Function tty_info

freebsd/kern/tty_info.c:277–406

* Report on state of foreground process group. */

 * Report on state of foreground process group.
 */
void
tty_info(struct tty *tp)
{
	struct timeval rtime, utime, stime;
#ifdef STACK
	struct stack stack;
	int sterr, kstacks_val;
	bool print_kstacks;
#endif
	struct proc *p, *ppick;
	struct thread *td, *tdpick;
	const char *stateprefix, *state;
	struct sbuf sb;
	long rss;
	int load, pctcpu;
	pid_t pid;
	char comm[MAXCOMLEN + 1];
	struct rusage ru;

	tty_assert_locked(tp);

	if (tty_checkoutq(tp) == 0)
		return;

	(void)sbuf_new(&sb, tp->t_prbuf, tp->t_prbufsz, SBUF_FIXEDLEN);
	sbuf_set_drain(&sb, sbuf_tty_drain, tp);

	/* Print load average. */
	load = (averunnable.ldavg[0] * 100 + FSCALE / 2) >> FSHIFT;
	sbuf_printf(&sb, "%sload: %d.%02d ", tp->t_column == 0 ? "" : "\n",
	    load / 100, load % 100);

	if (tp->t_session == NULL) {
		sbuf_printf(&sb, "not a controlling terminal\n");
		goto out;
	}
	if (tp->t_pgrp == NULL) {
		sbuf_printf(&sb, "no foreground process group\n");
		goto out;
	}
	PGRP_LOCK(tp->t_pgrp);
	if (LIST_EMPTY(&tp->t_pgrp->pg_members)) {
		PGRP_UNLOCK(tp->t_pgrp);
		sbuf_printf(&sb, "empty foreground process group\n");
		goto out;
	}

	/*
	 * Pick the most interesting process and copy some of its
	 * state for printing later.  This operation could rely on stale
	 * data as we can't hold the proc slock or thread locks over the
	 * whole list. However, we're guaranteed not to reference an exited
	 * thread or proc since we hold the tty locked.
	 */
	p = NULL;
	LIST_FOREACH(ppick, &tp->t_pgrp->pg_members, p_pglist)
		if (proc_compare(p, ppick))
			p = ppick;