From 3acf8e092f95233bc3d854e161569487dce83ba2 Mon Sep 17 00:00:00 2001
From: Mark Andrews <marka@isc.org>
Date: Fri, 3 Feb 2017 14:22:03 +1100
Subject: [PATCH] 4567. [port] Call getprotobyname and getservbyname prior to
 calling chroot so that shared libraries get loaded. [RT #44537]

---
 lib/isc/unix/dir.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/lib/isc/unix/dir.c b/lib/isc/unix/dir.c
index 0d64778..ee80f41 100644
--- a/lib/isc/unix/dir.c
+++ b/lib/isc/unix/dir.c
@@ -31,6 +31,7 @@
 
 #include <isc/dir.h>
 #include <isc/magic.h>
+#include <isc/netdb.h>
 #include <isc/string.h>
 #include <isc/util.h>
 
@@ -172,6 +173,15 @@ isc_dir_chroot(const char *dirname) {
 	REQUIRE(dirname != NULL);
 
 #ifdef HAVE_CHROOT
+	/*
+	 * Try to use getservbyname and getprotobyname before chroot.
+	 * If WKS records are used in a zone under chroot, Name Service Switch
+	 * may fail to load library in chroot.
+	 * Do not report errors if it fails, we do not need any result now.
+	 */
+	if (getprotobyname("udp"))
+		(void)getservbyname("domain", "udp");
+
 	if (chroot(dirname) < 0 || chdir("/") < 0)
 		return (isc__errno2result(errno));
 
-- 
2.9.3