On Tue, Dec 10, 2013 at 09:12:43PM -0800, Joe Perches wrote:
> diff --git a/net/batman-adv/gateway_client.c b/net/batman-adv/gateway_client.c
> index 2449afa..dfa5d2d 100644
> --- a/net/batman-adv/gateway_client.c
> +++ b/net/batman-adv/gateway_client.c
> @@ -517,29 +517,28 @@ static int batadv_write_buffer_text(struct batadv_priv
> *bat_priv,
> {
> struct batadv_gw_node *curr_gw;
> struct batadv_neigh_node *router;
> - int ret = -1;
>
> router = batadv_orig_node_get_router(gw_node->orig_node);
> if (!router)
> - goto out;
> + return -1;
This (as well as the original) means "fail read(2) with -EINVAL", which
might or might not be correct behaviour.
> curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
>
> - ret = seq_printf(seq, "%s %pM (%3i) %pM [%10s]: %u.%u/%u.%u MBit\n",
> - (curr_gw == gw_node ? "=>" : " "),
> - gw_node->orig_node->orig,
> - router->bat_iv.tq_avg, router->addr,
> - router->if_incoming->net_dev->name,
> - gw_node->bandwidth_down / 10,
> - gw_node->bandwidth_down % 10,
> - gw_node->bandwidth_up / 10,
> - gw_node->bandwidth_up % 10);
> + seq_printf(seq, "%s %pM (%3i) %pM [%10s]: %u.%u/%u.%u MBit\n",
> + (curr_gw == gw_node ? "=>" : " "),
> + gw_node->orig_node->orig,
> + router->bat_iv.tq_avg, router->addr,
> + router->if_incoming->net_dev->name,
> + gw_node->bandwidth_down / 10,
> + gw_node->bandwidth_down % 10,
> + gw_node->bandwidth_up / 10,
> + gw_node->bandwidth_up % 10);
>
> batadv_neigh_node_free_ref(router);
> if (curr_gw)
> batadv_gw_node_free_ref(curr_gw);
> -out:
> - return ret;
> +
> + return seq_overflow(seq);
... and this is utter junk.
This sucker should return 0. Insufficiently large buffer will be handled
by caller, TYVM, if you give that caller a chance to do so. Returning 1
from ->show() is a bug in almost all cases, and definitely so in this one.
Just in case somebody decides that above is worth copying: It Is Not.
Original code is buggy, plain and simple. This one trades the older
bug ("fail with -EINVAL whenever the buffer is too small") with just as buggy
"silently skip an entry entirely whenever the buffer is too small".
Don't Do That.
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