From 6a3287f889b0fa4d3dc3f56286305ce8245aa527 Mon Sep 17 00:00:00 2001
From: Hans Petter Selasky <hselasky@FreeBSD.org>
Date: Sat, 28 Jun 2014 03:59:04 +0000
Subject: [PATCH] Fix regression issue after r267961. Handle special string
 case for SYSCTLs like previously.

MFC after:	2 weeks
Reported by:	several people
---
 sys/kern/kern_sysctl.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/sys/kern/kern_sysctl.c b/sys/kern/kern_sysctl.c
index cb5a266e4e2..149b90e7431 100644
--- a/sys/kern/kern_sysctl.c
+++ b/sys/kern/kern_sysctl.c
@@ -1210,9 +1210,12 @@ sysctl_handle_string(SYSCTL_HANDLER_ARGS)
 	size_t outlen;
 	int error = 0;
 
-	/* check for zero-length buffer */
+	/*
+	 * A zero-length buffer indicates a fixed size read-only
+	 * string:
+	 */
 	if (arg2 == 0)
-		return (ENOMEM);
+		arg2 = strlen((char *)arg1) + 1;
 
 	if (req->oldptr != NULL) {
 		char *tmparg;