From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: Re: [PATCH] netlink: Change rtnl_dump_done to always show error Date: Tue, 30 May 2017 17:35:08 -0700 Message-ID: <20170530173508.0b895904@xeon-e3> References: <20170516212246.10134-1-dsahern@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org To: David Ahern Return-path: Received: from mail-pf0-f182.google.com ([209.85.192.182]:33365 "EHLO mail-pf0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750938AbdEaAfM (ORCPT ); Tue, 30 May 2017 20:35:12 -0400 Received: by mail-pf0-f182.google.com with SMTP id e193so1850046pfh.0 for ; Tue, 30 May 2017 17:35:12 -0700 (PDT) In-Reply-To: <20170516212246.10134-1-dsahern@gmail.com> Sender: netdev-owner@vger.kernel.org List-ID: On Tue, 16 May 2017 14:22:46 -0700 David Ahern wrote: > The original code which became rtnl_dump_done only shows netlink errors > if the protocol is NETLINK_SOCK_DIAG, but netlink dumps always appends > the length which contains any error encountered during the dump. Update > rtnl_dump_done to always show the error if there is one. > > As an *example* without this patch, dumping a route object that exceeds > the internal buffer size terminates with no message to the user -- the > dump just ends because the NLMSG_DONE attribute was received. With this > patch the user at least gets a message that the dump was aborted. > > $ ip ro ls > default via 10.0.2.2 dev eth0 > 10.0.2.0/24 dev eth0 proto kernel scope link src 10.0.2.15 > 10.10.0.0/16 dev veth1 proto kernel scope link src 10.10.0.1 > 172.16.1.0/24 dev br0.11 proto kernel scope link src 172.16.1.1 > Error: Buffer too small for object > Dump terminated > > The point of this patch is to notify the user of a failure versus > silently exiting on a partial dump. Because the NLMSG_DONE attribute > was received, the entire dump needs to be restarted to use a larger > buffer for EMSGSIZE errors. That could be done automatically but it > has other user impacts (e.g., duplicate output if the dump is > restarted) and should be the subject of a different patch. > > Signed-off-by: David Ahern Applied. It is easier to seen iproute2 patches with: Subject: [PATCH iproute2] netlink: Change rtnl_dump_done to always show error