1 files changed, 65 insertions, 1 deletions

diff --git a/sys/kern/sys_procdesc.c b/sys/kern/sys_procdesc.c
index 0c2743f47c7c9..1039dac6e2a8e 100644
--- a/sys/kern/sys_procdesc.c
+++ b/sys/kern/sys_procdesc.c
@@ -236,6 +236,7 @@ procdesc_new(struct proc *p, int flags)
 	if (flags & PD_DAEMON)
 		pd->pd_flags |= PDF_DAEMON;
 	PROCDESC_LOCK_INIT(pd);
+	knlist_init_mtx(&pd->pd_selinfo.si_note, &pd->pd_lock);
 
 	/*
 	 * Process descriptors start out with two references: one from their
@@ -270,6 +271,7 @@ procdesc_free(struct procdesc *pd)
 		KASSERT((pd->pd_flags & PDF_CLOSED),
 		    ("procdesc_free: !PDF_CLOSED"));
 
+		knlist_destroy(&pd->pd_selinfo.si_note);
 		PROCDESC_LOCK_DESTROY(pd);
 		uma_zfree(procdesc_zone, pd);
 	}
@@ -296,6 +298,7 @@ procdesc_exit(struct proc *p)
 	    ("procdesc_exit: closed && parent not init"));
 
 	pd->pd_flags |= PDF_EXITED;
+	pd->pd_xstat = p->p_xstat;
 
 	/*
 	 * If the process descriptor has been closed, then we have nothing
@@ -314,6 +317,7 @@ procdesc_exit(struct proc *p)
 		pd->pd_flags &= ~PDF_SELECTED;
 		selwakeup(&pd->pd_selinfo);
 	}
+	KNOTE_LOCKED(&pd->pd_selinfo.si_note, NOTE_EXIT);
 	PROCDESC_UNLOCK(pd);
 	return (0);
 }
@@ -460,11 +464,71 @@ procdesc_poll(struct file *fp, int events, struct ucred *active_cred,
 	return (revents);
 }
 
+static void
+procdesc_kqops_detach(struct knote *kn)
+{
+	struct procdesc *pd;
+
+	pd = kn->kn_fp->f_data;
+	knlist_remove(&pd->pd_selinfo.si_note, kn, 0);
+}
+
+static int
+procdesc_kqops_event(struct knote *kn, long hint)
+{
+	struct procdesc *pd;
+	u_int event;
+
+	pd = kn->kn_fp->f_data;
+	if (hint == 0) {
+		/*
+		 * Initial test after registration. Generate a NOTE_EXIT in
+		 * case the process already terminated before registration.
+		 */
+		event = pd->pd_flags & PDF_EXITED ? NOTE_EXIT : 0;
+	} else {
+		/* Mask off extra data. */
+		event = (u_int)hint & NOTE_PCTRLMASK;
+	}
+
+	/* If the user is interested in this event, record it. */
+	if (kn->kn_sfflags & event)
+		kn->kn_fflags |= event;
+
+	/* Process is gone, so flag the event as finished. */
+	if (event == NOTE_EXIT) {
+		kn->kn_flags |= EV_EOF | EV_ONESHOT;
+		if (kn->kn_fflags & NOTE_EXIT)
+			kn->kn_data = pd->pd_xstat;
+		if (kn->kn_fflags == 0)
+			kn->kn_flags |= EV_DROP;
+		return (1);
+	}
+
+	return (kn->kn_fflags != 0);
+}
+
+static struct filterops procdesc_kqops = {
+	.f_isfd = 1,
+	.f_detach = procdesc_kqops_detach,
+	.f_event = procdesc_kqops_event,
+};
+
 static int
 procdesc_kqfilter(struct file *fp, struct knote *kn)
 {
+	struct procdesc *pd;
 
-	return (EOPNOTSUPP);
+	pd = fp->f_data;
+	switch (kn->kn_filter) {
+	case EVFILT_PROCDESC:
+		kn->kn_fop = &procdesc_kqops;
+		kn->kn_flags |= EV_CLEAR;
+		knlist_add(&pd->pd_selinfo.si_note, kn, 0);
+		return (0);
+	default:
+		return (EINVAL);
+	}
 }
 
 static int