ip: add error reporting when RTM_GETNSID failed

`ip addr` when run under qemu-user-riscv64, fails. This likely is due
to qemu-5.1 not doing translation of RTM_GETNSID calls. Aborting ip
completely is not helpful for the user however. This patch reworks
the error handling.

Before:

rtest:/ # ip a
2: host0@if4: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
request send failed: Operation not supported
    link/ether 46:3f:2d:88:3d:db brd ff:ff:ff:ff:ff:ffrtest:/ #

Afterwards:

rtest:/ # ip a
2: host0@if4: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
rtnl_send(RTM_GETNSID): Operation not supported. Continuing anyway.
    link/ether 46:3f:2d:88:3d:db brd ff:ff:ff:ff:ff:ff link-netnsid 0
    inet 192.168.72.147/28 brd 192.168.72.159 scope global host0
       valid_lft forever preferred_lft forever
    inet6 fe80::443f:2dff:fe88:3ddb/64 scope link
       valid_lft forever preferred_lft forever

Signed-off-by: Jan Engelhardt <jengelh@inai.de>
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>

diff --git a/ip/ipnetns.c b/ip/ipnetns.c
index 46cc235b76066c17bef0458cb94c709c4e8d26f1..14e8e087eee3470422ab52a1c2c59fa116f07313 100644 (file)
--- a/ip/ipnetns.c
+++ b/ip/ipnetns.c
@@ -75,9 +75,12 @@ static int ipnetns_have_nsid(void)
        };
        int fd;
 
-       if (have_rtnl_getnsid < 0) {
+       if (have_rtnl_getnsid >= 0) {
                fd = open("/proc/self/ns/net", O_RDONLY);
                if (fd < 0) {
+                       fprintf(stderr,
+                               "/proc/self/ns/net: %s. Continuing anyway.\n",
+                               strerror(errno));
                        have_rtnl_getnsid = 0;
                        return 0;
                }
@@ -85,8 +88,12 @@ static int ipnetns_have_nsid(void)
                addattr32(&req.n, 1024, NETNSA_FD, fd);
 
                if (rtnl_send(&rth, &req.n, req.n.nlmsg_len) < 0) {
-                       perror("request send failed");
-                       exit(1);
+                       fprintf(stderr,
+                               "rtnl_send(RTM_GETNSID): %s. Continuing anyway.\n",
+                               strerror(errno));
+                       have_rtnl_getnsid = 0;
+                       close(fd);
+                       return 0;
                }
                rtnl_listen(&rth, ipnetns_accept_msg, NULL);
                close(fd);