helps generate the "proc on q"
 *	diagnostic.  By putting a 9600 keyboard in
 *	CBREAK mode and pounding on the keyboard,
 *	we have been able to consistently produce the
 *	diagnostic in the first line or two of typing.
 *	This diagnostic comes from an interrupt window
 *	in the following code in sig.c:
 *		if(p->p_stat == SSLEEP && p->p_pri > PZERO)
 *			setrun(p);
 *	The fix is to bracket the code as follows:
 *		s = spl6();
 *		<above code>
 *		splx(s);
 */
brkpt() { }
main()
{
	char	c;
	int	child;

	switch(child = fork()) {
	case 0:
		for (signal(5, brkpt); ; )
			read(0, &c, 1);
	case -1:
		perror("fork");
		break;
	default:
		sleep(2);
		printf("start typing\n");
		for ( ; ; )
			kill(child, 5);
	}
}