From 77d4acf332abd24025f31455f492fa83d97cb2e1 Mon Sep 17 00:00:00 2001
From: Kai Ruhnau <Kai.Ruhnau@live.com>
Date: Wed, 15 Jun 2016 12:33:24 +0200
Subject: [PATCH] socket-util: Run the fallback when the kernel complains about
 the null buffer (#3541)

Calling recv with a NULL buffer returns EFAULT instead of EOPNOTSUPP on
older kernels (3.14).

Fixes #3407

Signed-off-by: Kai Ruhnau <kai.ruhnau@target-sg.com>
---
 src/basic/socket-util.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/basic/socket-util.c b/src/basic/socket-util.c
index 2aa4daca49b..385c3e4df33 100644
--- a/src/basic/socket-util.c
+++ b/src/basic/socket-util.c
@@ -986,7 +986,7 @@ ssize_t next_datagram_size_fd(int fd) {
 
         l = recv(fd, NULL, 0, MSG_PEEK|MSG_TRUNC);
         if (l < 0) {
-                if (errno == EOPNOTSUPP)
+                if (errno == EOPNOTSUPP || errno == EFAULT)
                         goto fallback;
 
                 return -errno;