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Date: Fri, 8 Jun 2012 15:20:53 +0100
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From: Stefan Hajnoczi <stefanha@gmail.com>
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Subject: Re: [Qemu-devel] [PATCH v5 2/2] net: add the support for -netdev
 socket, listen
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To: Zhi Yong Wu <zwu.kernel@gmail.com>
Cc: pbonzini@redhat.com, Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>, qemu-devel@nongnu.org, stefanha@linux.vnet.ibm.com

On Fri, Jun 8, 2012 at 3:15 PM, Zhi Yong Wu <zwu.kernel@gmail.com> wrote:
> On Fri, Jun 8, 2012 at 6:31 PM, Stefan Hajnoczi <stefanha@gmail.com> wrot=
e:
>> On Thu, Jun 7, 2012 at 3:54 PM, =A0<zwu.kernel@gmail.com> wrote:
>>> @@ -86,7 +82,16 @@ static void net_socket_send(void *opaque)
>>> =A0 =A0 =A0 =A0 /* end of connection */
>>> =A0 =A0 eoc:
>>> =A0 =A0 =A0 =A0 qemu_set_fd_handler(s->fd, NULL, NULL, NULL);
>>> + =A0 =A0 =A0 =A0qemu_set_fd_handler(s->listen_fd, net_socket_accept, N=
ULL, s);
>>
>> What happens when this is not a listen socket? =A0I suggest setting
>> listen_fd to -1 during creation and not calling qemu_set_fd_handler()
> listen_fd isn't -1 here, and is one valid value when this function is exe=
cuted.
>> when listen_fd is -1 here. =A0If listen_fd is 0 then we'll register
>> net_socket_accept when standard input becomes ready!
>>
>>> =A0 =A0 =A0 =A0 closesocket(s->fd);
>>> +
>>> + =A0 =A0 =A0 =A0s->fd =3D 0;
>>
>> -1 should be used since 0 is a valid file descriptor (standard input).
> OK. done, but In fact, some other places default fd to zero.

Where?  Maybe those places need to be fixed too.  The danger with fd=3D0
is that we call functions like read()/write()/close() on standard
input by mistake.

Stefan