[iproute PATCH] ip: add error reporting when RTM_GETNSID failed

Jan Engelhardt
2020-10-12T13:56:12Z

`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
rtest:/ #

Signed-off-by: Jan Engelhardt <jengelh@inai.de>
---
ip/ipnetns.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/ip/ipnetns.c b/ip/ipnetns.c
index 46cc235b..e7a45653 100644
--- a/ip/ipnetns.c
+++ b/ip/ipnetns.c
@@ -78,6 +78,8 @@ static int ipnetns_have_nsid(void)
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 +87,11 @@ 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);
--
2.28.0