From 70b939ecd382cbc9142887a8efe7f49e211d0940 Mon Sep 17 00:00:00 2001
From: Edward Tomasz Napierala <trasz@FreeBSD.org>
Date: Tue, 11 Feb 2014 11:33:44 +0000
Subject: [PATCH] So, it turns out SIGCHLD is discarded by default, so we have
 to set up a dummy handler to make it interrupt an ioctl(2) or select(2).

This makes those short-lived ctld(8) zombies disappear.

Sponsored by:	The FreeBSD Foundation
---
 usr.sbin/ctld/ctld.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/usr.sbin/ctld/ctld.c b/usr.sbin/ctld/ctld.c
index c5f5771d51b..27e790cee9f 100644
--- a/usr.sbin/ctld/ctld.c
+++ b/usr.sbin/ctld/ctld.c
@@ -1741,6 +1741,17 @@ sigterm_handler(int dummy __unused)
 	sigterm_received = true;
 }
 
+static void
+sigchld_handler(int dummy __unused)
+{
+
+	/*
+	 * The only purpose of this handler is to make SIGCHLD
+	 * interrupt the ISCSIDWAIT ioctl(2), so we can call
+	 * wait_for_children().
+	 */
+}
+
 static void
 register_signals(void)
 {
@@ -1763,6 +1774,11 @@ register_signals(void)
 	error = sigaction(SIGINT, &sa, NULL);
 	if (error != 0)
 		log_err(1, "sigaction");
+
+	sa.sa_handler = sigchld_handler;
+	error = sigaction(SIGCHLD, &sa, NULL);
+	if (error != 0)
+		log_err(1, "sigaction");
 }
 
 int