On 2015/04/22 5:19, Nikolay Nikolaev wrote:
> On Tue, Apr 21, 2015 at 9:36 AM, Tetsuya Mukawa <muk...@igel.co.jp> wrote:
>> Current QEMU cannot detect vhost-user backend disconnection. The
>> patch adds ability to know it.
>> To know disconnection, add watcher to detect G_IO_HUP event. When
>> G_IO_HUP event is detected, the disconnected socket will be read
>> to cause a CHR_EVENT_CLOSED.
>>
>> Signed-off-by: Tetsuya Mukawa <muk...@igel.co.jp>
>> ---
>> net/vhost-user.c | 14 ++++++++++++++
>> 1 file changed, 14 insertions(+)
>>
>> diff --git a/net/vhost-user.c b/net/vhost-user.c
>> index 1d86a2b..55c05a5 100644
>> --- a/net/vhost-user.c
>> +++ b/net/vhost-user.c
>> @@ -19,6 +19,7 @@ typedef struct VhostUserState {
>> NetClientState nc;
>> CharDriverState *chr;
>> VHostNetState *vhost_net;
>> + int watch;
>> } VhostUserState;
>>
>> typedef struct VhostUserChardevProps {
>> @@ -113,12 +114,23 @@ static void net_vhost_link_down(VhostUserState *s,
>> bool link_down)
>> }
>> }
>>
>> +static gboolean net_vhost_user_watch(GIOChannel *chan, GIOCondition cond,
>> + void *opaque)
>> +{
>> + VhostUserState *s = opaque;
>> + uint8_t buf[1];
>> +
>> + qemu_chr_fe_read_all(s->chr, buf, sizeof(buf));
> So you read the date from the buffer and just discard it?
> Are you going to miss messages this way?
>
> Please clarify.
Hi Nikolay,
Thanks for comment.
Yes, some messages might be lost, but it will be only happened after
unix domain socket is closed by vhost-user backend.
So I guess there is no side effect.
Anyway, I just want to know vhost-user disconnection, so other ways are
also nice.
Do you have any suggestions about how to implement?
Regards,
Tetsuya
> regards,
> Nikolay Nikolaev
>
>> + return FALSE;
>> +}
>> +
>> static void net_vhost_user_event(void *opaque, int event)
>> {
>> VhostUserState *s = opaque;
>>
>> switch (event) {
>> case CHR_EVENT_OPENED:
>> + s->watch = qemu_chr_fe_add_watch(s->chr, G_IO_HUP,
>> net_vhost_user_watch, s);
>> vhost_user_start(s);
>> net_vhost_link_down(s, false);
>> error_report("chardev \"%s\" went up", s->chr->label);
>> @@ -126,6 +138,8 @@ static void net_vhost_user_event(void *opaque, int event)
>> case CHR_EVENT_CLOSED:
>> net_vhost_link_down(s, true);
>> vhost_user_stop(s);
>> + g_source_remove(s->watch);
>> + s->watch = 0;
>> error_report("chardev \"%s\" went down", s->chr->label);
>> break;
>> }
>> --
>> 1.9.1
>>
>>
