interfaces: show a warning if we don't have permissions for ethtool ioctls

diff --git a/src/daemon/interfaces-linux.c b/src/daemon/interfaces-linux.c
index b61d12933c7f56f9532a54827b3b94610ba856f4..98b526782121299c620c36afc4039c5b66f67031 100644 (file)
--- a/src/daemon/interfaces-linux.c
+++ b/src/daemon/interfaces-linux.c
@@ -495,7 +495,16 @@ iflinux_ethtool_glink(struct lldpd *cfg, const char *ifname, struct ethtool_link
                if (rc == 0) {
                        nwords = -ecmd.req.link_mode_masks_nwords;
                        log_debug("interfaces", "glinksettings nwords is %" PRId8, nwords);
-               } else nwords = -1;
+               } else {
+                       static int once = 0;
+                       if (errno == EPERM && !once) {
+                               log_warn("interfaces",
+                                   "cannot get ethtool link information "
+                                   "with GLINKSETTINGS (requires 4.9+)");
+                               once = 1;
+                       }
+                       nwords = -1;
+               }
        }
        if (nwords > 0) {
                memset(&ecmd, 0, sizeof(ecmd));
@@ -543,6 +552,14 @@ iflinux_ethtool_glink(struct lldpd *cfg, const char *ifname, struct ethtool_link
                uset->base.duplex = ethc.duplex;
                uset->base.port = ethc.port;
                uset->base.autoneg = ethc.autoneg;
+       } else {
+               static int once = 0;
+               if (errno == EPERM && !once) {
+                       log_warn("interfaces",
+                           "cannot get ethtool link information "
+                           "with GSET (requires 2.6.19+)");
+                       once = 1;
+               }
        }
 end:
        return rc;