tools: hv: Check return value of setsockopt call

Check return value of setsockopt call and if it fails print error
to the system log and exit with non-zero value.

Signed-off-by: Tomas Hozza <thozza@redhat.com>
Acked-by:  K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tools/hv/hv_kvp_daemon.c

@@ -1457,7 +1457,13 @@ int main(void)
 		exit(EXIT_FAILURE);
 	}
 	nl_group = CN_KVP_IDX;
-	setsockopt(fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP, &nl_group, sizeof(nl_group));
+
+	if (setsockopt(fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP, &nl_group, sizeof(nl_group)) < 0) {
+		syslog(LOG_ERR, "setsockopt failed; error: %d %s", errno, strerror(errno));
+		close(fd);
+		exit(EXIT_FAILURE);
+	}
+
 	/*
 	 * Register ourselves with the kernel.
 	 */