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 af87065309e2831a37c662f308f1bc793ee4afaf..ccc652c13263a46235b498aeb3ffa35295930b6b 100644 (file)
--- 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);