From: Liping Zhang <liping.zhang@spreadtrum.com>
Date: Tue, 20 Sep 2016 09:09:02 +0000 (-0700)
Subject: ipmonitor: fix ip monitor can't work when NET_NS is not enabled
X-Git-Tag: v4.8.0~7
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c44003f7e7254ac972eaa1b22a686471ea4ce2d7;p=thirdparty%2Fiproute2.git

ipmonitor: fix ip monitor can't work when NET_NS is not enabled

In ip monitor, netns_map_init will check getnsid is supported or not.
But when /proc/self/ns/net does not exist, we just print out error
messages and exit. So user cannot use ip monitor anymore when
CONFIG_NET_NS is disabled:
  # ip monitor
  open("/proc/self/ns/net"): No such file or directory

If open "/proc/self/ns/net" failed, set have_rtnl_getnsid to false.

Fixes: d652ccbf8195 ("netns: allow to dump and monitor nsid")
Signed-off-by: Liping Zhang <liping.zhang@spreadtrum.com>
Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
---

diff --git a/ip/ipnetns.c b/ip/ipnetns.c
index af8706530..ccc652c13 100644
--- a/ip/ipnetns.c
+++ b/ip/ipnetns.c
@@ -72,8 +72,8 @@ static int ipnetns_have_nsid(void)
 	if (have_rtnl_getnsid < 0) {
 		fd = open("/proc/self/ns/net", O_RDONLY);
 		if (fd < 0) {
-			perror("open(\"/proc/self/ns/net\")");
-			exit(1);
+			have_rtnl_getnsid = 0;
+			return 0;
 		}
 
 		addattr32(&req.n, 1024, NETNSA_FD, fd);